Cheap ebay pre amp, opinions please - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 20th August 2013, 04:45 PM   #1
davym is offline davym  Scotland
diyAudio Member
 
Join Date: Jul 2013
Location: Under a cloud
Default Cheap ebay pre amp, opinions please

Hi folks, I came across a cheap pre amp on ebay, (zoe tsang) same seller as the dual TDA7293 boards that are being praised on here.

Nice looking dual layer board, parallel class A, i'll try to link to it but I don't know if the link issues have been sorted yet.

Parallel Class A power Preamplifier kit-19 | eBay

Looks like the rectifier is on the amp board so maybe not so good!

Ebay rover failed again

They must hate selling things/making money.

Last edited by davym; 20th August 2013 at 04:50 PM.
  Reply With Quote
Old 20th August 2013, 05:44 PM   #2
davym is offline davym  Scotland
diyAudio Member
 
Join Date: Jul 2013
Location: Under a cloud
Click the image to open in full size.

I made a copy of the sellers pic off ebay, I do like the selectable gain feature.
  Reply With Quote
Old 21st August 2013, 02:05 PM   #3
diyAudio Member
 
Join Date: Oct 2006
Why is it a problem to have the rectifier on the board?
  Reply With Quote
Old 21st August 2013, 02:09 PM   #4
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
Beware of a seller using the fact that the pre-amp runs in Class A as a selling point. The very low power output of a pre-amp enables most good designs to run in Class A.

I second the comment above too, there is no drawback to having the PSU on the same PCB as long as the layout is correct.

The only advantage of having a separate PSU is that you can play with the supplies to the pre-amp.

Last edited by KatieandDad; 21st August 2013 at 02:16 PM.
  Reply With Quote
Old 21st August 2013, 03:00 PM   #5
davym is offline davym  Scotland
diyAudio Member
 
Join Date: Jul 2013
Location: Under a cloud
I was told some time ago that it is preferable to have the PSU diodes on an external board to reduce switching noise.

I agree it is better to have a well designed track layout than a average one with external PSU however and class A doesn't mean much at that low a level output.

The fake looking alps pot doesn't help much either.
  Reply With Quote
Old 21st August 2013, 03:14 PM   #6
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
IME the LM3886 is only a mediochre amp anyway so any good NE5532 will serve well as a pre-amp.

It has its followers, its a good bang for the buck, it's cheap to build. But with a few more bucks it can be surpassed by quite a substantial degree.

Those on a limited budget should try the JLH Class A amps as a starting point. OK the JLH, being only 10W isn't as powerful, but most of us use our amps at less than 10W anyway.

Last edited by KatieandDad; 21st August 2013 at 03:18 PM.
  Reply With Quote
Old 21st August 2013, 05:57 PM   #7
davym is offline davym  Scotland
diyAudio Member
 
Join Date: Jul 2013
Location: Under a cloud
Funny you should sat that, I've got a JLH 10W in my watch list on epay, i'd link to it but this forum has issues with ebay links.

I was thinking about building it next but i'm still building my LM3886 and a passive preamp so it'll have to wait a bit.
  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
Opinions on the eBay amp modules - EBB250 JPM14 Solid State 4 30th September 2012 11:42 AM
6L6 SE Tube Amp Kit on eBay... opinions? bermtoog Tubes / Valves 12 19th February 2012 07:53 PM
ebay TA2022 amp board w/tube pre ..opinions? Bill poster Class D 5 12th June 2011 01:32 PM
Opinions on Mic Pre-Amp circuit gmikol Parts 10 12th February 2008 11:06 PM


New To Site? Need Help?

All times are GMT. The time now is 10:02 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