Great video Salas - where do you get them!? 
I rejigged the heater supplies with bigger heatsinks... they are now OK to go in a semi closed box. The shunt sink is still fairly hot. I was dropping more volts than neccesary so I adjusted that for about 22-24v drop and it seems a little cooler now. I think it will be ok.
I also installed the k40y-9 coupling caps instead of the panasonic pp cheapo ones. Sound is a bit smoother alright - there is a gentle smoothing of sibilants. I think they will stay in there.
I also have 2 more k40y caps for the RIAA instead of the silver micas. They measure a little lower than the micas (15. 7nf) at 15.2-15. 3 nf. So I will try them when I get a chance. Rcruz you liked them so it's a no-brainer to try it. I'd be interested to hear your final thoughts.
Fran
I rejigged the heater supplies with bigger heatsinks... they are now OK to go in a semi closed box. The shunt sink is still fairly hot. I was dropping more volts than neccesary so I adjusted that for about 22-24v drop and it seems a little cooler now. I think it will be ok.
I also installed the k40y-9 coupling caps instead of the panasonic pp cheapo ones. Sound is a bit smoother alright - there is a gentle smoothing of sibilants. I think they will stay in there.
I also have 2 more k40y caps for the RIAA instead of the silver micas. They measure a little lower than the micas (15. 7nf) at 15.2-15. 3 nf. So I will try them when I get a chance. Rcruz you liked them so it's a no-brainer to try it. I'd be interested to hear your final thoughts.
Fran
I remembered the song as we posted itches & scratches and looked it up.
Good you cooled everything down a bit. In Michael's black box build, given its SUT was different than yours, we had do go nearer 15n than 16n both measurably and subjectively so, when I went to his place examining it. And it had PP RIAA caps. PIOS will change tonal shades too beyond adding any (missing?) HF. If you feel the tonality gets better but you miss the Mica for other aspects, you can project other quality caps but you gonna know the value by then. Or all dandy first hit. You gotta experience it. Don't expect a Jimmy Hendrix video this time.
Good you cooled everything down a bit. In Michael's black box build, given its SUT was different than yours, we had do go nearer 15n than 16n both measurably and subjectively so, when I went to his place examining it. And it had PP RIAA caps. PIOS will change tonal shades too beyond adding any (missing?) HF. If you feel the tonality gets better but you miss the Mica for other aspects, you can project other quality caps but you gonna know the value by then. Or all dandy first hit. You gotta experience it. Don't expect a Jimmy Hendrix video this time.
Are you experienced was released this week in 1967.....
Of course the other thing to experiment with is the cart loading. In the ono, the 1k load sounded much better than 800r. So I think it's worth trying a few things there.
Question raw rectified dc comes from the separate psu box. If the cable is unplugged for any readon, the hv caps will hold a charge for a long time. It seems a good idea to fit a bleeder resistor across the cap. What's a suitable value? 100k seems to make sense....
Of course the other thing to experiment with is the cart loading. In the ono, the 1k load sounded much better than 800r. So I think it's worth trying a few things there.
Question
raw rectified dc comes from the separate psu box. If the cable is unplugged for any readon, the hv caps will hold a charge for a long time. It seems a good idea to fit a bleeder resistor across the cap. What's a suitable value? 100k seems to make sense....
I usually put one bleeder there, its safer especially while tweaking still. A DC blast is a nasty thing. 220K 2W. 100K will have 1W on it, gets a bigger one, 3W at least. Don't forget to take some more photos of the innards when you will tweak again. People would like to see the before/after arrangements I am sure.
About Rload for carts, interstage & Riaa capacitors etc. Yes, many interesting voicing options. From the moment you got it silent, its just joy tweaking. Did you listen to many records by now? Seems like having keeper potential?
About Rload for carts, interstage & Riaa capacitors etc. Yes, many interesting voicing options. From the moment you got it silent, its just joy tweaking. Did you listen to many records by now? Seems like having keeper potential?
Thanks - I will see what I have in the parts box!
Getting it silent just allows the sound to come through - means that you can hear clearly the tweaks.
Adding the k40y cap definitely improved the treble - removed a touch of harshness I think. It does still sound slightly dull I think - but between both the RIAA changes and the cart loading, I would be confident that can be overcome. Also there is my output cap. That will also need examination I think.
I've played about maybe 15 records at this point. It definitely is keeper potential. Right now, its about level (and very similar) to the Pass ono. However, it has an extra trick- the soundstage is deeper making vocals in particular stand forward with more realism. The bass is "fuller" with the ono, but with the itch its tighter and the itch in general seems more dynamic.
I think if I can hit on the right tweaks for the cart loading, RIAA caps, and output caps, I will be on a winner.
the high voltage is a pity, I have a good number of russian K73 and MKT caps in high values but only 160V rating.... I hear ebay calling! I have some huge PIO caps that I must dig out as well, but I don't think they would fit in the chassis!
Fran
Getting it silent just allows the sound to come through - means that you can hear clearly the tweaks.
Adding the k40y cap definitely improved the treble - removed a touch of harshness I think. It does still sound slightly dull I think - but between both the RIAA changes and the cart loading, I would be confident that can be overcome. Also there is my output cap. That will also need examination I think.
I've played about maybe 15 records at this point. It definitely is keeper potential. Right now, its about level (and very similar) to the Pass ono. However, it has an extra trick- the soundstage is deeper making vocals in particular stand forward with more realism. The bass is "fuller" with the ono, but with the itch its tighter and the itch in general seems more dynamic.
I think if I can hit on the right tweaks for the cart loading, RIAA caps, and output caps, I will be on a winner.
the high voltage is a pity, I have a good number of russian K73 and MKT caps in high values but only 160V rating.... I hear ebay calling! I have some huge PIO caps that I must dig out as well, but I don't think they would fit in the chassis!
Fran
Hi Fran
Initially I used K40 PIO caps for the riaa and interstage but than I found the wonderfull Russian Teflons Ft-3. For interstage these are so much more transparent and extended.
I am now listening to Rel Cap RT tin Foil Polystyrenes for the 15nF // 330pF SM and this value is much better than 15,72. I miss the extension of the SM but I got a much more "real" mid high freq presentation.
Going from 15.72 to 15.33 produced a BIG improvement in spatiality. And there is no hint of harsness or thin sound.
Now that my "cooking" has stabilized (48hours on) I am really apreciating the styroflex´s nice virtues (No wonder JC likes those so much).
As a matter of fact I asked for 600v and that is what I got.
After 3 days burining, these are finally showing themselves and the highs are now very clear and extended. I also apreciate the female voices that are much more real and somehow more forward than with the micas.
I have been listening to Mahler´s Kindertotenlieder and the voices are really beautifull.
After 3 days burining, these are finally showing themselves and the highs are now very clear and extended. I also apreciate the female voices that are much more real and somehow more forward than with the micas.
I have been listening to Mahler´s Kindertotenlieder and the voices are really beautifull.
Well, I've been working hard at this over the last few days... well, ok, not working hard, but listening hard!
I now have a really really really good phonostage I think!!
The first change was the coupling caps. I did have some k40Y-9 0.1uF 600V (metal can ones) in there, and changed them out for some k42Y-2 0.1uF 1000V (green ones). Well the improvement in spatiality and clarity was pretty large. This was a major step forward.
So I was happy that I was on the right track ...... so now I went back to look again at the silver mica vs k40Y-9 caps in the RIAA. If you remember, the SMs were 15.7nF and the K40Y-9 measured a little lower at 15.3nF (many many thanks to vgeorge for these caps).
Again, a really good improvement, but this time it was more about the highs and lows. It seems there may be a little improvement in the clarity, but thats probably wrapped up in the better highs.
The sound now is very open and clear, great side to side and depth in the soundstage. It still had that really nice treatment of voices - it pulls off this trick where the singer stands forward from the rest of the music. The other thing is that it seems very "fast" and dynamic. By this I mean bass and treble are very tight, stops and starts of notes are very clean.
Other things I did are to add back in the MM inputs - I did the same trick of adding 2 x 0.01uF caps from input ground to chassis ground to keep hum out. The result is zero added noise and I did do a quick test (albeit with my LOMC cart) and it does work, just with lower volume. I don't have a MM so that will have to wait for a while.
I tightened everything up and put the sleeve back on the box, and I have to say, it is looking nice now I think!
I have yet to order the other russian caps etc etc (my paypal is down because some bastard got my CC details, used it fraudently and I had to set up a new CC with paypal.... thats still not through yet). So the main things left to experiment with are the TF-3 coupling caps and something else as the output caps. The tonal balance seems very "right" to my ears, so I feel no impulse to trick about with the cartridge loading.
finally some pics:
http://www.diyaudio.com/forums/attachment.php?attachmentid=222883&stc=1&d=1305409449
You can see the shunt and the 2 heater regs, and then the platform that holsd the valves. At the rear you can see the input transformers.
http://www.diyaudio.com/forums/attachment.php?attachmentid=222884&stc=1&d=1305409449
One more interesting thing. The left hand 6N2 in that pic is the input valve. if I put my fingers around it, I get an increased/decreased hum - doesn't happen with any of the other valves. I put a valve shield over it and get the same effect - if I push the shield down so it contacts the chassis the hum drops away. Its not an issue really - I won't be listening with my hand around the input valve! But if you are building this and have some bases that can take shields, it might be worth using one for this valve.
Anyway - I've easily played 20 albums today since powering up and it seems very stable!! What a nice way to spend most of a day... and beats the Eurovision any day!!
Fran
I now have a really really really good phonostage I think!!
The first change was the coupling caps. I did have some k40Y-9 0.1uF 600V (metal can ones) in there, and changed them out for some k42Y-2 0.1uF 1000V (green ones). Well the improvement in spatiality and clarity was pretty large. This was a major step forward.
So I was happy that I was on the right track ...... so now I went back to look again at the silver mica vs k40Y-9 caps in the RIAA. If you remember, the SMs were 15.7nF and the K40Y-9 measured a little lower at 15.3nF (many many thanks to vgeorge for these caps).
Again, a really good improvement, but this time it was more about the highs and lows. It seems there may be a little improvement in the clarity, but thats probably wrapped up in the better highs.
The sound now is very open and clear, great side to side and depth in the soundstage. It still had that really nice treatment of voices - it pulls off this trick where the singer stands forward from the rest of the music. The other thing is that it seems very "fast" and dynamic. By this I mean bass and treble are very tight, stops and starts of notes are very clean.
Other things I did are to add back in the MM inputs - I did the same trick of adding 2 x 0.01uF caps from input ground to chassis ground to keep hum out. The result is zero added noise and I did do a quick test (albeit with my LOMC cart) and it does work, just with lower volume. I don't have a MM so that will have to wait for a while.
I tightened everything up and put the sleeve back on the box, and I have to say, it is looking nice now I think!
I have yet to order the other russian caps etc etc (my paypal is down because some bastard got my CC details, used it fraudently and I had to set up a new CC with paypal.... thats still not through yet). So the main things left to experiment with are the TF-3 coupling caps and something else as the output caps. The tonal balance seems very "right" to my ears, so I feel no impulse to trick about with the cartridge loading.
finally some pics:
http://www.diyaudio.com/forums/attachment.php?attachmentid=222883&stc=1&d=1305409449
You can see the shunt and the 2 heater regs, and then the platform that holsd the valves. At the rear you can see the input transformers.
http://www.diyaudio.com/forums/attachment.php?attachmentid=222884&stc=1&d=1305409449
One more interesting thing. The left hand 6N2 in that pic is the input valve. if I put my fingers around it, I get an increased/decreased hum - doesn't happen with any of the other valves. I put a valve shield over it and get the same effect - if I push the shield down so it contacts the chassis the hum drops away. Its not an issue really - I won't be listening with my hand around the input valve! But if you are building this and have some bases that can take shields, it might be worth using one for this valve.
Anyway - I've easily played 20 albums today since powering up and it seems very stable!! What a nice way to spend most of a day... and beats the Eurovision any day!!
Fran
Attachments
Very good results. Congratulations. Did you listen to it on your stacked Quads also? A check on them using your Ono as reference for some A/B will be very revealing of where your build stands by now or what way to head it for tweak. The pure impulse response of dipole statics is a ruthless tool.
Did you listen to it on your stacked Quads also? A check on them using your Ono as reference for some A/B will be very revealing of where your build stands by now or what way to head it for tweak. The pure impulse response of dipole statics is a ruthless tool.