Pio1980
AK Member
I will be very interested how this one does compared to your original .
DIY High or Low Ouput Moving Coil Phono Stage
- Thread starter HypnoToad
- Start date
I will be very interested how this one does compared to your original .
Only the parts listed for the Phonoclone, not the X-Reg.
You will also need a DPDT switch, a LED, 8.2k resistor for the LED, and 2 sets of RCA's and wire etc.
From Mouser I use these:
2 X 568-NYS367-2 Red RCA
2 X 568-NYS367-9 White RCA
1 X 696-SSL-LX5093IT Std Red LED
1 X 71-RN60D-F-8.2K Resistor 8.2k current limiting for LED.
One of these toggle switches should be fine: 506-A205P3YZQ04
For RIAA capacitors I get 8 of these:
505-FKP21000/100/2.5 Pulse Film Capacitors 100V 1000pF 2.5%
The 2 X 2.2uf output caps you can use these:
667-ECW-F2225JA Panasonic 2.2uF 250V 5% METAL POLY
If you have trouble with the other components just ask.:yes:
I etched the PCB and already soldered a few components that I had on hand, the rest are on order from Mouser and will be here next week.
It's still 3" X 4" but fingers crossed it works well. I put the 0.1uf ceramic caps on the supply rails as close as I can get them to the op amp voltage inputs.
The main thing is I am putting these in for R1 & R2 so the resistors can be changed out quickly, no soldering, it will make it much easier when changing carts and adjusting the gain.
Pio1980
AK Member
I etched the PCB and already soldered a few components that I had on hand, the rest are on order from Mouser and will be here next week.
It's still 3" X 4" but fingers crossed it works well. I put the 0.1uf ceramic caps on the supply rails as close as I can get them to the op amp voltage inputs.
The main thing is I am putting these in for R1 & R2 so the resistors can be changed out quickly, no soldering, it will make it much easier when changing carts and adjusting the gain.
I had these with the Chinese line preamp kits, check tightness occasionally after assembly. I'd use micro-pin sockets instead as spring pressure maintains contact integrity.
I did toy with the idea of using those but the legs of the thicker vishay-dale resistors won't fit so went with these.
The latest iteration of the PC3, the dual circuit op amp version, with screw in terminal blocks for the gain resistors, no soldering involved in swapping them out. This will make cart swapping a breeze, I used the 10mm wide ones but the 7mm's should be fine as these are a bit big IMO.
I used some 1.5uf Panasonic ECW Polypropylene's as the output caps, it has spare slots for the 0.1uf caps as well for the detail freaks.
I put in a pair of AD823's and fired it up, sounds fine, has all the fine traits of the original but a little more forward with the AD823's. Other candidates would be OPA2134's and LME49720's for a start. It's certainly a cheap and easy build that's for sure and offers fantastic bang for you buck, you would be hard pressed to find something commercially made under a grand that would compare IMO.
I used some 1.5uf Panasonic ECW Polypropylene's as the output caps, it has spare slots for the 0.1uf caps as well for the detail freaks.
I put in a pair of AD823's and fired it up, sounds fine, has all the fine traits of the original but a little more forward with the AD823's. Other candidates would be OPA2134's and LME49720's for a start. It's certainly a cheap and easy build that's for sure and offers fantastic bang for you buck, you would be hard pressed to find something commercially made under a grand that would compare IMO.
Fasterdamnit
Super Member
Another home run, Phillip! Thanks!!
IC sockets and RF
I recently installed IC sockets for R1 in each channel so I could re-tune the HypnoPC3 for my Talisman LOMC. Now I notice that I'm getting a bit of RF at extremely high volume with no record playing (arm in the armrest). Not a big deal at all since it's only audible at approx 3 times my maximum listening level. I'd be afraid to drop the needle in the groove at this horsepower level!
I know it's RF cause I can hear music, etc from a radio station!
I'm wondering if installing the IC sockets with press-fit resistors would account for this?
I recently installed IC sockets for R1 in each channel so I could re-tune the HypnoPC3 for my Talisman LOMC. Now I notice that I'm getting a bit of RF at extremely high volume with no record playing (arm in the armrest). Not a big deal at all since it's only audible at approx 3 times my maximum listening level. I'd be afraid to drop the needle in the groove at this horsepower level!
I know it's RF cause I can hear music, etc from a radio station!
I'm wondering if installing the IC sockets with press-fit resistors would account for this?
I had to look at the schematic. R1 is grounded on one end.
I would suspect that R2 would more likely cause RF because of the position in the circuit.
I would suspect that R2 would more likely cause RF because of the position in the circuit.
If you want to get rid of it you can put in some 100pf caps across the input RCA's, like Steve was talking about, it would have little if any affect on the response of the cart, but I would only do that if it's annoying you.
I wonder if the poorly shielded OEM interconnects coming from my QL-A75 could have anything to do with it? It's long overdue for a upgrade anyway. Perhaps I should order a pair of those panel mount RCAs along with the 100pf's and fix it properly.
Poorly shielded interconnects could have everything to do with it, change those out first and see how it is.
For want of better things to do I have been playing around with the two op amp version and found that a OPA2134 in the first stage and the AD823 in the second is really good. It's still opening up but sounds as sweet as sweet with the combo. Having both AD823's was a bit two forward in the top end IMO. I will have to check it out with the scope to see how it measures up. But the OPA2134/AD823 is as good as I have heard.
The BB's have always been a bit too laid back for me but in this circuit they really perform well.
I etched the PCB and already soldered a few components that I had on hand, the rest are on order from Mouser and will be here next week.
It's still 3" X 4" but fingers crossed it works well. I put the 0.1uf ceramic caps on the supply rails as close as I can get them to the op amp voltage inputs.
The main thing is I am putting these in for R1 & R2 so the resistors can be changed out quickly, no soldering, it will make it much easier when changing carts and adjusting the gain.
Philip,
Do you have a part number on this? Is it Mouser?
Scott