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Old 23rd November 2008, 05:52 PM   #321
Thomo is offline Thomo  United Kingdom
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Tonight, I'm taking the TT downstairs onto my main system where it belongs. Tomorrow I'll properly fit the phono stage into my preamp case and use an off board supply.

I also order a load of those russian Silver Mica caps and also some paper in oil, thanks for the hint Salas. When they arrive I'll do a proper version, 'til then I shall be enjoying my already growing vinyl collection.

Regards, Lee.

edit: Surprising how it sounds with pretty standard parts isn't it Jonners?
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Old 23rd November 2008, 06:31 PM   #322
Salas is offline Salas  Greece
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Quote:
Originally posted by jonners
Here's a photo of my first attempt at putting a 'Salas Pacific' RIAA together. I've mostly just used R's and C's that were available at my local electronics store (Maplin), apart from the Audio Note output caps which I had already.
First impressions are favourable. The sound has more body and presence than before. 'Before' was with opamps: The Hagerman Bugle with LM4562s.
Thanks to Salas and all who have contributed to this interesting thread.
Hi!

I like dead bug ground plane constructions. So purely DIY!
Hagerman Bugle with 4562 is already a very high standard to surpass. We are doing well here I guess. What topology and gain version did you put together and what is your cart, arm, and TT?
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Old 23rd November 2008, 06:57 PM   #323
jonners is offline jonners  United Kingdom
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Hi Salas, thanks for your reply.

The version I'm using is pretty much as your 'September 2008' but with a 33V supply and fixed source resistors of 39 Ohms, which gives Vd around 8V.
TT is Technics SL1210 with DIY PS upgrade, standard arm plus KAB fluid damper, Denon DL110. Haven't measured the gain, but it seems a bit less than I expected.


nicoch46 - Thanks for your tips. I shall certainly explore better parts etc and eventually put it in a box with decent wiring to the phonos.

John
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Old 23rd November 2008, 09:31 PM   #324
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why box? we always upgrade


my mad_k look the same....
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Old 23rd November 2008, 10:00 PM   #325
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found on diyaudio:

REgarding heavily loading MC carts - on this we agree. The 5 cartridge makers I know personally all said to me privately that they use 47k loading at home, in their own systems, but don't want to buck the writers upinions around loading. I strongly advise all our clients that they at least try 47k before killing the cartridge's life with a heavy loading.

Regards, Allen (Vacuum State GmbH)

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Old 24th November 2008, 01:58 AM   #326
Salas is offline Salas  Greece
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Quote:
Originally posted by jonners
TT is Technics SL1210 with DIY PS upgrade, standard arm plus KAB fluid damper, Denon DL110. Haven't measured the gain, but it seems a bit less than I expected. John
I have 2 SL1200 and I used one with the DL160. Very good match with the standard tonearm. For sure you are getting a bit less gain than expected bcs you use a bit less bias current due to 39R instead of 33R target trim value and, less than 36V PSU.
But the gain of my post#110 hand drawn schematic was too much for my 15dB line stage, 28dB amp and 95dB speakers. So I put it down to 40dB. That schematic is good for 0.5mV MC cartridges. Why you need so much gain with the DL110? Passive preamp? Single ended amp with less than 20dB gain? Maybe you drive less than 50k line in and you lose amplitude? You can add a buffer.
You must use a test record with 1khz 5cm/second lateral modulation track, and measure the mV RMS at the phono stage output, then divide by DL110's true 2mV. Log that number and multiply by 20. That will be the gain in dB.
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Old 24th November 2008, 03:21 AM   #327
Salas is offline Salas  Greece
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I went to Michael's place today to measure and listen to his Salas 52dB cascoded version using the Salas shunt PSU at 38V. We could compare with the Steve Bench parallel 12AY7 and ECC88 cascode, which runs off a separately boxed high voltage PSU and Mosfet Maida reg. It has a hardwired Dynavector silver wire step up inside too. Both had shown same frequency response for the Benz Ace Low (Red).

Click the image to open in full size.

The Salas phono output was 225mV for 1kHz 5cm/sec Telarc Omnidisc side 2 # 13 track. The gain looked to me suspiciously 3dB more than expected, but Michael informed me that the Benz Ace Red measures at 0.55mV. +0.15mV over its nominal output. 52dB then. As expected.
The phono alone THD was 0.07%. He did a very good job with modifying his TT motor bearings, and the rumble was -60dB unweighted on the silence test track. The Bench with step up, hit 56dB. We knew to keep it lower when comparing. Both units put out no audible hiss or hum or buzz. The shunt PSU was using small heat sinks and was just warm enough, not hot at all. The smallest one is on the CCS IRFP.

Click the image to open in full size.

Salas + Shunt listening impressions:

I felt like it got 30% bigger stage than before. Bass was resolute and more present and pacey, but had natural decay. Could follow it very naturally. It was a new bass, like with master tapes.
Mids and highs presented such a non electronic tone along with strong image focus, like listening from a mic feed. The resolution was more than before, but it was not a separate thing. The musical interplay got very interesting now, from just very good. I felt happy about that because that was the main area that the Bench phono was standing out in comparison before the shunt addition.

VS Bench:

Curiously there was no comparison to make any more. The tube unit sounded thinner and narrower now. A bit of glare was its aftertaste. But its not the tube unit. Its an excellent unit. Its the new presentation of the Salas RIAA married with the Salas Shunt, that just points out electronic signatures of the other unit.
I have to make a High Voltage Salas Shunt for the tube gear. I feel like I am not comparing them fairly without.
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Old 24th November 2008, 10:29 AM   #328
jonners is offline jonners  United Kingdom
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Quote:
Originally posted by salas


Maybe you drive less than 50k line in and you lose amplitude? You can add a buffer.
.

That probably accounts for it. Gain is still adequate, but nevertheless I may add the buffer at some point.
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Old 25th November 2008, 12:03 PM   #329
jonners is offline jonners  United Kingdom
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I'm wondering about Obbligato caps for the 'Salas RIAA'. Has anyone tried them?
http://www.diyhifisupply.com/?q=cata...d_premium_caps

John
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Old 25th November 2008, 01:38 PM   #330
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Salas
OK I'm ready to give up the tube in the second stage, have you tried the cascode, fet, zener in the second stage? I think I will keep the Pass B1 buffer-I like the current source in the buffer. Still shooting for as much gain as I can get. Did anyone use the cap bypass on the fet in the first stage (w/ the cascode-fet-zener setup)? I've never really liked a cap there, as you can alway hear it-maybe a black gate is the only thing I should use there if I do? Anyone have a few they don't need?
Also if you figure out a HV shunt reg, I would like to add it to my DHT line stage, which should make a big difference. Currently using a Lambda No. 28 tube reg with CLCLCL filter? Maybe I will try a version of the LV one with HV parts...who knows?
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