ps filter cap bypass question? - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 26th December 2003, 07:36 PM   #1
diyAudio Member
 
crippledchicken's Avatar
 
Join Date: Dec 2003
Location: south east mo.
Unhappy ps filter cap bypass question?

hi, my power amp has 2 10,000 mfd. and 2 12,000 mfd. caps, one of each per side. i bypassed each cap with a 0.1mfd. metalized polypropylene film not the best i know, but all i had on hand. the sound seems to be alot brighter, with most of the power in the mid to high frequencys. should i try different values of bypass caps, give these caps break in time, or no bypasses at all? thanks for your input crippledchicken
  Reply With Quote
Old 28th December 2003, 11:49 AM   #2
diyAudio Member
 
Jan Dupont's Avatar
 
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
It's well known that using small bypass decoupling caps on the larger caps in the PSU, can give a more well defined sonic reproduction.

Quote:
with most of the power in the mid to high frequencies.
Is this to be understood as the whole sonic of the amplifier has changed to the brighter??? It's more likely that the sonic of the mid and top has become more clear and well defined....

Yes. You can try different types and values. A basic rule is that the decoupling caps should be at least 100 times smaller that the big cap it's bypassing.

You should also use small decoupling caps on the PSU rectifiers..
Try some 100 nF across each diode in the rectifier bridge. These can also result in even more well defined sound

What amp is it???
__________________
Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com
  Reply With Quote
Old 28th December 2003, 07:42 PM   #3
diyAudio Member
 
crippledchicken's Avatar
 
Join Date: Dec 2003
Location: south east mo.
hi ACD, the sound of the amp with the bypasses, seems that it is more detailed and refined, at lower volumes say 9:00 but, seems when i turn it up to 10:00 or more the vocals seem to get more harsh, and not as easy to understand as, without the caps and the extra brightness kind of masks the detail. my listening distance is rather close like 8 0r 9 feet tops. if i sit in the other room which is all open area, the sound seems more mellowed out. could i be too close? sort of like being to close to a live band to make a proper judgement? i have replaced the original cheap inline bridge rect. with home made 30 amp stealth diode bridge awhile back which seemed to be a big improvement. also replaced the fixed lm7812 and lm7912s regulators with lm317 and lm337s also awhile back so, i believe those components should of had plenty of burn in time. also, the filter caps i'm bypassing are nichicon gold tunes. thanks very much, crippledchicken
  Reply With Quote
Old 28th December 2003, 10:23 PM   #4
diyAudio Member
 
Jan Dupont's Avatar
 
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
Hi Crippledchicken,
I'm not the greatest speaker expert, however the "correct" listening distance from the speakers depends on many things.... The speakers, the room, the volume etc...
I use High End VIFA and Audax tweeters in my speakers, and if I'm close to the speakers (2 meters=6 feet???)) the tweeters can sound a bit hard, however angeling the speakers just a bit changed that..... Try some different positions for your speakers

I will say that bypass caps in the PSU can only make an amp better... The reason for your sound experience could be, that the amp is now much more clear and defined, and are now showing the some problems in the rest of your system.... Is it the same for both CD and Tuner??? Do you have some kind of reference CD so you could try different speaker angels and amp settings???

Also... What kind of speakers are you using??? Do they match the amp???
__________________
Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com
  Reply With Quote
Old 29th December 2003, 04:17 AM   #5
diyAudio Member
 
crippledchicken's Avatar
 
Join Date: Dec 2003
Location: south east mo.
well ACD, i think you might be right about the speakers. they are just a cheap set of technics with replacement tweeters from radio shack. i bought them used and after you mentioned about the speakers, i decided to check them out real good. for sure, someone has replaced the original tweeters with radio shack brand. of course the originals probably wer'nt worth a crap either hehe. i don't see any possibility of any better speakers in the near future so, maybe i can mount some L pads to help balance them out a little. i think i will check into a good reference cd of known good testing qualities instead of several different cds since there all recorded differently any way good idea! thanks you've been a big help and HAPPY NEW YEAR, crippledchicken
  Reply With Quote
Old 29th December 2003, 09:44 AM   #6
diyAudio Member
 
Jan Dupont's Avatar
 
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
Yes... L-pads should do the trick regarding the tweeters.
Always glad to help
And a happy new year to you tooooooo....
__________________
Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com
  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
Question about cathode bypass capacitor: rockgardenlove Tubes / Valves 4 24th October 2008 09:34 AM
Bypass digital filter in PCM1794? ezkcdude Digital Source 5 11th April 2006 04:35 AM
Engine noise, no luck with bypass filter silentblackhat Car Audio 6 30th October 2005 07:57 PM
Question about cathode bypass capacitor argo Tubes / Valves 15 20th February 2005 11:26 PM
EQ Bypass Question cadman Tubes / Valves 9 7th August 2003 09:58 AM


New To Site? Need Help?

All times are GMT. The time now is 04:50 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