Dear All,
I am thinking about putting together a phono stage based around the S&B stepup and riaa transformers. To go with this I will need some sort of buffer amp preferably discrete. I am considering the Welbourne labs miniamp, the borbely super buffer and the lcaudio zapfilter2, along with their corresponding PSUs. I am not a electronics wizard so a third party unit is the only option. Is anyone aware of any other transistor based options? Gain needs to be about 2500 overall but this could be achieved in two stages. The riaa and stepup seem to cancel each other out at a gain and loss of 20db respectively but the stepup could go up to a gain of 26 dB.
The unit would then feed my existing preamp or perhaps I would switch to the S&B attenuation transformer so the buffer would need to be able to drive difficult loads.
Regards,
Nick.
I am thinking about putting together a phono stage based around the S&B stepup and riaa transformers. To go with this I will need some sort of buffer amp preferably discrete. I am considering the Welbourne labs miniamp, the borbely super buffer and the lcaudio zapfilter2, along with their corresponding PSUs. I am not a electronics wizard so a third party unit is the only option. Is anyone aware of any other transistor based options? Gain needs to be about 2500 overall but this could be achieved in two stages. The riaa and stepup seem to cancel each other out at a gain and loss of 20db respectively but the stepup could go up to a gain of 26 dB.
The unit would then feed my existing preamp or perhaps I would switch to the S&B attenuation transformer so the buffer would need to be able to drive difficult loads.
Regards,
Nick.
Addition
Or peranders discrete diamond buffer...
http://home.swipnet.se/~w-50719/hifi/qrv05/index.html
Can this type of approach be reconfigured for gain?
Or peranders discrete diamond buffer...
http://home.swipnet.se/~w-50719/hifi/qrv05/index.html
Can this type of approach be reconfigured for gain?
Hi bovizier,
which source do you thinking of? MC?
Do you mean this configuration:
stepup transformer -> buffer -> riaa transformer
If so, I don't think it works. A gain of 2500 by simply using a transformer is impossible. A transformer can do 1 : 10, maybe 1 : 100 with a reduced bandwidth. If you want to do a 1 : 2500 stepup you also do a 1 : (2500)^2 = 1:6.250.000 impedance transformation. If your buffer has a 10meg input impedance your input impedance of the transformer is less than 2 ohms which loads your cartridge. The same with capacitors: A buffer input capacitance of 10pF (typical) gives a 62.5µF load of your cartridge.
which source do you thinking of? MC?
Do you mean this configuration:
stepup transformer -> buffer -> riaa transformer
If so, I don't think it works. A gain of 2500 by simply using a transformer is impossible. A transformer can do 1 : 10, maybe 1 : 100 with a reduced bandwidth. If you want to do a 1 : 2500 stepup you also do a 1 : (2500)^2 = 1:6.250.000 impedance transformation. If your buffer has a 10meg input impedance your input impedance of the transformer is less than 2 ohms which loads your cartridge. The same with capacitors: A buffer input capacitance of 10pF (typical) gives a 62.5µF load of your cartridge.
phono
Thats right the transformer cant provide all that gain of course. Given that the transfomrer and RIAA virtually cancel out in terms of gain all of the gain of 2500 will need to be provided using active gain stages. At least one and possibly two. Which is why I was looking at the borbely super buffer or the zap filter. The borbely has 66 db OLG so that might do it at a pinch.
I am referring to the two units produced by Stevens and Billington. One is a step up transformer and the other provides the RIAA EQ.
Its an MC cartridge - brinkmann EMT.
From what you have said of the diamond buffer it is just a buffer and cant provide gain.
Thats right the transformer cant provide all that gain of course. Given that the transfomrer and RIAA virtually cancel out in terms of gain all of the gain of 2500 will need to be provided using active gain stages. At least one and possibly two. Which is why I was looking at the borbely super buffer or the zap filter. The borbely has 66 db OLG so that might do it at a pinch.
I am referring to the two units produced by Stevens and Billington. One is a step up transformer and the other provides the RIAA EQ.
Its an MC cartridge - brinkmann EMT.
From what you have said of the diamond buffer it is just a buffer and cant provide gain.
The idea is shown here:
http://www.stevens-billington.co.uk/riaapage.htm
Power or voltage in the first place?
Regards,
Milan
http://www.stevens-billington.co.uk/riaapage.htm
peranders said:
Power or voltage in the first place?
Regards,
Milan
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.