Thought I'd share this to return the help this forum has offered me. Some of us on the Hoffman forum were working on low watt push/pull amps and we came up with this one using ECL84 tubes.
I posted the schematic once before, but it has been updated now (after additional tweaks) along with a soundbit. And someone else has built one with apparently similar positive results.
This is probably around a 3-4 watt amp that I think has decent bass response for a small amp , nice harmonics and is fairly touch sensitive to play. Sustain is reasonably decent.
There are some great pictures of one that JBP (Hoffman forum member) built that looks really nice:
http://www.el34world.com/Forum/index.php?topic=13151.0
With respect, 10thtx
SoLow Watt ECL84 amp
Moderators: pompeiisneaks, Colossal
SoLow Watt ECL84 amp
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Last edited by 10thTx on Sun Feb 05, 2012 1:11 pm, edited 1 time in total.
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martin manning
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Re: SoLow Watt ECL84 amp
Looks great! Remind me again what the deal is with the small cap bypassing one of the PI plate resistors? There was some discussion about that recently as I recall.
Re: SoLow Watt ECL84 amp
I called it an "enhance" cap and it added a significant amount of smoothness to the tone & it seemed like it added some harmonics also.
With respect, 10thtx
With respect, 10thtx
Re: SoLow Watt ECL84 amp
Bump. What impedance does a pair of ECL84s want to see? Suggested OT?
I build and repair tube amps. http://amps.monkeymatic.com
Re: SoLow Watt ECL84 amp
[IMG:800:597]http://i497.photobucket.com/albums/rr333/valvetone/6DX8.jpg[/img]xtian wrote:What impedance does a pair of ECL84s want to see? Suggested OT?
![[IMG:800:597]http://i497.photobucket.com/albums/rr333/valvetone/6DX8.jpg[/img]](http://s497.photobucket.com/user/valvetone/media/6DX8.jpg.html){kind=link}
I use this PA line transformer as the OT. It is readily available here in Australia, but there should be similar low-cost transformers available elsewhere.
http://www.jaycar.com.au/productView.as ... ID=1002#12
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Stevem
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Re: SoLow Watt ECL84 amp
Pretty darn nice!
Looks like a take off on a Univox U45B with a pentode first gain stage and a tone stack!
Looks like a take off on a Univox U45B with a pentode first gain stage and a tone stack!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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dorrisant
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Re: SoLow Watt ECL84 amp
Thanks for posting, Jeff. Very interested in the soundbit... Where is it? Also, was there a 6BM8 version?
Tony
Tony
"Education is what you're left with after you have forgotten what you have learned" - Enzo
Re: SoLow Watt ECL84 amp
The SoLow Watt link and sound bite got deleted. I sold that amp to a guy who is a really great guitar player (much better then I'll ever be) whose band opened up for Derek Truck quite a few yrs ago.
I had a 56T which was a 6BM8 version of Geezer's HoSo56. Pretty similar amp to the SoLow Watt but it had reverb and a VVR instead of the PPIMV.
Very mediocre playing but you can get a gist of what the tone is like with the 56T with this sound bit.
http://www.soundclick.com/player/single ... i&newref=1
With respect, 10thtx
I had a 56T which was a 6BM8 version of Geezer's HoSo56. Pretty similar amp to the SoLow Watt but it had reverb and a VVR instead of the PPIMV.
Very mediocre playing but you can get a gist of what the tone is like with the 56T with this sound bit.
http://www.soundclick.com/player/single ... i&newref=1
With respect, 10thtx