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Old 30th December 2008, 01:29 AM   #561
Salas is offline Salas  Greece
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I use 1k for the Denon DL-160. Try it.
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Old 30th December 2008, 03:08 AM   #562
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Default Shunt reg added...

...and it is a keeper! Comparison with the SUT's is very similar; the SUT base sounds less articulate now. Had to lump together some vintage PIO's to get the 3 uF...

I have been playing with VTA to get to a happy place...

The next step is to improve component quality. I might try putting in a bypass cap on the first stage to get a tad more gain.

Electrolytics- Sanyo oscons good? Or Nichicon Muse? A lot of opinions, I'm sure!

Resistors- I've been using the PRP's. Any other recommendations for r-load, etc?
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Old 30th December 2008, 09:09 AM   #563
Salas is offline Salas  Greece
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You probably mean buffer stage added! How many mA you run through the buffer you finally used?

OK, basic things are set sonically by now, and on the right line.

Which model is your cartridge? If you use a bypass capacitor on first stage its going to be +6dB gain. Black Gate there, red non polar 6.3-10V. Or Elna Silmic. Also the RC filters are lending themselves for good 50V electrolytics and they are audible enough there. BG FK maybe. Shinkoh for cartridge load and drain loads, & 43k.

You are determined for top sonics it seems...
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Old 30th December 2008, 09:40 AM   #564
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HI kstlfido

for drain loads if Dr Salas agrees interesting are percy vishay vhs bulk for lower noise at 3,95$ or the better nude from texas component , if you go for texas call me becouse dont ship to overseas.....I can paypal to you
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Old 30th December 2008, 10:00 AM   #565
Salas is offline Salas  Greece
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Those hi tec resistors are very clean and neutral, excellent components also for noise and ppm, it just depends on where the total system stands by the time they will be tested. If the cartridge and speakers are still rather cold, I would not chose them. If the total mix is already heading to rather warm, I would. Shinkoh for cartridge load and 43k series Riaa resistor I would not change as a favorite though.
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Old 5th January 2009, 12:52 PM   #566
RCruz is offline RCruz  Switzerland
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Hi Salas

While I wait for Lee´s work, I have been experimenting with the load resistor in the 101b MM RIAA.

I replaced the stock 47k for a 1k82 and the sound was too shut in.
Then I tried a 464 ohm, and the bass was very tight but lacking body and the stage was confined in the space between the speakers. In this case I noticed a dramatic reduction in output volume.

Finally I tried 27k and the stage widened a lot, the bass loosened a bit but gained fullness and the high freq seems to have a good balance between speed and detail.

The stock MM RIAA has a 1k ohm resistor in series with the signal input (just before the loading resistor and 120pf cap).

I believe this 1k resistor is responsible by the lack of volume when experimenting with 464ohm load, forming a voltage divider.

Would you please explain why there is such a series resistor there and if I can reduce it or remove it ?

Sorry for the off topic but this knowledge will be used when I build the real thing.

Regards

Ricardo
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Old 5th January 2009, 01:22 PM   #567
Salas is offline Salas  Greece
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It is probably there to protect from possible instability. Many circuits can be disrupted when enough cable inductance is directly fed to them. Especially loop feedback circuits. In our RIAA there is not such a problem. Even a 100R series resistor that I have used to experiment with early, could be heard to clearly compress the dynamics. It is adding to the cartridge source resistance virtually and reduces the cartridge generator's current output. Off course it also makes for an L pad attenuator in your case too. Yes you can experiment in reducing it step by step in your 101b, even bypass it. If there is a real problem with your cables and the circuit without that resistor or some lower one, it is going to sound like it. If you manage to avoid or reduce that resistor successfully, it is possible that you are going to chose a different optimum Rload than 27k too. In my case the Denon is happy with 1-10k, but this is an overall system balance thing non the less.
Rload is one of those variable hands on things between logical limits.
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Old 5th January 2009, 05:57 PM   #568
RCruz is offline RCruz  Switzerland
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Hi Salas

Thanks to your input, I am starting to perfectly understand the several issues related with cart loading.

This 1k on series with the signal might be responsible for the compressed sound stage and lo output with 464 ohms loading.

I will follow your instructions and find the best combination.

Additionally, can I modify the 120pF loading cap value without fear ?

What would be the result by just removing it ?

Ricardo
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Old 5th January 2009, 06:36 PM   #569
Salas is offline Salas  Greece
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That capacitor is there for MM cartridges that need it additionally to the cable capacitance so to form a resonance and maintain enough HF output. It is not interacting with MC and Grado carts due to their far lower self inductance VS MM. Since it is not a textbook quality component, better take it out, it may be adding some small residual quality to the subjective mix. Especially if it is ceramic.
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Old 5th January 2009, 07:06 PM   #570
RCruz is offline RCruz  Switzerland
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Thank you again Salas.

Just removed the 120pf caps... seems to be improving detail and transient ttack.

Now I will experiment 464 ohm instead of 1k in series and keep posting the results.

Ricardo
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