[sdiy] best opamps for line level to synth level preamps

[megaohm]

I've built a bunch of these and similar (EFM) preamp circuits. Some I
used dual opamps, others single opamps. I used this setup to test the
preamps - Serge Gainsbourg mp3s of "Psychasténie" and "Requiem Pour Un
Con" output through a M-Audio Delta 66 soundcard into a Mackie
1604VLZ.I sent the line level outputs into the Preamps (stompbox
adaptors)inputs. Far from the ideal test setup but it's the best I can
do. I've swapped the following opamps for the TL071/TL072:

MAX437 - I couldn't detect a difference.

OP27 - same.

OP275 - same. This distorted earlier as I raised the input level.

OPA2134 - same

I repatched and changed channels so many times I became confused as to
which opamp or preamp channel I was hearing. I thought this would make
me more objective. It must have because I couldn't tell one opamp from
the other.

The circuit itself may have to be tweaked for each opamp to bring out
their best performance. Also, different qualities and size of caps
could play a significant role.
My studio setup may be to blame for the nondifferences between opamps.
I consider it far from ideal.

It would be good if others could give some listening test results
(you, too). Just order samples, bread boad the circuit, and swap
opamps in and out.

peng


--- In cgs_synth at yahoogroups.com, "modulardiyer" <vcrac at h...> wrote:
> Hi,
> 
> In the Stomp Box Adapter CGS-60,
> which IC would best substitute the TL071 without to many problems...?
> 
> NE5534 ?
> 
> OP275 ?
> 
> Thanks.
> Emmanuel