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
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
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
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
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.
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.
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
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
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.
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.
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
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
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
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
After break in...
Hello,
I have had the time to review and listen to this phonoclone.
I must note I had no problems with the construction. The PCB pads are a little too small for the RIAA components that I used (250V poly caps - all matched)
my impressions:
A little too noisy to be considered high end but not noisy enough to be annoying.
Bass response is good, actually very good. rich and full.
I managed to filter the high frequency interference with placing a small poly cap on the opamps' power +/- and also to filter the power supply. I don't know which or if both worked but it seems to have resolved the problem. I don't remember the value either (I did this a few months ago).
Top frequencies break up easily especially with orchestra/symphonic music. I have tried the same pieces with CD (on a cheap CD player) and the problems are not there. Most other generes of music are ok but this phonoclone has problems with the high frequencies. Anybody maybe has noticed this?
Thanks and greetings,
MV
Hello,
I have had the time to review and listen to this phonoclone.
I must note I had no problems with the construction. The PCB pads are a little too small for the RIAA components that I used (250V poly caps - all matched)
my impressions:
A little too noisy to be considered high end but not noisy enough to be annoying.
Bass response is good, actually very good. rich and full.
I managed to filter the high frequency interference with placing a small poly cap on the opamps' power +/- and also to filter the power supply. I don't know which or if both worked but it seems to have resolved the problem. I don't remember the value either (I did this a few months ago).
Top frequencies break up easily especially with orchestra/symphonic music. I have tried the same pieces with CD (on a cheap CD player) and the problems are not there. Most other generes of music are ok but this phonoclone has problems with the high frequencies. Anybody maybe has noticed this?
Thanks and greetings,
MV
Thanks for sharing your opinion.
Your evaluation probably isn't far off the mark, but such a lot depends on details which you didn't provide.
Associated equipment: deck, arm, cartridge.
Power supply (VA, mono/stereo, torroid/EI...)
Regulation circuitry, and rail voltage used: LM317, LM7812, RC filter...
Also... what do you mean by "noisy"? Hum, hiss, or lack of "black" background?
Enough people experience noise and interference that I concede there is a problem somewhere. Since I've never, ever had an issue myself its hard for me to get to the bottom of it.
/R
Your evaluation probably isn't far off the mark, but such a lot depends on details which you didn't provide.
Associated equipment: deck, arm, cartridge.
Power supply (VA, mono/stereo, torroid/EI...)
Regulation circuitry, and rail voltage used: LM317, LM7812, RC filter...
Also... what do you mean by "noisy"? Hum, hiss, or lack of "black" background?
Enough people experience noise and interference that I concede there is a problem somewhere. Since I've never, ever had an issue myself its hard for me to get to the bottom of it.
/R
Hello RJM,
It is always the same:
Dual mono, PSU is separate with torroids on 230V 50hz mains.
I have two TTs, the one I'm using is the XpressionII w/ Denon 103.
Regulator used is the LM3xx. I have placed some small ceramic/poly caps for some filtering of the diodes and opamps. These have effectively removed the radio waves in the signal output and other buzzes.
Having a black background would be nice but there is a the famous OpAmp hiss for the background. The other noises I have managed to eliminate (which are easy to identify and remedy).
These are not major problems however! The major concern I think is the higher frequencies becoming instable. It seems that the higher frequencies tend to overload. If I use the NAD PII this isn't a problem. But with the NAD there is no detail.
troystg: sorry, no photos, yet. I haven't the time.
Best,
MV
It is always the same:
Dual mono, PSU is separate with torroids on 230V 50hz mains.
I have two TTs, the one I'm using is the XpressionII w/ Denon 103.
Regulator used is the LM3xx. I have placed some small ceramic/poly caps for some filtering of the diodes and opamps. These have effectively removed the radio waves in the signal output and other buzzes.
Having a black background would be nice but there is a the famous OpAmp hiss for the background. The other noises I have managed to eliminate (which are easy to identify and remedy).
These are not major problems however! The major concern I think is the higher frequencies becoming instable. It seems that the higher frequencies tend to overload. If I use the NAD PII this isn't a problem. But with the NAD there is no detail.
troystg: sorry, no photos, yet. I haven't the time.
Best,
MV
rjm,
I'd like to thank you for your excellent Construction Guide for Phonoclone & VSPS.
(see link below)
Phonoclone is a DIY project to consider, if you have a MC Ceramic Cartridge in your Turntable Pickup.
And you are looking for a suitable upgrade.
Phonoclone,
uses 2 Op-Amp RIAA design for MC phono RIAA amplifier.
I would rate this a project for intermedium DIY-ers.
Example of your very good information (see images below):
Regards, Lineup
-------------------------------------------------------------------------------------------
External Power Supply Unit, wiring diagram:
An externally hosted image should be here but it was not working when we last tested it.
Stereo MC Phono Amplifier Unit, wiring diagram:
An externally hosted image should be here but it was not working when we last tested it.
Web source:
RJM Audio Construction Guide for Phonoclone
Hello all,
I think my problem is related to humidity. I am currently researching this because I am not sure. I have suspected this because we have a change for humid weather so this may be just a problem anyway with no direct relation to the high frequency problem of before. Someone knows the effect of vinyl playback in different humidity levels? I am not experieinced because I have always been in a arid climate until only three years ago. Perhaps somebody in Asia where humidity is common?
More to come!
Best,
MV
I think my problem is related to humidity. I am currently researching this because I am not sure. I have suspected this because we have a change for humid weather so this may be just a problem anyway with no direct relation to the high frequency problem of before. Someone knows the effect of vinyl playback in different humidity levels? I am not experieinced because I have always been in a arid climate until only three years ago. Perhaps somebody in Asia where humidity is common?
More to come!
Best,
MV
Hello, mavallarino.
I live in europe, too.
I wonder how the rainy or humid weather can effect your turntable audio system playback?
It should not, if correctly designed.
But your idea makes good logic, in that sense that humidity, water, moisture can effect electrical conductance.
Wet surface can make less resistance to electricity.
( If you touch AC mains with DRY hands vs. WET hands makes difference! )
We should know that even some states in USA have very much rain & thunderstorms. Usually at the coast is higher humidity, than in e.g south-west Arizona desert areas.
Maybe some of our american diy friends have some experiences to share.
Asia, South-America Amazonas, Africa & India, Bangladesh .. everywhere are rain-zones.
Quote:
I have suspected this because we have a change for humid weather
so this may be just a problem anyway
with no direct relation to the high frequency problem of before.
Is there any more info of your audio system setup
and what more can you tell us of this issue?
Regards, Lineup
mavallarino said:
It's already rather wretchedly hot here, and the rainy season is still a month away. Not that this gives me any special insight into the nature of your problem, unfortunately.
It would belpful if you could post a couple of photos of your setup, and describe the problem is some detail. However in general based on what we've learnt so far:
- no "that's it" solution has been found. Most people have no problems, but some do. Those that did never got rid of the issue completely to my knowledge.
- my prime suspects are the OP27 op-amps, the phono cable and tonearm wiring and shielding, possibly in combination with the grouding layout of the phonclone itself.
- two tests I recommend are to replace the OP27s with a FET input type like the OPA134, and also to replace the phono cartridge (and all the input wiring) with a dummy 50 ohm load across the input RCA jack.
/R
mavallarino said:
Just wanted to share that I don't encounter this problem. High frequencies are top notch and very clean in my set up (I am using a 103R cart). Also not any noticeable hiss/humm anywhere normal to loud listening levels. The only noise I get is when I have my cell phone anywhere nearby.
Ralph