A word of advice. If you wish to leave the units on all the time, consider using a ventilated case. I used the rectangular aluminum tube. The PS caps (Nichicon muze KZ series) 1000uF@25V (C1/C2) are failing -- the electrolyte is boiling out of the top already. Or, they are at end of life simply by time spent on....
A question:
Is the value of C1/C2 in the power supply critical? Can this be increased?
A question:
Is the value of C1/C2 in the power supply critical? Can this be increased?
Two tests:
Added C11/C12. This solved some issues I had with the hardness of the sound. I used Nichicon Muse here, and yes, the result sounds like Nichicon Muse. Elna Cerafine is used for the pre-regulator. These are crazy fast by themselves, adding C11/12 makes for a change that some people may enjoy. As for other caps here, I can't tell you. This is the first try.
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Adding 1uF tantalum caps on the power rails to the chips presented some very interesting problems. Gnd was power supply common -- the same ground used by the TT ground lug.
The hiss level went way down....but turning the volume control could now be heard at the speaker. Then the speaker fuse blew. I removed the work, replaced the fuse and all was well.
The gnd was power supply common -- same as the TT ground. I'm still searching for reasons why this hisses. It may be possible that the op amps I have are fakes? The hiss is not heard when music plays, but can be heard at listening volumes. I tend to listen at high volume.
Added C11/C12. This solved some issues I had with the hardness of the sound. I used Nichicon Muse here, and yes, the result sounds like Nichicon Muse. Elna Cerafine is used for the pre-regulator. These are crazy fast by themselves, adding C11/12 makes for a change that some people may enjoy. As for other caps here, I can't tell you. This is the first try.
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Adding 1uF tantalum caps on the power rails to the chips presented some very interesting problems. Gnd was power supply common -- the same ground used by the TT ground lug.
The hiss level went way down....but turning the volume control could now be heard at the speaker. Then the speaker fuse blew. I removed the work, replaced the fuse and all was well.
The gnd was power supply common -- same as the TT ground. I'm still searching for reasons why this hisses. It may be possible that the op amps I have are fakes? The hiss is not heard when music plays, but can be heard at listening volumes. I tend to listen at high volume.
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The Nichicon Muse at C11/C12 were taken out of circuit. The new IC I was using has broken in enough to be listenable now, and the muse slowed things down quite a bit.
Current preferences for PS caps:
Elna Cerafine in pre-regulator position (C1/C2)
Elna Silmic II post regulator (C4/C5)
These have detail and larger soundstage. Nichicon Muse are coloured in comparison: much warmer, but less detail.
Elna Cerafine in pre-regulator position (C1/C2)
Elna Silmic II post regulator (C4/C5)
These have detail and larger soundstage. Nichicon Muse are coloured in comparison: much warmer, but less detail.
Peter or any others...
Have you tried other devices for current sources than the LM317/337's? I was looking at the DN2540 which is used by K&K Audio and a lot of others in their CCSs.
Any thoughts as whether this is a good or bad idea?
Thx!
Greg in Mississippi
P.S. Finally getting my PD Phono Stage built up. I'm splitting the packaging up into three boxes... one for the transformers/diodes/main filter caps with a pair of 3-connection leads to a small box with the regulators and mounted directly on top of it a pair of copper cap enclosures for the active circuits. Hardest thing to do was cutting up those beautiful boards! Circuitry will be dual-mono and the regulator case (cast aluminum) will be the heatsink for the reg devices.
Have you tried other devices for current sources than the LM317/337's? I was looking at the DN2540 which is used by K&K Audio and a lot of others in their CCSs.
Any thoughts as whether this is a good or bad idea?
Thx!
Greg in Mississippi
P.S. Finally getting my PD Phono Stage built up. I'm splitting the packaging up into three boxes... one for the transformers/diodes/main filter caps with a pair of 3-connection leads to a small box with the regulators and mounted directly on top of it a pair of copper cap enclosures for the active circuits. Hardest thing to do was cutting up those beautiful boards! Circuitry will be dual-mono and the regulator case (cast aluminum) will be the heatsink for the reg devices.
I tried my phono stage with an SAE high output MC. There was no hiss. NONE. You could not tell the unit was on. Seems to me it's external to the phono stage...
Koetsu and SP-10 maybe not getting along?
Koetsu and SP-10 maybe not getting along?
maybe, but he might complain about the quality of it and then we would have to fork out big money for an exotic switched type.
And at these voltage levels you would be hard pressed to go wrong with silver solder and solid connections instead of using RCA plugs.
I prefer the sound of Elna Cerafine over Nichicon MUSE caps, sorry to hear that your MUSE caps have gone nuclear in the power supply, this is why I prefer to battery power critical equipment...
And at these voltage levels you would be hard pressed to go wrong with silver solder and solid connections instead of using RCA plugs.
I prefer the sound of Elna Cerafine over Nichicon MUSE caps, sorry to hear that your MUSE caps have gone nuclear in the power supply, this is why I prefer to battery power critical equipment...
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The Elna Cerafine are wonderful sounding caps in this phono section. Or should I say without sound.
Swapped the FT-903(G) for WBT 210 Ag, with excellent results. Sound is bigger, bigger stage, taller images, more low level detail.
No longer aggressive sounding, which I believe is a good thing, as the cartridge is a koetsu black goldline which should not be aggressive sounding to begin with.
No longer aggressive sounding, which I believe is a good thing, as the cartridge is a koetsu black goldline which should not be aggressive sounding to begin with.
A 110K ohm in parallel with the 1K62 will give you very close to 1K596 (1K596448). That should be close enough.
I've build this project and it does sound wonderfull. However I'm struggling to get rid of the humm.
Even more strange...when I mount the PCB in the alu tube, the humm increases.
Any suggestions where I could start looking?
Played with various grounding points for the grounding cable of the turntable and got the hum down but there is stull an audible hum when listening to vinyl.
Thx
Even more strange...when I mount the PCB in the alu tube, the humm increases.
Any suggestions where I could start looking?
Played with various grounding points for the grounding cable of the turntable and got the hum down but there is stull an audible hum when listening to vinyl.
Thx
For the TT ground, I used an insulated speaker post that does NOT touch the chassis.
The chassis is connected to earth/safety ground through one of the PCB standoffs. You must use a metal standoff for this.
The speaker post is connected to power supply common on the RIAA circuit board, not the chassis.
I have no hum at all.
The chassis is connected to earth/safety ground through one of the PCB standoffs. You must use a metal standoff for this.
The speaker post is connected to power supply common on the RIAA circuit board, not the chassis.
I have no hum at all.
Well...This IS how I've connected the grounding.
I'm in the dark as to where I need to look next
I'm in the dark as to where I need to look next
I've disconnected the amp bd from the PWR supply and made a copper casing for the amp. I've checked the output voltage and its clean.
When disconnecting the input I just get a bit of noise (no hum). When I connect the turntable I get a 100hz hum. That is strange to me because I would expect a 50hz hum when the turntable is picking up mains hum.
i use a SME20 / SME-V with Ortofon Rohman
When I disconnect the ground wires from the turntable, I get a bit more hum, but that is 50Hz hum.
100Hz hum would indicate a power supply / after rectification issue but the voltages are OK and I cant see any hum on the output with my scope.
When disconnecting the input I just get a bit of noise (no hum). When I connect the turntable I get a 100hz hum. That is strange to me because I would expect a 50hz hum when the turntable is picking up mains hum.
i use a SME20 / SME-V with Ortofon Rohman
When I disconnect the ground wires from the turntable, I get a bit more hum, but that is 50Hz hum.
100Hz hum would indicate a power supply / after rectification issue but the voltages are OK and I cant see any hum on the output with my scope.
I see no reason why it shoudn't. The only thing that could be changing the interface to the phono is the much larger output impedance of the stepup.
Furher to my humm issue. Today i connected my phono board to alkiline batteries (2x10 AA) = 15-0-15V. There was no hum what so ever.
Question now is: Would this be a ground loop issue or a power supply issue?
Question now is: Would this be a ground loop issue or a power supply issue?