The Phonoclone and VSPS PCB Help Desk - Page 93 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

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 8th February 2008, 11:12 PM   #921
diyAudio Member
 
Join Date: Jan 2006
Location: Ireland
Word back a bit from RJM was that it would take about 3 weeks for the phonoclone to burn in fully - leaving it powered on 24/7 and an hour or 2 pf play each day. My experience would tend to bear that out.

Glad to hear you got it up and going!

Fran
  Reply With Quote
Old 28th February 2008, 05:55 PM   #922
diyAudio Member
 
Join Date: Aug 2005
I just break my cartridge
I have no good mc cart anymore but have a good mm a
Shure V15 Vxmr output 3 mv
resistance 1000 ohm dc
Inductance 425 at 1kHz
is it possible to use the Phonoclone with this cartridge?
Or with a modification of the Phonoclone maby lower the gain or 1 stage bypased or so ?

Robert
  Reply With Quote
Old 28th February 2008, 09:24 PM   #923
rjm is offline rjm  Japan
Richard Murdey
diyAudio Member
 
rjm's Avatar
 
Join Date: May 2004
Location: Kyoto
Blog Entries: 98
The quick answer is "no" of course.

However, if your realy have to: add a series resistor at the input equal to the recommended cartridge load. Adjust the feedback resistor of the first stage as needed.

Even if the nominal recommended load is 47kohms, try to use a smaller value if you can get away with it, 1kohm, 4.7 kohm, or 10 kohm.

Lets say its 47kohm. That goes in series between the cartridge input and the inverting input of the first stage. Total input impedance is 47k + 1k or so from the cart. The feedback resistor will need to be about 220kohms. The gain of teh first stage is then 4x, the second stage about 30x, total is 120x or just over 40 dB.

Questions?

/R
  Reply With Quote
Old 28th February 2008, 09:33 PM   #924
rjm is offline rjm  Japan
Richard Murdey
diyAudio Member
 
rjm's Avatar
 
Join Date: May 2004
Location: Kyoto
Blog Entries: 98
.....
Attached Images
File Type: jpg mm.jpg (31.3 KB, 568 views)
  Reply With Quote
Old 28th February 2008, 10:01 PM   #925
diyAudio Member
 
Join Date: Aug 2005
hello Richard
i will try it tomorrow
i try the 47k and the feedback resistor at 220k
what do you mean with the third resistor adjust to equal?
Robert
  Reply With Quote
Old 29th February 2008, 12:12 AM   #926
rjm is offline rjm  Japan
Richard Murdey
diyAudio Member
 
rjm's Avatar
 
Join Date: May 2004
Location: Kyoto
Blog Entries: 98
In principle the inverting and non-inverting impedances should balance, so if 47k added to the inverting side, then R1 should be 47k to match. Likewise it would be advisable to use a unity gain stable FET input opamp instead of the OP27 in the first stage.

But its not necessary, and I assume you are looking for quick and dirty, I need it to work, now! solution.

Its not meant to be a "good" design. From a noise standpoint its a poor design by nature, no matter what you do.
  Reply With Quote
Old 20th March 2008, 06:59 PM   #927
amt is offline amt  United States
diyAudio Member
 
Join Date: Feb 2003
Location: oregon
Default few questions

Ive decided to build the PC but have a couple of questions:

First, will the PC work with a GC thats sans a preamp/buffer? Not sure if adjusting the gain on the chipamp and the PC are going to be adequete/optimal. The 47Labs version is apparently used with the Gaincard, but is it the high gain version only? A Benz with very low output will be used. I would rather not use an additional gain stage unless its really sonically advisable or actually needed.

Also, is using the standard mail to the U.S. a safe bet when ordering from Olimex? The cost is pretty high if using an insured/trackable service. Looks like I will receive 4 RC boards so I would have a couple available for someone else.

amt
  Reply With Quote
Old 21st March 2008, 12:49 AM   #928
rjm is offline rjm  Japan
Richard Murdey
diyAudio Member
 
rjm's Avatar
 
Join Date: May 2004
Location: Kyoto
Blog Entries: 98
You should find the gain of the Phonoclone (low gain, standard : 75dB) and Gainclone (30dB) to be more than sufficient for just about any situation.

Olimex shipping my regular mail should not be an issue, not any more risk than any other low value package.

I've never had any trouble on either point.
  Reply With Quote
Old 16th April 2008, 06:35 PM   #929
amt is offline amt  United States
diyAudio Member
 
Join Date: Feb 2003
Location: oregon
Well they arrived in good condition but not very quickly. Good service and they were very responsive in emailing me with ordering/mailing info.

I do need a suggestion now, for a cap substitute. The BG N/4.7 is gone - I cant find it anywhere. I read a previous post that a 1uf film would be the next best choice. Anyone have a particular cap that they feel will offer similar sonics at reasonable cost? Isnt there some other electrolytic that is comparable to the BG?

amt
  Reply With Quote
Old 16th April 2008, 09:44 PM   #930
amt is offline amt  United States
diyAudio Member
 
Join Date: Feb 2003
Location: oregon
Default I found some.

I decided to do a more thorough search, hoping that even though all the usual suppliers no longer have any, some may still exist for purchase.

I found two sources that have stock. Musical Concepts and Audio Dimensions in the Netherlands(who by the way returned an email very quickly)

I picked up half a dozen at Musical Concepts since they are much closer for shipping considerations. But had they not had them, Audio Dimensions would have gotten an order.

amt
  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



New To Site? Need Help?

All times are GMT. The time now is 02:31 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