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CivicProtection 9th April 2010 11:27 PM

Beginner Tube Stereo
Has anybody seen this page?
Five Tube Stereo Amplifier

I'm thinking of building my own tube stereo amplifier.
What are your opinions on this schematic? It looks fairly easy to build for me, but what kind of audio quality should I expect from this "push pull" design?

I'd be using this to drive normal magnet speakers. But I'd like to add a headphone jack. I'm not totally sure if the chassis would be HOT. I think it might be. Also I will be using it with my computer's sound card.

CivicProtection 9th April 2010 11:54 PM

No bass and treble controls?

wakibaki 9th April 2010 11:57 PM



rdf 9th April 2010 11:59 PM

Zero bias input tube with plate-plate feedback? It's an odd one.

bill_a 9th April 2010 11:59 PM

I think there are a few caveats first.

Yes, it's fairly easy, but...

One, It's not push-pull - it's single-ended.
Two, the chassis is only hot if you make it hot. The schematic doesn't show that.
Three, audio quality will be very dependent on the bias point, the OT load and the parts you choose.
Four, it's not meant for headphones, unless you have 4 or 8 ohm 'phones.

Maybe you might consider a bit more research/learning before you dive in....

Arnulf 10th April 2010 12:11 AM

Iron will be expensive considering the power output (it is Single-Ended, not Push-Pull design).

Replace input tube with 1x ECC83/12AX7 for both channels, use any of the bazillion ECC83 gain stage schematics floating around.

If you're fond of plate-to-plate feedback, have a look at RH84 schematic. It is just as simple as this one, but tested by quite some members of this forum so they might be able to give you some tips (plus the author is/was a member here as well).

A very simple schematic otherwise, only volume control. Some people might like that - are you one of them ?

Eli Duttman 10th April 2010 12:15 AM

1 Attachment(s)

Originally Posted by CivicProtection (
No bass and treble controls?

Omitting tone controls is par for the course, these days. FEW recordings benefit from tone controls. Unless they can be totally switched out of the signal path, tone controls garble good recordings. A decent circuit for tone controls is not simple. Please refer to the uploaded schematic designed by Max Robinson, which requires 2X 12AX7s for a single channel. :(

Eli Duttman 10th April 2010 12:23 AM


Originally Posted by rdf (
Zero bias input tube with plate-plate feedback? It's an odd one.

Grid leak bias for the voltage amplifier might be viable, but NOT with a 500 KOhm volume control whose wiper is connected to the grid.

When you read the write up closely, you see that the circuit was "ripped", at least in part, from an AM radio. IMO, another design should be chosen.

Bob, W7ETA 10th April 2010 12:33 AM

Price out the xformers when you look at designs, and then compare that cost to the cost of buying a 60 era integrated that you can rebuild. You get the power xformer, output xformers chosen for the output tubes, a chassis, face plate, and a wire layout that should minimise hum. Plus, generally the feed back circuit has been is in place.

After you rebuild it, you can then decide if you want to build from a schematic, source the xformer, chassis and parts.

Best from Tucson

ScoopLV 10th April 2010 01:48 AM

How about this one?
How about this one? Untitled

This seems to be within my skill set.

If this amp is a no-go, could you point me in the direction of something better?

If this amp is a go, would you recommend the pre-amp (or tone control) add-on that is available?


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