Valve Itch phono

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diyAudio Chief Moderator
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6N2P-ER

A rarer equivalent to EV possibly meaning radiation proof.
I listened to a year 1971 matched pair with equally wide triple mica supports in a friend's Valve Itch and it was even cleaner than the EV. Possibly due to better vacuum of this version. But it could simply be they used to make all versions better in the early 70s at the Voskhod factory, I don't know. Maybe worth your while so I thought to mention about it.
 
Firstly many thanks to Salas. My phono itch is 10 years old and let me know it with a pop and smoke signals after lots of use. Now up for a bit of a rebuild. It did seem to have an occasional crackle from the HV shunt and even sparked towards its demise (which was a bit of a warning). Seemed to be around the three LEDs possibly to R1 (56ohm). I possibly have the shunt too compacted on a board or not sufficiently insulated?



Any thoughts before I rebuild?



many thanks for years of enjoyment.
 
diyAudio Chief Moderator
Joined 2002
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Firstly many thanks to Salas. My phono itch is 10 years old and let me know it with a pop and smoke signals after lots of use. Now up for a bit of a rebuild. It did seem to have an occasional crackle from the HV shunt and even sparked towards its demise (which was a bit of a warning). Seemed to be around the three LEDs possibly to R1 (56ohm). I possibly have the shunt too compacted on a board or not sufficiently insulated?

Any thoughts before I rebuild?

many thanks for years of enjoyment.

You are welcome. From what I see in post #757 it was an SSHV1 shunt PSU made on protoboard, right? (SSHV1)

Since it served for thousands of hours into many years it can't be you did something too wrong originally, could be simply needing lower working temperature for even better long term reliability as you said.

Maybe the C1 Leds bypass capacitor failed or a semiconductor or an insulation mica. Identify all failed components so to specifically pay more attention on their mounting and their working conditions in the rebuild.
Could be anything. Even a trimmer or a main reservoir capacitor. Use higher voltage rating 105C caps.
Inspect the board itself for signs of alteration also. If moisture and dust slowly crept in, cooked, and the board's insulation properties got eventually compromised. There are more matrix board types on offer these days. Like in green FR4.

Given the opportunity you could also modify the main circuit to Rev 1.2
 
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Its not my favorite dcg3 companion in absolute terms but rather the go to dual mono psu solution. I recommend it since I developed them together for maximum practicality and good tonal synergy without losing too much quality vs deploying dual mono shunts.

Yes I had thought about it, both for the Valve Itch and the 6V6 line preamp.
 
You are welcome. From what I see in post #757 it was an SSHV1 shunt PSU made on protoboard, right? (SSHV1)

Since it served for thousands of hours into many years it can't be you did something too wrong originally, could be simply needing lower working temperature for even better long term reliability as you said.

Maybe the C1 Leds bypass capacitor failed or a semiconductor or an insulation mica. Identify all failed components so to specifically pay more attention on their mounting and their working conditions in the rebuild.
Could be anything. Even a trimmer or a main reservoir capacitor. Use higher voltage rating 105C caps.
Inspect the board itself for signs of alteration also. If moisture and dust slowly crept in, cooked, and the board's insulation properties got eventually compromised. There are more matrix board types on offer these days. Like in green FR4.

Given the opportunity you could also modify the main circuit to Rev 1.2


Δάσκαλοι όπως εσείς δεν είναι εύκολο να βρεθούν.


which I think says teachers like you are not easy to find!


Working through your suggestions thanks.
 
I should say a BIG THANKS to Salas for the perfect phono design, although had been asking a lot here with got perfect support while never express my appreciation.

Recently on the journey of LCR phono, tried shishido (wth voskhod 6n23p) and silk circuit (with voskhod 6n2p-ev and GE 5 stars 6072a), Valve Itch is still the best of all (voskhod 6n2p-ev and melz 6n8s).

So I went back to the VIP circuit and added a source follower as mentioned in link below, it drives LCR very well.

Cheers!

Hello,
I've read some posts about 600 ohm LCR implementation in this circut.
As wrote It's anoter circuit but what do you think about this:
http://emisukeaudio.sakura.ne.jp/EM-TUBE_EQ3_Ver2_KAI.pdf
Can be used a similar solution in the valve-itch-phono
Redards
Guglielmo
 
Instead of building a transistor based (Simplisitc Folded)phono I, now, decided it's best to try something different. A tube phono :)
I came across two possible designs: "Valve Itch" and "Mini-Me phono"
Mini-Me phono preamp
The is based around 6N16 miniature tubes.

How do I choose between these two designs and what do you look for? Tube type? Is 6N16 miniature tube good or better in phono application?
 
Instead of building a transistor based (Simplisitc Folded)phono I, now, decided it's best to try something different. A tube phono :)
I came across two possible designs: "Valve Itch" and "Mini-Me phono"
Mini-Me phono preamp
The is based around 6N16 miniature tubes.

How do I choose between these two designs and what do you look for? Tube type? Is 6N16 miniature tube good or better in phono application?

difficult to answer, one has to have built both and have listening experience to compare. And then again this will be subjective and also dependent on the other components of the system.

Of the two I have only experience with the Mini-Me and is one of the three phono preamps I have now and exchange in my system from time to time. A very nice preamp, measures and sounds really good. RIAA accuracy is excellent and has low distortion, essentially 2nd order only.

The author, Koifarm, offers a very nice pcb that also include the ps components which makes assembly a snap. He has also published the gerber files in case you wish to order by yourself.

One caveat only, for MM use it is really excellent as it is. However for an MC stage he proposes an additional stage with 6N16. I have tried it but it is very microphonic, you can hear the acoustic feedback howl if you turn up the volume high enough :) To be fair this not not a problem of the specific circuit, it is next to impossible to built a tube based pre-pre stage that will be quite enough and free of microphonics. In my case as I use MC cartridges I built a simple battery powered JFET mc front end that works great. The alternative would be to use a step up xformer. Of course if you are using a MM you may disregard all the above.

On the other hand Valve Itch is receiving so many enthusiastic comments that makes me think it could be even better :) So my proposal is, by using a common power supply to built both (the beauty of diy ;)) and then decide which one to built in a proper chassis. After all, the power supply and chassis is by far the most costly part of the amplifiers