IT WORKS! Tube Phono Stage

JesseG · 25th July 2007, 05:33 AM

Hi all:

Like the title says, it works!!! My first tube build. It is my interpretation of Thorsten's now-classic 2-tube ultra-simple MM phono stage. And, I did it

- right from laying out and etching the PCB to debugging the final cct.

Here's some photos...

This is the PCB under test

Ahhhh, the satisfaction. It doesn't hum, it doesn't buss or crackle - in fact it is dead silent until I feed it some signal. Then, it makes all of the right noises and so far they sound pretty right.

As always, comments welcome

Jess

JesseG · 25th July 2007, 05:36 AM

More photos

JesseG · 25th July 2007, 05:38 AM

And, with the lid on...

Please excuse the clumsy work on the case top - I had an idea of a different type of tube guard - it didn't work out

Soon it will get polished and look pretty

Jess

arnoldc · 25th July 2007, 06:01 AM

Congratulations! I'm envious because I have never made a phonostage before!

Shoog · 25th July 2007, 08:28 AM

Looks a fantastic job. Good sounding preamp isn't it.
I had issues with the front end oscillating, but that was because I had flying leads to the loads. Plate stoppers solved that and I'm now very happy.

Love the case work - nearly as bad as mine

Shoog

ethermion · 25th July 2007, 11:58 AM

Phono stage with no noise? You are in the club! Well done!

JesseG · 25th July 2007, 04:13 PM

Thank you all for the kind words

Quote:

Phono stage with no noise?

Yeah, I was really amazed. Once I got it running and ready to hear, at first I thought that it wasn't working. I had to turn the volume almost to the max before I heard that faint rushing sound that tubes make. It really is quiet.

Next steps will be adding CCS to the plate supply of the 6DJ8 and a better PS, maybe FET regulated. And, of course, some work on the cabinetry

Jess

antomas · 25th July 2007, 04:35 PM

Hi Jess, great stuff!
Would you mind posting a link to Thorsten's schematics and (eventually) details about the components you have used?
Thanks a lot in the anticipation,
Massimo

JesseG · 25th July 2007, 04:56 PM

The thread where I found Thorsten's phono schematic is here:

dc phono

(it's about 2/3 of the way down the page.)

As for parts - well.....

As said, I laid out and etched the PCB myself (hence the unjustified pride

) I used ExpressPCB software and the toner transfer method. If anyone wants the artwork, I could post it, but I don't think it is anything special.

As may be seen, I cut 7/8" holes for the tube sockets in the PCB material and brought the various traces up to the sockets, with very short wire jumpers to bring the signals and voltages from the PCB to the tube socket pins. (I will try to take a photo of the underside of the board, but that will be next week).

Parts are carefully matched, but probably not the best 'audiophile' choices. Most of the Rs are salvaged from an old Grundig radio. The caps are all new, but parts I have had hanging around for years, except for the 2.2uf output caps (a gift from a buddy-thanks Jerry).

I won't get into the PS now, 'cause I am feeding it with suitable power from another tube device. When I build a dedicated PS for this phono stage, I will post it.

Jess

antomas · 25th July 2007, 08:56 PM

Thanks a lot!
Ciao,
Massimo

25th July 2007, 05:33 AM	#1
JesseG diyAudio Member Join Date: Jul 2005 Location: Mid coast of British Columbia	IT WORKS! Tube Phono Stage Hi all: Like the title says, it works!!! My first tube build. It is my interpretation of Thorsten's now-classic 2-tube ultra-simple MM phono stage. And, I did it - right from laying out and etching the PCB to debugging the final cct. Here's some photos... This is the PCB under test Ahhhh, the satisfaction. It doesn't hum, it doesn't buss or crackle - in fact it is dead silent until I feed it some signal. Then, it makes all of the right noises and so far they sound pretty right. As always, comments welcome Jess

25th July 2007, 11:58 AM	#6
ethermion diyAudio Member Join Date: Apr 2005 Location: ffx station, va	Phono stage with no noise? You are in the club! Well done! __________________ -e

25th July 2007, 04:35 PM	#8
antomas Maître sans marteau diyAudio Member Join Date: Feb 2003 Location: Torino, Italy	Great! Hi Jess, great stuff! Would you mind posting a link to Thorsten's schematics and (eventually) details about the components you have used? Thanks a lot in the anticipation, Massimo

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25th July 2007, 05:36 AM	#2
JesseG diyAudio Member Join Date: Jul 2005 Location: Mid coast of British Columbia	More photos

25th July 2007, 05:38 AM	#3
JesseG diyAudio Member Join Date: Jul 2005 Location: Mid coast of British Columbia	And, with the lid on... Please excuse the clumsy work on the case top - I had an idea of a different type of tube guard - it didn't work out Soon it will get polished and look pretty Jess

25th July 2007, 06:01 AM	#4
arnoldc diyAudio Member Join Date: Apr 2003 Location: Makati	Congratulations! I'm envious because I have never made a phonostage before!

25th July 2007, 08:28 AM	#5
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	Looks a fantastic job. Good sounding preamp isn't it. I had issues with the front end oscillating, but that was because I had flying leads to the loads. Plate stoppers solved that and I'm now very happy. Love the case work - nearly as bad as mine Shoog

25th July 2007, 04:56 PM	#9
JesseG diyAudio Member Join Date: Jul 2005 Location: Mid coast of British Columbia	The thread where I found Thorsten's phono schematic is here: dc phono (it's about 2/3 of the way down the page.) As for parts - well..... As said, I laid out and etched the PCB myself (hence the unjustified pride ) I used ExpressPCB software and the toner transfer method. If anyone wants the artwork, I could post it, but I don't think it is anything special. As may be seen, I cut 7/8" holes for the tube sockets in the PCB material and brought the various traces up to the sockets, with very short wire jumpers to bring the signals and voltages from the PCB to the tube socket pins. (I will try to take a photo of the underside of the board, but that will be next week). Parts are carefully matched, but probably not the best 'audiophile' choices. Most of the Rs are salvaged from an old Grundig radio. The caps are all new, but parts I have had hanging around for years, except for the 2.2uf output caps (a gift from a buddy-thanks Jerry). I won't get into the PS now, 'cause I am feeding it with suitable power from another tube device. When I build a dedicated PS for this phono stage, I will post it. Jess

25th July 2007, 08:56 PM	#10
antomas Maître sans marteau diyAudio Member Join Date: Feb 2003 Location: Torino, Italy	Thanks a lot! Ciao, Massimo

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