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Old 5th October 2005, 05:31 PM   #1011
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Quote:
Originally posted by Russ White
Huge difgference? Wow I hope so, if so I think I will shoot straight to self actuallization in a euphoric climax of pure audio bliss.... I wait a second, I am already there! Haha JK.

I know what you mean.

well it was a eye opener for me a Ryan. try the bigger cap aswell. what you you using now.

what we found with the previous versions were that they did have a good mid. but not to the liking of both if us. we were very used to the digital that had a valve type sound and with that i do not mean woolly and warm ( that is a very bad valve) but without any grain and lots dimension

i am sure the setup with be even better with toroidals instead of the cheap e-core i was using (test bed trafo's) actually this is not my final product it stull have to be build into a nice case

cheers
Rudi
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Old 5th October 2005, 05:40 PM   #1012
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this is what i am using to compare it with

left - Tripath RB-tk2350
middle - mosfet amp 1000va per rail ( crazy I know )
right - JLH 1996 version
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Old 5th October 2005, 05:51 PM   #1013
mikelm is offline mikelm  England
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Hi Rudi

How does it now compare to the JLH ?

Does your JLH have DC feedback ?

mike
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Old 5th October 2005, 05:52 PM   #1014
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currently using 2.2uf KimberCap 200V

Nice amps.

Just a few minutes and I should have a working "Rudi" channel, well as close as I can easily approximate today. Everything is essentially the same as yours but the channel is on its own PCB and its own heatsink and the byapassing is like my monoblocs. Also I am using low ESR caps(some nichicon some panasonic FC) for all the bypassing electrolitics.

The NFB cap I will try both bypassed, and solo.

Cheers!
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Old 5th October 2005, 05:59 PM   #1015
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Quote:
Originally posted by mikelm
Hi Rudi

How does it now compare to the JLH ?

Does your JLH have DC feedback ?

mike
Hi Mike

the JLH is great amp but unfortuneately can't modify them any more.

the new one is Much better than the JLH (hate to say that - seeing that i loved these amps since i was 12) and it was my benchmark for a long time

I do not know of a JLH without DC feedback

cheers
Rudi
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Old 5th October 2005, 06:09 PM   #1016
mikelm is offline mikelm  England
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The originals had a 220uF cap in the feedback path some of the later ones had just resistors. I was wondering which yours had ?

mike
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Old 5th October 2005, 06:26 PM   #1017
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hi Mike

I see what you are getting at. Mine uses a cap but to get same results as just a resistor i used two caps to make a non polar cap and the bypassed it with a 100nf. this way you get the same effect as removing it but without the DC offset problem

cheers
rudi
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Old 5th October 2005, 06:46 PM   #1018
mikelm is offline mikelm  England
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Quote:
Originally posted by rudi
hi Mike

I see what you are getting at. Mine uses a cap but to get same results as just a resistor i used two caps to make a non polar cap and the bypassed it with a 100nf. this way you get the same effect as removing it but without the DC offset problem

cheers
rudi
Mmm.... are you sure about that ?

I will do all of the mods you suggest and compare it to my balanced JLH with DC feedback and report my findings.

mike
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Old 6th October 2005, 08:16 AM   #1019
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Default Class A and LM318

Since the LM318 appears to be a standard op-amp and responds well to the usual op-amp tlc (low noise power supplies and good decoupling), has anyone here tried the Class A bias trick?

Using a 3-5k resistor from output to V- is a simple enough solution, but it may sound even better by gioing the JFET route.

Also, with such poor PSRR (-60dB at 10k), perhaps the Goudreau triplets (search usenet for the name and DAC-1) are worth pursuing as well?

Ryan
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Old 6th October 2005, 08:34 AM   #1020
plovati is offline plovati  Italy
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Default My_Ref PCB blowout

Last high-quality gold plated stereo PCB for Rev.A and Rev.C available. 18 euro plus shipping. Worldwide (more or less) delivery.
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