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Old 11th May 2011, 09:14 PM   #221
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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
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Old 11th May 2011, 10:54 PM   #222
Salas is online now Salas  Greece
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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.
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Old 11th May 2011, 11:07 PM   #223
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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....
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Old 11th May 2011, 11:15 PM   #224
Salas is online now Salas  Greece
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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?
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Old 11th May 2011, 11:29 PM   #225
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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
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Old 11th May 2011, 11:31 PM   #226
Salas is online now Salas  Greece
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Put a K72 0.047u 500V Teflon interstage 1st thing. Will give it resolution boost. Output caps are more about bass.
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Old 11th May 2011, 11:34 PM   #227
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by woodturner-fran View Post
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
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).
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Old 12th May 2011, 12:02 AM   #228
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Thanks guys, I think the guy on ebay I bought the other ones from also has both K72 and the FT-3 so I might get a few of each to try. They aren't expensive at least.

Fran
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Old 12th May 2011, 09:32 AM   #229
RCruz is offline RCruz  Switzerland
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Inexpensive but very goog.
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Old 12th May 2011, 09:58 AM   #230
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Quote:
Originally Posted by RCruz View Post
I am now listening to Rel Cap RT tin Foil Polystyrenes for the 15nF
Are 5% tol. have you checked it's real value, 200V or 600V?
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