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Post by lowbudget on Mar 10, 2020 14:24:13 GMT -7
Frankie, is the switch you mention visible from outside the amp or must you pull the chassis?
FWIW, anticipating a potential problem with the Flint and it's power supply being too close to the amp I tried moving it 6-8 feet away and using a completely different outlet than the amp itself. Same noise. The Flint is new and was ordered just to test the Cure. I never changed the factory settings. I even moved the entire amp and pedal package to other parts of the house trying to eliminate all variables. It's unlikely to be the house wiring given the house is brand new and I admonished the electricians about proper grounding just for this reason. Even my Maz 18 MKI reverb model is quiet here, with the reverb up. .I have no problems with any of my other 12 Z amps with the Flint.
I should also add that when I hit the button to engage functions on the Flint I got a very loud pop, and an even louder pop when the amp was put on standby.
I'm certainly no amp builder or tech but the only thing I can figure is something like the switch you reference, especially given the problem was the same across two Jettas. Just wondering: when y'all test the amps, do you try the full sweep of the MV up to max with the loop engaged?
Any thoughts would be appreciated because although my two have gone back I'd buy another in a heartbeat if I could be assured that it would be trouble free. Nobody wanted a Jetta more than I did.
P.S. Frankie, is the Jetta more sensitive to cable and pedal placement than other Z amps? I've never had a problem with that on any of my others and if you're playing at home and keeping the Flint engaged it's pretty natural to put it on top of the amp.
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Post by rollyfoster on Mar 10, 2020 14:45:58 GMT -7
Thanks! I’ll crack her open after work and take a look. I was looking into the metro loop and came across that feature. Will check the switch and trim pot positions. If you are looking at the top of the the amp down at the guts, with the controls facing you, and the speaker outputs facing away from you, the switch should be in the DOWN position. that's -10dB. Now for the trimmer. I have to STRONGLY advise against this. Not only is there high voltage in that area, the trimmer is EXTREMELY sensitive and we set the unity gain both by scope on a QA bench and then check by ear. It WILL change the gain structure and tone of the amp, even the smallest adjustment of the pot will drastically change how things sound. So if you move it, getting it back to how the amp should sound at unity gain will be a crap shoot without scoping and knowing exactly how it should sound. That's why I would say, the trim pot is probably not going to solve the problem. What I would like ask about from the video you post, is the background hum. Not necessarily the white noise that gets amplified, but I hear a hum that isn't dependent on volume. Do you have any idea what the source of that is? I'm point towards a grounding issue possibly. I just pulled it and the switches were in the up (+4) position. There’s no marking or anything on the trim pot so I have no idea where it’s set. Flipping them both down (-20) didn’t change anything. Here’s a pic of when I pulled it: imgur.com/OFLTDcMNot sure if there’s a grounding issue. My outlets all test fine with a tester, my power strips don’t show any signs of grounding alerts. There’s nothing else plugged into anything in the room. Both the plus and jetta have a small amount of hum at idle. It doesn’t increase with volume or anything. |
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Post by frankie on Mar 10, 2020 15:02:00 GMT -7
Frankie, is the switch you mention visible from outside the amp or must you pull the chassis? FWIW, anticipating a potential problem with the Flint and it's power supply being too close to the amp I tried moving it 6-8 feet away and using a completely different outlet than the amp itself. Same noise. The Flint is new and was ordered just to test the Cure. I never changed the factory settings. I even moved the entire amp and pedal package to other parts of the house trying to eliminate all variables. It's unlikely to be the house wiring given the house is brand new and I admonished the electricians about proper grounding just for this reason. Even my Maz 18 MKI reverb model is quiet here, with the reverb up. .I have no problems with any of my other 12 Z amps with the Flint. I should also add that when I hit the button to engage functions on the Flint I got a very loud pop, and an even louder pop when the amp was put on standby. I'm certainly no amp builder or tech but the only thing I can figure is something like the switch you reference, especially given the problem was the same across two Jettas. Just wondering: when y'all test the amps, do you try the full sweep of the MV up to max with the loop engaged? Any thoughts would be appreciated because although my two have gone back I'd buy another in a heartbeat if I could be assured that it would be trouble free. Nobody wanted a Jetta more than I did. P.S. Frankie, is the Jetta more sensitive to cable and pedal placement than other Z amps? I've never had a problem with that on any of my others and if you're playing at home and keeping the Flint engaged it's pretty natural to put it on top of the amp. We have gone as far as turn the amp ALL the way up on all knobs (maximum potential gain). Have not encountered any gain increases or pops with the pedal in the loop or out of the loop. This is very odd. We tested it last night. |
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Post by frankie on Mar 10, 2020 15:07:14 GMT -7
If you are looking at the top of the the amp down at the guts, with the controls facing you, and the speaker outputs facing away from you, the switch should be in the DOWN position. that's -10dB. Now for the trimmer. I have to STRONGLY advise against this. Not only is there high voltage in that area, the trimmer is EXTREMELY sensitive and we set the unity gain both by scope on a QA bench and then check by ear. It WILL change the gain structure and tone of the amp, even the smallest adjustment of the pot will drastically change how things sound. So if you move it, getting it back to how the amp should sound at unity gain will be a crap shoot without scoping and knowing exactly how it should sound. That's why I would say, the trim pot is probably not going to solve the problem. What I would like ask about from the video you post, is the background hum. Not necessarily the white noise that gets amplified, but I hear a hum that isn't dependent on volume. Do you have any idea what the source of that is? I'm point towards a grounding issue possibly. I just pulled it and the switches were in the up (+4) position. There’s no marking or anything on the trim pot so I have no idea where it’s set. Flipping them both down (-20) didn’t change anything. Here’s a pic of when I pulled it: imgur.com/OFLTDcMNot sure if there’s a grounding issue. My outlets all test fine with a tester, my power strips don’t show any signs of grounding alerts. There’s nothing else plugged into anything in the room. Both the plus and jetta have a small amount of hum at idle. It doesn’t increase with volume or anything. Dropping both switches to -20dB does not help lower the noise floor at all!? There’s certainly something wrong. I will interface with Don and Dr. Z tomorrow. |
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Post by frankie on Mar 10, 2020 15:10:36 GMT -7
rollyfoster is this a brand new (as in not demo or floor model) amp? If so, email me the serial number of the amp and name of the dealer at media@drzamps.com.
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Post by rollyfoster on Mar 10, 2020 15:14:04 GMT -7
I just pulled it and the switches were in the up (+4) position. There’s no marking or anything on the trim pot so I have no idea where it’s set. Flipping them both down (-20) didn’t change anything. Here’s a pic of when I pulled it: imgur.com/OFLTDcMNot sure if there’s a grounding issue. My outlets all test fine with a tester, my power strips don’t show any signs of grounding alerts. There’s nothing else plugged into anything in the room. Both the plus and jetta have a small amount of hum at idle. It doesn’t increase with volume or anything. Dropping both switches to -20dB does not help lower the noise floor at all!? There’s certainly something wrong. I will interface with Don and Dr. Z tomorrow. No changes with anything. I’ll email you, thanks! |
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Post by rollyfoster on Mar 10, 2020 18:11:02 GMT -7
Here’s a comparison of the idle noise in the Plus and Jetta. It said it was too big to email.
Both in same power strip. Nothing plugged into front or loops. This is also after the dip switches were put at -20.
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Post by frankie on Mar 10, 2020 18:33:26 GMT -7
Here’s a comparison of the idle noise in the Plus and Jetta. It said it was too big to email. Both in same power strip. Nothing plugged into front or loops. This is also after the dip switches were put at -20. Now I’m starting to believe this is tube issue. That’s not a normal amount of idle noise and your input gain is only at noon. I don’t know if this is even a loop issue at all since the noise did not change when you flipped the loop sensitivity switch. Take the first preamp tube (closest to the input) from the z plus and put it in the second preamp slot of the Jetta (closest to power tubes). See if that quiets things down. If it doesn’t, take the second tube from the Z Plus and out and put it in the first slot of the Jetta. This could be faulty preamp somewhere. |
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Post by rollyfoster on Mar 10, 2020 18:55:46 GMT -7
Here’s a comparison of the idle noise in the Plus and Jetta. It said it was too big to email. Both in same power strip. Nothing plugged into front or loops. This is also after the dip switches were put at -20. Now I’m starting to believe this is tube issue. That’s not a normal amount of idle noise and your input gain is only at noon. I don’t know if this is even a loop issue at all since the noise did not change when you flipped the loop sensitivity switch. Take the first preamp tube (closest to the input) from the z plus and put it in the second preamp slot of the Jetta (closest to power tubes). See if that quiets things down. If it doesn’t, take the second tube from the Z Plus and out and put it in the first slot of the Jetta. This could be faulty preamp somewhere. The noise is the same when the input gain is at zero, too. It doesn’t change when the input gain is full on or off. It’s when the master goes up that the noise is introduced. When something is in the effects loop then it seems like the noise gets amplified. If I plug in a guitar and roll the volume on it down then the noise is maybe a tad bit lower in volume but still there. I just tried the preamp tubes and it didn’t change. Maybe power tubes? I dunno...there has to be some common denominator between this one and the others who are reporting the same thing. |
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Post by lowbudget on Mar 10, 2020 19:04:50 GMT -7
Now I’m starting to believe this is tube issue. That’s not a normal amount of idle noise and your input gain is only at noon. I don’t know if this is even a loop issue at all since the noise did not change when you flipped the loop sensitivity switch. Take the first preamp tube (closest to the input) from the z plus and put it in the second preamp slot of the Jetta (closest to power tubes). See if that quiets things down. If it doesn’t, take the second tube from the Z Plus and out and put it in the first slot of the Jetta. This could be faulty preamp somewhere. The noise is the same when the input gain is at zero, too. If I plug in a guitar and roll the volume on it down then the noise is maybe a tad bit lower in volume but still there. I just tried the preamp tubes and it didn’t change. Maybe power tubes? I dunno...there has to be some common denominator between this one and the others who are reporting the same thing. That would only seem to make sense. But with my two anyway, it only manifested with the loop engaged. Wouldn’t that eliminate tubes? |
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Post by rollyfoster on Mar 10, 2020 19:11:14 GMT -7
The noise is the same when the input gain is at zero, too. If I plug in a guitar and roll the volume on it down then the noise is maybe a tad bit lower in volume but still there. I just tried the preamp tubes and it didn’t change. Maybe power tubes? I dunno...there has to be some common denominator between this one and the others who are reporting the same thing. That would only seem to make sense. But with my two anyway, it only manifested with the loop engaged. Wouldn’t that eliminate tubes? Probably  |
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Post by perryr on Mar 10, 2020 23:16:22 GMT -7
The noise is the same when the input gain is at zero, too. It doesn’t change when the input gain is full on or off. It’s when the master goes up that the noise is introduced. Yep, exactly the same as mine. I can turn input volume wide open with no ‘gain’ noise. We all know what ‘gain’ noise sounds like, that white noise hiss as you wind up that gain stage. We are all use to that coming from the first preamp volume or input volume control. Crank that 1st volume control wide open on most any amp and you will hear it, right? Im not an amp tech, but it didnt take me long to come to the assumption that the Unique preamp/tone circuit around tube V1, the Jetta input volume and tone controls, is not high gain. And when i first seen the Jetta circuit in the Guitar Player Mag review, it pretty much validated what i was hearing: www.guitarplayer.com/gear/review-dr-z-jetta-1x12-comboDr Z is using just 1/2 of a 12ax7 for the input and to drive a passive tone control! The beauty is in the simplicity, that purity of tone and character, and that voice that sets the Jetta apart from virtually any other amp I've ever played, well its by design! 7591’s are unique amongst octal power tubes in that they have gain. Its technical and above my understanding, but im guessing Dr Z has a good deal of gain built in that phase inverter and output section, hence why the sound of ‘gain’ comes forward when the master is raised. Guys, this is some electrickery going on.. everyone who has played a Jetta immediately acknowledges the balls and authority in character. There is a big power tranny and its running hot, Dr Z definitely hot rodded the output section of the Jetta, that Master control has more than enough drive/gain for me before it even hits noon. I am getting great, gig level tones with absolutely no noise concerns... its a killer club amp with a ballsy tone in a compact and lite weight format, absolutely would not change a thing. I have a collider, I run it in the front, and yes its noisy as heck in the loop and pops when engaged, But Its also a bit noisy up front, its definitely not the best s/n ratio. My other digital reverb (space race) is less noisy in the loop and my analog pedals are quiet in the loop. IMO the higher noise floor of some digital effects (and their connectivity quirks) does not do well being returned to that point in the circuit. |
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Post by DRZ on Mar 11, 2020 4:14:55 GMT -7
The noise is the same when the input gain is at zero, too. It doesn’t change when the input gain is full on or off. It’s when the master goes up that the noise is introduced. Yep, exactly the same as mine. I can turn input volume wide open with no ‘gain’ noise. We all know what ‘gain’ noise sounds like, that white noise hiss as you wind up that gain stage. We are all use to that coming from the first preamp volume or input volume control. Crank that 1st volume control wide open on most any amp and you will hear it, right? Im not an amp tech, but it didnt take me long to come to the assumption that the Unique preamp/tone circuit around tube V1, the Jetta input volume and tone controls, is not high gain. And when i first seen the Jetta circuit in the Guitar Player Mag review, it pretty much validated what i was hearing: www.guitarplayer.com/gear/review-dr-z-jetta-1x12-comboDr Z is using just 1/2 of a 12ax7 for the input and to drive a passive tone control! The beauty is in the simplicity, that purity of tone and character, and that voice that sets the Jetta apart from virtually any other amp I've ever played, well its by design! 7591’s are unique amongst octal power tubes in that they have gain. Its technical and above my understanding, but im guessing Dr Z has a good deal of gain built in that phase inverter and output section, hence why the sound of ‘gain’ comes forward when the master is raised. Guys, this is some electrickery going on.. everyone who has played a Jetta immediately acknowledges the balls and authority in character. There is a big power tranny and its running hot, Dr Z definitely hot rodded the output section of the Jetta, that Master control has more than enough drive/gain for me before it even hits noon. I am getting great, gig level tones with absolutely no noise concerns... its a killer club amp with a ballsy tone in a compact and lite weight format, absolutely would not change a thing. I have a collider, I run it in the front, and yes its noisy as heck in the loop and pops when engaged, But Its also a bit noisy up front, its definitely not the best s/n ratio. My other digital reverb (space race) is less noisy in the loop and my analog pedals are quiet in the loop. IMO the higher noise floor of some digital effects (and their connectivity quirks) does not do well being returned to that point in the circuit. As always Perry is spot on. I have worked with Perry since the inception of Z Amps and he has always a great source of of player real world knowledge for me to tap into, and for that I can't thank him enough. Perry's observations are spot on regarding the Effects Loop in the Jetta, also these same points are echoed by Frank in prior posts. When using most analog devices in the Jetts's loop no issues are observed. The Metro Loop is an amazing device , and one I thought would answer all the issues of a E/F design. But with the hundreds of universal non standard devices produced today there is no one answer to the loop issue. it seems that some of the buffered digital devices don't play nice with Jetta design/Metro loop combination. An issue that I do not have the capability to 100% test every possible effect into the Jetta. The many units I have and those I also have access to all have worked flawlessly in test at the factory, but it seems some units don't play so nice. As Perry stated the the unique and original straight forward design of the Jetta creates an amazing powerful rich sounding guitar amp. It relies on its output drive circuits to develop its pure Output tube tones one that no transistor or chip can reproduce, all at a VERY reasonable price point. This is why the Jetta has become such a successful instrument. As an engineer my ability to solve problems is what separates me from other amp cloners, don't mean to sound so full of myself it's just the truth. I have a solution but like all fixes there is a yin and yang , fix one thing cause another the law of engineering. I can remove the Metro loop and install a simple series loop witch fixes all the noise issues , but at a cost of a slight loss of high end and gain when long cable lengths are used with a non buffered effect, but this can be compensated by slight Tone Control and Volume adjustments on the amp or pedal. Also the removal of the costly Metro loop will allow me to maintain the $1399.00 price tag of the Jetta for the seeable future with no increase in price for the time being. Also remember that inputing the effects into the front of the Jetta works perfectly as it is not a high gain amp design. If this way was good enough for Jimi , I would say it's good enough for most of you. So OK I ask my members of my forum for their options on this . As for hollyfoster and lowbudget I will need to investigate more, as the issues they are having aren't typical , but digital effects do play havoc with the Jetta some times. DR.Z |
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Post by rollyfoster on Mar 11, 2020 5:15:07 GMT -7
The noise is the same when the input gain is at zero, too. It doesn’t change when the input gain is full on or off. It’s when the master goes up that the noise is introduced. Yep, exactly the same as mine. I can turn input volume wide open with no ‘gain’ noise. We all know what ‘gain’ noise sounds like, that white noise hiss as you wind up that gain stage. We are all use to that coming from the first preamp volume or input volume control. Crank that 1st volume control wide open on most any amp and you will hear it, right? Im not an amp tech, but it didnt take me long to come to the assumption that the Unique preamp/tone circuit around tube V1, the Jetta input volume and tone controls, is not high gain. And when i first seen the Jetta circuit in the Guitar Player Mag review, it pretty much validated what i was hearing: www.guitarplayer.com/gear/review-dr-z-jetta-1x12-comboDr Z is using just 1/2 of a 12ax7 for the input and to drive a passive tone control! The beauty is in the simplicity, that purity of tone and character, and that voice that sets the Jetta apart from virtually any other amp I've ever played, well its by design! 7591’s are unique amongst octal power tubes in that they have gain. Its technical and above my understanding, but im guessing Dr Z has a good deal of gain built in that phase inverter and output section, hence why the sound of ‘gain’ comes forward when the master is raised. Guys, this is some electrickery going on.. everyone who has played a Jetta immediately acknowledges the balls and authority in character. There is a big power tranny and its running hot, Dr Z definitely hot rodded the output section of the Jetta, that Master control has more than enough drive/gain for me before it even hits noon. I am getting great, gig level tones with absolutely no noise concerns... its a killer club amp with a ballsy tone in a compact and lite weight format, absolutely would not change a thing. I have a collider, I run it in the front, and yes its noisy as heck in the loop and pops when engaged, But Its also a bit noisy up front, its definitely not the best s/n ratio. My other digital reverb (space race) is less noisy in the loop and my analog pedals are quiet in the loop. IMO the higher noise floor of some digital effects (and their connectivity quirks) does not do well being returned to that point in the circuit. Check out the above video where I have it next to a Plus with nothing plugged into either amp at all. You’re telling me that’s normal operational sound? I understand digital pedals can impart some noise but this whole thing coincided with me turning the amp louder with the Collider plugged in so my original though was the loop. Once I unplugged the collider and it was making the same sound I started to feel differently. As does Frankie. I’ve watched every single demo video and not a single one of them sound like this when the master is turned up. |
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Post by rollyfoster on Mar 11, 2020 5:19:49 GMT -7
Yep, exactly the same as mine. I can turn input volume wide open with no ‘gain’ noise. We all know what ‘gain’ noise sounds like, that white noise hiss as you wind up that gain stage. We are all use to that coming from the first preamp volume or input volume control. Crank that 1st volume control wide open on most any amp and you will hear it, right? Im not an amp tech, but it didnt take me long to come to the assumption that the Unique preamp/tone circuit around tube V1, the Jetta input volume and tone controls, is not high gain. And when i first seen the Jetta circuit in the Guitar Player Mag review, it pretty much validated what i was hearing: www.guitarplayer.com/gear/review-dr-z-jetta-1x12-comboDr Z is using just 1/2 of a 12ax7 for the input and to drive a passive tone control! The beauty is in the simplicity, that purity of tone and character, and that voice that sets the Jetta apart from virtually any other amp I've ever played, well its by design! 7591’s are unique amongst octal power tubes in that they have gain. Its technical and above my understanding, but im guessing Dr Z has a good deal of gain built in that phase inverter and output section, hence why the sound of ‘gain’ comes forward when the master is raised. Guys, this is some electrickery going on.. everyone who has played a Jetta immediately acknowledges the balls and authority in character. There is a big power tranny and its running hot, Dr Z definitely hot rodded the output section of the Jetta, that Master control has more than enough drive/gain for me before it even hits noon. I am getting great, gig level tones with absolutely no noise concerns... its a killer club amp with a ballsy tone in a compact and lite weight format, absolutely would not change a thing. I have a collider, I run it in the front, and yes its noisy as heck in the loop and pops when engaged, But Its also a bit noisy up front, its definitely not the best s/n ratio. My other digital reverb (space race) is less noisy in the loop and my analog pedals are quiet in the loop. IMO the higher noise floor of some digital effects (and their connectivity quirks) does not do well being returned to that point in the circuit. As always Perry is spot on. I have worked with Perry since the inception of Z Amps and he has always a great source of of player real world knowledge for me to tap into, and for that I can't thank him enough. Perry's observations are spot on regarding the Effects Loop in the Jetta, also these same points are echoed by Frank in prior posts. When using most analog devices in the Jetts's loop no issues are observed. The Metro Loop is an amazing device , and one I thought would answer all the issues of a E/F design. But with the hundreds of universal non standard devices produced today there is no one answer to the loop issue. it seems that some of the buffered digital devices don't play nice with Jetta design/Metro loop combination. An issue that I do not have the capability to 100% test every possible effect into the Jetta. The many units I have and those I also have access to all have worked flawlessly in test at the factory, but it seems some units don't play so nice. As Perry stated the the unique and original straight forward design of the Jetta creates an amazing powerful rich sounding guitar amp. It relies on its output drive circuits to develop its pure Output tube tones one that no transistor or chip can reproduce, all at a VERY reasonable price point. This is why the Jetta has become such a successful instrument. As an engineer my ability to solve problems is what separates me from other amp cloners, don't mean to sound so full of myself it's just the truth. I have a solution but like all fixes there is a yin and yang , fix one thing cause another the law of engineering. I can remove the Metro loop and install a simple series loop witch fixes all the noise issues , but at a cost of a slight loss of high end and gain when long cable lengths are used with a non buffered effect, but this can be compensated by slight Tone Control and Volume adjustments on the amp or pedal. Also the removal of the costly Metro loop will allow me to maintain the $1399.00 price tag of the Jetta for the seeable future with no increase in price for the time being. Also remember that inputing the effects into the front of the Jetta works perfectly as it is not a high gain amp design. If this way was good enough for Jimi , I would say it's good enough for most of you. So OK I ask my members of my forum for their options on this . As for hollyfoster and lowbudget I will need to investigate more, as the issues they are having aren't typical , but digital effects do play havoc with the Jetta some times. DR.Z I appreciate the response! I believe the Collider was the focus because it happened to be plugged in the first time I got to open up the MV. I didn’t have a frame of reference for the amp or the pedal. But when I unplugged it and had no pedal in the loop and it does the same thing. Personally, the style of loop doesn’t really matter much to me. I use 10’ cables so tone loss hasn’t been an issue on the occasion I do use a loop. The loop had nothing to do with why I wanted the amp. I’d rather plug straight into the amp and thought it would be nice to have a little reverb or whatever when needed so I figured why not use the included feature. I’d have bought the amp without a loop because it has the tone I love. Here’s a Plus and a Jetta with nothing plugged into to the front OR the loop of either amp. This is normal for the Jetta? |
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Post by lowbudget on Mar 11, 2020 5:50:02 GMT -7
Doc it’s only one guy’s self-centered opinion but I’d vote for the tried and true old style loop. I’ve never had a problem with it on any other Z amp. Guys could then get a dedicated buffer or use a buffered pedal as needed. Tell the truth, I’d be fine with no loop at all given I’m not a high gain guy anyway and pretty much just throw stuff in the front.
So why then you may ask not just ignore the metro loop altogether and go in the front? Problem solved, right? Not so fast. This would ignore the laws of human nature. If it’s there that means I’ve paid for it and need to use it!
So I would say that for me the metro loop solves a problem that I didn’t know I had, while creating another problem that is hard to deal with. Plus, I would think from a pure marketing and sales standpoint Z Amps as a company would realize far more benefit from the $1399 price than the inclusion of the seemingly troublesome metro loop.
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Post by DRZ on Mar 11, 2020 7:03:45 GMT -7
Here’s a Plus and a Jetta with nothing plugged into to the front OR the loop of either amp. This is normal for the Jetta? Yes that is normal. The Jetta is more then twice as powerful ( LOUD ) as the Z Plus , the Jetta is a 30 plus watt amp yes it will have some white noise when volume is maxed due its unique design. Z |
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Post by DRZ on Mar 11, 2020 7:30:01 GMT -7
Doc it’s only one guy’s self-centered opinion but I’d vote for the tried and true old style loop. I’ve never had a problem with it on any other Z amp. Guys could then get a dedicated buffer or use a buffered pedal as needed. Tell the truth, I’d be fine with no loop at all given I’m not a high gain guy anyway and pretty much just throw stuff in the front. So why then you may ask not just ignore the metro loop altogether and go in the front? Problem solved, right? Not so fast. This would ignore the laws of human nature. If it’s there that means I’ve paid for it and need to use it! So I would say that for me the metro loop solves a problem that I didn’t know I had, while creating another problem that is hard to deal with. Plus, I would think from a pure marketing and sales standpoint Z Amps as a company would realize far more benefit from the $1399 price than the inclusion of the seemingly troublesome metro loop. Thanks I appreciate your response. I feel I'm between a rock and a hard place , but yes cost is always the most beneficial item in today's economy. I have a Collider in the shop today and will test , but the Flint has never produced the issues to mention and we use the flint to test each Jetta prior to shipping. So that will need a bit more investigation . Z |
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Post by rollyfoster on Mar 11, 2020 7:40:12 GMT -7
Here’s a Plus and a Jetta with nothing plugged into to the front OR the loop of either amp. This is normal for the Jetta? Yes that is normal. The Jetta is more then twice as powerful ( LOUD ) as the Z Plus , the Jetta is a 30 plus watt amp yes it will have some white noise when volume is maxed due its unique design. Z Ok thanks! |
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Post by perryr on Mar 11, 2020 8:50:37 GMT -7
rollyfoster asked: Check out the above video where I have it next to a Plus with nothing plugged into either amp at all. You’re telling me that’s normal operational sound? Yessir, that is exactly the same as mine, as the master approaches noon I can hear the gain come on, and increase from there. It’s gain in the output section. I would never need that additional gain in the Master unless I was recording and after full on power tube crunch, and oh my does the Jetta deliver when set to stun, both volumes wide open into a bigger cab.
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Post by rollyfoster on Mar 11, 2020 9:03:46 GMT -7
rollyfoster asked: Check out the above video where I have it next to a Plus with nothing plugged into either amp at all. You’re telling me that’s normal operational sound? Yessir, that is exactly the same as mine, as the master approaches noon I can hear the gain come on, and increase from there. It’s gain in the output section. I would never need that additional gain in the Master unless I was recording and after full on power tube crunch, and oh my does the Jetta deliver when set to stun, both volumes wide open into a bigger cab. Gotcha. I’m taking it to rehearsal tonight so will see how it goes. Thanks! |
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Post by perryr on Mar 11, 2020 9:03:51 GMT -7
DRZ my vote would be save the cost. There will be those that will use first volume at max and want a loop, so maybe the passive. But I’d guess most will use with first volume less than max and as a pedal platform.. which seems to work fine straight in the front (to me).
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Post by frankie on Mar 11, 2020 13:19:28 GMT -7
rollyfoster Yes, we just confirmed, the Collider does pop when engaged and does increase the noise floor. It is audibly noisier in the loop than the Flint, and my Strymon large format pedals. While not nearly as noisy, if you dime the master on your Z Plus, you can also hear the Collider raise the noise floor. It's more audible in the Jetta because the Jetta has a high voltage, active buffered loop while the Z-Plus does not. No matter what we do with the Flint, however, we can not get it to make more noise than is already naturally present. It simply does not change the noise floor no matter what we do. Dr. Z suspects that the Collider popping issue is due to the fact it is a higher current pedal. The noise floor issue is really not something we can fix, as the Source Audio pedal just seems to have a higher noise floor than any of the strymons we have tested. rollyfoster , the Jetta does have more gain in the front end than the Z-Plus and it is also twice as loud (at least) as the Z-Plus, so yes, once the master starts getting up a noon, you are approaching the end of it's headroom, and then pushing the power tubes with will raise the idle noise floor. So I don't think there is a problem there. If you need reassurance, Don at repairs@drzamps.com is more than happy to help.
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Post by rollyfoster on Mar 11, 2020 15:35:01 GMT -7
rollyfoster Yes, we just confirmed, the Collider does pop when engaged and does increase the noise floor. It is audibly noisier in the loop than the Flint, and my Strymon large format pedals. While not nearly as noisy, if you dime the master on your Z Plus, you can also hear the Collider raise the noise floor. It's more audible in the Jetta because the Jetta has a high voltage, active buffered loop while the Z-Plus does not. No matter what we do with the Flint, however, we can not get it to make more noise than is already naturally present. It simply does not change the noise floor no matter what we do. Dr. Z suspects that the Collider popping issue is due to the fact it is a higher current pedal. The noise floor issue is really not something we can fix, as the Source Audio pedal just seems to have a higher noise floor than any of the strymons we have tested. rollyfoster , the Jetta does have more gain in the front end than the Z-Plus and it is also twice as loud (at least) as the Z-Plus, so yes, once the master starts getting up a noon, you are approaching the end of it's headroom, and then pushing the power tubes with will raise the idle noise floor. So I don't think there is a problem there. If you need reassurance, Don at repairs@drzamps.com is more than happy to help. I appreciate you looking into it! |
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Post by gearmana on Mar 12, 2020 8:41:00 GMT -7
The noise is the same when the input gain is at zero, too. If I plug in a guitar and roll the volume on it down then the noise is maybe a tad bit lower in volume but still there. I just tried the preamp tubes and it didn’t change. Maybe power tubes? I dunno...there has to be some common denominator between this one and the others who are reporting the same thing. That would only seem to make sense. But with my two anyway, it only manifested with the loop engaged. Wouldn’t that eliminate tubes? I had called Dr. Z and reported pretty much the same thing. Initially I thought it was the loop, and while something being in the loop definitely seems to make it worse, the master seems to introduce A LOT of noise on its own, loop or not. I can have the input volume all the way down, and turning the master up to even noon creates an incredible amount of, I guess I'd call it white noise. More than any other amp I have, by a wide margin. That said, the amp sounds great, and if I'm playing, I don't notice the noise, but it seems REALLY unusual, and seeing other people report the same thing definitely makes me think it's either something inherent to the amp, or there is some issue. |
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Post by gearmana on Mar 12, 2020 8:43:55 GMT -7
To clarify on the above - I'd assume it's just inherent to the amp design, and not an issue, more than likely. I'm thrilled with the Jetta, either way.  |
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Post by rollyfoster on Mar 12, 2020 15:33:36 GMT -7
Took this little puppy to practice last night and let ‘er rip.
Quite a beastly little amp when it gets going! Hit it with the Fulldrive 3 and look out!
I sent the collider back and used my belle epoch deluxe in front and it was old school through and through. I never thought I’d call the BED “quiet” but compared to the collider in the loop it’s a mouse.
Even though I understand the power tube gain noise I still don’t understand why I haven’t heard it in any of the pro shot demos. Sorry if I ruffled any feathers!
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Post by perryr on Mar 12, 2020 22:48:48 GMT -7
To clarify on the above - I'd assume it's just inherent to the amp design, and not an issue, more than likely. I'm thrilled with the Jetta, either way. Ya, absolutely, its a crazy killer Z Amp! This kinda reminds me of when Dr Z introduced the Route 66 there was a lot of discussion regarding the Bass and Treble controls, no one had ever played anything like it, they were like gain controls for each respective bandwidth. But get them in the right spot and oh ya! Same with the Jr, it takes a while getting use to turning down the treble and cut controls. Like you and others have noticed, the Jetta controls are unique, and I too have NEVER experienced the way the Master gains up the output. On other amps Its always that first control that drives the gain, and if you crack that first control wide open on other amps you will hear the gain and noise floor rise. Crank the input volume on a Fender or Marshall and there it is, we expect it. But when you crank the first volume on the Jetta its quiet as a mouse, like uncanny quiet. You can not make the amp noisy by cranking the input volume, which tells me there is very little gain in that stage. And after looking at the circuit in the guitar player magazine photo, you can see he is only using 1/2 of a 12ax7 for the preamp! Who does that? Well, Leo Fender did on the Tweed Deluxe, he used 1 side of a 12AX7 for each set of inputs. But even if you put 7591's or 5881's in a tweed deluxe you would get nowhere near the balls of the Jetta. Dr Z is making up for it in the Jetta output, he's hotrodded the **** out of the output, thats where the balls and authority is coming from. Now Dr Z did get away with a single preamp stage in a handful of his other amps, the Route 66, KT45, Delta 88, Z28, but he's doing it in those amps with an EF86, which the EF86 has about 2X the gain of a 12AX7. So back to the Jetta, I fully get what everyone is saying, I've never played anything like it. But as a club player, I find the 18watt amps to be a little light in the authority department. I mean they can get up and rock, but if I want some low mid thrust, well, dual EL84's or Dual 6v6 can fall a bit short at times (for me). Where on the other hand, The bigger amps have that thrust, especially when you get them turned up a bit, but then things start getting a little hot for the venues so need to use an attenuator to capture that output section fullness. The Jetta on the other hand seems to deliver dead on that sweet spot, right in the middle. I'm getting that big amp sound with a Celestion 12" at levels that are EZ to manage. I set the input Volume to noon, the tone to noon, the master to 10:30-11am and man its killer with my little pedal board. And at those settings there is no noise, I mean its dead quiet on stage. If I start turning the master up to noon or greater with my pedal board, it gets loud! And if I have to play that loud, the Signal to noise level is still acceptable. All this from a studio combo footprint. I applaud Dr Z for designing with his ears. We all have an expectation of how amp controls should work, and Dr Z does his best to keep it mainstream, but he found a sound and he stuck with it and man I dig it. I would bet $1mil that any other designer would have used that other side of that V1 12ax7 to increase the preamp gain, just because its open and available. Not Z, the beauty (and genius) was in not using it, keeping that purity, and hotrodding the output, then installing a post phase inverter Master Volume to keep it under control.. its a brilliant amp, totally a Dr Z. |
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Post by DeanG on Mar 13, 2020 1:41:39 GMT -7
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Post by DRZ on Mar 13, 2020 2:00:04 GMT -7
Thanks Perry for your very eloquent design review of the JETTA.
I'm sorry but every time I try to describe my design intensions I feel like a polyester jacket waring Used Car Salesman, I'm just not that good at being a salesman for my products. This is where experienced users like Perry are so important, real word evaluation with in depth understanding.
I have designed 50 differant models of guitar amps to date , and I must say I'm very proud of the JETTA. To me it stands in line to take the place of the Carmen Ghia as a stalwart DR.Z Amp. Unlike the Ghia it is capable filling large venues with rich output tube driven tones the likes of no other amp on todays market. All for a very reasonable price of $1399.00 , believe me other amp companies and I won't name names would price the JETTA at twice my list price. I was so proud of its sound and package I wanted to make it available to as many players as I could and price point is a deciding factor for many players purchase. damn my profit margin.
I have always tried to design amps with an " outside of the Box " approach.
This does lend to criticism by those who want to compare my designs to other standard amps and their standard operation.
Guitarists by nature do not except change in gear very easily , and tend to resort to old tried and true designs.
Well, thanks to players like Perry, Brad Paisley, Joe Walsh, Walter Becker RIP, Buddy Whittington, Steve Miller, Adrian Raso, just to name a few my amps have graced some of the largest stages in the world, and have been enjoyed by world class Guitarists.
Please don't let the unique white noise gain that tracks with the Master Volume , not the typical input gain of other designs limit you from trying a JETTA, it is a surprisingly loud amp in a small package and its S/N ratio is very typical for amps of this power range.
The JETTA will reward you with the richest Output Tube tone you have ever experienced, its not your daddies typical 12AX7 driven tube amp .
Rant off,
DR.Z
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