Hi, I'm trying to sort the history of this tube in commercially-built amps. It's an interesting tube but for the life of me I don't recall any product that actually used them. Do you remember any? Also, are there any current products using it? Thanks...
The 6AS7 always seemed like a solution in search of a problem. The datasheet mentions television use but did it ever show up in any tv? Pretty sure there were claims for audio use too but beyond a published schematic it always seemed to show up in power supplies.
It was originally designed for a pass device for regulation in power supplies, hence the low 280R (IIRC) plate resistance.
It just so happens that alot of OTL headphone tube amps also use it as it's cheap and 'reliable' although it has some quirks. Other high current tubes took over from it for other OTLs.
The Bankok Clone by TS Audio. Several years ago I got a msg from a guy in Europe who had bought one of these.
Its a poor copy of my PP Boosted 6080 Amp. The builder went cheap & the amp almost caused a fire.
The 6080/6AS7 cathode resisters dissipate a lot of heat & need to be properly ventilated/heatsinked.
Some how the owner tracked me down having read the article in AudioXpress. And sent photos & contact info.
So I suppose that qualifies as production. Still in business, don't know. 🙂
Its a poor copy of my PP Boosted 6080 Amp. The builder went cheap & the amp almost caused a fire.
The 6080/6AS7 cathode resisters dissipate a lot of heat & need to be properly ventilated/heatsinked.
Some how the owner tracked me down having read the article in AudioXpress. And sent photos & contact info.
So I suppose that qualifies as production. Still in business, don't know. 🙂
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I owned an Audio Mirror set of Monoblocks that used a pair of 6as7 per side in parallel SE. Sounded amazing. Nowadays he only makes amps with the 6c33cb and I'm sure they are excellent as well.
Not so much commercial audio but speech amplifier for radio - nonetheless, you might find RCA Ham Tips, Volume VII No.4, October-December 1947, of interest as it includes good information and commentary on using the 6AS7 to reproduce music:
https://www.google.com/url?sa=t&rct...47-10-12.pdf&usg=AOvVaw3mmqM5CXcKmWK_y1qNw8LU
The design notes in the article are well worth a read and it concludes with RCA's recommended operating conditions for push-pull operation. 😊
Maybe OT since a diy design. Blog Mentions some of the alternative similar tubes and variability in some of them. In my own I have tried the 6080 and 6n13s. I hope to get some 6as7 and alternatives but now on the pricey side here. https://www.cascadetubes.com/the-6as7-purpleheart-set/. For 2.5 clean watts, sounds great.
