Cgs synth

Hi,

In the Stomp Box Adapter CGS-60,
which IC would best substitute the TL071 without to many problems...?

NE5534 ?

OP275 ?

Thanks.
Emmanuel

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

On 2005-07-21 20:17 -0000, modulardiyer wrote:

> > In the Stomp Box Adapter CGS-60,
> > which IC would best substitute the TL071 without to many

problems...?

> I understand that the 5532/5534 is conducive to low input
> impedances. Guitar amps have high input impedance, 1M or more.

Yeah ! Thank you for your answer.

I've seen peng3002 swapping results :

MAX437 - I couldn't detect a difference.
OP27 - same.
OP275 - same. This distorted earlier as I raised the input level.
OPA2134 - same

Arghhhh !I have a small stock of expensive op275...

All in all, TL7x are quite good chips compared to the uA741s that
feed most of my pedal/box effect !

Thank you Ken ! ;-)

Emmanuel.