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Ultimate spud amp - any ideas ?

Hi all,
I have built some nice fairly specialist amps over the last few years and I have some designs which I am really happy with and will be keeping. However they are in the 6-20W range and I recently concluded that my main speakers are only using a tiny amount of that power. I am thinking I could probably get by with between 1-3W and be more than happy.

So I am searching for a really special design for a nice Spud amp.
I have worked with the ECL82 before and have found it to be a really nice sounding tube - so its an option.
Of all the designs out there the Mighty Midget by Peter Millet strikes me as in best conformity with my design philosophy. However all my amps are now direct coupled and I would like to keep to that practice. However compactrons are a bit of a drag since they have to come from America.
I have seen a few single stage PP designs which i like the concept of, but they are not really spuds since they don't use dual triodes or pentodes.
Single stage designs are appealing.
Maybe an experiment in DHT ?

If I do this - Iwould like it to have the potential to better the amps I already have so this is something of a no holds barred though experiment.

Any ideas.

A few mor 6C45 P schematics that I gathered over the years...


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Spud amplifiers are as close to wire with a gain as you can get. They have a very special character.

Try a single EL55 per channel.

Use a SSHV2 per channel, bias it with Leds, Use a 2.5k:8 OPT the output impedance of the SSHV is so low that the power supply is out of the signal path Gives a very pure 2watts of power.

That is an excellent suggestion! Some time I will also try the E55L in a spud implementation!

Best regards


Thanks - that got me there.
Interesting indeed. Power drive looks in order considering th 1k input resistance. This would allow some form of plate to grid feedback which would significantly raise performance at almost no cost.

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Nice and simple with no caps in the signal path , but you need a high gain line stage.

Tube CAD Journal: Tube balanced phono stage, July 1999

See page 2 for more stages added.

With those low cost tubes also in production hopefully it may work for you, but is it really a spud? Maybe not as you need the high gain linestage. I like the low parts count and no coupling caps anyway.

Modular for more power also!

Also no parafeed trans. needed.
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