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Post by myles on Feb 2, 2012 11:01:11 GMT -7
Myles, what wall voltage do you guys use when building, testing, and developing amps? I'm looking at getting a variac and want to know the voltage Dr. Z amps are designed around. I have a Stang Ray, and looking at a ZWreck. Thanks so much. I normally set things at 120 VAC here in the US. |
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Post by randalp3000 on Feb 4, 2012 13:04:19 GMT -7
Myles, I've been biasing my Galaxie with the JJ's it came with and I am also trying some Winged C 6l6's. I looked at the data sheets for both and the JJ are listed at 30 watts dissipation and the winged C is listed as 32 watts. I currently have the Winged C's in with a 5ar4 biased at 60%, 25 watts at 34mA with a plate voltage of 443 volts. Should I keep these biased at 25 watts or should I go up to the 30-32 watts with more current?
I also want to go with a SS recto which should bump the plate voltage up to around 460 volts. Will the JJ's, Winged C's, or the GT 6l6GE's hold up with that much plate voltage. Do you have any preferences for new 6L6's.
thanks for your time, always much appreciated
rp
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Post by myles on Feb 4, 2012 16:18:35 GMT -7
Myles, I've been biasing my Galaxie with the JJ's it came with and I am also trying some Winged C 6l6's. I looked at the data sheets for both and the JJ are listed at 30 watts dissipation and the winged C is listed as 32 watts. I currently have the Winged C's in with a 5ar4 biased at 60%, 25 watts at 34mA with a plate voltage of 443 volts. Should I keep these biased at 25 watts or should I go up to the 30-32 watts with more current? I also want to go with a SS recto which should bump the plate voltage up to around 460 volts. Will the JJ's, Winged C's, or the GT 6l6GE's hold up with that much plate voltage. Do you have any preferences for new 6L6's. thanks for your time, always much appreciated rp The Svet =C= is really a 30 watt tube on the plate. It is a copy of the great Sylvania 387. These like to be biased closer to 50% than 60% in Fender amps as when pushed hotter they tend to get harsh. There is a quick xls tool I have a link to on my GAB website that some of my clients use as it is available anywhere on have a PC with Internet access and xls. Go to this link page ... and in the upper right hand corner of this particular page there is a little red button that has no label or info. If you click it, you will download my xls tube sheet with some of my own notes. Just plug in your B+ and the plate rating and voila ... stay between 50% and 60% for most amps (class a/b grid biased) and you will be in business. if you have a cathode biased amp and want to play with the resistor value in the bias network in most cases you want 100% to 120% as a side note at idle with no input signal. www.guitaramplifierblueprinting.com/index2.html |
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Post by randalp3000 on Feb 4, 2012 20:20:05 GMT -7
Thanks much Myles. I've been using that chart for quite a few months, comes in very handy. Looks like 60% at 25 watts is almost the same as 50% at 30 watts so I should be all set.
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Post by myles on Feb 5, 2012 10:22:07 GMT -7
Thanks much Myles. I've been using that chart for quite a few months, comes in very handy. Looks like 60% at 25 watts is almost the same as 50% at 30 watts so I should be all set. Happy playing. |
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Post by hymns on Feb 13, 2012 15:04:04 GMT -7
Myles,just ordered a quad set of nos Siemans E84L tubes. I got them for 100 dollars. Could you give me alittle info on this tube and what to expect. I know the man checked them on a Maxi tester and said they are pretty tight as he had a quanity.
Thanks
hymns
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Post by electricflag on Feb 14, 2012 9:32:13 GMT -7
Happy New Year Myles! A traveling musician was in town last night with a Z model SRZ65. The amp was real weak. I'm not a tech, but I wanted help the poor guy out. So, I switched out V1, V2, and V3 and the EL34's with Sino made Marshall tubes. This got him up and running. I didn't bias the power tubes, because we were pressed for time. The owner couldn't get over how good it played clean. But, he did complain about the overdiven tone. I had to agree with him. It sounded like solid state amp clipping. In after thought I was wondering if replacing the the voltage rectifier tube and biasing the power tubes would have made the overdrive tone more musical? Rick Rick, If an amp is overbiased and running too cold it will sound grainy and not develop full power. If an amp is underbiased it will run too hot, sound harsh, run hot and have short tube life. The player needs to have his amp properly biased as soon as possible. : The owner had his SRZ65 biased by a retired professional radio and TV electrician. The bias wasn't too far off. What is interesting was the old-timer's explaination for the "solid state" tone problem. He explained the amp was suffering from reduced interaction between the amp and the speaker - The result of a broken Presence knob. The pot's shaft was bent and stuck wide open, thus flooding the amp with negative feedback. I am happy to report with the Presence pot replaced and turned down low, the proud SRZ65 owner tells me it is restored to full health. Guess I have been lazy in my thinking. I assumed the Presence and Resonance knobs were just part of the tone stack. Surprised too much Presence can affect more than your treble. -Rick |
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Post by myles on Feb 14, 2012 9:40:53 GMT -7
Outstanding and happy playing.
The presence circuit on the SRZ65 is different that on most other amps and unique. It is a big part of the magic of these amps.
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Post by myles on Feb 14, 2012 9:42:45 GMT -7
Myles,just ordered a quad set of nos Siemans E84L tubes. I got them for 100 dollars. Could you give me alittle info on this tube and what to expect. I know the man checked them on a Maxi tester and said they are pretty tight as he had a quanity. Thanks hymns No info to give you other than NOS tubes are generally nicer than production tubes and meet spec on a regular basis. As far as tone ... impossible to really articulate, sort of like comparing a one burger to another from two different places. If you like how they sound you have a winner. |
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Post by aufamily on Feb 16, 2012 5:53:28 GMT -7
Myles - I'm chasing down a very strong "buzz" sound when I hit a low G note. New Jr NR head as of Christmas...had an output tube red plate last week. Got a new set from the Doc (EH's). Have swapped guitars, cables, speaker cabs, and output tubes...and moved the amp and cab around the room...still have it. The amp is new so we're still "bonding", but I'm certain this buzz is new. Any ideas? I haven't swapped out the stock JJ preamp tubes or sovtek LPS PI.
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Post by randalp3000 on Feb 16, 2012 8:32:07 GMT -7
I just had the exact same problem, same note. Brand new set of GT6L6's, found it by holding the tube with a rag while playing said G note.
Also take the covers off the preamp tubes and tap them gently with a pencil while the amp is on to see if one is microphonic or has a rattle.
Good luck
Rp
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Post by Scott on Feb 27, 2012 6:34:51 GMT -7
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Post by myles on Feb 27, 2012 9:40:16 GMT -7
Scott - you have more clean headroom but the level will drop a bit.
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Post by myles on Feb 27, 2012 9:42:41 GMT -7
Myles - I'm chasing down a very strong "buzz" sound when I hit a low G note. New Jr NR head as of Christmas...had an output tube red plate last week. Got a new set from the Doc (EH's). Have swapped guitars, cables, speaker cabs, and output tubes...and moved the amp and cab around the room...still have it. The amp is new so we're still "bonding", but I'm certain this buzz is new. Any ideas? I haven't swapped out the stock JJ preamp tubes or sovtek LPS PI. Sorry for the late reply, I must have missed the notification here. You just need to have somebody play play the note to make the buzz (or use a signal generator) and then press on things (careful of heat and shocks) until you find the offending part or tube. |
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Post by Deleted on Feb 27, 2012 13:48:50 GMT -7
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Post by Scott on Feb 27, 2012 13:51:06 GMT -7
Scott - you have more clean headroom but the level will drop a bit. Thanks Myles... |
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Post by myles on Feb 27, 2012 18:18:14 GMT -7
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Post by myles on Feb 27, 2012 18:18:45 GMT -7
Scott - you have more clean headroom but the level will drop a bit. Thanks Myles... You are quite welcome |
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Post by Deleted on Feb 27, 2012 18:31:10 GMT -7
I was hoping you would comment. Thanks Myles. |
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Post by myles on Feb 27, 2012 18:39:08 GMT -7
I was hoping you would comment. Thanks Myles. Thanks for sending me the link. |
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Post by Scott on Mar 6, 2012 6:04:44 GMT -7
Myles, just wanted to run this past you...
Mike at KCA Tubes is telling us about NOS 5R4GB rectifier tubes as an option for the Maz Jr.
A NOS 5R4GB is only 30 bucks, so less that allot of other NOS rectifiers.
Do you have any Pros or Cons, about using a NOS 5R4GB rectifier in the Jr?
And if it is fine to use... Where would it fall on my listing power wise?
What I currently have...
Again, keep in mind our Maz 18 Jr. is a self biasing amp (cathode biased), so we are free to experiment.
Valid Rectifier Tubes to try in a Maz Jr. - The stock 5AR4 or (GZ34 The way the were marked in Europe.)
5V4
5U4
5Y3
Each tube going down the line will give you progressively: Less Power, Earlier Breakup, More Compression, with a difference in the way the amp responds, now having a softer feel or 'More Sag'... ;D
The tone of the amp (brightness) may also change, due to the new voltages being supplied to the other tubes, by the rectifier.
Thanks...
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Post by myles on Mar 6, 2012 9:50:07 GMT -7
Myles, just wanted to run this past you... Mike at KCA Tubes is telling us about NOS 5R4GB rectifier tubes as an option for the Maz Jr. A NOS 5R4GB is only 30 bucks, so less that allot of other NOS rectifiers. Do you have any Pros or Cons, about using a NOS 5R4GB rectifier in the Jr? And if it is fine to use... Where would it fall on my listing power wise? What I currently have... Again, keep in mind our Maz 18 Jr. is a self biasing amp (cathode biased), so we are free to experiment.
Valid Rectifier Tubes to try in a Maz Jr. - The stock 5AR4 or (GZ34 The way the were marked in Europe.)
5V4
5U4
5Y3
Each tube going down the line will give you progressively: Less Power, Earlier Breakup, More Compression, with a difference in the way the amp responds, now having a softer feel or 'More Sag'... ;D
The tone of the amp (brightness) may also change, due to the new voltages being supplied to the other tubes, by the rectifier.Thanks... These rectifiers are actually quite a bit different and it is not a matter of where it fits in a power scale as there really is no such thing as a power scale. There is output voltage but also current, voltage drop and other factors. 5R4 Vh Ih VaMax IkMax Notes 5 2.0 PIV=2800V 650 Tube drop = 67V @ 250mA DC 5R4 Application Data Class RMSin Irect Cout Rser FW rectifier 750-0-750 250 4 250 .... 5AR4 Vh Ih 5 1.9 5AR4 Application Data Class RMSin Irect Cout Rser FW rectifier 550-0-550 160 60 175 ........... Output voltages, current and drop quite different. Stick with the intended rectifier or a 5V4 which also work quite nicely. |
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Post by bigben55 on Mar 6, 2012 11:46:57 GMT -7
I posted a thread in the Z28 forum about Z28 tubes and was told to PM you. If you would, give me some tube complement recommendations: good, better best. I probably wont be dropping $150 for a single tube, but want the best bang for the buck set I can get from either KCA, Dougs, or the Tube Store. It currently has a newish set of JJ 6V6's, and I don't know what else(only had the amp a few days and havent really checked. Give me the best "$200 or under" set. And what fuses does it take and where can I get some?
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Post by myles on Mar 6, 2012 15:33:05 GMT -7
I posted a thread in the Z28 forum about Z28 tubes and was told to PM you. If you would, give me some tube complement recommendations: good, better best. I probably wont be dropping $150 for a single tube, but want the best bang for the buck set I can get from either KCA, Dougs, or the Tube Store. It currently has a newish set of JJ 6V6's, and I don't know what else(only had the amp a few days and havent really checked. Give me the best "$200 or under" set. And what fuses does it take and where can I get some? Under $200 is a piece of cake. First off, on the 6V6s, I would not recommend JJ tubes. They sound and trace more like a 6L6 than a 6V6. They have a edge to them which is aggressive and not sweet. If you want an edgy rock tone they might be fine but for the great Fenderish tones of the past I'd stick with a real 6V6. Secondly, the JJs have been showing quality issues and rattle issues in my own testing over the last year or more. There are many great NOS 6V6 tubes out there and all the vendors you mention do a very nice job at matching. Do not go for any of that early or late distortion stuff. Tell any vendor you want a midrange tube that meets design spec in regard to plate current. For V1 there are good NOS EF86 tubes out there but the current Tung Sol EF806 is a nice production tube as well. ( thetubestore.com/tungsolef86g.html ) Keep a known good and tested (in your amp) as a spare as EF86s can go microphonic without warning. Tone is a personal taste issue. Side note ... the Z-28 is pretty darn easy on it's EF86 compared to just about any other amp out there that utilizes the EF86 which is a big plus. V2 your phase inverter. Lots of options. A 5751 will yield more clean headroom. A 12AX7 will make the amp more aggressive. A 12AY7 will yield even more clean headroom. In Brad Paisley's Z-28 and in Gary Hooker's (Brad Paisley band) Z-28 I even used a 12AU7 as the phase inverter for a lot of clean headroom for some applications. Again, personal choice is the issue here but I would have a nice long or medium plate 12AX7 like an RCA, GE, Sylvania on hand or a Sovtek 12AX7LPS or JJ 803S work nicely too for a long plate. I would also have a 12AY7 on hand. Stay clear of new production 5751 tubes as they are little more than substandard 12AX7s that were low on gain. A real 5751 has other aspects rather than slightly lower gain. Hope this helped. If you have other questions feel free to post here. Happy playing. |
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Post by bigben55 on Mar 6, 2012 16:39:11 GMT -7
Awesome. Here's, specifically, whats in it now: JJ 6V6's, Sovtek 5AR4 rectifier, Sovtek 5751, ElectroHarmonix EF86. I want to buy the EF86 first, then will probably get a NOS GE 5751(liked it in the past in a BF Tremolux), then another 5AR4. Then a matched pair or quad of 6V6's. Give me specific tubes to get and where from, if you would.
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Post by myles on Mar 6, 2012 17:53:51 GMT -7
Awesome. Here's, specifically, whats in it now: JJ 6V6's, Sovtek 5AR4 rectifier, Sovtek 5751, ElectroHarmonix EF86. I want to buy the EF86 first, then will probably get a NOS GE 5751(liked it in the past in a BF Tremolux), then another 5AR4. Then a matched pair or quad of 6V6's. Give me specific tubes to get and where from, if you would. Specific tubes are hard to suggest as I know nothing about your taste, style, etc. It would be like me asking you what I should eat for dinner tonight. Lose the Sovtek 5751. Lose the JJ's Here are some thoughts ... www.kcanostubes.com/content/nos-tesla-ef806s-not-jj-high-grade-ef86www.kcanostubes.com/content/nos-dario-miniwatt-ef86www.kcanostubes.com/content/nos-jan-sylvania-6v6gty-singles-and-matched-pairswww.kcanostubes.com/content/nos-ge-and-jan-ge-6v6gtwww.kcanostubes.com/content/nos-marconi-6v6g-singles-and-pairs... and you need to tell me what you intend to run in the PI position and why you are thinking in that way. V2 is ultra important in these amps. It is a huge part of the distortion character of the output stage. |
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Post by bigben55 on Mar 6, 2012 19:19:18 GMT -7
I play blues and rock. The blues runs the gamut tonally, but I'm mostly talking overdriven amp tone. Rock-wise, I'm more the Alt-country/rootsy rock guy. Early AC/DC or ZZ Top is as crunching as I will ever need to be. I play a strat, a tele, and a P90 guitar. I want the amp to sound its best, but in the way that its supposed to sound, if that makes any sense. No pedals or effects other than an old Fulldrive 2. I like to set it up so that its just on the edge of OD, as in, if I pick hard, ir ODs but if I pick soft it's still clean. Rolling the guitar volume back from 10 to 7 should be almost all clean.
I was thinking JAN GE 5751 for the PI, simply because 10 years ago I had one in my 1965 Fender Tremolux and liked the way it sounded, and felt it cleaned up the amp a bit. My Z28 volume knob is between 12 and 1 o'clock. I just sold 7 stompboxes, but dont think I can lose the FD2. If I get a humbucker guitar and plug right in, I may put a 12AX7 in there, but will be keeping the FD2 in line with my single coil guitars, so I would rather have a little cleaner of an amp.
But, I would put in what you think would sound best. I've been a Z owner for less than a week. I wouldnt be asking you all these questions if I had just bought another blackfaced Fender, because I know what I like in those.
Is the Sovtek rectifier tube "good?" If so, I'll just buy another for a backup.
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Post by Scott on Mar 7, 2012 1:51:19 GMT -7
Myles, just wanted to run this past you... Mike at KCA Tubes is telling us about NOS 5R4GB rectifier tubes as an option for the Maz Jr. A NOS 5R4GB is only 30 bucks, so less that allot of other NOS rectifiers. Do you have any Pros or Cons, about using a NOS 5R4GB rectifier in the Jr? And if it is fine to use... Where would it fall on my listing power wise? What I currently have... Again, keep in mind our Maz 18 Jr. is a self biasing amp (cathode biased), so we are free to experiment.
Valid Rectifier Tubes to try in a Maz Jr. - The stock 5AR4 or (GZ34 The way the were marked in Europe.)
5V4
5U4
5Y3
Each tube going down the line will give you progressively: Less Power, Earlier Breakup, More Compression, with a difference in the way the amp responds, now having a softer feel or 'More Sag'... ;D
The tone of the amp (brightness) may also change, due to the new voltages being supplied to the other tubes, by the rectifier.Thanks... These rectifiers are actually quite a bit different and it is not a matter of where it fits in a power scale as there really is no such thing as a power scale. There is output voltage but also current, voltage drop and other factors. 5R4 Vh Ih VaMax IkMax Notes 5 2.0 PIV=2800V 650 Tube drop = 67V @ 250mA DC 5R4 Application Data Class RMSin Irect Cout Rser FW rectifier 750-0-750 250 4 250 .... 5AR4 Vh Ih 5 1.9 5AR4 Application Data Class RMSin Irect Cout Rser FW rectifier 550-0-550 160 60 175 ........... Output voltages, current and drop quite different. Stick with the intended rectifier or a 5V4 which also work quite nicely. Thanks Myles... |
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Post by myles on Mar 7, 2012 9:34:26 GMT -7
I play blues and rock. The blues runs the gamut tonally, but I'm mostly talking overdriven amp tone. Rock-wise, I'm more the Alt-country/rootsy rock guy. Early AC/DC or ZZ Top is as crunching as I will ever need to be. I play a strat, a tele, and a P90 guitar. I want the amp to sound its best, but in the way that its supposed to sound, if that makes any sense. No pedals or effects other than an old Fulldrive 2. I like to set it up so that its just on the edge of OD, as in, if I pick hard, ir ODs but if I pick soft it's still clean. Rolling the guitar volume back from 10 to 7 should be almost all clean. I was thinking JAN GE 5751 for the PI, simply because 10 years ago I had one in my 1965 Fender Tremolux and liked the way it sounded, and felt it cleaned up the amp a bit. My Z28 volume knob is between 12 and 1 o'clock. I just sold 7 stompboxes, but dont think I can lose the FD2. If I get a humbucker guitar and plug right in, I may put a 12AX7 in there, but will be keeping the FD2 in line with my single coil guitars, so I would rather have a little cleaner of an amp. But, I would put in what you think would sound best. I've been a Z owner for less than a week. I wouldnt be asking you all these questions if I had just bought another blackfaced Fender, because I know what I like in those. Is the Sovtek rectifier tube "good?" If so, I'll just buy another for a backup. I do not rely on Sovtek rectifiers. If you are gigging or doing live work use an NOS rectifier and have a solid state plugin as a backup. If you liked a 5751 in your Fender amp it would have no bearing on how it will sound in a different amp. |
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Post by boptometrist(david) on Mar 7, 2012 11:37:22 GMT -7
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