Hy, i'm planing on building a phono pre-amplifier and i found a scheme on the net, but i have one question about the grounding of the circuit. The original scheme i found is part of an amplifier, but i extracted only the phono stage from it. Here are the two images for the phono stage and psu (only the bridge part).
I've also started working on the pcb, and i will post that any time soon. Till then i'm waiting for opinions.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I've also started working on the pcb, and i will post that any time soon. Till then i'm waiting for opinions.
I know this is a very old post but I hope someone will advise me.
Does the RIAA circuit above require an additional circuit to be added to the outputs to provide enough gain to feed my preamp?
If so does the gain of the circuit using the jrc2068dd effect the choice of op amp in the 2nd stage?
If a 2nd stage is required I like use a AD825 (or OPA827, OPA1641 or AD797) but don't know where to find suitable designs that would be compatible with the above circuit.
hope someone can help I can't keep rolling op amps in my first diy phono stage (bozure)
that uses opa2134 and expect them to be properly implemented.
thanks
Does the RIAA circuit above require an additional circuit to be added to the outputs to provide enough gain to feed my preamp?
If so does the gain of the circuit using the jrc2068dd effect the choice of op amp in the 2nd stage?
If a 2nd stage is required I like use a AD825 (or OPA827, OPA1641 or AD797) but don't know where to find suitable designs that would be compatible with the above circuit.
hope someone can help I can't keep rolling op amps in my first diy phono stage (bozure)
that uses opa2134 and expect them to be properly implemented.
thanks
The circuit outputs a "line level" amplitude signal and does not need extra gain. It is intended to feed into a standard "aux" "tape" "line level" input etc.
I would think something like the LM4562 would be most suited to something like this, both for noise, drive ability of the feedback/shunt elements and for bandwidth (that single opamp is used at high gain)
I would think something like the LM4562 would be most suited to something like this, both for noise, drive ability of the feedback/shunt elements and for bandwidth (that single opamp is used at high gain)
Thanks for you advice and suggestions.
I have already given the lm4562 a go and found it a bit too revealing for the type of music I was intending to use the preamp with thats why I chose the 2068dd.
My dj mixer uses 2068d and although its not a great mixer I like the way the music feels and general vibe it has.
I was hoping to build a 2 stage circuit with riaa correction then a output buffer
the first stage using the jrc2068d and buffer using a jrc4556ad or another bipolar op amp.
I am having a bit of trouble locating suitable circuits if you could let me know where I might find some I'd appreciate it.
thanks again
I have already given the lm4562 a go and found it a bit too revealing for the type of music I was intending to use the preamp with thats why I chose the 2068dd.
My dj mixer uses 2068d and although its not a great mixer I like the way the music feels and general vibe it has.
I was hoping to build a 2 stage circuit with riaa correction then a output buffer
the first stage using the jrc2068d and buffer using a jrc4556ad or another bipolar op amp.
I am having a bit of trouble locating suitable circuits if you could let me know where I might find some I'd appreciate it.
thanks again
I found this information yesterday, looks to be a fine MM phono-amp.
If you look at many fine, hi-end phono amp designs, from the likes of Sansui(AU-919),Pioneer(A27/90), they usually used jfet inputs. If you want MM, many examples as well.
Linear Systems || Literature
http://www.linearsystems.com/assets...LSK489_Application_Note_Preliminary_Draft.pdf
Have fun!!
If you look at many fine, hi-end phono amp designs, from the likes of Sansui(AU-919),Pioneer(A27/90), they usually used jfet inputs. If you want MM, many examples as well.
Linear Systems || Literature
http://www.linearsystems.com/assets...LSK489_Application_Note_Preliminary_Draft.pdf
Have fun!!
If you find the LM4562 a bit cold and clinical then it might be worth trying the OPA2604 which is very "musical" (don't like using terms like that but it really is)
Hi Mooly,,
Yes I need to give the OPA2604 a try, Bob Cordell seems to think so, from the gain Clone.
What did you think of Bob's app note LSK489, he wrote for Linear Systems? Hi Ciss = Hi IMD?
Still think that a BF862 is a finer part, too bad they do not make a dual, so have to select them instead.
Need to get a copy of the Vinyl Track Article that he wrote in Linear Audio, as well
Yes I need to give the OPA2604 a try, Bob Cordell seems to think so, from the gain Clone.
What did you think of Bob's app note LSK489, he wrote for Linear Systems? Hi Ciss = Hi IMD?
Still think that a BF862 is a finer part, too bad they do not make a dual, so have to select them instead.
Need to get a copy of the Vinyl Track Article that he wrote in Linear Audio, as well
the user guide shows a typical 5mV mismatch of the matched pair.
That is similar to the mismatch quoted in the LSK389 and 2SK389 datasheets.
You can do much better with hand selecting just the Idss.
Then thermally couple them.
You can also hand match for gm and then you have a far better pair than the 389
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.