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

Headphone Systems Everything to do with Headphones

adding more caps to my headphone amp? upgrade transistor?
adding more caps to my headphone amp? upgrade transistor?
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 23rd December 2017, 12:23 PM   #21
phase is offline phase  United States
diyAudio Member
 
Join Date: Oct 2004
Those two op amps are bipolar input, and higher speed, the 8066, fet input op amp just didnít like that circuit apparently, and may be oscillating it appears. Have you measured for dc offset at the outputs?

Looking at the feedback arrangement, I would stick with bipolar op amps for this one.
I always try to connect and disconnect my headphones with the power off to prevent that, but my amp also has a relay to delay the connection of the load when turning on, and immediately disconnect the load when shutting off.
  Reply With Quote
Old 23rd December 2017, 01:18 PM   #22
laserscrape is offline laserscrape
diyAudio Member
 
Join Date: Dec 2017
Quote:
Originally Posted by cliffforrest View Post
You will need to do a bit of research on data-sheets and details of op-amps before blindly stuffing different parts in!

The AD8066 is a very fast amplifier specified for video NOT audio and has a maximum supply rating of 24V or +-12v.

It was almost certainly oscillating like crazy and might have blown up depending on the rail voltages in your circuit.
yeah, you are right. rail voltages are +/- 9v so no risk blowing it but the only reason I tried it was because a few people said it sound better than LM4562 in their amps, I suppose audio forums arent the best place to get electronics recommendations
  Reply With Quote
Old 23rd December 2017, 05:57 PM   #23
phase is offline phase  United States
diyAudio Member
 
Join Date: Oct 2004
You must not have been on the Mihalcz Heqdphone Amp forum when you got that advice I am assuming?
  Reply With Quote
Old 25th December 2017, 04:07 PM   #24
hpeter is offline hpeter  Slovakia
diyAudio Member
 
hpeter's Avatar
 
Join Date: Feb 2013
Location: Electrostats or bust
Quote:
Originally Posted by laserscrape View Post
yes I doubt they chose they large electrolytic caps for any reason other than cost reduction.

just by ear alone I can tell the amp performs imuch worse in the HF but it does sound good, could the current caps be contributing to the smooth/rich sound?
i added a bunch 470n, huge 10u/600 polyprops into my tube amp, it was very noticeable. Even so the 1000u/450 wet cap.
but as i said, tube amps have low psrr..so every effort counts.

chargeable batteries are low impedance supply. i believe that is the reason why some prefer batteries.
__________________
BLOG. XMOS_U8/PCM5102A > LL1544A > 6H9C+gyrator > 2A3_SOV/JJ > LL1660 > STAX SR207 _ SR L300 _ SR007 # LL2748 > 394A > LC 12H/1000Ķ
  Reply With Quote
Old 12th March 2018, 03:45 AM   #25
laserscrape is offline laserscrape
diyAudio Member
 
Join Date: Dec 2017
Im thinking about adding voltage regulators to this amp and I noticed the RC circuits on the Op amp rails. Would these have any use or even negatively effect the circuit if there were voltage regulators?

Also if the purpose of R5/105 is to increase output impedance, what effects does that have? the headphones are 45 ohm if that means anything

Last edited by laserscrape; 12th March 2018 at 04:11 AM.
  Reply With Quote
Old 13th March 2018, 03:26 AM   #26
PRR is offline PRR  United States
diyAudio Member
 
PRR's Avatar
 
Join Date: Jun 2003
Location: Maine USA
Quote:
Originally Posted by laserscrape View Post
...if the purpose of R5/105 is to increase output impedance,....
It does not. The NFB resistors R3 R103 tap after the 22r resistors. Output impedance is essentially zero. R5 R105 prevent "infinite" current flowing through the transistors to a short.

_I_don't see any "sloppy" here. Very conventional design with ample values. The change from 4700u to 8000u should not be "wow". If your ears are so discerning, I would look at C2 as directly affecting the low end; a crap cap here will sound bad, so a super-duper cap may please you more.
  Reply With Quote
Old 17th March 2018, 05:22 PM   #27
anti is offline anti  Slovakia
diyAudio Member
 
Join Date: Jun 2008
Imho the output stage has a low PSRR at the neg. rail, causing the opamp to constantly "fight" against it as it gets injected directly into the nfb. As each chanell idles at 120mA-ish each, there sure must be some ripple in the rails (should sim that but ...). So any upping the psu caps would in consequence be an improvement. Perhaps just upping the neg. reservoir cap would be an improvement?
  Reply With Quote
Old 9th April 2018, 09:58 PM   #28
laserscrape is offline laserscrape
diyAudio Member
 
Join Date: Dec 2017
Would it be possible/advisable to add another op amp to each channel to increase the current output? the NJM4556 is a high current op amp and its drives the headphones noticeably better at higher volumes, it doesnt sound very good so im looking for a way to increase current of my preferable op amps such as LM4562 and AD823.
  Reply With Quote
Old 11th April 2018, 06:34 PM   #30
laserscrape is offline laserscrape
diyAudio Member
 
Join Date: Dec 2017
pretty simple like most things with this amp. quick test on a breadboard it works well, thanks for that
  Reply With Quote

Reply


adding more caps to my headphone amp? upgrade transistor?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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Adding headphone output to Aikido LV Elkaid Tubes / Valves 5 2nd July 2016 01:31 PM
Adding headphone output to Darling amp jpsimons Tubes / Valves 6 3rd April 2013 06:43 AM
tube preamp: adding headphone out then_dude Headphone Systems 10 19th July 2012 11:02 AM
Adding a Headphone output to my amp. Roulston Tubes / Valves 15 14th February 2012 07:54 PM
adding a headphone jack Bama Slamma Headphone Systems 1 13th March 2007 01:36 PM


New To Site? Need Help?

All times are GMT. The time now is 06:58 PM.


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
Wiki