Hi!
Would appreciate if someone can advise me.
I built a Pearl phonostage sometime back and was happy with the performance. I recently went for a passive pre-amp, and found that the Pearl does not have enough gain to drive the passive pre amp.
I have a pair of 35V 5amp toroidal transformers lying around, can I use it to power the Pearl over the recomended 30V trannies. Will 35V be too high input power for the Pearl?
Also would a higher voltage result in higher gain for the Pearl?
Thanks for looking and look forward to your guidance.
Would appreciate if someone can advise me.
I built a Pearl phonostage sometime back and was happy with the performance. I recently went for a passive pre-amp, and found that the Pearl does not have enough gain to drive the passive pre amp.
I have a pair of 35V 5amp toroidal transformers lying around, can I use it to power the Pearl over the recomended 30V trannies. Will 35V be too high input power for the Pearl?
Also would a higher voltage result in higher gain for the Pearl?
Thanks for looking and look forward to your guidance.
henkel said:
The voltage regulation would just run hotter. If you want the gain section to run at a higher voltage, you'll have to recalculate the regulation. But I think Wayne would have already included that in his design, if it is so simple.
I'm quite sure what you need is another gain stage with a lower output impedance.
cviller said:
Bride-of-Zen
may be a nice matching preamp from Mr. Pass.
One IRF610 amplifier MOSFET
using zener shunt regulated single supply ~60Volt.
BoZ, Bride of Zen, has got rather low output impedance.
No problem driving 5kohm.
The original Gain is like x10 ( +20dB ), but could be easily modified a bit.
Only change one or two resistors to set gain.
Could you use same +- 35VDC supply???
You know this is ~70V.
===========================================
Some links:
BoZ preamp project
http://www.diyaudio.com/forums/showthread.php?threadid=86555
Using BoZ, improved version
for 10 V RMS output driving, SEWA - Seven Watt Amplifier (buffer power amp)
http://www.diyaudio.com/forums/showthread.php?threadid=66822&perpage=50&pagenumber=14
http://www.passdiy.com/legacy.htm
Download Project Theory, description, instructions and schematics:
http://www.passdiy.com/pdf/brideofzen.pdf
lineup
lineup said:
Sounds like good suggestions!
Maybe I should add pins for some gain to my layout...
lineup said:
Pearl is only running on a single + rail, so the 5 volts different wouldn't change much but some of the capacitors are rated quite close their operating point so they might not last as long.
Hi Cviller. I thought it was best to continue in your own thread If you could squeeze in a set of holes for the outputcap with 37,5 mm dist, it would be great. The Rifa PHE 426 10uF has that dist and I would like to try it for this. I will also try some polyprop-rolls and maybe some MKT's. The pic shows a couple of couplingcaps for the output; the Rifa and a Clarity SA cap that will be testet.
To have a baseline of how bad (?) it can sound, I matched a pair of Siemens stackfoil MKT's for the RIAA eq. I know they are supposed to sound bad, but I do want to hear it for myself From then on I will try and climb the audio-ladder to see how much influence the caps has.
Steen
If you could squeeze in a set of holes for the outputcap with 37,5 mm dist, it would be great. The Rifa PHE 426 10uF has that dist and I would like to try it for this. I will also try some polyprop-rolls and maybe some MKT's. The pic shows a couple of couplingcaps for the output; the Rifa and a Clarity SA cap that will be testet.To have a baseline of how bad (?) it can sound, I matched a pair of Siemens stackfoil MKT's for the RIAA eq. I know they are supposed to sound bad, but I do want to hear it for myself
From then on I will try and climb the audio-ladder to see how much influence the caps has. Steen
Attachments
Looks like your components are getting ready to become a new pearl.
I used some Elko bipolars - cheap but with golden letters
so they must be good.
The sound is extremely good, but I don't know if some better ones could make it even better.
I have updated the design...
http://viller.org/audio/2006nov_pearl/pearlpcb.pdf
I'll send you a B/W pdf.
I used some Elko bipolars - cheap but with golden letters
so they must be good. The sound is extremely good, but I don't know if some better ones could make it even better.
I have updated the design...
http://viller.org/audio/2006nov_pearl/pearlpcb.pdf
I'll send you a B/W pdf.
steenoe said:Wow, that was fast. We better watch out, the other guys might start calling us "The Dynamic Danish Duo"
I dont think the Bipolar eltrolytic is the best choice, but if you think it sounds good, why not?
Steen
I read a test of different caps written by someone here on diyaudio and he gave some bipolars a quite good review. I don't remember who it was and I cannot find the link - maybe one of your friends can dig up the thread.
I needed some stuff from a supplier who doesn't stock any MKP's so I took a chance on some of his better bipolars. The pearl is not mine anymore, so I don't think I'll test different caps, unless he thinks it would be interesting.
steenoe said:Wow, that was fast. We better watch out, the other guys might start calling us "The Dynamic Danish Duo"
I dont think the Bipolar eltrolytic is the best choice, but if you think it sounds good, why not?
Steen
hehe..........why not ..........TDDD...........
when TDSD is pretty lazy in last few months..........
Ho ho ho
If you get bored during Christmas you can try out my layout:
http://viller.org/audio/2006nov_pearl/pearl_fab_a4.pdf
http://viller.org/audio/2006nov_pearl/pearl_fab_letter.pdf
I haven't fabricated this exact layout my self. It is very close to the one I finished a month ago, but with the mosfet turned, so it should work perfectly.
The files are on my server and I might update them from time to time. (steenoe has so many capacitors he wants to try out)
If you need gerber you can send me an email.
If you get bored during Christmas you can try out my layout:
http://viller.org/audio/2006nov_pearl/pearl_fab_a4.pdf
http://viller.org/audio/2006nov_pearl/pearl_fab_letter.pdf
I haven't fabricated this exact layout my self. It is very close to the one I finished a month ago, but with the mosfet turned, so it should work perfectly.
The files are on my server and I might update them from time to time. (steenoe has so many capacitors he wants to try out)
If you need gerber you can send me an email.
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