IT WORKS! Tube Phono Stage

[Shoog]

I just had a better chance to listen to the phono amp with the CCS. Theres definately a tightening of the overall presentation, with a cleaner bass sound.
Very simple to implement and well worth a try.

Shoog

 

[fred76]

Hi JesseG,

Nice build. Are those 10nF caps Russian Mica, and the 1nF pair radial polystyrene? Thanks.

 

[JesseG]

from Shoog

Arnold - Any ideas where we might find the revised circuit.

I would very much like to see that too...


from zarniwoop

maybe a $50 project. i'll have to post a schematic

Please do - I am curious about the 'back-to'back' trafos you mention

from Jeb-D

Those are some pretty serious caps your using

Yes, they are They were what was dug from the bin. They seem to work, but I am surre Thorsten would upbraid my use of electrolytics for B+ decoupling


from Shoog

Theres definately a tightening of the overall presentation

I have a variation of the basic KYW design that uses CCS to load the plates on the 2nd stage (6DJ8). Is that where you have installed yours?

from fred76

Are those 10nF caps Russian Mica, and the 1nF pair radial polystyrene?

Exactly! (although I'm not sure that the 10nF mica's are Russian or not). In any case, they are fugitives from my parts bin. I intend to order some 'proper' caps from Solen now that I know the cct works.

Jess

 

[Shoog]

quote:
Theres definately a tightening of the overall presentation

I have a variation of the basic KYW design that uses CCS to load the plates on the 2nd stage (6DJ8). Is that where you have installed yours?

Yes thats where I have mine.
On further listening I have a slight feeling that the bass is a bit more recessed than it was. I don't know how that might have come about because the input impedance of the ECC88 should remain the same I think. Could be because my rail voltage has sagged a bit.

Shoog

 

[kmj]

If anyone wants the artwork, I could post it, but I don't think it is anything special.

You did it yourself so ofcourse it is special. So post it
And since I just upgraded my turntable at least I will be intrested

 

[JesseG]

So post it

OK, here it is...

An externally hosted image should be here but it was not working when we last tested it.

Cheers

Jess

 

[arnoldc]

Arnold,
Any ideas where we might find the revised circuit.

Shoog

Shoog, I found it in my offline files, and it's called Thorsten's Not so simple phono stage.

 

[Shoog]

Thanks Arnold,
I saw that one in my searches. Unfortunately it would require a complete rebuild to implement. I hope I'm getting most of the benefit just by adding the CCS on the ECC88.

Shoog

 

[JesseG]

from arnoldc

Shoog, I found it in my offline files, and it's called Thorsten's Not so simple phono stage.

I did a search throughout the forum and couldn't find it - would you mind posting a link or maybe the schematic?

Jess

 

[mus]

Hi,
How about also a CCS on the first stage too? Would it be made the sound even better?

 

[Shoog]

Hi,
How about also a CCS on the first stage too? Would it be made the sound even better?

It would alter the RIAA curve tracking as the load is part of the network. The Not so simple phono stage addresses these problems.

Shoog

 

[mus]

Thanks, Shoog! Indead it's already a very good sounding phono stage. BTW, I used all Russian PIO caps on the whole phono stage.

 

[jnb]

Of course the output impedance of the stage can be calculated, or measured, or simulated so in changing it you could simply add a resistor at the output of the stage to make up the difference.

 

[fred76]

from fred76

Exactly! (although I'm not sure that the 10nF mica's are Russian or not). In any case, they are fugitives from my parts bin. I intend to order some 'proper' caps from Solen now that I know the cct works.

Jess

Thanks, I think you already have good Eq caps. Try to bypass the decoupling Aerovox lytics with some cheap 1uF/400VDC (or any small value) polyesters and see if the highs smoothen out.

A good CCS at the top of the ECC88 might help the bass part. Another alt are plate chokes but it would cost more and require more space and placement consideration.