What do we know about....

[al newall]

TL072CP opamps?

I spotted a battered old phono amp in a secondhand shop, and the seller didn't know if it worked or not. So I coughed up a fiver after some serious negotiation.
Big money by my standards.

Its an EMO branded pro type ( Made in England) thing with XLR balanced or unbalanced output.
Works nicely, and is a step up from the plastic box phono, in terms of clarity and noise.
But its got a rather uninviting, cold
and not particularly dynamic sound.. Like a cheap seventies reciever.

Can't find out much about the internal TL072 opamps, except they're considered obselete, and scorned by many and liked by a few. Used in a lot of studio and instrument stuff.

Anyone ever come across these phonos/opamps.
Would anyone like to hazard a guess if its worth doing a little opamp rolling, or tell me that i'm wasting my time.
I won't cry.
Much.

[Mike H]

If I remember right they're supposed to be ultra-low noise hi-fi / instrumentation quality, tho depends by whose standards. Might account for the 'flat' sound, they're "too good". I might have some but never tried 'em.

If you wanted to be really adventurous you could make up your own op-amps using discrete trannies.

[cressy]

discrete trannies.

is there such a thing, look at lily savage! (bad schoolboy humour )

[pre65]

In my young and innocent days I used to buy Exchange and Mart for the car ads (before Auto Trader and the interweb !) and was puzzled by the back page ads for TV clothing.

I wondered why anyone would dress up like that to watch the telly.

Oh to recapture the age of innocence.

[Neal]

AL, the LM4562 is a much better and modern opamp, you may struggle to get them as DIP and would need the SMD version and something like a Browndog adapter.

Or you can go for other dual packages like the OPA2604, OPA2134 or AD826

I would avoid the ultra wide bandwidth types like the LM6172 as they could oscillate in cct.

[al newall]

I agree Neal. It's the worry of putting something new in an old circuit that's held me back from rushing out and buying.
From what bit i've read, it seems the 4562 is a fairly safe bet.
There's a couple on Epay.

[Neal]

AL, you may need to look at the decoupling on the board it may not suit the 4562 fully, check the datasheet for recommendations, I would suspect you may need a .1uf small film cap accross the - and + supply right under the opamp...assuming it uses a balanced supply...

[Mike H]

discrete trannies.

is there such a thing, look at lily savage! (bad schoolboy humour )

Indiscrete trannies?

[al newall]

Well i've just put a pair of temporary 5532s in with no other mods, and things seem ok.
A much more pleasant sound now, but perhaps not a radical improvement in other areas.
At least its a bit easier on the ears. Might be able to hear it better later on, when the washer and dryer have finished.