How convert Creek OBH-8 to MC cartridges?

Ludwik · 12th September 2009, 06:21 PM

As above: is there any possibility to adapt OBH-8 circuit to MC cartridges? Any comments is welcome.

Ludwik

h_a · 17th September 2009, 11:21 AM

I assume this phono amp is MM only?

If so, there's no real way to 'convert' it to MC, as these MC-buggers need much more voltage gain (with the exception of high-output MCs, but in that case a MM-stage is already perfectly suited).

Of course you could use an input transformer.

Have fun, Hannes

Ludwik · 17th September 2009, 07:30 PM

Here is OBH-8 circuit diagram. Any comments?

es44 · 14th November 2009, 10:28 PM

Quote:

Originally Posted by Ludwik

Here is OBH-8 circuit diagram. Any comments?

Yes... Can You upload in a better resolution

I'm about to get one myself, and would like to see if there are any chance of improving it.

Best regards
Ebbe

Ludwik · 15th November 2009, 09:05 PM

OK, I try.

tiefbassuebertr · 09:32 PM

Quote:

Originally Posted by Ludwik

OK, I try.

Exactly this topology also used by the Cambridge Audio phono modul for the integrated amp "Atac 3" and the "A3i". It sounds very fine. Because this modul uses a SRPP, you must add for moving coil cartridges with low output (200-400uV) a MC head line amp (gain approx. 10 times). I recommend a used JC-1 from Mark Levinson,
http://www.zenn.com.sg/ML_JC1.JPG
for MC cartridges >500uV output voltage (medium- and high output) gain factor of your OBH-1 must be enough. Perhaps a lower value of input termination resistor you must choice (mostly arround 1-2 kohms).
From the low cost MM RIAA preamplifiers this is one of the best sounded, that I know.

jah_zoldat · 17th November 2009, 12:35 PM

There is another edition of OBH-8 - special edition with jfet.
http://obh-8se.narod.ru/obh8SE_S.jpg

jah_zoldat · 19th November 2009, 11:09 AM

As Alex Nikitin said, it is possible to raise voltage up to 40V and changing R13 to 1Watt. It will double the output voltage and gives ~70dB gain.

tiefbassuebertr · 20th November 2009, 07:31 PM

Quote:

Originally Posted by jah_zoldat

There is another edition of OBH-8 - special edition with jfet.
http://obh-8se.narod.ru/obh8SE_S.jpg

The developer of this RIAA head amp from Creek with interesting descriptions is to find there:
Cambridge Audio A3i repairs and mods

12th September 2009, 06:21 PM	#1
Ludwik diyAudio Member Join Date: Feb 2004 Location: Warsaw, Poland	How convert Creek OBH-8 to MC cartridges? As above: is there any possibility to adapt OBH-8 circuit to MC cartridges? Any comments is welcome. Ludwik

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17th September 2009, 11:21 AM	#2
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	I assume this phono amp is MM only? If so, there's no real way to 'convert' it to MC, as these MC-buggers need much more voltage gain (with the exception of high-output MCs, but in that case a MM-stage is already perfectly suited). Of course you could use an input transformer. Have fun, Hannes

17th November 2009, 12:35 PM	#7
jah_zoldat diyAudio Member Join Date: Apr 2009	There is another edition of OBH-8 - special edition with jfet. http://obh-8se.narod.ru/obh8SE_S.jpg

19th November 2009, 11:09 AM	#8
jah_zoldat diyAudio Member Join Date: Apr 2009	As Alex Nikitin said, it is possible to raise voltage up to 40V and changing R13 to 1Watt. It will double the output voltage and gives ~70dB gain.

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