Differences between HP 8903A and HP 8903B - diyAudio
Go Back   Home > Forums > Design & Build > Equipment & Tools

Equipment & Tools From test equipment to hand tools

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th June 2010, 10:14 PM   #1
cl84 is offline cl84  Germany
diyAudio Member
 
Join Date: Jul 2009
Default Differences between HP 8903A and HP 8903B

Hi all,

at the moment someone from my town is offering a HP 8903A distortion analyzer on ebay. I consider to buy that device, because I save the shipping then. Heavy parcel like test equipment costs a lot (approx $100-$200) when sent from another European country!

While reading some posts here I found out that there are some differences between the 8903A and the 8903B: The B revision offers more possible filters, a true differential input etc.

Especially the fact that the HP 8903A has no true differential input makes me wonder, if I should buy the HP 8903A or if it's better to wait for a 8903B.

I want to measure THD in tube and opamp circuits.

What's the advantage of the true differential input of the 8903B when compared to the input of the 8903A? Or is there no difference between the quality of the results, when the input is floating?

- cl
  Reply With Quote
Old 14th June 2010, 04:34 AM   #2
1audio is offline 1audio  United States
diyAudio Member
 
Join Date: Mar 2004
Location: SF Bay Area
Blog Entries: 3
Differential input is necessary when testing balanced amps. The 8903A can only handle a few volts on its -in before its no longer reading right.

While its not my favorite instrument its good and you don't need the balanced inputs that often, especially for what you are doing.
__________________
Demian Martin
Product Design Services
  Reply With Quote
Old 16th June 2010, 07:34 PM   #3
tomchr is offline tomchr  United States
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Greater Seattle Area
If the price is right, buy it!

The only filters I use are the HP (400 Hz) and LP filters (30 kHz, 80 kHz). There is a fourth filter, which on the B model can be swapped out. I see no use for this for the hobbyist.

If you are measuring single ended circuits, the A version will do just fine. And for differential measurements, as long as the signal amplitude with respect to ground on the (-) terminal is within a few volts you're fine with the A version. I've used my HP8903A for measurements on differential line level circuits with great results.

Should the pseudo-differential input of the A version bother you, just build a differential amp with an LME49710 and some precision resistors. As long as the four resistors in the diff amp are completely balanced, the performance of such a circuit will exceed that of the HP8903A/B.

It's a great instrument. I use mine all the time. The source is good to 0.002 % THD and the analyzer noise floor permits measurements down to 0.005 % or thereabout.

Note that OPT #001 moves the inputs to the rear panel. That's the only difference between the "straight" and OPT 001 versions.

~Tom

Last edited by tomchr; 16th June 2010 at 07:38 PM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale: HP 8903A Audio Analyzer tomchr Swap Meet 11 24th January 2010 08:33 AM
Have you used the HP 3582A? firechief Parts 2 8th April 2009 02:24 AM
Problem with HP 8903B distortion analyzer HighTower Solid State 6 26th December 2008 03:16 AM
hp-8903B advice?? idealinnovat Tubes / Valves 14 5th September 2008 11:23 PM
HP 8903B w/manual Michael Rothacher Swap Meet 0 27th November 2002 04:42 PM


New To Site? Need Help?

All times are GMT. The time now is 02:07 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2