SET amp recommendation for Altec A7's

invalidbuffa

invalidbuffa

Super Member
I'm looking to build a SE amp(s) for my Altec A7's (16 ohm) and I'm seeking recommendations on a design that would sound good with them. Something between 6-10 watts would be plenty.

I've never built a tube amp before (I've worked on them) but I'm eager to start.

Thanks
 
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As far as I am concerned, you don't need 6 watts. What drivers in the A7?
SE 2A3 - or 300B if you want to go big - will do you fine; even SE 45 will be beautiful to listen to.

The "Simple 2A3" amp is, well... simple. I am using a slightly modified version thereof, made by AK's Redboy with 604Es to good effect.

http://members.myactv.net/~je2a3/simple45.htm
 
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for starter, i have build only a few amps so for me i try to pick something simple and well documented.
the RH84 is a very nice and simple build
SE KT88 also well documented and have been my best amp so far
 
Check out the DIY Tube get*set*go. It uses a 6B4G, which is a cousin to the 2A3. It can be built from about $500 on up.
 
BadassBob said:
Check out the DIY Tube get*set*go. It uses a 6B4G, which is a cousin to the 2A3. It can be built from about $500 on up.
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+1 on this amp. Ashok built one and I thought it was a great sounding amp. There is a lot of support on their site as well.
 
6B4 is a nice tube (it's basically an octal 2A3 with a 6 volt filament/ DH cathode). Not too easy to find anymore, though, AFAIK, whereas one can buy very decent new production 2A3s at various price points.
 
AKAIK...the only new production 6B4 is made by Sovtek. The get*set*go will also run 2A3s if you add 2.5v filament transformers, its documented on the DIY Tube site. The get*set*go is very similar to the JE Labs Simple 2A3...but was conceived at a time when the 6B4 was significantly cheaper than the 2A3. Fastforward a few years, and now 6B4 prices are neck and neck with the 2A3.
 
SE 6BQ5 should get you 5-6 WPC, and won't hurt you as much in the tube department. I use one to run my whole Altec stack, and it has no problems getting as loud as I want....:thmbsp:
 
The nice think about the G*S*G is it is built on a circuit board which makes it easier for a first time builder. There is a nice Dynaco ST70 kit available that sounds great as well....and will have all the headroom you will ever need.
 
Thanks to this thread and to Google - I now have a hankerin' to build a single-ended (not OTL!) 12B4 amplifier... :-P
http://www.atma-sphere.com/Resources/The_6AS7G.php

Oh, note that the single-ended EL84 implementation mentioned earlier is in pentode mode - SE EL84 in triode mode is more like a watt and a half or so. I have a stereo SE pseudo-triode EL84 amp up in the attic - a Decware "Zen" SE-84B - it's a sweet sounding little amplifier but it doesn't have enough grunt to drive (in my case at the time) a pair of Klipsch Cornwalls (which are at least sometimes quoted as having triple-digit sensitivity) running fullrange, as loud as I wanted (not terribly), on music I really liked ("little girl with guitar"), in my living room (which isn't terribly big). I've never tried it on the 604Es (come to think of it).


That said - the EL84 sounds good either way - but (in an "A/B" test on a switchable amp someone here in MA built and brought to a shindig coupla years back) triode mode was easily distinguished as more "immediate" sounding than pentode mode.
 
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analog addict said:
SE 6BQ5 should get you 5-6 WPC, and won't hurt you as much in the tube department. I use one to run my whole Altec stack, and it has no problems getting as loud as I want....:thmbsp:
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Same with SE 6V6 family. I use SE 6V6s with 16 Ohm drivers, and it gets plenty loud enough for my tastes. :yes: I imagine it would be pretty satisfying to put together one of those others, but something a little more "common" might be a good along the way project. :smoke:
 
+1 on the RH 84 amplifier build.

I built a 'standard' RH84 amplifier (12at7/EL84) and an all-Octal (6sl7/6v6) RH84 amplifier.
BOTH easy builds with less than $300 in parts for each build.
EDCOR transformers are quite good and inexpensive....but....with a wait time of generally 4-5 weeks for delivery.

Steve
 
invalidbuffa said:
I'm looking to build a SE amp(s) for my Altec A7's (16 ohm) and I'm seeking recommendations on a design that would sound good with them. Something between 6-10 watts would be plenty.

I've never built a tube amp before (I've worked on them) but I'm eager to start.

Thanks
Click to expand...

I ran a custom build 2A3 amp with Lundhal transformers with very good results. Lots of solid bass and magical midrange with UX245 tubes in lieu of 2A3s.
 
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