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Old 24th April 2010, 06:50 PM   #1221
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Hi Joachim,

Are you talking about the ADA4898-1 opamp?
In that case I have to make it with the LSK389 cause I will only work with + 24 volt and not with +/_ 24 volt in my own RIAA.

But I'll try the new buffer with your RIAA though! I'll keep you posted.

Thanks again.

Regards,

José

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Old 25th April 2010, 02:59 AM   #1222
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I will post what i am using now tomorrow. Then we see if we talk about the same things.
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Old 25th April 2010, 11:34 AM   #1223
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Here is a collection of the JG-Self circuits with all the recent changes i made.
In my version i do not use servos. In the Balanced INA input it is not neccessasy. I measured only 2.5mV at the output with cartridge connected.
I trim DC in the linestage with P2. Alternatively you could substitude P2 with fixed resistors and let the servo do the work or you could trim with P2 and use an aditional servo like in the schematic i show.
Attached Files
File Type: pdf Bal Input for JG Self.TSC - TINA.pdf (48.5 KB, 133 views)
File Type: pdf DSJG MM RIAA.TSC - TINA.pdf (51.0 KB, 121 views)
File Type: pdf JG Self Linestage Mono-Stereo +.TSC - TINA.pdf (61.5 KB, 115 views)
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Old 25th April 2010, 12:26 PM   #1224
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Hi Joachim,

This is nice indeed, being a guy with so much talent it's almost impossible to think that you're not going to use a Self main amp

The one you're using now is probably the Berendsen?
I wonder how this whole set will perform on a set of ESL's

I can't wait for my OPAmp's to come in so I can start building this master piece of yours.

Again thanks for sharing it with us.

I'll do my best to finish mine asap.

Tjuus,

José

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Old 25th April 2010, 01:52 PM   #1225
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That sounds good. Well, the Berendsen is only intermediate but it works suprisingly well on my hign sensitivity MPL. It´s shunt feedback and has a lot of class a so it may not leave class a on my speakers. Actually i am working on several solutions. One is a class A with Fet, one is Jan Diddens Pax and one amp gets build by Brianco. It´s a SUSY balanced design with hingh power Opamps. In the factory is a Camebridge Azur poweramp designed by Self with Class XD so i have no desire to build one myself. It sounds excellent and is not expensive. Of cause i am studying what Self is doing. I am just reading his new book : "Audio Power Amplifier Design Handbook". I like his clear and pragmatic style very much but as you have seen in my redesign of his preamp i prefer DC coupling whenever safely posible and do other component choices. I am more of a high speed, wide bandwidth guy.
i am looking now for a simple amp that needs not more then 10W. I have 96dB / 8 Ohm sensitive speakers in an open baffle so sensitivity in praxis of a pair is around 100dB. when i measure 5V on the speaker, talkig without jelling is imposible and when i measure more then 7V my ears start to hurt.
Maybe i do the Class A Fet.
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File Type: pdf Class A Fet Amp with FB.TSC - TINA.pdf (44.2 KB, 139 views)
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Old 25th April 2010, 07:19 PM   #1226
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Quote:
Originally Posted by Joachim Gerhard View Post
i am looking now for a simple amp that needs not more then 10W. I have 96dB / 8 Ohm sensitive speakers in an open baffle so sensitivity in praxis of a pair is around 100dB. when i measure 5V on the speaker, talkig without jelling is imposible and when i measure more then 7V my ears start to hurt.
Maybe i do the Class A Fet.
Maybe you should try simple chipamp based on LM1875 (like 47 Labs Shigaraki) or TDA2050? Some prefer them over famous LM3875.
You can use simple split supply or even +/- 12V battery supply. These amps sounds excellent with wideband drivers and some says they are even better than Pass constructions. There is a lot of opinions here.

There is another option: experiments with single supply car chips. Look here:
The Altmann BYOB amplifier
My friends tried TDA1554 and mono TDA1516 and like them better than LM3875 with premium parts.

But "de gustibus non est disputandum"

Best regards,
a_men
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Old 25th April 2010, 09:14 PM   #1227
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Thanks for this sugestions but i have tryed chipamps in the past and they did not sound the way i like it. I had a long discussion on the phone with Altmann and he certainly has interesting ideas. Anyway, my search is not over and ideally i whould like to build something where i have more design input then just optimising an application.
Do not take me wrong, gainclones can sound very good but i visited the designer of the 47 Labs many years ago in Japan and it is simply not the adventure i am seaking.
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Old 25th April 2010, 09:43 PM   #1228
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Quote:
Originally Posted by Joachim Gerhard View Post
Thanks for this sugestions but i have tryed chipamps in the past and they did not sound the way i like it. I had a long discussion on the phone with Altmann and he certainly has interesting ideas. Anyway, my search is not over and ideally i whould like to build something where i have more design input then just optimising an application.
Do not take me wrong, gainclones can sound very good but i visited the designer of the 47 Labs many years ago in Japan and it is simply not the adventure i am seaking.
Joachim,

You are speaking my language


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Old 26th April 2010, 08:17 AM   #1229
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Did you both manage to keep the appointment? Any News? (Yes, i'm nosy )

Regards
difool

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Allen Wright of Vacuum State will visit me on sunday. He brings some tube equipment, so this will be interseting to compare with what i have.
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Old 26th April 2010, 12:01 PM   #1230
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I met with Allen and Johanna yesterday and today. Yesterday night we listened to his diferential 300B monoblocks and later we put on his big Preamp. Allen listenes very soft so i will do more listen today.
We also set up his small preamp and the big Monoblocks with KT88 in the factory.
i will listen to this too.
I was very surpised how lightweight the 300B monoblocks are.
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