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Post by Paul (TRANE) on Jan 31, 2006 8:06:13 GMT -7
I just re-tubed my 6545 (pre-amps and rectifier) with NOS tubes from KCA NOS TUBES. Big thanks to Mike for all his help and for answering all my long emails and questions. Now I am running:
V1: Brimar CV4004 V2: Brimar CV4004 V3: GEC EF86 V4: Brimar CV4004 (Balanced) V5 & 6 Power Tubes: Stock GT-E34LS Hardness 6 V7: JAN Philips\Sylvania 5AR4
I only had a short time to try them out last night. But I did not an immediate difference. More gain and clarity. Also the lows were deeper, bigger but more controlled and exhibited a tightness I have not experienced with any other set up on this amp. Will post more once I get more time with this set up. I can not wait for practices this week and recording!!!
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Post by terryg on Jan 31, 2006 10:14:51 GMT -7
Hey, we almost have the same configuration. Those Brimars are pretty nice, huh? Real sleepers, and great bang for the buck. Where'd you bias your GTs at? I'm using a GT12AX7C "MPI" as a phase inverter, and I'm using GT E34LS #5s instead. Right now I'm seeing 410V/28mA, but I'm going to increase the bias a bit. This amp is so nice.
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Post by myles on Jan 31, 2006 10:23:58 GMT -7
Hey, we almost have the same configuration. Those Brimars are pretty nice, huh? Real sleepers, and great bang for the buck. Where'd you bias your GTs at? I'm using a GT12AX7C "MPI" as a phase inverter, and I'm using GT E34LS #5s instead. Right now I'm seeing 410V/28mA, but I'm going to increase the bias a bit. This amp is so nice. Terry .... Just a hello .... Get your bias up to 34mA or bring the amp out to me next time you are at my place and I will do it.
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Post by Paul (TRANE) on Jan 31, 2006 15:17:25 GMT -7
Terry,
I am sitting right at 30ma on my power tubes. I will be putting new tubes in around August. I will go with the same GT-E34LS H:6 as always. I may go for the 34ma that Myles notes at that point. I really love the Brimars. Can't wait to get home and get playing.
Paul
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Post by terryg on Jan 31, 2006 15:37:16 GMT -7
Terry .... Just a hello .... Get your bias up to 34mA or bring the amp out to me next time you are at my place and I will do it. Hi Myles! 34mA - you bet! Current == life, right? I've been so into the Z28 lately that I haven't faced the other part of my room where the 6545 is patiently waiting. I'll certainly bring it out when I'm driving there, so you can "admire my work" or some silly thing. Paul, me too! I get so bummed out now that I've been working so hard - it really cuts into my playing and practicing! But hey, no work means no amps, eh? I've finally delurked.......maybe this fresh exposure will help me "realign" my priorities somewhat. Sleep? I need that?
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Post by terryg on Jan 31, 2006 23:35:00 GMT -7
OK -- I measured 424V, with 34mA. That's actually still lower than 50%, but the amp sounds real nice. I've got an R&B rehearsal tomorrow night (where I'd usually take the Z28), but I think I'd better take the 6545 just to air it out a bit. This amp really seems to be speaking "rock" to me. Did I mention that I'm using GT E34LS #5s?
Actually, being a little nutty I did this at about 11PM here in Chicago, and frittered (frettered?) away at least another hour just trying different guitars...I have to wake up in a few hours!
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Post by Paul (TRANE) on Feb 1, 2006 7:33:15 GMT -7
Terry,
Chicago!!! I am up in Chicago land area about once a year. My wife's family is in Highland, IN and I love to go into Chicago to check out the music stores and clubs. Really love the new store for Makin Music. Nice place. Went there about a month ago. So much great music in that area. Not so true about the music scene here in Albuquerque. Oh well, great to hear from a fellow 6545 user and one who obviously has great taste in tubes. Do you have any music up on the net?
Paul
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Post by myles on Feb 1, 2006 10:08:20 GMT -7
Terry,
The E34LS is a 30 watter and I'd even go higher with your B+:
50% 60% 35 42
Run it up to 38mA and tell me how you like it then! You will still be running cool and have great tube life.
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Post by terryg on Feb 1, 2006 11:02:53 GMT -7
Myles, I was having the exact same thoughts the entire time last night. If I recall correctly my Z28 is closer to 60% and it sounds great to my ears. The #5 E34LS tubes do seem "crispier" earlier on - I'll have a assessment after I get to play it up a bit tonight. I might go into a longer plate PI as well (a balanced R2 you dropped on me recently). I should drill a hole in the bottom of my chassis cabinets......that would be a useful modification! Paul, Albuquerque!! I actually have no relation to ABQ whatsoever...... but I did live in Durango CO for a few years! I'm certainly impressed with the live music scene here in Chicago - seems like I could go out any night of the week and see anything I felt like seeing. Starting a band is showing itself to be a little rough, though, partly because I don't know too many folk here. No music on the net...I'd probably get arrested for bad taste, and I don't really have a facility for recording at my disposal....not yet, anyway! Is "trane" an allusion to "john col"?
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Post by johnnyl on Feb 1, 2006 11:28:51 GMT -7
hey terry, what type of sound are you shooting for w/ your band? Just curious. I'm out here in the Chicago burbs and the scene's kinda lame out here. Lot's of 80's cover bands....
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Post by terryg on Feb 1, 2006 12:58:39 GMT -7
johnnyl! The guy that's putting the band together described his goal as something based on the Muscle Shoals vibe, but with a stronger blues and "country soul" feel. He's bringing tunes in from guys like Dan Penn, the Hacienda Bros, Booker T, Delbert McClinton....but at the same time I'm seeing some exposure to Steely Dan, Johnny "Guitar" Watson, and Burt Bacharach. I think the singer has something to do with that, which is fine with me....and I like playing behind her voice, it's strong, moves across notes well, and has depth.
It's early stages, a few at-home arrangement sessions and some attempts and band practice in rehearsal studios. We haven't locked down a drummer, and bass players don't seem to exist. I'm kind of a half-gun in this project, the other half going into having some say as to the direction of the project. I'm looking forward to it, but I'm sure I'll be doubly excited when there's a group defined.
It's a total departure from the 80's cover band I just left!
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Post by Paul (TRANE) on Feb 1, 2006 14:23:29 GMT -7
Terry,
Yep!! You guessed it right up front. It is a nickname I was given by the guys that I played with a lot. Pretty cool one so I use it here and there. Starting a band is always hard. I am currently in three and it can be a real pain just getting people to practice and learn their parts for one of the groups.
Paul
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Post by terryg on Feb 1, 2006 14:58:34 GMT -7
Terry, Yep!! You guessed it right up front. It is a nickname I was given by the guys that I played with a lot. Pretty cool one so I use it here and there. I don't blame you - that's respectably awesome! I mean, to earn that ... Sensei, you're here! Love is work, isn't it? Let's see, this thread started out as a discussion of tube implementation and configuration in a 6545, which effectively controls current, which effectively drives our desires, which effectively motivates, and here we are...right on topic! In 200 years people will read this and think of Dr. Z as a wise sage, and his amplifiers as vessels to greater understanding (of course we know that they are now). uh...I just ate a whole box of thin mints So, 38mA coming up after tonight. One question I've been pondering: measure with the SS rectifier installed and swap into the tube, or just leave the tube and set it. I've been leaving the tube every time, but I pack the SS rectifier in my bag as backup.
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Post by Paul (TRANE) on Feb 1, 2006 15:24:06 GMT -7
I know from the good Dr's site that the voltages for the SS rectifier are higher 480 Volts (center tap) and 440 Volts (center tap) for GZ34. Not sure what would happen if you set up with SS then put in the tube. Could be interesting or disasterous. Would have to defer to the "all wise" Myles on that one. I am looking forward to re-doing my power tubes and re-biasing now. Man I can not wait to get home and get cookin on those tubes.
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Post by terryg on Feb 1, 2006 15:54:47 GMT -7
Me too, and it's a PITA (not really, but I'm whining) to pull the chassis out. I'm measuring B+ at the socket, with one of those Weber bias-rite adapter things that I simply plug into my DMM, and I calculate idle dissipation percentages from that....well, Myle's spreadsheet does.
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Post by mikekca on Feb 1, 2006 20:40:31 GMT -7
I just re-tubed my 6545 (pre-amps and rectifier) with NOS tubes from KCA NOS TUBES. Big thanks to Mike for all his help and for answering all my long emails and questions. Now I am running: V1: Brimar CV4004 V2: Brimar CV4004 V3: GEC EF86 V4: Brimar CV4004 (Balanced) V5 & 6 Power Tubes: Stock GT-E34LS Hardness 6 V7: JAN Philips\Sylvania 5AR4 I only had a short time to try them out last night. But I did not an immediate difference. More gain and clarity. Also the lows were deeper, bigger but more controlled and exhibited a tightness I have not experienced with any other set up on this amp. Will post more once I get more time with this set up. I can not wait for practices this week and recording!!! Hey Trane, glad they worked out so well for you. That's a hell of a tube lineup, I'm not surprised that it sounds killer. Rock on!
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Post by Paul (TRANE) on Feb 2, 2006 7:33:03 GMT -7
Terry,
I am getting a bias rite myself, to make the whole thing easier to do. Using a DMM and probing around inside per the DR's notes is kind of worrisome to me. I am a physicist and I know what electricity can do to you. So the Bias Rite is what I am going for to make it safer over all.
Paul
Mike,
Thanks for all your help on the tubes and answering my questions. What a killer, killer sound. I got some good hours in with the head last night and it was so impossibly sweet. I wanted to quit work and just stay home and play all day every day. I have fallen in love all over again with the 6545. I will have to post some sounds when I get them mixed down and burned to CD.
Thanks again,
Paul
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Post by terryg on Feb 2, 2006 9:04:06 GMT -7
Terry, I am getting a bias rite myself, to make the whole thing easier to do. Using a DMM and probing around inside per the DR's notes is kind of worrisome to me. I am a physicist and I know what electricity can do to you. So the Bias Rite is what I am going for to make it safer over all. Paul Those were my precise thoughts in purchasing that adapter as well. It has paid for itself over and over (and over and over). Yes! Thanks Mike for all I've gained from you as well - I think all my tube amps have little bit of KCA in them! Paul, I had that experience with my 6545 last night as well, and how sweet it was indeed. R&B tunes, predominantly the 45 side, excellent voicings with the tone controls....I was warm, fat and happy all night. However, I'll be increasing to 38mA tonight. I had a nagging sense that regardless how nice it was sounding, I think there's more to be discovered. I think I'm finding that I'm generally most satisfied with idle dissipations approaching 60%. My Z28 is around that, and I think that amp is just oozing with mojo. Terry
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Post by johnnyl on Feb 2, 2006 10:20:17 GMT -7
Yeah, that bias rite adapter is very cool. Worked great w/ my SRZ. I gotta say the doc really builds his amps well - I was able to bias my power tubes w/in .4 mA of each other. My Goblin.. not so well built... w/ matched tubes I could only get w/in 6 mA of each other. It's a cool little amp but Myles told me that if you go much over a 10% difference you start losing sustain.. bummer..
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Post by prowler on Feb 2, 2006 14:37:53 GMT -7
johnnyl.....
I would like to get a bias rite adapter for my SRZ. I have yet to take out the chassis so I don't know exactly where the adjustment pot is. As a matter of fact I have never even tried to bias my own amp but I am willing to learn & my electronics knowledge is good enough to be able to do it safely. I just need to know what the procedure is. I assume that you need to hook the amp up to a load.
If you get a chance, can you type out the procedure for me? Maybe send it to me via PM? If not, thats ok too.
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Post by terryg on Feb 6, 2006 19:00:57 GMT -7
Hi everyone - I just wanted to note that I'm set at 38mA, seeing about 418V. Tube rectified (Mike K's "mislabeled" 5AR4s), GTE34LS. I think I'm all set for at least the next 2.7 minutes.
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Post by hdahs143 on Feb 6, 2006 21:46:28 GMT -7
Hi everyone - I just wanted to note that I'm set at 38mA, seeing about 418V. Tube rectified (Mike K's "mislabeled" 5AR4s), GTE34LS. I think I'm all set for at least the next 2.7 minutes. Mike's "mislabled 5AR4's" are a jewel. I have one in my MAZ and found it to let the amp breathe better. An excellent purchase!
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Post by terryg on Feb 7, 2006 9:43:32 GMT -7
No doubt - all my amps have one, in fact. I'm all saggy over here, and I'm a dude!
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Post by myles on Feb 7, 2006 10:35:09 GMT -7
Myles, I was having the exact same thoughts the entire time last night. If I recall correctly my Z28 is closer to 60% and it sounds great to my ears. The #5 E34LS tubes do seem "crispier" earlier on - I'll have a assessment after I get to play it up a bit tonight. I might go into a longer plate PI as well (a balanced R2 you dropped on me recently). I should drill a hole in the bottom of my chassis cabinets......that would be a useful modification! Paul, Albuquerque!! I actually have no relation to ABQ whatsoever...... but I did live in Durango CO for a few years! I'm certainly impressed with the live music scene here in Chicago - seems like I could go out any night of the week and see anything I felt like seeing. Starting a band is showing itself to be a little rough, though, partly because I don't know too many folk here. No music on the net...I'd probably get arrested for bad taste, and I don't really have a facility for recording at my disposal....not yet, anyway! Is "trane" an allusion to "john col"? Terry - drop in the MPI I gave you and let me know what you think. I can also "adjust" from there as that was a traced tube and I can go "harder or softer". next time you are out I will give you some more M MPIs and R2 MPIs.
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Post by myles on Feb 7, 2006 10:42:02 GMT -7
I know from the good Dr's site that the voltages for the SS rectifier are higher 480 Volts (center tap) and 440 Volts (center tap) for GZ34. Not sure what would happen if you set up with SS then put in the tube. Could be interesting or disasterous. Would have to defer to the "all wise" Myles on that one. I am looking forward to re-doing my power tubes and re-biasing now. Man I can not wait to get home and get cookin on those tubes. At 440 plate volts the ID for mA looks like this (sorry if my cut and paste format messed up): 50% 60% 70% 34 41 48 I would bias in the above setup at 38mA or so. In the 480 B+ setup we see things this way: 50% 60% 70% 31 38 44 And even here, I would go for 38mA again. If you biased for the Solid state rectifier at 38mA and popped in a tube one you would drop down to maybe 34mA or so, without changing the bias. This would still be fine. So .... set up the bias with the SS and then just pop in the tube rectifier when you want a bit of cool touch sensitivity and to drop things a bit. You do not want to bias at say, 38mA with the tube rectifier and then pop in the SS one though. The tube life will be short and the amp will sound harsh. You will not blow anything up but it will be running too hot.
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Post by myles on Feb 7, 2006 10:50:30 GMT -7
Me too, and it's a PITA (not really, but I'm whining) to pull the chassis out. I'm measuring B+ at the socket, with one of those Weber bias-rite adapter things that I simply plug into my DMM, and I calculate idle dissipation percentages from that....well, Myle's spreadsheet does. Terry, Since you brought up my "spreadsheet" .... for all the folks here, I will give out a bit of info. There are times when I am working with an amp designer and we start talking "tube specs". As I start yacking "well, at book spec of 250 plate volts on the plates of the EF86 and 140 volts on the screen .... ". The person I am talking to generally starts to try to write down these things. I ask if they have a PC handy. One of the great aspects of being on the road at times is that I DO NOT carry a PC or cell phone. There are tons of these things around you every moment. So .... I have them bring up mu website. On the first page of my website at the upper right hand top corner, there by the date that the page was last updated, is a little red unmarked "nothing". If you click on the button an XLS spreadsheet will download to your PC and if you have excel on your PC it will launch. It has a lot of little notes on some tube specifics and will also calculate bias for any class A/B amp using any tube at any plate voltage. By the way .... you can also use this sheet when designing class A amps ... just stay in the 100% - 120% range adjusting the cathode bias resistor as necessary to stay in this range. There are other "red buttons" in other areas of the website but I do not remember what they are at the moment.
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Post by myles on Feb 7, 2006 10:52:21 GMT -7
johnnyl..... I would like to get a bias rite adapter for my SRZ. I have yet to take out the chassis so I don't know exactly where the adjustment pot is. As a matter of fact I have never even tried to bias my own amp but I am willing to learn & my electronics knowledge is good enough to be able to do it safely. I just need to know what the procedure is. I assume that you need to hook the amp up to a load. If you get a chance, can you type out the procedure for me? Maybe send it to me via PM? If not, thats ok too. Prowler, Feel free to email me and I will send you my home phone number. Any evening or weekend when I am home we can talk and I will walk you through this step by step over the phone. It is very quick and easy.
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Post by terryg on Feb 7, 2006 14:04:30 GMT -7
Prowler, it's true. The very first time I was really nervous, now it's really easy.
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Post by myles on Feb 7, 2006 18:12:53 GMT -7
Prowler, it's true. The very first time I was really nervous, now it's really easy. Terry ... I made a few comments to your "M" post in the 6545 area.
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Post by johnnyl on Feb 7, 2006 21:53:26 GMT -7
Hey Prowler, I'd feel better if you took Myles up on his offer. Myles is the MAN - he helped me figure out what my target bias was for my SRZ and he's probably biased more amps than we all could shake a stick at. Although I know how to do it now I actually wish I'd had somebody walking me through it after I pulled the chassis. It's definitely nerve racking when your dealing w/ all that voltage. Once you get it down though it feels pretty darn cool - like your more connected to your amp..
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