Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Unusual filtering scheme question
Unusual filtering scheme question
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
Thread Tools Search this Thread
Old 5th March 2013, 11:57 PM   #31
ITPhoenix is offline ITPhoenix  United States
diyAudio Member
Join Date: Mar 2012
Location: New York
Originally Posted by GoatGuy View Post

The original question was "what is that 1 ohm 17 watt wire-wound resistor doing in series with the 560 nF power supply distal capacitor? There have been a number of answers, but the best were along the lines of a high-frequency snubber. Indeed - if the amplifier sections are prone to HF (radio frequency) oscillation, then a whole lot of oscillation can travel down those power-supply wires. If the power supply has "naked caps" along the chain, they can aggravate - increase - the RF feedback problem. Having a moderately resistive cap could serve to quench RF oscillation before it gets carried away.

Apart from that though, it serves little to no other purpose. It might very slightly take the edge off the most spiky treble passages ... if the wiring from power supply to that last distal capacitor is long, and of thin-gauge wire (intentionally having a very low resistance element in series with the main power supply!) I've done this before, with results that are surprisingly good. But by no means am I advocating it. It takes careful calculation, and actually finding the right kind of wire to do the job in just the right way.

Anyone remember when all turntables had tall spindles where one could [horrors!] stack LPs to DROP onto each other automatically? Oh my, was that a bad idea.

Have fun, don't get wrapped up in the falderal, and keep your first attempts SIMPLE....

Thank you for that. I agree. It reminds me of a scathing commentary on the opamp chipmakers. Their advertizing is designed to convince you that you would be out of your mind not to buy the latest chip to benefit from all its improvements. The writer quoted a double-blind study between an audio device with TL072s, and another with almost unbelievable specs. The result was that in some cases, the device with the older chip sounded better!!

My aunt had the 45rpm "stacker spindle". It jammed on occasian, but Chubby Checker's The Twist and The Singing Nun's "Dominique" sounded awesome at the time, as well as anything Phil Specter produced.

Just to clarify, my DC heaters are regulated. Nothing else is at the moment, except the AC power supply, which is regulated +-4% (don't ask). I should keep is simple at the moment so that debugging will be easier. I could always add the Zobels later.

I just ordered a rect/cap board with lower quality caps, higher ESR for sure. If they work, there is no point in purchasing audio quality. I hear you on the wiring. One way might be a blessing; but another may bring disaster.

What do you mean by the ZN filter taking "the edge off the most spiky treble passages". Do you mean the higher fundamentals plus their harmonics? The fundamentals with this project max at 1.3kHz, but losing whatever harmonics are generated by the overdriven tubes is prohibited, even if most people cannot hear them.
Venturing where the wise refuse to go, may or may not yield great revelations theretofore unknown; either with considerable expense.
  Reply With Quote
Old 6th March 2013, 12:13 AM   #32
ITPhoenix is offline ITPhoenix  United States
diyAudio Member
Join Date: Mar 2012
Location: New York
Sorry, we went on to tangents. We have here an hybrid, high gain, treble guitar amp, 4 tubes in, with overdrive channel, feeding a 100w BJT power section.

Here's the Aikido manual which explains the regulated DC heater supply. It's very short. http://www.tubecad.com/2009/03/13/Ai...20in%20One.pdf

They are recommending elevation even with the DC, or letting it float on a capacitor to ground.

Yes, I know it's possible to obtain dead quiet with AC heaters, but I need DC because of the tube socket switches, where the wire separation will act as 60Hz transmitters. Moreover, my layout is experimental so I do not welcome the extra burden of testing various twisting and routing schemes.
Venturing where the wise refuse to go, may or may not yield great revelations theretofore unknown; either with considerable expense.
  Reply With Quote


Unusual filtering scheme questionHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
unusual passive x-over question amp88 Parts 7 9th November 2010 12:43 PM
Baffle step Question for unusual enclosure REM Multi-Way 4 18th August 2007 07:31 PM
Regulating tube amp power supply - can Iget away with a simpler CLC filtering scheme? zobsky Power Supplies 0 12th October 2006 04:10 AM
AC Filtering question HIPCHECK Power Supplies 13 4th October 2006 04:02 PM
AC mains filtering question thylantyr Solid State 4 26th March 2003 08:28 PM

New To Site? Need Help?

All times are GMT. The time now is 05:13 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio