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Old 27th January 2009, 02:46 PM   #781
Salas is offline Salas  Greece
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This is an open loop minimal circuit. Has 2 main qualities. A. Transparency. It will not show self color so to smother lesser TTs and carts. You can play the best there is. Non the less it will not exaggerate them faults either. Smooth. B. Revelatory. It will throw in to stark relief all components quality. No feedback to tide them up.
Fortunately it is simple, hence low parts count. You can plan a few better components maybe. Clever minimal high quality upgrade, will be: 4 Riken 47K, 2 K40u-9 CCCP 100nF, 2 Auricap 2.2-3.3uF. You can leave the Auricap for later and bypass with 100nF K40u-9 what you have (?) for output capacitors now. What are you RIAA capacitors? Again Ebay CCCP silver Mica there, will be very cheap and great. Even generic carbon resistors will do better than generic metal film if you have access to such. Lee has Grado too, and he is chuffed, so there must be a way you will tune up too. A picture of your build will help recommendations.

Regards
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Old 27th January 2009, 02:48 PM   #782
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for resistor you need to play a little, on the cheap side prp dale resita and kiwane , my best are tantalium , but there are caddok -vishay nude s102
tray, resistor do not cost so much
but caps are more important , percy audio or in canada Parts connexion

buy the best caps you can ,add a bypass for tweek a little , than use a resistor for adjust to taste

ps
in my system Rload

tamtaliun great mid
riken open up too mach for my taste but very good
kiwane rocks solid bass
the serie R are more important
hope this helps
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Old 27th January 2009, 06:54 PM   #783
Thomo is offline Thomo  United Kingdom
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Hi guys. I just swapped the 100nF cap from a Mundorf Supreme, to a Russian Paper in Oil 47nF and got quite an improvement! Treble is definitely better and mids seem more open. The soundstage also seems more 3d.

I am really surprised by this, as the Supreme's are really great caps.

Salas, the reg I am using is an SPower. These are the best voltage regs I have yet found, but I don't like to mention them as I don't want people to think I am advertising etc.

As always, I am looking for ways to improve what I have, so that is why I was asking about caps and psu. At the moment I have a large toroid - Schottky diodes - 22,000uF 50v Mundorf - SPower reg - and 2 x 220uF Rubycon ZA's on the phono stage. All resistors are Kiwame, nice and smooth.

I shall try and find some time soon to try the Shunt reg, it will be interesting to compare.

I also got a fantastic deal on a shiny new Jelco sa-750 tonearm, which I should receive next week.

Cheers, Lee.
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Old 27th January 2009, 07:01 PM   #784
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SA-750D Retail price 449.00
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Old 27th January 2009, 07:06 PM   #785
Salas is offline Salas  Greece
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Quote:
Originally posted by Thomo
Hi guys. I just swapped the 100nF cap from a Mundorf Supreme, to a Russian Paper in Oil 47nF and got quite an improvement! Treble is definitely better and mids seem more open. The soundstage also seems more 3d.

I am really surprised by this, as the Supreme's are really great caps.

Salas, the reg I am using is an SPower. These are the best voltage regs I have yet found, but I don't like to mention them as I don't want people to think I am advertising etc.
...
I shall try and find some time soon to try the Shunt reg, it will be interesting to compare.

I also got a fantastic deal on a shiny new Jelco sa-750 tonearm, which I should receive next week.

Cheers, Lee.
And the CCCP ones I recommended cost peanuts... Did I ever do any ''theoretical recommendations''?

SPower maybe very good Series OpAmp controlled high feedback regulators? If so, you know the future comparison story... Make the shunt.

I am happy for your progress and results so far. Bravo! Expect more.
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Old 27th January 2009, 07:44 PM   #786
Salas is offline Salas  Greece
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Quote:
Originally posted by ikoflexer
The electrolythic caps I measured for low ESR. The resistors are generic metal oxide.
Get Panasonic FC. You will enjoy them. Normal price, up there with the best.
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Old 28th January 2009, 02:00 AM   #787
iko is online now iko  Canada
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Here we go...

Click the image to open in full size.

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Some parts are different between the first and the current version of the prototype.

By the way, are the power mosfets on the regulator supposed to get really hot? Mine do.

Guys, many thanks for all the advice concerning better parts. I've already ordered some russian pio caps, and some better resistors. We'll see.
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Old 28th January 2009, 02:10 AM   #788
Salas is offline Salas  Greece
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Very practical boards! Don't forget Russian Silver Mica too!
Good work. What are those traces on the scope represent?
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Old 28th January 2009, 03:19 AM   #789
iko is online now iko  Canada
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I'm not good at making pretty boards, so at least I hope they're practical, with lots of room. I think I should have left more room for the interstage caps of various sizes. Well, perhaps in version 1.1

The lower trace on the scope is before the regulator, the upper one after the regulator. Too bad I don't have a movie of it, showing the lower one moving up and down, especially when some device turns on in the house. Nothing crazy, but you did ask for a scope pic. I mean, can we really have a serious thread on diyaudio without some scope traces? Never mind this one doesn't actually carry any information

Are you sure about the silver micas? Some people recommend polystyrene in the RIAA filter. Notably, Thorsten, I think. What's your opinion about this?
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Old 28th January 2009, 07:53 AM   #790
Thomo is offline Thomo  United Kingdom
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I've always found Silver Mica caps to have a smoother top end, maybe not quite as "bright" sounding.

Lee.
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