SMPS powered tube amp - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Siliconray Online Electronics Store

Siliconray Online Electronics Store Amplifier boards, HiFi components, tubes and all kinds of electronics for the DIYer from Siliconray

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 22nd February 2012, 07:22 AM   #1
diyAudio Member
 
Join Date: Sep 2011
Default SMPS powered tube amp

Today I received the SMPS power modules and SMPS powered tube amp. Tubes are 6N3+6P1. It could be used as headphone amplifier as well as 3W small power amplifier. The first impression it's light weight. Don't have time to listen to it. Pics first. I will post more testing result later.
Attached Images
File Type: jpg DSCN9254.JPG (137.7 KB, 588 views)
File Type: jpg DSCN9256.JPG (129.2 KB, 531 views)
File Type: jpg DSCN9257.JPG (122.2 KB, 538 views)
File Type: jpg DSCN9259.JPG (177.6 KB, 572 views)
__________________
www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services
Chat with me
  Reply With Quote
Old 22nd February 2012, 02:19 PM   #2
diyAudio Member
 
malibujeff's Avatar
 
Join Date: Mar 2010
Location: Georgia
Looks nice.
  Reply With Quote
Old 23rd February 2012, 04:37 AM   #3
JZatopa is offline JZatopa  United States
diyAudio Member
 
Join Date: May 2003
Location: Chicago
I'm really curious to hear your review. Shame you don't have a copy with a linear power supply to compare it to.
  Reply With Quote
Old 1st March 2012, 01:58 PM   #4
diyAudio Member
 
Join Date: Sep 2011
Sorry for delay so long. Finished most of testing today, all I can say is awesome. It the best tube amp below 5Wx2 I've ever seen. I will compare with transformer powered amp tomorrow. Results will be posted soon
__________________
www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services
Chat with me
  Reply With Quote
Old 2nd March 2012, 04:41 AM   #5
diyAudio Member
 
Join Date: Sep 2011
Default Frequency Response

Sorry for so late. It's a time cost work to measure and adjust and measure and adjust. Now we are sure the R2 is in it's best condition. We are also sure it's the best status for a low cost 6P1 tube.

This design has no feedback from the output of the transformer. So the quality of transformer is important for the bandwidth. See the following result:
Instrument: HP3563A
Load: 8 Ohm
Signal Level: about 3V RMS
Sweep Freq: 10Hz to 100KHz
Click the image to open in full size.
According to the curve, the amp has a very flat freq response between 40Hz to 20KHz, swing less than 1dB. 3dB bandwidth is 25Hz to 35KHz.
__________________
www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services
Chat with me
  Reply With Quote
Old 2nd March 2012, 11:39 AM   #6
diyAudio Member
 
Join Date: Sep 2011
Default Distortion

The distortion is tested at 1KHz, 8Ohm, 0.5W, 1W, 2W and 3W output power. THD is kept less than 1.8% when the output power is less than 3W. It goes high rapidly when the power is above 3W.

1.275% @ 0.5W
Click the image to open in full size.

1.45% @ 1W
Click the image to open in full size.

1.34% @ 2W
Click the image to open in full size.

1.95% @ 3W
Click the image to open in full size.
__________________
www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services
Chat with me

Last edited by siliconray; 2nd March 2012 at 11:43 AM.
  Reply With Quote
Old 2nd March 2012, 11:47 AM   #7
diyAudio Member
 
Join Date: Sep 2011
Default Waveforms

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
__________________
www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services
Chat with me
  Reply With Quote
Old 2nd March 2012, 11:51 AM   #8
diyAudio Member
 
Join Date: Sep 2011
Default SNR

I had thought the SNR would be high due to the switching mode power supply. To my surprise, the figure is even better than transformer powered amp, about 88dB!
Click the image to open in full size.
__________________
www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services
Chat with me
  Reply With Quote
Old 2nd March 2012, 11:58 AM   #9
diyAudio Member
 
Join Date: Sep 2011
Default Listening

tested with a pair of full range with 91dB sensitivity. I don't know how to describ the listen due to my poor English. Just want to say it's the best small (<3W) tube amp I have ever heard. Human voice is very sweet, treble is clear, bass is soft. I believe it could be better if replace 6P1 with better tubes.
__________________
www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services
Chat with me
  Reply With Quote
Old 2nd March 2012, 12:18 PM   #10
diyAudio Member
 
Join Date: Sep 2011
Default Comparing with transformer

We did a compare testing between SMPS and transformer.

Freq response: almost the same. slight higher (about 0.1dB) better than transformer.

Hum: Transformer has audiable hum at 20cm away from the speaker. SMPS may also has audiable hum, but I can't hear it even when my ear touched the speaker. Maybe a bat can hear it.

Distortion: SMPS has lower distortion, especially when the output power is close to 3W. SMPS is 1.85% while transformer is 3% when @3W 1KHz

SNR: 88dB vs 78dB, SMPS win

Sound quality: Similar in midrange and treble. But SMPS wins in Bass.

Weight: 4.2kg VS 2.5kg
__________________
www.siliconray.com High Quality Audio Enclosures, Amp Kits, Amplifiers, PCB Fab Services
Chat with me
  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
Battery Powered Tube Amp Alexrmc92 Tubes / Valves 11 13th September 2011 06:00 PM
Using a powered sub with my tube amp Guytute Tubes / Valves 11 29th December 2008 10:54 PM
High Powered 3cx300a1 Tube Amp BlackUnikorn Tubes / Valves 22 21st June 2006 12:17 AM
Line-powered SMPS for Power Amp? marcus66 Class D 47 8th October 2004 12:49 PM
Battery powered tube headphone amp mig-ru Headphone Systems 1 3rd February 2004 10:59 PM


New To Site? Need Help?

All times are GMT. The time now is 08:16 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