Kd-261 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

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 22nd March 2005, 06:37 AM   #1
zek is offline zek
diyAudio Member
Join Date: Aug 2003
Question Kd-261

Just find this schematic on the web.


What are yours oppinion about this amp, it looks very promissing for the price.
How it compare to NAD, Rotel or CA amps.
Attached Images
File Type: jpg kd-261.jpg (27.1 KB, 415 views)
  Reply With Quote
Old 22nd March 2005, 03:49 PM   #2
diyAudio Member
Jan Dupont's Avatar
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
I have never hard this amp, however if the schematic is correct, I find one set of output devices for +/- 45VDC rails to cheap
Free Schematic and Service Manual downloads www.audio-circuit.dk, Spare time company (just for fun): www.dupont-audio.com
  Reply With Quote
Old 23rd March 2005, 01:37 AM   #3
Leolabs is offline Leolabs  Malaysia
diyAudio Member
Leolabs's Avatar
Join Date: Dec 2004
Location: Bukit Mertajam
Send a message via MSN to Leolabs
Standard good quality product
  Reply With Quote
Old 23rd March 2005, 06:11 AM   #4
zek is offline zek
diyAudio Member
Join Date: Aug 2003
More details on


The PSU are good with two separeted rectifiers and total of 40.000 uF in caps.

The price is realy good, but what about the sound ....

Are there anybody from Germany who own or heard this amp.
  Reply With Quote
Old 26th April 2005, 03:28 PM   #5
diyAudio Member
Join Date: Apr 2005
Location: Dresden
Send a message via ICQ to schildkroet Send a message via AIM to schildkroet Send a message via MSN to schildkroet Send a message via Yahoo to schildkroet
Default KD-261

hey dudes! i purchased that amplifier and it is great, but not for everybody! It has got power, it's really heavy :-) but there is not plug for stereo headphones... the sound is okay! never heard some anoying sounds ore something like that! but my speakers are heavy, too. don't know if it is good sound or not (maybe not for enthousyastics <- how the hell do we write that)
  Reply With Quote
Old 26th April 2005, 08:25 PM   #6
JohnW is offline JohnW  Czech Republic
diyAudio Member
JohnW's Avatar
Join Date: Jan 2004
Location: Discovery Bay, Prague, Paris...
Feedbacks taken from the driver stage???

Also, whats the fuction of V208 - V210 protection circuit & / or a simple Error correction?

Time is my worst enemy!
  Reply With Quote
Old 26th April 2005, 10:07 PM   #7
diyAudio Member
Greg Erskine's Avatar
Join Date: Jan 2002
Location: Sydney/Australia
Hi zek,

Thanks for the link to the schematics, I've been working from the schematics of a different model and this should make things easier for me.

I bought this amp, DSE A2760, which I believe is a rebadged version of the KD-261 for AU$146. My intention was to use the case for one of my gainclone projects, but it sounded almost as good as my gainclones I decided to mod it instead.


The first thing I noticed about this amp was the gain was way to high. So I changed R230 to 2k2 but still the gain is too high. On my amp R231 was actually 47k.

The next obvious issue was there is no adjustment for the Vbias, so I replaced R209 with a 1k pot and initially set it at 160R. I then adjusted the bias across the emitter resistors (R210 to R213) to 55mV, it was only 27.4mV.

I don't like the routing of the output wires. There are grouped with the power wires and run (touching) the toriod. All these things can be fixed.

The circuit pcb is big with lots of long tracks.This is a lot different to most DIY pcbs but I suppose is pretty typical for production amps.

The output devices on mine are 2SC5200/2SA1943 not what is indicated on the schematics.

Heatsinks are small, and run hotter than any of my other class AB amps. Nothing to worry about yet.

Sound wise I rate this as OK, especially for the money, I do have an AKSA so I have been spoilt.

Originally posted by JohnW
Feedbacks taken from the driver stage???

Also, whats the fuction of V208 - V210 protection circuit & / or a simple Error correction?
Yeah, taking the feedback from the driver stage is weird. I haven't checked if it is what they have done, as I have found the schematics are not always 100%. This would be another area for modification.

V208 to V210 is the SOAR protection circuit and I guess it is needed because the rails are so high, mine was 42 to 44 volts. I would like to remove this circuit in the future.
Greg Erskine
  Reply With Quote
Old 26th April 2005, 11:59 PM   #8
Account Disabled
Join Date: Aug 2004
Location: Earth
This one's got plenty of room for improvement.

Take the 5534 on the input stage, that could be a drop in OPA134 or similar just check the offset adjust.

can switch out the tone stage.

Look at the vol pot, 100K! - at centre it will source as 25k adding to the 1K8 and rolling off with the 100pF at 60KHz. Could soften an edgy top a bit.

12K tail resistor for the input diff'l pair and single ended output stage will cause significant 2nd HD which won't be reduced by feedback. Euphonic maybe.

The 220 ohm resistors from the drivers could be reduced to 33 ohms and replace the 75 ohm. FEEDBACH should be moved to the output to include the output stage distortions in the feedback.

The protection circuit doesn't track the 'off' half cycle ( needing pull up as well as pull down SOAR tracking) rendering a fairly fragile output stage prone on reactive loads.

For starters.
  Reply With Quote
Old 27th April 2005, 12:22 AM   #9
Join Date: Mar 2005
Location: Australia
i dont know the product
i cant comment
on it
  Reply With Quote


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

New To Site? Need Help?

All times are GMT. The time now is 09:23 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2