New pearl layout with MC - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th December 2006, 08:32 AM   #1
cviller is online now cviller  Denmark
diyAudio Member
 
cviller's Avatar
 
Join Date: Dec 2005
Location: Copenhagen
Blog Entries: 2
Default New pearl layout with MC

After some good results with my pearl layout and a bunch of feature requests/ideas, mostly from steenoe, I have decided to make the board bigger.

The new design will be based on my old layout from here:
(Pearl layout - how to organise things to avoid noise)

New feature list:
- Pearl preamp by Wayne
- MC input (see attachment and The Analogue Addicts Phono Preamplifier 2006 Edition)
- 9V supply for MC (lm317 or mosfet regulated?)
- Flexible capacitor footprints for riaa part (5,7.5,10,12 and 15mm pin spacing)
- Parallel capacitors for C10,C11 and C13 (exotic capacitors are sometimes hard to get in the large values need for pearl)
- Suitable for home etching - I can make a fab version later.

The board will be approximately 180x110mm (for each channel).

I would like to get some input (ideas, comments, additions) before I go ahead. The feature list is not closed!
Attached Files
File Type: pdf mcpre.pdf (4.7 KB, 488 views)
  Reply With Quote
Old 25th December 2006, 04:27 PM   #2
steenoe is offline steenoe  Denmark
diyAudio Member
 
steenoe's Avatar
 
Join Date: Mar 2004
Sounds like that will be a very nice layout
Quote:
- 9V supply for MC (lm317 or mosfet regulated?)
I suggest to tap the excisting supply just after C15 and add another mosfetreg to bring the voltage down to around 14 volts, then duplicate the capacitance multiplier based around Q3 and make that bring down the voltage to 9V. That should hopefully be quiet enough. Another option would be to power the MC stage from a 9V battery.

Steen
  Reply With Quote
Old 27th December 2006, 08:22 PM   #3
cviller is online now cviller  Denmark
diyAudio Member
 
cviller's Avatar
 
Join Date: Dec 2005
Location: Copenhagen
Blog Entries: 2
Nice idea about the supply - I think battery should be optional.

What about adding a balanced output buffer? Would anyone appreciate that?
  Reply With Quote
Old 27th December 2006, 08:52 PM   #4
diyAudio Member
 
spzzzzkt's Avatar
 
Join Date: May 2005
Location: Melbourne
Yes please!!! Balanced outputs would be a very nice/worthwhile addition for those of us whom can't justify the cost of building a (x)ono

there was some discussion on the topic here:

A differential output PEARL... ...?

edit: and here:

The Pearl-X

but perhaps you have some better ideas ?


pj
  Reply With Quote
Old 27th December 2006, 09:28 PM   #5
steenoe is offline steenoe  Denmark
diyAudio Member
 
steenoe's Avatar
 
Join Date: Mar 2004
Quote:
What about adding a balanced output buffer?
Yep, thanks a lot, generally.
Depends on how it would look like, though Do you have anything specific in mind?
Normally I have no concerns at all, letting my X-BosoZ do the conversion
BTW I wrote partly some; not usefull suggestions about the reg supply for the simple French MC headamp supply! The capacitance multiplier will not bring the voltage down that much. The initial reg has to take it all the way down to nearly 9V I agree about the battery supply being optional, indeed. What about implementing a MC-frontend with more suitable supply voltage?
Aleph ONO would be the obvious choice, but with some more parts?

Steen
  Reply With Quote
Old 27th December 2006, 10:15 PM   #6
steenoe is offline steenoe  Denmark
diyAudio Member
 
steenoe's Avatar
 
Join Date: Mar 2004
Quote:
Aleph ONO would be the obvious choice, but with some more parts?
If Mr. Pass accepts and give his permission ofcourse Glad I caught that one!

Steen
  Reply With Quote
Old 28th December 2006, 08:39 AM   #7
cviller is online now cviller  Denmark
diyAudio Member
 
cviller's Avatar
 
Join Date: Dec 2005
Location: Copenhagen
Blog Entries: 2
I would prefer to keep it more simple than the ONO.
To me, something like
http://www.diyaudio.com/forums/showt...245#post566245
would be the best option, but the gain must be adjusted and I think the number of jfets needs to be increased too. It would be nice to have proper line level on the output.
  Reply With Quote
Old 29th December 2006, 09:20 AM   #8
Buhl is offline Buhl  Denmark
diyAudio Member
 
Buhl's Avatar
 
Join Date: May 2002
Location: Aalborg, Denmark
Hello Cviller

I think its a nice and natural expansion of the things people have been working on in here - especially promitheus' work with the ono mcstage - I have build a couple of them for my self and some friends, and that stage sounds really awsome (in the good way)!!! - low noise, "black" background, no feeling of coloration, and very, very dynamic.... (of course some migth say, cause its taken direct from the ono....hehe)

If you could incorporate theese two circuits on one pcb, I think that would be nice - but I dont know if the ono MCstage is to complicated compared to what you have in mind ?

The gain of the Ono MCstage is however, plentyfull - I feel the 30 dB is way enough, 20 dB could do with most cartrdiges I think, so maby you can spare some of the macthed jfets ??

About the 9-volt battery, well, I used it in the beginning on my pearl, and on a friends pearl to - but the battery only lasted a month or so (continious operation), so I changed them to a zener, and none of us could hear any difference. I fact, the only tweak we have tried, that made a difference, was upgrading the external PSU to 80000uF(like the ono) and including a couple of extra CRC's - that seemed to lower the noisefloor a bit, but not much, but made it sound powerfull in a way thats hard to dsescribe....

Happy work - Im exited to see how it turns out !

Cheers !
Hans
__________________
"Calculations? We don't need no stinkin calculations! We just make them really big!" Quote: Nelson Pass
  Reply With Quote
Old 29th December 2006, 10:15 AM   #9
steenoe is offline steenoe  Denmark
diyAudio Member
 
steenoe's Avatar
 
Join Date: Mar 2004
Quote:
To me, something like
That looks pretty nice, for balanced out. I think Hans's suggestions about a "downscaled" ONO MC is pretty good. It would make things easier if it could be powered from the Pearls psu, more or less directly. An additonal capacitance multiplier would probably be in order to lower the noise as much as possible. BTW. Hans, the 9V battery was for powering the simple French MC stage specifically, since it uses 9V.

Steen
  Reply With Quote
Old 29th December 2006, 10:49 AM   #10
cviller is online now cviller  Denmark
diyAudio Member
 
cviller's Avatar
 
Join Date: Dec 2005
Location: Copenhagen
Blog Entries: 2
I wouldn't mind adding ono mc preamp instead - I think I can squeeze it in somewhere, but the boards might get bigger then. And the cost of components will increase too.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Eagle vs. Sprint-Layout for PCB design/layout hollowman Parts 11 12th January 2014 09:01 PM
Another diy-pearl... lykkedk Pass Labs 18 15th June 2007 04:44 PM
pearl HELP! d to the g Pass Labs 24 31st May 2007 01:56 PM
Pearl layout - how to organise things to avoid noise cviller Pass Labs 56 22nd December 2006 10:04 PM
Get rid of cap from PEARL??? coffin Pass Labs 3 30th December 2002 01:05 AM


New To Site? Need Help?

All times are GMT. The time now is 01:53 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2