RE: Heath monoblocks complete, sounding very good (picture)

Peter
That amp is a fantastic williamson design.It has a bandwidth from 5hz to 160khz and at 25 watts its only .3% distortion.The 12au7s are run pretty hard and thats why I opted for the 6cg7 with a filament rewire..You won't increase gain but you do lower distortion by a lot being tube isn't saturated.
Now,if you want to increase gain without using a gain type presmp you have a couple options.One is to change V1 to a 12at7..You have to change plate load resistors as well as cathode resistors.The other option is to open the feedback loop more by changing the 4.7k to a 10k.You can also change the cathode resistor at V1 which is a 470 ohm to s 680 in series with a 100 ohm to ground.Insert the FB wire coming from the 16 ohm tap between the 680 and the 100 ohm.
I personally would use a gain preamp but I have done these things also.
Lastly,take out those 1uf polys from the 12au7s to the kt66s..The original black pyramid wax paper caps in there were gorgeous sounding.Get some .47 k40s and run two in parallel to each tube,or get some Jupiters because those little metallized caps will not give you the rich and layered original sound the amp was designed for.Those are gorgeous amps that you got for a steal so treat them to good stuff..You will hear a difference in the couplers.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

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Follow Ups Full Thread

Topic - Heath monoblocks complete, sounding very good (picture) - PeterI 13:02:22 06/27/12 (20)

RE: Heath monoblocks complete, sounding very good (picture) - Neff 05:01:03 06/28/12 (0)

RE: Heath monoblocks complete, sounding very good (picture) - Mossback 04:26:51 06/28/12 (9)

RE: Heath monoblocks complete, sounding very good (picture) - PeterI 17:38:09 06/28/12 (8)

RE: Heath monoblocks complete, sounding very good (picture) - Michael Samra 23:00:14 06/29/12 (6)

bypass film caps - PeterI 07:56:35 06/30/12 (5)

I think there are better caps than the Solens . . - John PA 17:09:03 06/30/12 (4)

RE: I think there are better caps than the Solens . . - Michael Samra 23:00:15 06/30/12 (1)

To me, everything is in the audio path but. . - John PA 12:23:58 07/01/12 (0)

Thank you; are there affordable alternatives in those sizes? and 600V? NT - PeterI 17:15:57 06/30/12 (1)

In the physical size, not so much. If you bypass them . . - John PA 21:08:51 06/30/12 (0)

RE: Heath monoblocks complete, sounding very good (picture) - Mossback 08:42:03 06/29/12 (0)

RE: Heath monoblocks complete, sounding very good (picture) - Michael Samra 22:25:10 06/27/12 (6)

Thanks for suggestions ... - PeterI 06:39:09 06/28/12 (5)

RE: HI-Q 5814 - Neff 12:05:16 06/28/12 (4)

Yes, will look for better... - PeterI 17:08:48 06/28/12 (1)

RE: Yes, will look for better... - Michael Samra 23:41:19 06/28/12 (0)

RE: HI-Q 5814 - coolhand 15:38:01 06/28/12 (1)

RE: HI-Q 5814 - Neff 16:25:07 06/28/12 (0)

Chassis pic - PeterI 16:43:42 06/27/12 (1)

Maybe something with the same current delivery but . . - John PA 21:40:20 06/27/12 (0)

Follow Ups

RE: Heath monoblocks complete, sounding very good (picture) - Michael Samra 22:25:10 06/27/12 (6)

Thanks for suggestions ... - PeterI 06:39:09 06/28/12 (5)

RE: HI-Q 5814 - Neff 12:05:16 06/28/12 (4)

Yes, will look for better... - PeterI 17:08:48 06/28/12 (1)

RE: Yes, will look for better... - Michael Samra 23:41:19 06/28/12 (0)

RE: HI-Q 5814 - coolhand 15:38:01 06/28/12 (1)

RE: HI-Q 5814 - Neff 16:25:07 06/28/12 (0)

RE: Heath monoblocks complete, sounding very good (picture)

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