Tube Audio

PP KT88 Triode

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LL1660S/AM/PP 

Lundahl Amorphous Core Transformer Phase Splitter

Now all Lundahl

With surplus Output Transformers

Much tweaking to get the final product.
6V6GT phase splitter driver replaced with 6SN7GT

Lundahl Phase Splitter Transformer w/ Amorphous Core

No power supply electrolytics (only 2 electrolytic cathode bypass caps)

Amphenol MilSpec Power Connectors

Neutrik Speakon & PowerCon

Started with different phase splitter transformers

Bias/VU Meter

Solen 100uf Metal Can films. Dual Mono power supply.

 

Heathkit AA-32- Archeology

 

The Heathkit AA-32

Good ol' Ebay

About 20 years ago I bought a sealed Heathkit AA-23 for about $200 and stuck it in a closet.  I felt an affinity to it because at that time I was working in a building Benton Harbor, MI that some of the Heathkit operations had used.  The last copyright date on the materials I could find was 1969.

Huge respect for people back then that could assemble this as a beginner with limited experience.  Society must have been better and more practical back in the day.

When I opened it everything looked brand new.

I replaced the electrolytic caps with modern equivalents.

The tubes are what you would expect from a 1960's budget kit amp, 6EU7s and the venerable 6GW8/ECL86 combo output tube.

The next pictures show the buid-up of the parts.  I have been building things for quite a while and this thing was a challenge. Part of it was the 34 page step by step instructions with non-intuitive 

"Connect a 4-1/2" wire from lug 1 of terminal strip D (S-3) to lug 1 of terminal strip E (S-2)" 

Looking up pictures of which terminal strip/lugs etc was headache inducing.  Ended up with just using the pictures and the schematic.

I uprated the voltage doubler from the supplied 30uf caps to 200uf caps and UF rectifier diodes.  I also used the Sprague Orange Drop 716p instead of the supplied caps as they looked rather powdery.  I also added a 100uf cap at the end of the chain to keep everything quiet.  The amp has virtually no hum despite the tiny 1" shallow chassis.  Full phono stage and bass/treble controls too.  It sounds like an amp, decent highs and bass for its 8 watt output.  

(One of the 6GW8 tubes did not survive hibernation so waiting on a replacement.)

With potentiometer upgrade.  The original volume control was all over the place channel to channel.