OK, an update:
I was having issues with my newly completed Phonoclone. It is very bass shy, and I am having to really pump the bass level out on my amp to make it sound decent. It's not a flat response at all.
It seems that the RIAA section of the circuit could be the issue.
I managed to have a look at what components and values I have there.
I double checked R5 and R6, both are OK. Correct values on both boards.
In C1 I have a capacitor marked "102K100" that is the 1.00nf capacitor.
In C2 I have two caps - One marked "222K100" that is the 2.2nf cap and the other cap marked "684K100" which is the 680pf cap.. or it should be. These two are in parallel to make a total of 2.90nF.
I have a feeling that the 680pf cap is where I have gone wrong. I am not very good with capacitor codes but if I am correct the value of this cap is 680,000pf. or 0.680uf. Is that correct, or am I way off the mark?
Also, would I be correct in saying that the C2 section of the RIAA circuitry is the one that attenuates bass?
Thanks,
Kaban
I was having issues with my newly completed Phonoclone. It is very bass shy, and I am having to really pump the bass level out on my amp to make it sound decent. It's not a flat response at all.
It seems that the RIAA section of the circuit could be the issue.
I managed to have a look at what components and values I have there.
I double checked R5 and R6, both are OK. Correct values on both boards.
In C1 I have a capacitor marked "102K100" that is the 1.00nf capacitor.
In C2 I have two caps - One marked "222K100" that is the 2.2nf cap and the other cap marked "684K100" which is the 680pf cap.. or it should be. These two are in parallel to make a total of 2.90nF.
I have a feeling that the 680pf cap is where I have gone wrong. I am not very good with capacitor codes but if I am correct the value of this cap is 680,000pf. or 0.680uf. Is that correct, or am I way off the mark?
Also, would I be correct in saying that the C2 section of the RIAA circuitry is the one that attenuates bass?
Thanks,
Kaban
Same here really - very happy, no distortion at all. In fact I had a slight hum at higher volumes due to EMF. Since I lowered the gain a little thats much reduced.
I actually have a second phonoclone and I using it with a Benz L2 which has an output of 0.35mV and I think I will drop the gain on that one too. Something like 680 or 780R would probably do. Theres 1.2K in there right now.
On extended listening I can't see that it has lost anything - no loss of any detail, dynamics etc. Doesn't seem to have any adverse effects.
Fran
I actually have a second phonoclone and I using it with a Benz L2 which has an output of 0.35mV and I think I will drop the gain on that one too. Something like 680 or 780R would probably do. Theres 1.2K in there right now.
On extended listening I can't see that it has lost anything - no loss of any detail, dynamics etc. Doesn't seem to have any adverse effects.
Fran
A little help please?
I have two questions before starting on a Phonoclone: any help much appreciated.
1) to save wading through 35+ pages, can I simply leave out the eq. stage? (I have a much loved and good preamp - so all I want is a step-up.)
2) My cartridge is an exceptionally low output original Audionote 1o. It is also very low impedence. Any suggested starting points on loading?
Many thanks,
Brian.
I have two questions before starting on a Phonoclone: any help much appreciated.
1) to save wading through 35+ pages, can I simply leave out the eq. stage? (I have a much loved and good preamp - so all I want is a step-up.)
2) My cartridge is an exceptionally low output original Audionote 1o. It is also very low impedence. Any suggested starting points on loading?
Many thanks,
Brian.
hum question
Hello play for a while now with the Phonoclone limited
but not much because i dont get complete rid of the hum
and i think i tried everything possible
I tried 1 transformer
and now i use 2 transformers.
I tried com to case and today i build it back for the forth time to input ground to case.
When i use a dummy load (47 ohm in a rca connector) i measure a hum of 0,014 volt on the output
thats audible in my system and to much .
When i use the tonearm cable i measure 0,026 volt on the output.
for the measurements i use a Fluke true rms voltage meter.
Can someone measure the output hum of his Phonoclone please
and post it here
Best regards Robert
Hello play for a while now with the Phonoclone limited
but not much because i dont get complete rid of the hum
and i think i tried everything possible
I tried 1 transformer
and now i use 2 transformers.
I tried com to case and today i build it back for the forth time to input ground to case.
When i use a dummy load (47 ohm in a rca connector) i measure a hum of 0,014 volt on the output
thats audible in my system and to much .
When i use the tonearm cable i measure 0,026 volt on the output.
for the measurements i use a Fluke true rms voltage meter.
Can someone measure the output hum of his Phonoclone please
and post it here
Best regards Robert
I have still a little hum in both of mine - but its low. Back a bit in the thread there was a new grounding scheme for anyone using a dual mono supply - it does help.
But also, I found that when I move around the interconnects from phonoclone to amp makes a huge difference. My leads from the TT to the phonoclone are screened, but not the interconnects to the amp. It does seem sensitive to picking up hum from other stuff. Another thing you could try is dropping the gain a little - the kit has R2 at 1.2K. You could try adding another in parallel - say a 550R. That would drop the gain a bit, is easily reversible and might help with the hum. I often wondered about adding some caps across the outputs to see if that would help but never did it.
Brianco: Use something that matches the DC resistance of the cart.
... OK I just looked it up and see thats its only 1R! I dunno - try say 5R or 10R to see. The kit RJM did had it at 10R I think.
Fran
But also, I found that when I move around the interconnects from phonoclone to amp makes a huge difference. My leads from the TT to the phonoclone are screened, but not the interconnects to the amp. It does seem sensitive to picking up hum from other stuff. Another thing you could try is dropping the gain a little - the kit has R2 at 1.2K. You could try adding another in parallel - say a 550R. That would drop the gain a bit, is easily reversible and might help with the hum. I often wondered about adding some caps across the outputs to see if that would help but never did it.
Brianco: Use something that matches the DC resistance of the cart.
... OK I just looked it up and see thats its only 1R! I dunno - try say 5R or 10R to see. The kit RJM did had it at 10R I think.
Fran
eh, this isn't exactly what you wanted:
I left the whole thing connected in place - left the arm cable connected and the interconnects to the preamp connected. I measure 0.005 and 0.006V ac. This is at the very low end of the meter so I can't vouch for its accuracy. I think my other meter is a bit better low down. When I get to it later I measure with it too.
Fran
I left the whole thing connected in place - left the arm cable connected and the interconnects to the preamp connected. I measure 0.005 and 0.006V ac. This is at the very low end of the meter so I can't vouch for its accuracy. I think my other meter is a bit better low down. When I get to it later I measure with it too.
Fran
Thanks Fran thanks a lot
I have way more hum than you !
maybe i must concentrate me in the fist place on the amp and
not anymore on the phono cable.
I tty now with the dummy loads on the inputs to get them around the 4 mV instead of 14mV
This is how its wired now:
I have 2 transformers Amplimo donuts
like this
http://www.amplimo.nl/download/5N966.pdf
The following is for 1 transformer:
the violet and the bleu wires are together and go to the com on 1 Phonoclone board
the red and the grey going to the rectifier and from there the + and - go to the Phonoclone board
each board have his own transformer.
Notting is shared for now (ecxept that the transformers are in the same enclosure and the primarys are togeter)
the input rca grounds are connected to the case the case is full aluminium and complete closed .
The output rca ground is not connected to the case
How is yours connected?
Robert
I have way more hum than you !
maybe i must concentrate me in the fist place on the amp and
not anymore on the phono cable.
I tty now with the dummy loads on the inputs to get them around the 4 mV instead of 14mV
This is how its wired now:
I have 2 transformers Amplimo donuts
like this
http://www.amplimo.nl/download/5N966.pdf
The following is for 1 transformer:
the violet and the bleu wires are together and go to the com on 1 Phonoclone board
the red and the grey going to the rectifier and from there the + and - go to the Phonoclone board
each board have his own transformer.
Notting is shared for now (ecxept that the transformers are in the same enclosure and the primarys are togeter)
the input rca grounds are connected to the case the case is full aluminium and complete closed .
The output rca ground is not connected to the case
How is yours connected?
Robert
Similar to yours I think:
heres a pic of the power supply:
Its just 2 transformers with 2 x 12V secondaries. Center taps are joined - these become COM. The outside 2 go to the rectifier and become +12V and -12V. Each side is the same.
The 3 wires then go to the second case housing the phonclone boards:
and are connected to the phonoclone boards.
So to summarise:
dual mono, separate cable run to 2 x 3 way XLR jacks. I used uninsulated rca sockets for the inputs, insulated for the outputs, and connecting the ground to the common made no difference - in my set up.
I must add though that in my set up, having the TT ground connected or not makes no difference anyway - on yours you may need to connect the ground lug to common.
Fran
heres a pic of the power supply:
An externally hosted image should be here but it was not working when we last tested it.
Its just 2 transformers with 2 x 12V secondaries. Center taps are joined - these become COM. The outside 2 go to the rectifier and become +12V and -12V. Each side is the same.
The 3 wires then go to the second case housing the phonclone boards:
An externally hosted image should be here but it was not working when we last tested it.
and are connected to the phonoclone boards.
So to summarise:
dual mono, separate cable run to 2 x 3 way XLR jacks. I used uninsulated rca sockets for the inputs, insulated for the outputs, and connecting the ground to the common made no difference - in my set up.
I must add though that in my set up, having the TT ground connected or not makes no difference anyway - on yours you may need to connect the ground lug to common.
Fran
hello Fran
The difference is i use a shielded case and i run a 6 wire cable to a 7 pin xlr jack
my secondairy is 13.6 volt
and i have 17 to 18 volt after the rectifier.
The strange thing is that when i run complete seperated supply and no com connection joined also not the rca ground connected
i measure from the + and - to the com around 17 volt
and from the same + and - to the other com 15 volt ?
Maby i must take the printed boards out of the case and use them unshielded .
Do you believe me that i hear the hum to much?
i have 4 to 5 times more hum then you have and speakers of 98 db efficiency
and then there is sometimes the radio playing trough my speakers but i think this has much to do with the hum
and i think this is solved when i get rid of the hum.
Robert
The difference is i use a shielded case and i run a 6 wire cable to a 7 pin xlr jack
my secondairy is 13.6 volt
and i have 17 to 18 volt after the rectifier.
The strange thing is that when i run complete seperated supply and no com connection joined also not the rca ground connected
i measure from the + and - to the com around 17 volt
and from the same + and - to the other com 15 volt ?
Maby i must take the printed boards out of the case and use them unshielded .
Do you believe me that i hear the hum to much?
i have 4 to 5 times more hum then you have and speakers of 98 db efficiency
and then there is sometimes the radio playing trough my speakers but i think this has much to do with the hum
and i think this is solved when i get rid of the hum.
Robert
I tried some things today
i run now only 1 board on 1 transformer.
The hum and radio is stil there when i walk trough my room the hum and radio signal get more or lesser
this works on about 1 meter from the Phonoclone .
It is so sensitive !
when i touch some metal or ground cable the hum reduce sometimes
i get crazy from this stupid hum
it must go away !!
Today i tried a low budget suppa phono amp and it works good
no hum but i hear trough the hum from the Phonoclone that it sounds much better.
i want that phonoclone
Robert
i run now only 1 board on 1 transformer.
The hum and radio is stil there when i walk trough my room the hum and radio signal get more or lesser
this works on about 1 meter from the Phonoclone .
It is so sensitive !
when i touch some metal or ground cable the hum reduce sometimes
i get crazy from this stupid hum
it must go away !!
Today i tried a low budget suppa phono amp and it works good
no hum but i hear trough the hum from the Phonoclone that it sounds much better.
i want that phonoclone
Robert
Yes, I agree - the phonoclone does sound very good!
But, I don't know how to get rid of your problems. Is there anyway you can use a shielded cable for the tonearm and the interconnect? Even if you stripped some braid from a coax aerial cable?
Other than that I don't know what to suggest. Maybe put up a post in the solid state forum about radio/EF interference and how to lessen it.
Sorry I can't be of more help - keep going and you will find a solution. If there is anything I can do to help, let me know.
Fran
But, I don't know how to get rid of your problems. Is there anyway you can use a shielded cable for the tonearm and the interconnect? Even if you stripped some braid from a coax aerial cable?
Other than that I don't know what to suggest. Maybe put up a post in the solid state forum about radio/EF interference and how to lessen it.
Sorry I can't be of more help - keep going and you will find a solution. If there is anything I can do to help, let me know.
Fran