01A tube amp Schematic???

[jmillerdoc]

I am lookinf for a fairly simple SE schematic to build an amplifier with the 01A type tube as the power output tube. Can anyone refer me to one? I would also consider a parallel version for the outputs. I am not too familar with this tube but recently came across 4 of them in good condition. What little I have read about this tube is that it is a pretty decsent little power triode and can produce around 1.5 watts (3 watts I guess in parallel) and is comparable with the 2A3 in sonics, just less power. I have not been able to find much else out there on a circuit for this tube. My next choice is to have someone help me design one possibly.....based on a circuit like the JEL 45/2A3 if possible.

Thanks for your help!
Jeff
Lawton, USA

[Arnulf]

Datasheet suggests under 1W anode dissipation (with max anode voltage), there is no way it will put 1.5W out in SE when operated under normal parameters. 0.15W is more likely.

Due to its low amplification it would take approx. 10+V p-p to drive the grid in its most linear region, ergo preamplification would be needed if you intend to hook it up to line source.

Zload of approximately 30K would be required to make best use of it, which is ungodly high (= unusual and therefore hard to come by when using only stock parts) number, unless you were to run higher Z load (headphones) with it; in this case you could quickly find a suitable OPT.

Are you sure it's the 01A tube you had in mind ? It's not impossible, it's just nowhere near your stated expectations. If you decide to proceed, we can help you cobble something up

[jmillerdoc]

Does that hold true for the variants 201 and 301 types, these are the 201's. I learned these numbers on a post here at diyaudio: vacuum tubes type 10 and UX201A

anyway, the 201A is the tube in question if that makes a difference.

I guess the second question is if this is not that good of a power tube for a low power flea amp than what to do with them??? I am in the process of building some Sachiko horns so it is conceivable I could use a 1/2 watt or so or power but I was hoping for closer to a watt.
Jeff

[jmillerdoc]

Maybe I could use them as drivers in a 45 type tube amp???
Jeff

[andyjevans]

The 01a is not a power tube - no way. It's a brilliant preamp or input tube - one of the very best there is. It's not really a driver tube either, and note it's max Vp of 135v.

What I would do is what I've done with great success - use it as an input tube in an all-DHT amp. Get a par of 31 - cheap enough - and use them as drivers. Great sound and a proper driver tube. Then choose your output tube - 2a3 or whatever. You'll need separate filament supplies for each tube, but that's not difficult, and neither 01a nor 31 consume much. You will get a lot of help from the "26 pre amp" thread which is very recent. It's worth reading the whole thread to become thoroughly familiar with working with DHTs.

One thing to seriously consider with an all-DHT amp - build on two chassis, PSU and signal. All the chokes and magnetic stuff in the PSU. Only DC in the signal chassis (unless you want AC for 2a3s or whatever).

If you try this type of amp, I promise you won't look back. If you don't just love it you ain't human!

andy