# 6V6s in a Traynor Bassmaster



## traynor_garnet (Feb 22, 2006)

I had this done to an amp I owned years ago but I am not sure what the tech really did. Is it simply a matter of rebiasing and finding 6v6s that can handle it? I may have it done to one of the ones I now own.

FWIW, I am talking about an early tube rectified unit running 7027s.

TG


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## dtsaudio (Apr 15, 2009)

You're probably looking at a very short life on the 6V6. Maximum plate voltage, plate dissipation and current are significantly lower than with the 7027. They are definitely not interchangeable. That is particularly true of modern 6V6 tubes 
You may be able to use 6L6GC providing you can change the bias. The Bassmaster doesn't have variable bias so the amp
will have to be modified slightly.


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## traynor_garnet (Feb 22, 2006)

Thanks for the info. I have JJ 6v6s and apparently they can handle just about anything. Also, I think one of my bassmasters has a bias pot mod already done.

TG




dtsaudio said:


> You're probably looking at a very short life on the 6V6. Maximum plate voltage, plate dissipation and current are significantly lower than with the 7027. They are definitely not interchangeable. That is particularly true of modern 6V6 tubes
> You may be able to use 6L6GC providing you can change the bias. The Bassmaster doesn't have variable bias so the amp
> will have to be modified slightly.


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## dtsaudio (Apr 15, 2009)

The rating of the JJ's is up to 450 volts. So apparently they can take it, assuming you can get the current down. They only have a 10 watt dissipation.


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## nonreverb (Sep 19, 2006)

Hmmm...I've read about guys doing this before. As dtsaudio points out, JJ6V6's would be the best choice by far. You might consider a 5U4 as the rectifier as well as there's a bigger voltage drop across it. Bias will definitely have to be modded and I'm not sure the transformer impedance would be optimal although I'm sure it would work.



dtsaudio said:


> The rating of the JJ's is up to 450 volts. So apparently they can take it, assuming you can get the current down. They only have a 10 watt dissipation.


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## traynor_garnet (Feb 22, 2006)

Is the 5U4 rectifier a direct replacement? Will it change the sound or just help keep the 6V6 within safe operating ranges.

I read that with this switch you should ideally double the impedance from when you were using 6L6s (if 8 ohms with 6L6s, use a 16 ohm cab with 6V6s). OTOH, almost everyone says that these massive Hammond trannies are more than safe with a mismatched load.

To be honest, I put some JJ 6V6s in the amp yesterday and tried it without rebiasing or switching rectifier tubes. It sounds amazing but I only played for a minute for fear of damaging something. I put the 7027s back in for now.

TG


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## traynor_garnet (Feb 22, 2006)

This rectifier looks interesting as it states "his 274B tube's filament draws 2.5A of current. This current draw makes it acceptable for many amps originally designed for a 5AR4/GZ34 tube."

www.thetubestore.com - Preferred Series 274B / 5U4G Rectifier Tubes

TG


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## nonreverb (Sep 19, 2006)

The 5U4 will drop more voltage. Since Traynors were built with rugged transformers, the power tranny can probably handle the higher filament current demand.
Some Traynors have a multitap transformer with one tap cut back. That's also an option.



traynor_garnet said:


> Is the 5U4 rectifier a direct replacement? Will it change the sound or just help keep the 6V6 within safe operating ranges.
> 
> I read that with this switch you should ideally double the impedance from when you were using 6L6s (if 8 ohms with 6L6s, use a 16 ohm cab with 6V6s). OTOH, almost everyone says that these massive Hammond trannies are more than safe with a mismatched load.
> 
> ...


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## WCGill (Mar 27, 2009)

dtsaudio said:


> They only have a 10 watt dissipation.


Dan, I'd bet that it's 14 watts. They can take an incredible amount of current.


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## dtsaudio (Apr 15, 2009)

You're right. It's 10 watts when wired in triode, but 14 watts when wired as a pentode.


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## traynor_garnet (Feb 22, 2006)

Thanks for the info and comments guys. So how many watts would I be pushing with 6v6s in the amp?

TG


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## traynor_garnet (Feb 22, 2006)

So I just heard from my tech and he said this: "You need a output transformer that have load of 10000 Ohm to 8000 Ohm plate to plate, the present transformer have 3400 Ohm to 4000 Ohm of load."

Would running a 16 ohm load on the amp alleviate this problem? 

I would simply ask my tech but he speaks very little English and I speak zero french and have no technical knowledge to boot.

TG


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## jb welder (Sep 14, 2010)

Your solution of running an 8 ohm tap into a 16 ohm load should solve the issue. Also your statement about the OT being big enough that the mismatch should not matter is valid. If you are trying to knock down the power level, you will get less power into the mismatched load. However, the frequency response will also be affected. Suggest you try it into both types of load and choose whichever you prefer the sound of.


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## Wild Bill (May 3, 2006)

traynor_garnet said:


> So I just heard from my tech and he said this: "You need a output transformer that have load of 10000 Ohm to 8000 Ohm plate to plate, the present transformer have 3400 Ohm to 4000 Ohm of load."
> 
> Would running a 16 ohm load on the amp alleviate this problem?
> 
> ...


Wrong way! LOL

Use a 4 ohm load, if you are worried! Actually, I wouldn't worry about it! The tubes won't really care! If you look at the data sheets for an output tube you will see curves plotting output power and distortion versus plate load. The curves show a range, not a precise figure. Things also demand a compromise. Running a tube in hifi service might mean less power but also less distortion for a different plate load.

Tubes are also surprisingly tough about such mismatches. You might lose a few hours of overall tube life, maybe even see them last longer!

The tone with the 3400 ohm load will definitely be different. My experience has been that a seriously lower plate load gives a grainier and dirtier sound. However, I kind of like it! You might very well like it too!

Sometimes techs either don't know or don't understand that being too anal about such specs as plate load is a hifi thing. A guitar amp is SUPPOSED to have some distortion! Are you wanting to sound like Barney Kessel in a 1930's jazz band or Eddie Van Halen?

Specs really only make sense if taken in the context of a specific application. They are not simple rules carved in stone that people repeat without understanding what they really mean.

Wild Bill/Busen Amps


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## traynor_garnet (Feb 22, 2006)

jb welder said:


> Your solution of running an 8 ohm tap into a 16 ohm load should solve the issue. Also your statement about the OT being big enough that the mismatch should not matter is valid. If you are trying to knock down the power level, you will get less power into the mismatched load. However, the frequency response will also be affected. Suggest you try it into both types of load and choose whichever you prefer the sound of.


Awesome, thanks so much for the info. I would really like to shave some volume off this amp without doing any drastic mods are changing the sound.


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## WCGill (Mar 27, 2009)

16 ohm load reflects a primary of 6.8 to 8k, if that's what you're after.


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## Wild Bill (May 3, 2006)

WCGill said:


> 16 ohm load reflects a primary of 6.8 to 8k, if that's what you're after.


Just about perfect for 6V6s!

Funny though, when I play nothing seems to help it sound better...:zzz:

Wild Bill/Busen Amps


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## traynor_garnet (Feb 22, 2006)

WCGill said:


> 16 ohm load reflects a primary of 6.8 to 8k, if that's what you're after.


Ok, now I am even more confused! LOL

If I have this switch done, should the cab be 4 or 16 ohms? Your post and Bill's are at odds, but perhaps it is my ignorance that is to blame for the problem.


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## dtsaudio (Apr 15, 2009)

You are dealing with a transformers "reflected impedance". The impedance ratio of the original is 4000/8 = 500. So with a 16 ohm load the reflected impedance 16 x 500=8000 ohms. With a 4 ohm load it's 4 x 500 = 2000 ohms. So you would be better off with the 16 ohm load.
I've estimated the impedance ratio from what your tech said about the transformer impedance. I don't want to get into the whole formula.


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## Wild Bill (May 3, 2006)

traynor_garnet said:


> Ok, now I am even more confused! LOL
> 
> If I have this switch done, should the cab be 4 or 16 ohms? Your post and Bill's are at odds, but perhaps it is my ignorance that is to blame for the problem.


I was wrong and MCGill was right!

You caught me just after waking up from a nap and my brain was foggy!:sSig_ImSorry:


Hey, cut me some slack! I'm so old I am pre-disco!kkjq


Wild Bill/Busen Amps


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## traynor_garnet (Feb 22, 2006)

Ok, I heard back from my tech once again. I asked him about running a 16 ohm load and mentioned the size and strength of the transformers. Here is what he wrote in response (please remember he is not writing in his first language because I am completely uni-lingual).
_
"The problem is not the strongness, is the wattage required to megnetise the core of the transformer is 30 watts RMS plate to plate two tube (BIAS) at idle, and left 20 watts RMS for the push-pull swing. The 6v6 develop 28 watts rms for two tube at the maximum ratings, it ok to bias but left noting for the push-pull swing and no performence. The wire is too big inside the transformer and too much iron."
_
Can anyone explain what he is getting at? The technical aspects are way beyond me. I _think _he is saying that although it would be safe, it wouldn't sound/perform all that well; many others, however, claim their bassmasters sound great running 6V6s.

TG


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## WCGill (Mar 27, 2009)

I think not. The Bassmaster transformer is not too big for 6V6's. The real danger in using too large a transformer is high-frequency loss because of increased capacitance, not lack of power or performance. I like to use over-sized transformers with 6V6's. An SVT transformer might be a problem.


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## traynor_garnet (Feb 22, 2006)

WCGill said:


> I think not. The Bassmaster transformer is not too big for 6V6's. The real danger in using too large a transformer is high-frequency loss because of increased capacitance, not lack of power or performance. I like to use over-sized transformers with 6V6's. An SVT transformer might be a problem.


Thanks Bill. I had never heard of transformers being "too big"for any tube. All in all, I think I may go ahead and have this switch done. I am not sure if my tech will even do it (he obviously doesn't think it is a great idea) but if it just a matter of substituting a rectifier tube and setting the bias, I may grab some equipment and try it myself.

Thanks to everyone who chipped in here and shared their technical knowledge. I realize that for some of you this is your job, you are offering free advice, and answering questions you have probably answered a million times before (I am a prof, so I can relate!). I just wanted to let you know that your efforts are truly appreciated.

TG


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