Cyrus 2 Phono stage

lfournier74 · 10th January 2008, 05:12 PM

Hi all,
I own a Cyrus One v07 since more than 10 years, I could not sell it when I bought my Micromega Tempo 2 since it is of such good quality. Now I am looking for the schema of the Cyrus 2 phono stage which is said to be better than the one's. In the meanwhile, I also bought a Cyrus Tuner v06.
Even if I designed a simple phono stage for the Tempo (based on the famous LT1028), does everyone have the schema of the Cyrus 2 phono stage ? I Had a look through all the posts concerning Cyrus amps - I got so many from you all, thanks ! - but I could not find what I am looking for.
Of course I have some knowledge in electronics, and I have seen that the improvement sould be done relatively easily.
Many thanks by advance... and apologies for my bad frenchy english !
Laurent

Geoff · 10th January 2008, 05:21 PM

Hi Laurant

I reverse engineered the Cyrus 2 phono stage some years ago. Email me and I will tidy up my rough sketch and send it to you.

Geoff

lfournier74 · 10th January 2008, 08:33 PM

Dear Geoff,
I remember having read very much from you in the forums.
Unfortunately I am new to diyaudio and I am not allowed to email you because I am under moderation.
Perhaps we can find an arrangement with a moderator.
Again, I thank you for your help.
Cheers from Annecy !
Laurent

Geoff · 10th January 2008, 11:30 PM

Laurent

Go via my website. There is an email address on the home page.

Geoff

lfournier74 · 11th January 2008, 01:27 PM

Hi Geoff,
Thank you ! I could not resist having a short look on your schematic.
Roughly, I would answer that C5 is "only" (what is hidden by "only" ?) a linking to the RIAA correction which follows because of the similarity between MC and MM input stages. Then if C17 and C5 have the same look then I would try C5 = C17 = 1u... I think that R15 and R29 seem only to be an input adaptation for the following RIAA corrector.
Besides this, I wonder if replacing the wired switch with a simple (gold plated) pin connector + jumper would be better, since we do not change the phono cartridge so often.
I expect having soon some time to mount and test this implementation. I'll give results as soon as I test this.
Cheers,
Laurent

Geoff · 11th January 2008, 02:24 PM

Quote:

Originally posted by lfournier74
Besides this, I wonder if replacing the wired switch with a simple (gold plated) pin connector + jumper would be better, since we do not change the phono cartridge so often.

The slide switch used on the Cyrus1/2 is not exactly high quality so anything is likely to be better. When I still used vinyl, I removed the switch completely and just had wire jumpers on the pcb but there again I only had one cartridge and so didn't have the need to switch from MM to MC.

lfournier74 · 31st August 2009, 03:08 PM

Well... some time has gone but now I equipped my Cyrus One with the components so that is has now a true Cyrus 2 phono stage... and it seems to work really fine !
Besides this, the summer holidays gave me enough time to desing a PCB for my Micromega Tempo2, based on this nice preamp. I woud like to thank Geoff once again for his helpful schema (but there is a small mistake in this schema which makes the MC part not work as expected).
I also replaced the slide switch with small wires and good contacts. For sure this is a cheap enhancement.

10th January 2008, 05:12 PM	#1
lfournier74 diyAudio Member Join Date: Dec 2007	Cyrus 2 Phono stage Hi all, I own a Cyrus One v07 since more than 10 years, I could not sell it when I bought my Micromega Tempo 2 since it is of such good quality. Now I am looking for the schema of the Cyrus 2 phono stage which is said to be better than the one's. In the meanwhile, I also bought a Cyrus Tuner v06. Even if I designed a simple phono stage for the Tempo (based on the famous LT1028), does everyone have the schema of the Cyrus 2 phono stage ? I Had a look through all the posts concerning Cyrus amps - I got so many from you all, thanks ! - but I could not find what I am looking for. Of course I have some knowledge in electronics, and I have seen that the improvement sould be done relatively easily. Many thanks by advance... and apologies for my bad frenchy english ! Laurent

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10th January 2008, 05:21 PM	#2
Geoff diyAudio Member Join Date: Apr 2001 Location: UK	Hi Laurant I reverse engineered the Cyrus 2 phono stage some years ago. Email me and I will tidy up my rough sketch and send it to you. Geoff

10th January 2008, 08:33 PM	#3
lfournier74 diyAudio Member Join Date: Dec 2007	Dear Geoff, I remember having read very much from you in the forums. Unfortunately I am new to diyaudio and I am not allowed to email you because I am under moderation. Perhaps we can find an arrangement with a moderator. Again, I thank you for your help. Cheers from Annecy ! Laurent

10th January 2008, 11:30 PM	#4
Geoff diyAudio Member Join Date: Apr 2001 Location: UK	Laurent Go via my website. There is an email address on the home page. Geoff

11th January 2008, 01:27 PM	#5
lfournier74 diyAudio Member Join Date: Dec 2007	Hi Geoff, Thank you ! I could not resist having a short look on your schematic. Roughly, I would answer that C5 is "only" (what is hidden by "only" ?) a linking to the RIAA correction which follows because of the similarity between MC and MM input stages. Then if C17 and C5 have the same look then I would try C5 = C17 = 1u... I think that R15 and R29 seem only to be an input adaptation for the following RIAA corrector. Besides this, I wonder if replacing the wired switch with a simple (gold plated) pin connector + jumper would be better, since we do not change the phono cartridge so often. I expect having soon some time to mount and test this implementation. I'll give results as soon as I test this. Cheers, Laurent

31st August 2009, 03:08 PM	#7
lfournier74 diyAudio Member Join Date: Dec 2007	Well... some time has gone but now I equipped my Cyrus One with the components so that is has now a true Cyrus 2 phono stage... and it seems to work really fine ! Besides this, the summer holidays gave me enough time to desing a PCB for my Micromega Tempo2, based on this nice preamp. I woud like to thank Geoff once again for his helpful schema (but there is a small mistake in this schema which makes the MC part not work as expected). I also replaced the slide switch with small wires and good contacts. For sure this is a cheap enhancement.

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