Archive of the former Yahoo!Groups mailing list: MOTM

Steering back to topic for a bit..... :)

I hope that as MOTM user, you can easily hear the overall sonic difference
between MOTM and you other synths.
Not in terms of types of sounds, but in general terms: noise floor, dynamic
range, sonic 'impact', etc.

Although I'm NOT one to use $1200 interconnect cables (I made mine for $25,
and they are Teflon), I can
say as an audio designer there are most definitely things you can do to
drastically elevate your audio
quality at the component level.

For example: when I was at Tandy I was given the task to design a small home
stereo (like 15W/ch) with a
digital display (all Radio Shack low end models used 'slide rule' tuners).
The #1 supplier of ICs for stereos
is Sanyo. I got out their lather large catalog/data sheets and started
looking for FM PLLs. Sure enough, they
had 3 seperate FM decoders. The low end, the mid, and the super-whiz bang.
The differences in specs was quite
large: the super whiz-bang had specs that were close to $600 discrete tuners
(like Marantz). I figured this
chip was big $$$, but just for fun I had Sanyo quote all three (at 50K/yr).
I was stunned to see the prices!
They were like:

low end $0.34ea
mid $0.47
super-whiz bang $0.94

I had about 40 different reveiver schematics (Pioneer, Technics, etc. This
was 1981). EVERY SINGLE ONE that
used Sanyo chips used the cheap one! It didn't matter if the retail price
was $100 or $500. Just shove in the cheap-o, baby!

The moral: sometimes getting really suberb sound is adding $1 to the cost at
the component level.

What I do is use the really good op amps. The world's standard "audio op
amp" is the 4558. This is a bipolar
op amp (noisy) that is just a 'souped-up' LM1458 (faster slew, higher GB).
NEC rep told me (in 1983) that they
made 1 million A WEEK. If you open up any Japanese audio product, you will
see 4558s. What cracks me up is seeing
16bit ADC or DACs with 4558s (Roland D-50, Yamaha FS1R, etc). They are not
bad but ∗certainly∗ not audiophile!
The OP275s blow away the 4558. Heck, a TL072 in most cases blows them away.
We use them only to replicate
the timbe of say the MS-20. 4558s have a indentifiable 'bipolar' sound. Very
'70s.

There are other examples, but I'll do 1 more. A huge contributor to "so-so
audio" are 3-terminal regualtors. The
VERY FIRST design decision I made for MOTM was NOT to use them as the main
supplies. That's why we use
the LM723-based Power One supplies. The LM723 is 10 TIMES better, but it's
not as easy to design with. I once
opened a $400 mic preamp that had fancy DC servo'd gain stages, decent
Burr-Brown op amps but LM7812/7912
voltage regulators! The owner was saying that this amp just didn't have the
"air" of other amps. We took out
the regulators, and ran a Power One over there. The difference was
IMMEDIATE! It just sounded better.

A heard a Fenix once. It sounded "muffled" and "bipolar" to me (I have very
good high frequency hearing).
I talked the owner to popping the lid. Sure enough: LM78xx/79xx regulators
and 4558 op amps. These designs
will have less 'punch' or 'oommph' or whatever adjective to MOTM.

Paul S.