Dear folks,
To be sure, I am very proud of the 31B amp that I designed. It was the first
dual-differential full-complementary amp in the world. It was the model for all
that followed. I believe if my memory serves me correctly that SAE made around
50,000 units. It has miraculously proven to be exceedingly reliable. As far as
the output devices go, I wouldn't worry to much about them. If they haven't
failed by this time, they will probably last forever. Motorola (now "ON"
semiconductor) does have a much newer and much stronger set of devices that can
be used if necessary however, the old saying still applies ie: if it ain't
broke, don't fix it. I would also strongly recommend that anyone into upgrading
these amps seriously consider replacing all of the comp caps with dipped
silvered mica types. Also, replace all of the ceramic bypass caps with high
frequency dipped polyesters. Also, replace the input and output jacks with gold
types. Finally and most important, REFURBISH ALL OF THE GROUNDS and check for
cold or poor solder joints. These things creep up on you over time. All for now.
James Bongiorno
gurriesm wrote:
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From: gurriesm <gurriesm@...>
Hi Luther
From: "Wardsweb" <wardsweb@...>
Where shall I jump in here? Well, I plan on posting pdf's for most all the
01/02 series owners manuals, some white papers and sales literature. I
collect almost exclusively the 01/02 Computer Direct-Line gear. My only
other gear at present are a 4000 and 4200.
I have some O1 and 02 literature to share. I will make a list and send
it to you. I was going half to do that anyway.
I own a T101 turner and I like it a lot. James thinks that might be the
best SAE tuner. The C101 I have is not a Nakamichi, but it is nice. I
have the original service manual for the C101. I also have the E101.
That works nice except there is a level left right level imbalance when
it inserted into the audio path with all flat settings (Default). In
other words, you here difference when you active it or bypass it with the
Line EQ button. I liked the E101 because it effects both left and right
channels exactly the same at the same time with one adjustment. The
Older 2800 type have separate left and right controls. They look cool,
but how often does one need to have separate controls for left and right.
I rather have more parametric controls for both than duplicate controls
for left and right. I buy the 01 and 02 stuff also because it takes less
rack space. So as much as I criticize it, I still buy it.
The LED module used on most the 01/02 are plug-in. Mark, you most likely
figured it out, when you remove the face plate pcb, the modules are glued
to the face plate. Most times I find the led has a burnt out segment and
you can just plug in another. That is, if you have a hanger queen to rob
from. I pick up most any non-working units I can, just to have for future
parts needs.
Yep, that what I have to do.
I'm trying to get Morris to remember who the parts manager was when the
company was sold to "?". When the company "?" sold to DAK they started the
SAE TWO mass market gear. Anyone correct me on this. Anyway, as the
company went thru different hand, so did the inventory and parts. Someone
somewhere has this stuff crated sitting on a shelf.
Hopefully we can find that "holy grail" of parts. I be willing to go in
on a buy of parts if we could locate them.
As James has pointed out, a really big problem is going to be the original
output transistors in the XX00 gear. All the major manufacturers have
stopped producing in this case.
True. But you can modify the equipment to work with the newer
transistors. The problem is the new ones are faster than the old ones.
It can lead to high frequency instability. You half to compensate for
the speed in the feedback and drive circuitry. James has already figured
out what to do. I have some parts in stock at home that will work as a
direct substitutes for 200W or less amps depending on the model. I
purchased some MJ15003 and MJ15004 a while back. It the 2n6XXX
darlingtons in my MK 31B that worries me the most. I have not looked to
see if I can still buy those. My 31B (XXX1B) that is my favorite. I
modified it a lot. I upgraded the bridge rectifier, added 40000uF to get
a awesome 60000uF of low ESR capacitance for the +/- 40V supplies using
12AWG wire soldered directly to the output transistors. I removed the
current limiting. Installed speaker fuses. Put polystyrene caps in
parallel with the input AL caps. Upgraded the floating regulator cap.
This amp got guts and clean highs. Everyone who has hear is surprised
how powerful and clean it is.
----- Original Message -----
From: gurriesm
To: $SAE
Sent: Friday, January 28, 2000 5:02 PM
Subject: Re: [SAE_Talk] C102
From: gurriesm <gurriesm@...>
Some of us on this list are actively pooling our existing resources and
trying to locate additional information and data on any SAE products. We
also want to build a knowledge data base about repairs and upgrades.
Finding parts sources is even more elusive. We believe we have secured a
lot of information about the SAE products up to but NOT including the
"01" series and plan to put together a new SAE website, based on the
exiting website, with all this information for down load. Check the
SAE_TALK onelist website links area for the existing web site address and
other cool websites like for GAS. The goal of our effort here is SAE
preservation. However, depending on the series, the newer the SAE unit
is the less information we got!!!
.....snip.....
So what does this all mean for your tape deck and for my CD players? I
do not expect one should assume SAE quality and reputation for products
that the SAE that we really know could not possibly make on its own.
Also given the age and reliability of the technology at the time,
problems are going to show up and all the equipment including mine will
someday be unrepairable. But as long as there are traditional multiple
sourced op-amps, bipolar transistors and such, the Amps, EQ's, PreAmps,
and Tuners that were made in the USA should live a longer life than the
Inkel stuff. My worse fear for older SAE stuff is finding linear slide
pots and push buttons for the PreAmps and EQ's. I see a growing need for
Part Boxes in the future.
Best Regards,
Mark Gurries
Best Regards,
Mark Gurries
----------------------------------------------------------
Battery Charging and Power Systems Application Engineer
Linear Technology,1630 McCarthy Blvd, Milpitas, CA, 95035
WRK(408) 954-8400 x3864 Email: gurriesm@...
FAX(408) 428-9413 WebSite:
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