On Mon, Nov 23, 2015 at 07:06:59PM +0000, Mark Sims wrote:

Hello Mark.

Yes, the AM502 is the thing I am searching, but they are not very cheap for
a 1977 vintage, in particular adding the mainframe.

It's possible that in 38 years no maker did anything like?
Looking better, all other modules I saw aren't equipped with front panel output,
because are in effect vertical oscilloscope amplifiers and thus the output is
on the backplane. And they are not cheap also.

Best regards,
Andrea Baldoni

Andrea
I would recommend the Tektronix AM502 if you can find one  - an excellent
unit. The TM501 mainframes are quite numerous, and are quite inexpensive -
also the TM503, some of these were on offer from a European dealer recently.
Good luck.
Roy Phillips

-----Original Message-----
From: Andrea Baldoni
Sent: Monday, November 23, 2015 8:00 PM
To: Discussion of precise voltage measurement
Subject: Re: [volt-nuts] Differential amplifier >=1Mhz

On Mon, Nov 23, 2015 at 07:06:59PM +0000, Mark Sims wrote:

Hello Mark.

Yes, the AM502 is the thing I am searching, but they are not very cheap for
a 1977 vintage, in particular adding the mainframe.

It's possible that in 38 years no maker did anything like?
Looking better, all other modules I saw aren't equipped with front panel
output,
because are in effect vertical oscilloscope amplifiers and thus the output
is
on the backplane. And they are not cheap also.

Best regards,
Andrea Baldoni

volt-nuts mailing list -- volt-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts
and follow the instructions there.

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7227 / Virus Database: 4460/11053 - Release Date: 11/23/15

The problem is a stand alone diff amp is going to be a low volume thing to
sell

Two of the best ones (one no longer made) are the Preamble DA1820/1822(A)
and DA1855(A)

http://cdn.teledynelecroy.com/files/manuals/da1820-1822_om.pdf

They were bought out by LeCroy and then LeCroy by Teledyne.

The 1855 (and 1855A) sell for quite a bit expect to pay around $1000 for
one.
I've seen 1822's for less the $200 but you have to have auto notify on the
auction sites set up.

I got one on the big auction site for $100 as a Buy-it-now. But that was
just luck.

Outside of the physics/chem/bio market there isn't anything.. a quick scan
on Google

http://www.tegam.com/product.asp?modelNumber=4040B

https://www.a-msystems.com/s-130-acdc-differential-amplifier-model-3000.aspx

http://www.bakelectronicsinc.com/2-3.html

On Mon, Nov 23, 2015 at 12:00 PM, Andrea Baldoni erm191ba3@ermione.com
wrote:

On Mon, Nov 23, 2015 at 12:35:29PM -0800, Pete Lancashire wrote:

At this point I think I'm trying to solve a problem everyone (except in
very rare cases) solves in another way, so it's me I'm wrong.

Anyway thank everyone for all the suggestions; I set up the auto notify for
everything and let's see.

Just there are so many "strange things" around like the XL741 that are of
very dubious sell

http://shop.evilmadscientist.com/productsmenu/762

that what I think is a useful item had not to be so rare.

By the way, if I can open-design one, what features should it have? Anyone
interested?

Best regards,
Andrea Baldoni