Sjöström Audio DIY forum

General => Vinyl => Topic started by: Marcos on July 02, 2005, 02:06:40 PM

Title: Phono Preamp IC
Post by: Marcos on July 02, 2005, 02:06:40 PM
Hi

What is the best choice for a MM cartridge 4 mV output, 1 or 1,5 Kohms internal resistance? An LT1115, OPA134, OPA637?

Marcos.
Title: Phono Preamp IC
Post by: Sigurd Ruschkowski on July 16, 2005, 07:03:07 PM
Depends on the design.
Do you have a schematics?




Sigurd
Title: Phono Preamp IC
Post by: Marcos on July 19, 2005, 01:43:05 AM
Hi!

The schematics may be
http://www.linear.com/pc/productDetail.donavId=H0,C1,C1154,C1009,C1026,P1293

http://www.hagtech.com/images/bugleschem.gif

http://www.geocities.com/fabiomauriciotimi/cm203.gif

CM203 components in
http://www.geocities.com/fabiomauriciotimi/cm203.htm

http://www.geocities.com/fabiomauriciotimi/cm204.png

CM204 components in
http://www.geocities.com/fabiomauriciotimi/cm204.htm

Marcos.
Title: Phono Preamp IC
Post by: Sigurd Ruschkowski on July 19, 2005, 10:54:36 AM
!Ola! Marcos

The link to LT is not working for me,
but all the other links are OK.

I have bought two PCBs of the Bugle. Great looking PCB!
I have not installed any components yet. I do have most
of the OPamps I will try for the Bugle:
OPA2134
OPA627B (by using Brown Dog's adapater PCB)
Maybe the OPA745 or 743 as input OPamp.
Maybe the 8610?
8065?

I would try the same OPamps for the CM phono amps.

Even as important as the OPamps are the capacitors! Use the best you can afford. Polypropylene or polystyrene.

The Bugle PCB only has one power supply for both channels which I do not like. Use two separate PS if you can.

Sigurd - a high end audio person
Title: Phono Preamp IC
Post by: Marcos on July 19, 2005, 08:44:25 PM
Hi Sigurd!

The LT correct link
http://www.linear.com/pc/productDetail.do?navId=H0,C1,C1154,C1009,C1026,P1293

Do you use one transformer for each channel?

Marcos
Title: Phono Preamp IC
Post by: Sigurd Ruschkowski on July 19, 2005, 09:31:57 PM
Quote from: MarcosHi Sigurd!
Do you use one transformer for each channel?
Marcos

Always. For power amps and for other amps.

My latest line amp prototype power supply uses 200VA transformers for each channel, and each channel even has its own AC line filter.



On the LT schematics I would change the buffer to a 634 buffer instead.


Sigurd