Gone over I'm sure, but are different transfomrer(s) involved when running 6V6s? Or do you go with the standard layout as if you were goign to run EL34s and of then adjust bias to for 6V6 which I belive is the case. Just wondered if there were variations on that?
Thinking about maybe trying one of these as a winter project, casual build, etc.
This is a great board, I have a short note Ken wrote me years ago, but not sure if it is appropriate to post it, but I could scan and post it, if you folks have an interest.
Running 6V6s in Express?
Moderators: pompeiisneaks, Colossal
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Littlejohn
- Posts: 7
- Joined: Sun Mar 01, 2009 10:02 pm
- Location: New Market, MD
Re: Running 6V6s in Express?
The Express was designed such that you can just stick 6V6 tubes in instead of EL34s, bias and play. So Ken always intended the regular EL34 transformers to be used.
If you haven't tried it with EL34s though, I'd keep a set of Siemens or RFT EL34s to hand as, in my opinion, they sound way better with the Express than the 6V6es.
If you haven't tried it with EL34s though, I'd keep a set of Siemens or RFT EL34s to hand as, in my opinion, they sound way better with the Express than the 6V6es.
Re: Running 6V6s in Express?
If the nature of the note isn't too personal, what would be the harm in posting it? I think folks would be very interested. I know I would. If you think it would/could be misconstrued or misused, then, no, probably not appropriate to post.
On the subject of 6V6's...well a bit astray...I built a TW Express-ish like amp with a pair of 6AQ5's. Because of the small bottle and plate structure, I was truly afraid these would not hold up under real Express voltages. I used a 275-0-275 PT and I tweaked the B+ supply ladder to keep the preamp at Express level voltages. I ended up with power tube Va ~335, which is still really high for the 6AQ5, but with a good result. Since I don't gig the amp, I'm not concerned. I'm not sure I'd let it out to a working musician at this operating point.
Anyhow, the point is, the 6AQ5 and 6V6 are electrically equivalent. It is just the bottle size that leans in favor of the 6V6 if you want to plug it into an EL34 circuit. This is a fixed bias amp, and with negative grid voltage compensating for the higher than typical plate voltage (for a 6V6), the tubes should operate OK. As Paul says, how they sound is another thing and a subjective thing at that. I think, if I had built mine with octal sockets, I would have used EL34's and not looked back. I built it with the 6AQ5's because I've got a modest stock of them and it seemed like a good idea at the time. I have no regrets, and aside from the hiss I can hear, this is a very unique sounding amp. Whether is sounds at all like a real Express, I have no live reference point for comparison.
On the subject of 6V6's...well a bit astray...I built a TW Express-ish like amp with a pair of 6AQ5's. Because of the small bottle and plate structure, I was truly afraid these would not hold up under real Express voltages. I used a 275-0-275 PT and I tweaked the B+ supply ladder to keep the preamp at Express level voltages. I ended up with power tube Va ~335, which is still really high for the 6AQ5, but with a good result. Since I don't gig the amp, I'm not concerned. I'm not sure I'd let it out to a working musician at this operating point.
Anyhow, the point is, the 6AQ5 and 6V6 are electrically equivalent. It is just the bottle size that leans in favor of the 6V6 if you want to plug it into an EL34 circuit. This is a fixed bias amp, and with negative grid voltage compensating for the higher than typical plate voltage (for a 6V6), the tubes should operate OK. As Paul says, how they sound is another thing and a subjective thing at that. I think, if I had built mine with octal sockets, I would have used EL34's and not looked back. I built it with the 6AQ5's because I've got a modest stock of them and it seemed like a good idea at the time. I have no regrets, and aside from the hiss I can hear, this is a very unique sounding amp. Whether is sounds at all like a real Express, I have no live reference point for comparison.
Re: Running 6V6s in Express?
In my experience ,just use the Standard Express Tranny set from Toneslut.
I like the 6.6 k tap on the OT. After experimenting with PT I find the Higher voltage tap sounds the best to my ears. I bias the 6v6's I have at 21-22 ma. I find after biasing the plates are around 385VDC.
You can really hear the difference between tubes though. My Favorites are the Old RCA's and the best is the Old Tungsols. Military GE's sound great too.
Other brands not so good. I confess , I have not tried any of the modern communist tubes. I would like to try the new Tungsols, I have had very poor experiences with the JJ brand recently, even though I hear their 6v6 is something else, literally.
Great tones all around. I actually do prefer the el34's, they seem to have more detail and depth of tone. But the 6v6's sound like a big fat Tweed Deluxe to my ears.
I like the 6.6 k tap on the OT. After experimenting with PT I find the Higher voltage tap sounds the best to my ears. I bias the 6v6's I have at 21-22 ma. I find after biasing the plates are around 385VDC.
You can really hear the difference between tubes though. My Favorites are the Old RCA's and the best is the Old Tungsols. Military GE's sound great too.
Other brands not so good. I confess , I have not tried any of the modern communist tubes. I would like to try the new Tungsols, I have had very poor experiences with the JJ brand recently, even though I hear their 6v6 is something else, literally.
Great tones all around. I actually do prefer the el34's, they seem to have more detail and depth of tone. But the 6v6's sound like a big fat Tweed Deluxe to my ears.
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Littlejohn
- Posts: 7
- Joined: Sun Mar 01, 2009 10:02 pm
- Location: New Market, MD
Re: Running 6V6s in Express?
Thanks much for all the replies, makes things simpler.
I'll take a stab at doing an express over the winter if energy allows, see how it goes.
Well, I found Kens note...it realy just mentions, welcoming me to his wait list and he makes a funny joke about how he has been ill for some time, and Leo's Doctor...maybe I'll put it up in the other section, it's not a long note, so maybe not.
I'll take a stab at doing an express over the winter if energy allows, see how it goes.
Well, I found Kens note...it realy just mentions, welcoming me to his wait list and he makes a funny joke about how he has been ill for some time, and Leo's Doctor...maybe I'll put it up in the other section, it's not a long note, so maybe not.