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Old 25th November 2008, 03:54 PM   #331
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Right choice

you can find in UE obbligato

tkd pot as well
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Old 25th November 2008, 05:32 PM   #332
Salas is online now Salas  Greece
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Quote:
Originally posted by cygnus x1
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?
Yes, I have fully cascoded it too. Both stages. And yes the RC on the first stage is audible, that is why I did not recommend it to Lee and RCruz. But it is a matter of taste. Michael likes to play there for instance. Only the local shunts don't create buzz problems with all stages cascoded. Central PSU for the cascode bases is difficult to cleanly layout. The BC5550C base lends susceptibility to hum fields due to the strong hfe and bandwidth created. Needs the trafo in another box and careful shielding, cabling. I will try to figure out an HV shunt. It may work with just with HV parts as is. Do that if you feel adventourous, and see. Maybe with MJEs,or TIPs and HV Mosfets? It will be slower off course. HV bipolars dont have strong Hfe, but a Darlington pairing may do. But they will probably oscillate.
See the all cascode in the picture. Tell me the output of your cart, the gain of your line stage, amp, sens of your speakers and the size of your room. I will calculate the proper gain and post a fully cascoded for you.


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Old 25th November 2008, 05:51 PM   #333
Salas is online now Salas  Greece
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Quote:
Originally posted by jonners
I'm wondering about Obbligato caps for the 'Salas RIAA'. Has anyone tried them?
http://www.diyhifisupply.com/?q=cata...d_premium_caps

John
Better capacitors are good to have. But don't forget to add the shunt PSU. Right on the money.
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Old 25th November 2008, 06:47 PM   #334
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Quote:
Originally posted by salas


Better capacitors are good to have. But don't forget to add the shunt PSU. Right on the money.

I'm using a shunt psu with a current source and TL431/mosfet shunt. Do you prefer a zener to the TL431?
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Old 25th November 2008, 06:52 PM   #335
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Haven't compared, but ZenMod had mentioned that a Zener is even better there. I would try it current sourced and bypassed as in my shunt only though. Because it tends to LF pump without its own CCS. Have seen it doing it. Led string are another idea for Vref...
How is your sound by now it burned in a bit? What is your cart and TT and rest of system?
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Old 25th November 2008, 07:10 PM   #336
Salas is online now Salas  Greece
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I am about to put together a maybe enhanced Led ref main feed CCS version tonight for my 40dB low B+ that I use for the Denon DL-160. It may be configured up to 36Vreg (up there the left hand SK still holds), by just changing the Vz and Vin=Vreg+6V. Ireg=(Vleds-Q1Vgs)/R1. Looks well trimmed and fast on transient simulation. Will see if it works OK. Its the glowing ''Simple Kitsch Shunt''.
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Old 25th November 2008, 07:12 PM   #337
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Salas,
System set up. Audioquest MC404I L -.23mV, VPI MKIII (stock AC motor-working on Maxon DC), DIY airbearing arm, Line stage- Type 340, CCs, ParaFeed OPT, PS Lambda No. 28 - Line stage gain- 24db, Amp 6SL7-6BL7-300b ParaFeed SET 7w/ch (gain ? have not measured), spks Fostex FE167-93db, room 12 X 20. I was trying to come up with phono stage with min. 50db gain.
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Old 25th November 2008, 07:21 PM   #338
Salas is online now Salas  Greece
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The SET is the gain black hole most probably. They normally go 12-18dB. Since gain is better to be at the front end, here is what to try. Be careful, more susceptible to buzzes. Use NJFETs around 7.5 Idss because more will pull down VRL too easily, and less will rob gain. Good luck!
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Old 25th November 2008, 08:13 PM   #339
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Salas
Thanks, I'll give it a try. I did have a horn set up that was +98 db, but lost out when we moved and the wife did not like it in a finished basement. The amp had plenty gain for that setup and I had a Blue Point MC HO (got broke in the move).
I will also let you know if I come up with something on the HV shunt.
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Old 26th November 2008, 09:34 PM   #340
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Default Simply Kitsch Shunt Rules OK

Working as predicted. I also see no 100Hz spike on the phono's FFT noise floor. Will do some listening tomorrow.

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