B&K 1607 notch filter activated - Page 4 - 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 October 2013, 11:27 PM   #31
richiem is offline richiem  United States
diyAudio Member
 
richiem's Avatar
 
Join Date: Sep 2010
Location: Grapeview, WA
Overall, the 1468 is a very fine amp, but as with the also outstanding OPA1641, the (very) wide GBW is not necessarily a wonderful thing. In this particular filter, the OPA134 works as well for me as anything and is unconditionally stable. I like all three a lot.
__________________
...................
Dick Moore
  Reply With Quote
Old 11th October 2013, 06:10 PM   #32
diyAudio Member
 
Join Date: Oct 2007
Location: Aarhus, Denmark
@richiem: Thanks for commenting Dick. As it is I happened to buy one too much of the OPA2134 for the HP339A oscillator I'm building so I will start out with that one and see how it works out.

Cheers,

Jesper
__________________
... Being mindful about sustainability also in my audio endeavors matters to me ... paying CO2 - and a quite fair pollution compensation helps create a good listening "energy" ...
  Reply With Quote
Old 11th October 2013, 06:28 PM   #33
diyAudio Member
 
Join Date: Jun 2004
Location: Connecticut
The LT1468 is bipolar input, is it not (10 nA Ibias)?
  Reply With Quote
Old 11th October 2013, 06:40 PM   #34
diyAudio Member
 
Join Date: Oct 2007
Location: Aarhus, Denmark
Yups ... see schematic on p.12 of the datasheet ...

Cheers,

Jesper
__________________
... Being mindful about sustainability also in my audio endeavors matters to me ... paying CO2 - and a quite fair pollution compensation helps create a good listening "energy" ...
  Reply With Quote
Old 11th October 2013, 09:22 PM   #35
1audio is online now 1audio  United States
diyAudio Member
 
Join Date: Mar 2004
Location: SF Bay Area
Blog Entries: 3
Can you post the spice file? It would help.

The buffer will define the performance possible with the notch. The 100 Ohms on the output of the buffer probably is not necessary. I have a preliminary design for a buffer that borrows from some of the Shibasoku input amp but is mixed discrete/IC so its much easier to build. I'll find it and post it. One key issue is making the input impedance as high as possible. Otherwise it can affect the circuit you are testing. The same would be true for the amp at the output of the filter.

I posted an LTspice model in the Shibasoku thread of the bridged t filter they use. It may give some ideas on optimizations.
__________________
Demian Martin
Product Design Services
  Reply With Quote
Old 14th October 2013, 06:57 AM   #36
diyAudio Member
 
Join Date: Oct 2007
Location: Aarhus, Denmark
@1audio:

Quote:
Can you post the spice file? It would help.
Hi ... I actually haven't made a spice simulation of this but calculated the values for the filter from richiem's (Dick Moore's) website. So LTSpice was mainly used to draw up the circuit in the "here and now".

I'm also aware that I'm at a point where I have an inner urge to get this part of my projects completed and ready to use so that my main goal - to accompany listening with measurements on components and circuitry with a quite reasonable degree of precision -can be started.

However, I'm on the side following what you are finding out in the oscillator and shibasoku threads (subscribed).

But thanks for suggesting, Demian

Greetings,

Jesper
__________________
... Being mindful about sustainability also in my audio endeavors matters to me ... paying CO2 - and a quite fair pollution compensation helps create a good listening "energy" ...
  Reply With Quote
Old 9th April 2014, 05:27 AM   #37
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Quote:
Originally Posted by gentlevoice View Post
Hi all,

Inspired by GHG's 1607 modification here I'm considering changing a twin-t that I make for an HP339A oscillator variant (courtesy richiem's webpages) into a passive/active one.

I've calculated some values that should make it possible to switch between 20 Hz, 1200 Hz & 12 kHz (for 48 kHz multiplas) frequencies. I've drawn up a crude schematic for this (there's just a bit in Danish ). The opamps are not LT1007 but OPA2134s.

Might I have your input on whether or not this is correct - and if I should omit/change something:

- e.g. related to the input buffer?
- or remove the 500 ohm potmeter now that there are potmeters across the resistors?

Cheers,

Jesper

Hi,

How did it go? Any progress to tell us about?


THx-RNMarsh
  Reply With Quote
Old 9th April 2014, 06:32 AM   #38
diyAudio Member
 
Join Date: Oct 2007
Location: Aarhus, Denmark
Quote:
Hi,

How did it go? Any progress to tell us about?


THx-RNMarsh
Hi & thanks for asking ... As it is it's progressing slowly.

I had an issue with a high 2nd harmonic on my HP339 variant that I was unable to find out why was there. And then I somehow have happened to break "something" in the oscillator which further increased the distortion - I haven't yet had the time to find out what it is.

Currently I'm making (very) shielded cabinets for the A/D converter, the DUT, the twin-t filters, and the oscillator(s) so as to be able to measure very low levels of distortion/noise also at low frequencies. Battery supplies for all. It takes time, though ... so don't know when there's something to tell ...

Cheers,

Jesper
__________________
... Being mindful about sustainability also in my audio endeavors matters to me ... paying CO2 - and a quite fair pollution compensation helps create a good listening "energy" ...
  Reply With Quote
Old 28th July 2014, 04:51 AM   #39
diyAudio Member
 
SyncTronX's Avatar
 
Join Date: Oct 2008
Location: Tejas, where blues are king
Blog Entries: 2
Default Another Thread

I started another thread. If y'all have any suggestions about
the B&K 1607 I'm cleaning up and trying to fix.

Here is a link to it.

B&K 1607 Repair
__________________
-- Sync
  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
notch filter/shelving filter for Alpair5? mondogenerator Full Range 0 29th June 2011 06:13 PM
Notch Filter Design - Seas L21 (H0955) Breakup Modes:Single or Multiple Notch Filters dtm1962 Multi-Way 10 8th February 2010 02:17 PM
need help wana change 60-Hz twin-T notch filter to 279 Hz filter prorms Solid State 0 9th February 2008 11:38 PM
Can Zaphs notch filter be used without the BSC filter? GuyPanico Full Range 0 21st July 2007 01:27 AM
SS 6600 tweeter & notch filter Virtalahde Multi-Way 0 16th January 2007 02:01 PM


New To Site? Need Help?

All times are GMT. The time now is 11:21 PM.


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