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-   -   Balanced input all DC coupled RIAA preamp (http://www.diyaudio.com/forums/analogue-source/165603-balanced-input-all-dc-coupled-riaa-preamp.html)

FdW 22nd April 2010 08:57 PM

Balanced input all DC coupled RIAA preamp
 
6 Attachment(s)
After building lots of prototypes, first unbalanced and later with balanced inputs, I settled at the configuration show in this post. The posted configuration was considered the best sounding one that I have build and presented to my listening panel (actually 4 people, all used to listen to life music and owning high end audio systems).

Im sure that posting these schematics is not going to make me famous, and I am aware of the fact that critiques here may make me look a bit silly. But I need to know, what do you diy people here, whose messages I am reading for years on end, think about the thing I concocted .

Let me know what you think of it

Regards,
Frans de Wit

FdW 22nd April 2010 09:05 PM

Balanced input all DC coupled RIAA preamp
 
1 Attachment(s)
There is also a MCHead

Regards,
Frans de Wit.

FdW 22nd April 2010 09:21 PM

Balanced input all DC coupled RIAA preamp
 
4 Attachment(s)
And the PCB's

Regards,
Frans de Wit.

FdW 22nd April 2010 09:28 PM

Balanced input all DC coupled RIAA preamp
 
Finaly, more pictures can be seen at RIAA Preamplifier - a set on Flickr

Regards,
Frans de Wit.

http://farm3.static.flickr.com/2576/...6e85e668_b.jpg

http://farm5.static.flickr.com/4044/...01540271_b.jpg

http://farm3.static.flickr.com/2598/...96c9e584_b.jpg

Joachim Gerhard 22nd April 2010 10:18 PM

Very nicely build ! I like the chambers. The LME49710 is a bit noisy for MC work, so are the 51 Ohm resistors. Topology is fine but i whould use the new LME4990, reduce the 51 Ohm to 10 Ohm and take 1.2kOhm feedback resistors. I really like the simplicity of your design and you did a major efford in the PSU so why waisting SN in the input stage ?
I do not know if that new OPamp is freely awaillable I got mine as free samples.
You could also try the AD797, LT1115, LT1020, OPA211, OPA1611 and there is a new low noise chip from Analog Devices.

Joachim Gerhard 22nd April 2010 10:20 PM

Sorry, not LT1020 but LT1028. What are the black resistors ? Welvyn ?

merlin el mago 22nd April 2010 10:32 PM

Quote:

Originally Posted by Joachim Gerhard (Post 2163044)
Sorry, not LT1020 but LT1028. What are the black resistors ? Welvyn ?

If not are Welvyn will be Holco.....

FdW 23rd April 2010 06:35 AM

Quote:

Originally Posted by Joachim Gerhard (Post 2163044)
Sorry, not LT1020 but LT1028. What are the black resistors ? Welvyn ?

The risistors are 1/4watt IRC metal film types
RC55LF-D-100K-B-B IRC Metal Film Resistors

FdW 23rd April 2010 06:50 AM

Quote:

Originally Posted by Joachim Gerhard (Post 2163038)
Very nicely build ! I like the chambers. The LME49710 is a bit noisy for MC work, so are the 51 Ohm resistors. Topology is fine but i whould use the new LME4990, reduce the 51 Ohm to 10 Ohm and take 1.2kOhm feedback resistors. I really like the simplicity of your design and you did a major efford in the PSU so why waisting SN in the input stage ?
I do not know if that new OPamp is freely awaillable I got mine as free samples.
You could also try the AD797, LT1115, LT1020, OPA211, OPA1611 and there is a new low noise chip from Analog Devices.

When possible I will do a test with the proposed components, as I do not own a MC cartridge and my TD160b with SME3009 is not suitable, I need to arrange to use my friends player (and he lives Paris [I am in Holland]).

There is an audio sample available that was recorded using a Koetsu Rosewood Signature on a SME Series 20/2 record player. (For me it sounds like virtually noise free).
http://www.diyaudio.com/forums/digit...ml#post2015941

Regards,
Frans de Wit.

FdW 23rd April 2010 07:17 AM

Quote:

Originally Posted by Joachim Gerhard (Post 2163038)
The LME49710 is a bit noisy for MC work... i whould use the new LME4990...

Is this the one you are recommending
http://www.national.com/ds/LM/LME49990.pdf


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