Ultimate spud amp - any ideas ?

[Shoog]

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.

Shoog

 

[sesquialtera]

Not really a spud, but how about Gary Pimm's David monoblock?

 

[Shoog]

Not really a spud, but how about Gary Pimm's David monoblock?

I know Garys work having cloned the Tabor - but don't know this one. I will give it a search.

Just looked - not spud enough.

i rather like this;

http://4.bp.blogspot.com/-UNVKnfLGT4g/TzP0dfSB_XI/AAAAAAAACKU/HKiLSNXAvEE/s400/6c45-pp.gif

Shoog

 

[Cassiel]

PCL86 is another option, dirt cheap and great sounding.

 

[faithintruth]

Decware Zenkit 1 is the PCB version of the Zen SE84 Amp. I built this. The cost is moderate (Edcor iron) the tube count is 3 and the imaging is astounding! 1.8W stereo into 8ohms; plenty for my fostex horns.

 

[Vinylsavor]

Hi!

For me the 6HS5 is the ideal tube for a spud amp:

VinylSavor: Tube of the Month: The 6HS5

Best regards

Thomas

 

[Stixx]

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

 

[regal]

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.

 

[Shoog]

Hi!

For me the 6HS5 is the ideal tube for a spud amp:

VinylSavor: Tube of the Month: The 6HS5

Best regards

Thomas

I read this in my trawl and it looks amazing. However 1000v is a little offputting.

Shoog

 

[Shoog]

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

Parafeed is out for me unfortunately.
DC compensated SE using PP transformers might be an option.

Shoog

 

[Shoog]

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.

Can't find a datasheet.

Shoog

 

[Vinylsavor]

Hi!

I read this in my trawl and it looks amazing. However 1000v is a little off putting.

Yes that's the draw back of this tube, I actually run it closer to 1300V.
I am planning a no compromise version of a 6HS5 spud amp which someone asked me to build. It will use 2-3 tubes in parallel and A Tango X10S OPT.

Best regards

Thomas

 

[Vinylsavor]

Hi!

Try a single EL55 per channel.

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

Best regards

Thomas

 

[Shoog]

Hi!



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

Best regards

Thomas

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.

Shoog

 

[Vinylsavor]

Hi!

Some info about the E55L can be found on my site:

VinylSavor: Tube of the Month: The E55L

Thomas

 

[Shoog]

Certainly not cheap though. They average about €50.00 each on ebay.

Shoog

 

[Vinylsavor]

Hi!

If you are patient and look around a little, you will find them for a bit less. But you will only need 2 of them and given the quality of that tube, I do not consider it as being expensive.

Best regards

Thomas

 

[Shoog]

Input transformer : E55L(in fixed bias): Output transformer

Simple.

Shoog

 

[rmyauck]

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.

 

[azazello]

6LR8 is very good idea...deep scene and good details....https://picasaweb.google.com/109570777566485968551/Amplifiers#5253639414520847666
https://picasaweb.google.com/109570777566485968551/KVM#5443216817227434082
I bouth from ABC Vacuumtubes for about 5-6 $.