Low-distortion Audio-range Oscillator - Page 102 - 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 4th December 2012, 03:14 AM   #1011
davada is offline davada  Canada
diyAudio Member
 
Join Date: Jul 2004
Location: Fort St John, BC Canada
I put the M1 marker on the 2nd and then brought it down so it easier to see.
Attached Images
File Type: png 2nd H.PNG (446.4 KB, 228 views)
__________________
David.
  Reply With Quote
Old 4th December 2012, 04:28 AM   #1012
richiem is offline richiem  United States
diyAudio Member
 
richiem's Avatar
 
Join Date: Sep 2010
Location: Grapeview, WA
@ Scott & Davada -- I'm impressed all the way around. Nice work.
__________________
...................
Dick Moore
  Reply With Quote
Old 4th December 2012, 08:04 AM   #1013
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Default The Goal is close -- low THD and variable freq -

Cut trace at pin 5? whats on pin 5?

[I did the 50K trim.]
Got that second down there quit aways. I hope the high freq THD are not much different. Then, we'll have a nice flexible, variable freq source.

I have been focused over on the analyzer... Its can be useful for general purpose (?) stand alone bench meter that will work down well below -120. Just a few IC and parts upgrades are all that is needed.

The lower THD limit for a working amp is about .00001%..... plus, external parts and contacts and the like are also at these numbers and you cant make anything real without such external parts.

Thx - RNMarsh [I too am very interested in the QA400.... esp if it is at least as good as this mod 339A]

Last edited by RNMarsh; 4th December 2012 at 08:12 AM.
  Reply With Quote
Old 4th December 2012, 08:13 AM   #1014
richiem is offline richiem  United States
diyAudio Member
 
richiem's Avatar
 
Join Date: Sep 2010
Location: Grapeview, WA
Rick, I think David meant pin 6, to add a small isolating resistance between the output of the amp and the load of the rest of the circuitry. This has worked well for me a couple of times -- I used 47 ohms recently on the output of an LT1468. But I haven't done anything to my 339 as yet -- still have a few other fish to fry first.

We are far from the initial topic of this thread now -- time to make a thread on modding the HP 339A?
__________________
...................
Dick Moore
  Reply With Quote
Old 4th December 2012, 12:58 PM   #1015
davada is offline davada  Canada
diyAudio Member
 
Join Date: Jul 2004
Location: Fort St John, BC Canada
Quote:
Originally Posted by richiem View Post
Rick, I think David meant pin 6, to add a small isolating resistance between the output of the amp and the load of the rest of the circuitry. This has worked well for me a couple of times -- I used 47 ohms recently on the output of an LT1468. But I haven't done anything to my 339 as yet -- still have a few other fish to fry first.

We are far from the initial topic of this thread now -- time to make a thread on modding the HP 339A?
Hi Dick,

Yes I meant pin 6. Sorry. I worked late into the evening got tired.
It is the isolation resistor.

Well we can a have a moderator move all this to a new thread. But I forgot what the topic is. Is this really not fitting? Maybe it's evolved this way.

What does everyone say?

Cheers,
__________________
David.
  Reply With Quote
Old 4th December 2012, 01:38 PM   #1016
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
I think it would be cool to create new board(s) for this analyzer using state of the art parts and then offer a group buy on them. But, I haven't seen this beast so that may be completely impractical.
  Reply With Quote
Old 4th December 2012, 01:43 PM   #1017
davada is offline davada  Canada
diyAudio Member
 
Join Date: Jul 2004
Location: Fort St John, BC Canada
Quote:
Originally Posted by dirkwright View Post
I think it would be cool to create new board(s) for this analyzer using state of the art parts and then offer a group buy on them. But, I haven't seen this beast so that may be completely impractical.
Hi Dirkwright,

At the least it would be incredibly expensive. I not convinced, for the total analyzer performance, it would be worth it. But who knows what will become of this greening.

Cheers,
__________________
David.
  Reply With Quote
Old 4th December 2012, 01:50 PM   #1018
diyAudio Member
 
dirkwright's Avatar
 
Join Date: May 2011
Location: Virginia
Quote:
Originally Posted by davada View Post
Hi Dirkwright,

At the least it would be incredibly expensive. I not convinced, for the total analyzer performance, it would be worth it. But who knows what will become of this greening.

Cheers,
Well, maybe just the oscillator board(s)? Power supply? I dunno, just throwing ideas out there.
  Reply With Quote
Old 4th December 2012, 04:01 PM   #1019
diyAudio Member
 
Join Date: May 2011
Location: Clifton, Maine
Well, as the opening poster it does not matter to me. I like the conversation. Even though I have contributed little past my intitial question, I have faithfully followed this thread. I have learned a lot and serveral members have been very helpful and generous helping me when I did not understand something.

One good point about starting a separate thread is providing an easier search for members in the future specifically looking for HP 339A information.

I recently purchased an HP 339A that was supposed to be fully functional. Unfortunately, it came to me not functioning. I have read the manuals circuit descriptions and studied the schematic and started trouble shooting. I think I have narrowed it down but I am not sure.

Anyone familiar with the HP 339A and willing to provide me a little mentoring on the side via email please PM me.

Regarding my opening post, I have an oscillator that I am quite happy with for my work. It is the HP 239A (which is very similar to the oscillator in the HP 339A Analyzer). And should I need a lower distortion oscillator I have the Victor 1 KHz Oscillator.

Thanks to all!
  Reply With Quote
Old 4th December 2012, 04:44 PM   #1020
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Default Test Equipment forum --

I think just changing the title of the forum to cover low thd oscillator and analyzer mods - Test and Measurment forum; Hardware and software.
So far we have several oscillators to choose from - Victor and Scotts and there are several HP models which could be in the running for upgrades.. like the HP239A. And, there are several measurment products which could be reviewed and discussed. In other words, the full spectrum of sources and analyzers for audio test and measurment. Right now such hard/software is scattered all over the place... speaker builders and thier hard/software etc. Put all the test equipment in a forum (with sub groups) to discuss them and any DIY mods et al and help in using them. Might even include SIM programs (?) Thx-RNMarsh

Last edited by RNMarsh; 4th December 2012 at 05:13 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
Radford Low Distortion Oscillator Series 2 audiomik Equipment & Tools 21 19th February 2014 10:46 AM
ultra-low distortion audio oscillator geekysuavo Analog Line Level 16 26th March 2013 03:04 PM
Low distortion oscillator? rjm Equipment & Tools 30 4th May 2011 10:45 PM
Can we improve this low distortion sine oscillator ? gaetan8888 Solid State 22 29th March 2009 12:30 PM
Simple, low distortion 1kHz oscillator jackinnj Solid State 4 6th October 2003 03:58 AM


New To Site? Need Help?

All times are GMT. The time now is 09:42 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