Mine is running fine now after removing the damaged caps. I left it for a night to allow it all the warm back up etc. Sound was a bit veiled I though... but then sonic memory is short enough. So on a whim I removed the 220uF caps I had installed in C12/13 and the veil went, and high treble sounds a bit better I think (I had them on sockets so swapping was easy).
I'll leave it for another night now to see how it goes.....
Fran
I'll leave it for another night now to see how it goes.....
Fran
The output voltage of the xreg is higher after you replace the capacitors, since the leakage dragged the divider voltage down before.
With the 22k resistors for R11-14 the output voltage is actually a fraction too high, I think somewhere in the region 25-33k would be better, whatever is convenient and depending on what voltage people what to run the phonoclone circuit at.
Personally I think it sounds pretty good at 9V, where R11-14 are 33k. Using 25k will give you a more traditional 12V.
For poor Rhys, pulling his hair out trying to put the kit together: I will take responsibility for this, and send you the resistors if necessary.
/R
With the 22k resistors for R11-14 the output voltage is actually a fraction too high, I think somewhere in the region 25-33k would be better, whatever is convenient and depending on what voltage people what to run the phonoclone circuit at.
Personally I think it sounds pretty good at 9V, where R11-14 are 33k. Using 25k will give you a more traditional 12V.
For poor Rhys, pulling his hair out trying to put the kit together: I will take responsibility for this, and send you the resistors if necessary.
/R
- updated the xreg web page to change the resistor values, add a download link for the worksheet, minor edit to the evaluation board.
- updated the pcb page to the latest phonoclone 3 version, also appended below/ [rev. 32d]
(the pins of the pass transistors are now labeled explicitly on the PCB)
A word about output voltage:
I think the circuit sounds (a lot) better when the output voltage from the xreg is lowered to about 9 V rather than 12 V or more. It's not clear whether this is because the phonoclone prefers low voltages, or whether the xreg likes a large Vin-Vout differential. I rather suspect a bit of both.
For Algar-emi and others with working circuits, I suggest increasing R11,12 or R11-14 in order to lower the xreg output voltage. As a guide the total value of R11+R13 (and R12+R14) should be about 60 k ohms. Either go with 33k in both positions as I have suggested in the latest eagle files, or leave R13,14 at 22k and increase R11,12 to ~40k for example.
Rest assured that Rhys' kit will have the latest approved parts values included.
- updated the pcb page to the latest phonoclone 3 version, also appended below/ [rev. 32d]
(the pins of the pass transistors are now labeled explicitly on the PCB)
A word about output voltage:
I think the circuit sounds (a lot) better when the output voltage from the xreg is lowered to about 9 V rather than 12 V or more. It's not clear whether this is because the phonoclone prefers low voltages, or whether the xreg likes a large Vin-Vout differential. I rather suspect a bit of both.
For Algar-emi and others with working circuits, I suggest increasing R11,12 or R11-14 in order to lower the xreg output voltage. As a guide the total value of R11+R13 (and R12+R14) should be about 60 k ohms. Either go with 33k in both positions as I have suggested in the latest eagle files, or leave R13,14 at 22k and increase R11,12 to ~40k for example.
Rest assured that Rhys' kit will have the latest approved parts values included.
Just to weigh in here with my own personal experience. When I first built the PC3 I used the standard figures and ended up with ~13.5V feed to the opamps. I was happy with that. Then after some questions from algar-emi and RJM about the voltages and those caps being in backwards, I started to check out the voltages. My feed voltage was stable at 13.5-14 but just within regulation. So on RJMs advice I dropped the voltage a bit - initially to ~10.5V (I think that was 22k-28k) and right enough the sound did improve. What were the changes? Well its hard to describe exactly but the sound was a little less "etched", I think a little more relaxed but I can't see that I've lost any detail or resolution. I think if I was to put a notion on it, I would say it sounded a little more valve like.
So then I went to go a bit further and replaced the 22K-28K with 2 x 33K and that brought the voltage down to about 9.2V or thereabouts. I couldn't hear any much difference between the 10.5 and 9.2V feeds but definitely a fairly big difference from 13.5 down to 10.
So to cut a long story short, if I was selecting parts I would go faor maybe 2 x 30K (rather than 33K) only because if someones raw DC is a little lower then the feed voltage to the opamps will also be lower. That should keep everyones voltage in the region of 8.5-10V which it would seem is the sweet spot here. This is all assuming that we are all working off a 12v AC primary, giving a raw DC in the 16-18V (unloaded) range. If someone is really fussy you could fit a 30K to one position and then rig in a 50k pot to the other one to allow for ultimate adjustability.
What do you think RJM?
Fran
So then I went to go a bit further and replaced the 22K-28K with 2 x 33K and that brought the voltage down to about 9.2V or thereabouts. I couldn't hear any much difference between the 10.5 and 9.2V feeds but definitely a fairly big difference from 13.5 down to 10.
So to cut a long story short, if I was selecting parts I would go faor maybe 2 x 30K (rather than 33K) only because if someones raw DC is a little lower then the feed voltage to the opamps will also be lower. That should keep everyones voltage in the region of 8.5-10V which it would seem is the sweet spot here. This is all assuming that we are all working off a 12v AC primary, giving a raw DC in the 16-18V (unloaded) range. If someone is really fussy you could fit a 30K to one position and then rig in a 50k pot to the other one to allow for ultimate adjustability.
What do you think RJM?
Fran
And another picture.
It is the first version of the phonoclone,
I had the parts but never made the jump.
In fact point to point is not so difficult if you like to puzzle a bit.
It worked right from the start, including hum and mobile phone noise.
I got the 50 Hz down to -70dB and 100 Hz down to 60-70 dB.
So I boought the parts for the X-reg yesterday!
Things I did for the hum:
Lower the amplification to 54 dB, hum is lower but so is the output.
Renewed the connectors for the turntable earth wires.
Twisted the input wires inside.
Connected the caseconnector to the left input-mass instead of the input-com of the powersupply. This made a real difference!
A real good help for this is a FFT on your computer like the audiotester program (audiotester.de)
And how does it sound? Incredible!
I never heard such a strong and natural bass in my house.
It is very detailed and a lot of space. When the music gets really loud everything stays comfortable and no change in character.
It is the first version of the phonoclone,
I had the parts but never made the jump.
In fact point to point is not so difficult if you like to puzzle a bit.
It worked right from the start, including hum and mobile phone noise.
I got the 50 Hz down to -70dB and 100 Hz down to 60-70 dB.
So I boought the parts for the X-reg yesterday!
Things I did for the hum:
Lower the amplification to 54 dB, hum is lower but so is the output.
Renewed the connectors for the turntable earth wires.
Twisted the input wires inside.
Connected the caseconnector to the left input-mass instead of the input-com of the powersupply. This made a real difference!
A real good help for this is a FFT on your computer like the audiotester program (audiotester.de)
And how does it sound? Incredible!
I never heard such a strong and natural bass in my house.
It is very detailed and a lot of space. When the music gets really loud everything stays comfortable and no change in character.
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