Sonic Tripath Investigations - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 4th February 2005, 01:47 AM   #11
diyAudio Member
 
Join Date: Apr 2003
Location: Seattle
Try replacing your current wallwart with Catalog #ACTX-152 on this page:

http://www.allelectronics.com/matrix...nsformers.html

15VAC @ 2.4 amps, or 36VA.

This should be plenty sufficient for your regulated PSU (after full bridge rectification you should get 21.2V.

Another option would be picking up one of the radioshack 12VAC/2amp transformers.

I don't think this little guy is going to draw more than 2 amps, so this should be plenty of juice.
  Reply With Quote
Old 4th February 2005, 11:34 AM   #12
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
Quote:
Originally posted by motherone
Try replacing your current wallwart with Catalog #ACTX-152 on this page:
Thanks for the link. Looks like just what the doctor ordered, and cheap. too.
  Reply With Quote
Old 4th February 2005, 06:01 PM   #13
diyAudio Member
 
Join Date: Apr 2003
Location: Seattle
Quote:
Originally posted by panomaniac


Thanks for the link. Looks like just what the doctor ordered, and cheap. too.
No problem. For a little added dash of irony, these wallwarts are used to power the "Powerbite" amp listed on their site (Also rated at 15x2 watts):

http://www.allelectronics.com/cgi-bi...-30&type=store

I picked up several of them -- they just seem like they'd be pretty handy for preamp power supplies. Little did I know that I'd wind up powering an amp with them!
  Reply With Quote
Old 5th February 2005, 10:44 PM   #14
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
Lightbulb Power and the Sonic

Quote:
Originally posted by bwbass
I'd be interested to see what current draw was when driving a 4 ohm load.
I tested yesterday. The Sonic does draw twice the current into a 4 ohm load. It can draw as much as 2.2 amps at onset of clipping into 4 ohms.

So:
Average draw on music - 200mA
Peak draw before clipping - 1.02A

Double this for 4 ohms. Measured at 12 & 13.2 volts.

Also - the amp is measurably bass shy. Response rolls off under 200 Hz. It's down 9dB at 20Hz
I will be posting a graph very soon.

The amp inverts the signal. This is mentioned in the documentation, but you have to look for it. My measurements confirm it. Fans of absolute phase be advised.

More later.

Aloha
MM
  Reply With Quote
Old 5th February 2005, 10:44 PM   #15
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
Default Bass Shy

We all know that the cute little Sonic Impact is bass shy.

Measurements show that it is. Have a look at this graph.
Level was 2V P-P for this measurement, but seemed the same for all levels.

This chart is not yet on my site. You saw it here first!

Aloha
MM
Attached Images
File Type: gif chart.gif (15.1 KB, 577 views)
  Reply With Quote
Old 6th February 2005, 07:54 PM   #16
diyAudio Member
 
Join Date: Dec 2002
Location: Houston
Default Re: Bass Shy

Quote:
Originally posted by panomaniac
We all know that the cute little Sonic Impact is bass shy.

Measurements show that it is. Have a look at this graph.
Level was 2V P-P for this measurement, but seemed the same for all levels.

This chart is not yet on my site. You saw it here first!

Aloha
MM
MM,
This is about what I hear. My speakers only go to about 38 Hz before they roll off steeply. The SI is rolling off way before they do.
But you mentioned that this is not level dependent. Is it loading dependent? Do the 4 ohm and 8 ohm curves overlay?
My speakers are 15 ohm, I wonder if the power transfer is better into higher impedances. The zobel on the output may be adjustable to compensate a little.
It is surprising that the lowend roll off is not power related. Guess it shows that the inductors are not saturating.

George
  Reply With Quote
Old 6th February 2005, 09:34 PM   #17
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
Default Re: Re: Bass Shy

Quote:
Originally posted by Panelhead
But you mentioned that this is not level dependent. Is it loading dependent? Do the 4 ohm and 8 ohm curves overlay?
It is surprising that the lowend roll off is not power related. Guess it shows that the inductors are not saturating.
Well, George,
to be honest I did not run the curves at a broad range of powers, just typical musical levels. Those tiny little inductors are certainly suspect (maybe for ringing too). But my guess is that the input may be to blame.

I'll check again at maximum output and under 16 & 4 ohm loads.
Thanks for the suggestion.

FWIW, I find it surprising that you are able to use the SI with 15 ohm speakers. It just doesn't put out enough power at that impedance. Your drivers must be very efficient.

Aloha
MM
  Reply With Quote
Old 6th February 2005, 10:47 PM   #18
diyAudio Member
 
Join Date: Dec 2002
Location: Houston
Default Re: Re: Re: Bass Shy

Quote:
Originally posted by panomaniac



I'll check again at maxium output and under 16 & 4 ohm loads.
Thanks for the suggestion.

FWIW, I find it surpising that you are able to use the SI with 15 ohm speakers. It just doesn't put out enough power at that impedence. Your drivers must be very effecient.

Aloha
MM

If the problem is in the input it is not easily fixable. That will also explain if not level or load dependent.
Also, the speakers are 100 dB efficient, so the 3 1/2 watts or so from the SI is more than enough. Even a 45 tube amp at about 1 watt is loud enough, just too soft and colored.

George
  Reply With Quote
Old 7th February 2005, 12:08 AM   #19
diyAudio Member
 
Join Date: Apr 2003
Location: Seattle
My guess on the bass-shyness of the Sonic Impact is the small chip caps used to block DC. I suspect replacing them with a larger value capacitor would probably fix this issue. I haven't been able to determine the value of the chip on-board, though. I don't have a capacitence meter, and there's no visible markings on the chip.
  Reply With Quote
Old 7th February 2005, 12:28 AM   #20
diyAudio Member
 
Join Date: Dec 2002
Location: Houston
Default Bypassable

Quote:
Originally posted by motherone
My guess on the bass-shyness of the Sonic Impact is the small chip caps used to block DC. I suspect replacing them with a larger value capacitor would probably fix this issue. I haven't been able to determine the value of the chip on-board, though. I don't have a capacitence meter, and there's no visible markings on the chip.

I use a transformer coupled preamp, can I bypass these caps?

George
  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
6c45pi : sonic utopia or sonic hell? Kashmire Tubes / Valves 30 25th November 2012 02:00 PM
help with mod on sonic t-amp thezaman Class D 0 28th September 2007 01:28 PM
bi-amping with sonic impact t amp/using sonic impact amp for headphones jon_m Class D 3 16th February 2006 11:16 AM
Sonic Impact / Tripath $16 each tiroth Swap Meet 10 26th February 2005 06:05 AM
Tripath Amp tab30 Solid State 1 22nd November 2001 02:15 PM


New To Site? Need Help?

All times are GMT. The time now is 03:50 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