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

Solid State Talk all about solid state amplification.

HQ Power VPA21000U1 low freq. oscillation?
HQ Power VPA21000U1 low freq. oscillation?
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 19th February 2015, 03:14 PM   #1
djduck is offline djduck  Estonia
diyAudio Member
Join Date: Dec 2012
Location: Tartu vald, Estonia
Default HQ Power VPA21000U1 low freq. oscillation?

I noticed that when playing certain songs from Spotify, there are some fairly large low frequency oscillations going on when the bass drops. And it's not all songs, only some. For an example, Delta 9's Speaker Worship shows some ~10Hz oscillations that I'm pretty sure are not supposed to be there.
My question is, whether this would be an amplifier issue or a Spotify issue or what?
The amp itself is very nice, tho. Very good quality not only for something made by HQ Power, but in general. For an amp rated at 100WPC/4Ohm and 70WPC/8Ohm, it certainly has a large heatsink, plus two Sunon fans. All caps except two big PSU caps are Nichicon or Panasonic, and there are even four ELNA audio grade lytics. All metal-film resistors, thick PCBs, large toroid, etc... Just all very nicely made. And it's easily one of the best sounding pro amps I've ever owned.
Maybe I could start by changing the input caps? There are 100uF Nichicons on the inputs, which would, with the 20K input impedance, make a low-pass filter of about 0.8Hz and 0.08Hz at -3db. If I, however, swap these for 4.7uF PETP caps, they would make a low pass filter of 16.93Hz and 1.69Hz at -3db, which would be a much more reasonable low filter, plus they're better quality caps.
I'd like to hear
  Reply With Quote
Old 20th February 2015, 12:09 AM   #2
MAAC0 is offline MAAC0  Portugal
diyAudio Member
Join Date: May 2010
Spotify and streaming service tracks suffer from the digital audio watermarking issue...perhaps you are hearing just that.
  Reply With Quote


HQ Power VPA21000U1 low freq. oscillation?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
F&T 105c ULTRA LOW INDUCTANCE VERY HIGH RIPPLE CURRENT HQ CAPACITORS! umut1001 Vendor's Bazaar 0 10th April 2014 09:00 PM
HQ low noise 5Vdc 2A PSU, kit or ready made? stijn001 Power Supplies 4 1st April 2014 08:26 PM
low power hq class d assembled modules panduro Class D 3 4th June 2012 09:56 AM
Help for low/bass freq. arma61 Multi-Way 13 27th February 2006 06:42 PM
Help needed for BZLS: low freq oscillation EJ Pass Labs 2 21st June 2002 09:11 AM

New To Site? Need Help?

All times are GMT. The time now is 09:58 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