OK, finally I made the cosmetic change and I think the PCB is now ready for production if someone is interested to test it 
May be Peter if you have a lot of PC900 you could make a kit with 1 PCB + 2 tubes ?
I put the last version below, it is also possible to use a smaller MOSFET : the STU9HN65M2 This is what I am using in this RIAA preamplifier and in the Baby Huey amplifier, a very good device
Cheers,
Marc
May be Peter if you have a lot of PC900 you could make a kit with 1 PCB + 2 tubes ?
I put the last version below, it is also possible to use a smaller MOSFET : the STU9HN65M2 This is what I am using in this RIAA preamplifier and in the Baby Huey amplifier, a very good device
Cheers,
Marc
Attachments
I can supply tubes yes. You want me to supply the boards to as reseller ?OK, finally I made the cosmetic change and I think the PCB is now ready for production if someone is interested to test it
May be Peter if you have a lot of PC900 you could make a kit with 1 PCB + 2 tubes ?
I put the last version below, it is also possible to use a smaller MOSFET : the STU9HN65M2 This is what I am using in this RIAA preamplifier and in the Baby Huey amplifier, a very good device
Cheers,
Marc
What about components ? Should i deliver those too ( i guess people have their
own ideas of resistor/cap brands )
Well, i would be happy to do but,
i'm not staffed for international distribution. If needed i will help, but
i will not strive to be an international distributor.
As for EC900 there is a source on ebay :
EI 6HM5 ( EC900 6HA5 6HQ5 ) - former Yugoslavia - MATCHED PAIR - TUBE - NOS | eBay
That might fulfill the need for ec900
If you are using EC97, EC900, 6HM5 or 6HA5 which are all 6.3 V heater, Rh the dropping voltage resistor must be by-passed, it is the best solution however these tube are not easily available and are often much more expensive than PC version
For PC97 4.5 V heater ( https://frank.pocnet.net/sheets/030/p/PC97.pdf ) Rh = 1.8 V / 0.3 A = 6 ohm, 5.6 or 6.8 ohm 3W will be OK
For PC900 3.9 V heater ( https://frank.pocnet.net/sheets/010/p/PC900.pdf ) Rh = 2.4 V / 0.3 A = 8 ohm, use 8.2 ohm 3W...
I will put the Gerber files on the forum since there are several requests, if someone want to make a Group Buy, let me know ?
Best regards,
Marc
For PC97 4.5 V heater ( https://frank.pocnet.net/sheets/030/p/PC97.pdf ) Rh = 1.8 V / 0.3 A = 6 ohm, 5.6 or 6.8 ohm 3W will be OK
For PC900 3.9 V heater ( https://frank.pocnet.net/sheets/010/p/PC900.pdf ) Rh = 2.4 V / 0.3 A = 8 ohm, use 8.2 ohm 3W...
I will put the Gerber files on the forum since there are several requests, if someone want to make a Group Buy, let me know ?
Best regards,
Marc
Hi,
These are two possible power supply for the RIAA preamplifier or the Line preamplifier, both have been built and tested in different systems. I have no more original PCB therefor I made a refresh of these two design with several little improvements, if someone want to make a Group Buy I can send him the Gerber files ? But I am not sure that there will be enough interest, may be Prasi is reading this thread
The first power supply use three 100 V Zener diodes for a fixed 300 V output with a common 115 V + 115 V (or 230 V) transformer, the second one can be adjusted with a on-board resistor and a trimmer (or an external pot). It use the old Maida high voltage concept with modern components which give very good result and low noise.
I have added two pictures of these power supply powering the RIAA preamp and a line preamp...
Cheers,
Marc
These are two possible power supply for the RIAA preamplifier or the Line preamplifier, both have been built and tested in different systems. I have no more original PCB therefor I made a refresh of these two design with several little improvements, if someone want to make a Group Buy I can send him the Gerber files ? But I am not sure that there will be enough interest, may be Prasi is reading this thread
The first power supply use three 100 V Zener diodes for a fixed 300 V output with a common 115 V + 115 V (or 230 V) transformer, the second one can be adjusted with a on-board resistor and a trimmer (or an external pot). It use the old Maida high voltage concept with modern components which give very good result and low noise.
I have added two pictures of these power supply powering the RIAA preamp and a line preamp...
Cheers,
Marc
Attachments
Are you still willing to share your files?
I received the tubes and some other parts to build the riaa preamp.
And if I have PCB's made, I'd certainly be willing to share the 8 PCB's out of the set that I don't use. It's not quite a 'group buy', but would get some of us some PCB's.
I know that it will a challenge. But i will have less hum from the B+, andI am not sure that SMPS would be a good solution for the RIAA amplifier since the input sensitivity is only few mV and it is therefor very sensitive to switching noise
high freq noise can be filtered out, it will take some time to find an optimal
solution.
To the few guys who asked for PCB's, do you have a color preference? The manufacturer I'm planning to use doesn't charge extra for different colors..
Green, Blue, or Matte Black?
I have enough red PCB's.. White would probably get ugly from hand soldering and heat from usage.
Black won't show heat marks, which might be good, but might also be bad, because you can't see which parts are getting too hot.
Anyway, it doesn't really matter. I might have ordered them before I get any replies....
Green, Blue, or Matte Black?
I have enough red PCB's.. White would probably get ugly from hand soldering and heat from usage.
Black won't show heat marks, which might be good, but might also be bad, because you can't see which parts are getting too hot.
Anyway, it doesn't really matter. I might have ordered them before I get any replies....
Please conduct group buy related discussions here: