Distortion Meter Suggestions

I use a Prologix GPIB adapter and Windows software I wrote myself in my favorite compiled language, PowerBASIC. I'm willing to share it, but it's specific to the Prologix adapter only. If you search a bit, there's at least one other sw out there for a different adapter.
 
I use a Prologix GPIB adapter and Windows software I wrote myself in my favorite compiled language, PowerBASIC. I'm willing to share it, but it's specific to the Prologix adapter only. If you search a bit, there's at least one other sw out there for a different adapter.

I am also using the Prologix GPIB adapter with my Rhode & Schwarz UPA Analyzer,but with software I found on the internet. Not great. I would love to try something better;)
 
A given adapter is usually straightforward to communicate with, as they provide a dll or other interface. Instruments are another story. Everybody has a different way to command different functions, but once you get one command working, the rest are usually easy. Rhode & Schwartz makes some really nice stuff that's well above my pay grade. A quick look at the features suggests it has a lot in common with the HP unit. Do you have any programming experience?
 
There are used Sound Technology units floating about, which are pretty decent if the photo couplers aren't shot.

For the 1701A, add "and if all the switches still work". The longer mine went without being used the worse it got. I finally bailed on it.
 
+1 for a 8903B, I got mine with Ray's help a little while back and it works great, the internal signal gen on mine can do about .0015%, more than low enough for almost any amp I'll ever test.
 
+1 for a 8903B, I got mine with Ray's help a little while back and it works great, the internal signal gen on mine can do about .0015%, more than low enough for almost any amp I'll ever test.
Thanks for chiming in, Matt. I bought the rest of the 8903B's that Mike had that met spec when looped to themselves. Figured I'd offer them here but never got around to it. Seems like I've always got stuff to do!
 
Thanks for chiming in, Matt. I bought the rest of the 8903B's that Mike had that met spec when looped to themselves. Figured I'd offer them here but never got around to it. Seems like I've always got stuff to do!

I know how that feels Ray. I have a couple of Amber 3501's that I've been meaning to ''liquidate'' (just how many distortion analyzers does one man need anyways?) but I never seem to get around to it either. At least they are a lot smaller tha the HP's:rolleyes:
 
I bought one of them and all the buttons were stuck in when it arrived due to crappy packaging by the seller
The seller is a prick and started being very agressive stating I had broken it ?, anyway paypal gave me a refund and I sent it back
I wouldnt get another one it did seem cheap IMO

I ended up buying one of these ferrograph units, just need to work out how to use it

IMG_2968 by Alan Towell, on Flickr

Alan
 
I bought one of them and all the buttons were stuck in when it arrived due to crappy packaging by the seller
The seller is a prick and started being very agressive stating I had broken it ?, anyway paypal gave me a refund and I sent it back
I wouldnt get another one it did seem cheap IMO

I ended up buying one of these ferrograph units, just need to work out how to use it

IMG_2968 by Alan Towell, on Flickr

Alan
Alan, those look like cool old units. I did a search for them and found this:

http://www.audiomasterclass.com/new...distortion-using-the-ferrograph-rts2-test-set

Looks similar to the procedure for the old HP distortion analyzers.
 
BTW, the 8903b has five potential filter options and will usually have the wrong one. It's hard to believe that somebody went to the trouble, but this is a cute little solution, assuming he still has them- http://www.deckardaudio.com/products/HP8903Bfilter.php

The Amber 3501's aren't much better.The majority of them (around here,at least) seem to have been factory equipped with telecom-oriented filters.Mind you,this is easily remedied,as most of the types needed for audio work are the A-types that are constructed on 16 pin dip plugins. The specs and diagrams for these networks were thoughtfully included in the manual:)

I would love to find the reverse RIAA filter network,but that was one of the C-types constructed on a rather large PCB.
 
One could conceivably implement most any filter on the little board. I got one, but haven't had time to play with it. What I wanted was A weighting for "other" projects, not the C-message my machine came with. IMO, a reverse RIAA needs to be done between the generator and the preamp, not at the output where the THD meter would see it. Overload and all that. Plus, at the input, the usual inverse RIAA will also attenuate a large signal down to the mV required at the phono input.
 
I wasn't all that happy with the budget vs. what was available as a common go to. Ended up building the Pete Millett atest box.
There was already a good external sound card here and everything else that I needed. The most expensive part was the display which I found new on ebay for a fraction of the cost. The display isn't absolutely required either.
 
Does anyone have a good suggestion on acquiring a decent distortion meter without breaking the bank? I've not seen any on eBay that appear to be of any quality for less than $300, and there's no guarantee that the used ones for that price actually work correctly. There's also some brand new Chinese units that ship from overseas for just over $300, but I don't trust them to be any good. I've also watched Craigslist for a while to no avail.
Are you trying to read THD or the full spectrum of distortion?
 
The Chinese AP’s are not a great buy. I have had several System One in my shop for repair and some of them were basket cases. BIG THUMBS repair’s, burnt PCB’s and others with missing parts. I worked for AP for many years and service old unsupported systems. A System One in good working order usually goes for $2000-$3500. Looking I recommend the QA401 as an instrument and it is $450.

Duke
 
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