Leach amp - Page 7 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

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
Reply
 
Thread Tools Search this Thread
Old 28th July 2004, 02:11 PM   #61
diyAudio Member
 
Join Date: Jul 2004
Location: the 3rd rock from the Sun
Quote:
Originally posted by djk
"Is there anyone out there could advise me on making any modification to the circuit so that I can get more bass output out of the Amps?"

A few questions.

What is the rated impedance of the speakers, and what does the DC resistance measure?

How many dB/2.83V/1M are they?

What is the V of your Leach SuperAmp ?

How many VA is the transformer rated?

Size of the main filter caps?
Hi djk,

Thanks for looking into my query. The nominal resistance of my loudspeaker is 8 Ohm. Rated sensitivity is 86dB/W/m. I use 1200VA toroid transformer for each monoblock. Capacitors are 8 x 10000uF, 100V, BHC Aerovox for each monoblock. DC bus voltage is +/-85V.

Hope the above answered your questions. I am thinking of reducing resistance of R19 by 10%. I wonder if that will help.

Regards,
jtcc
  Reply With Quote
Old 4th August 2004, 04:54 AM   #62
diyAudio Member
 
Join Date: Jun 2004
Location: Indore , India
reducing R19 will increase the gain , yes it will also change the R/C ratio , but I feel that the bass responce of this amp is pretty good and clean
__________________
RL
  Reply With Quote
Old 4th August 2004, 09:39 AM   #63
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
I think you may need a tone control, or baffle step correction.

It sounds like the amp is fine.
  Reply With Quote
Old 6th August 2004, 05:18 AM   #64
diyAudio Member
 
Join Date: Jul 2004
Location: the 3rd rock from the Sun
Quote:
Originally posted by rajeev luthra
reducing R19 will increase the gain , yes it will also change the R/C ratio , but I feel that the bass responce of this amp is pretty good and clean

Quote:
Originally posted by djk
I think you may need a tone control, or baffle step correction.

It sounds like the amp is fine.

Hi rajeev & djk,

Thanks for your reply, I am totally agree that the Leach Amp perfrom superbly in any aspect. It can faithfully reproduces and ampilifies the source signal with grace. However, I don't know about yours, my main purpose of spend the money and most importantly my time and effort on DIY project was that I get a freedom of customizing the end product to suit my needs. I know there is no problem with the Leach Amp design, and I may also have compatibility problem between it and my DIY tube pre-amp (Jadis JP200 circuit).
I was simply trying to explore all the aspects of the issue before I start making modification to my system.

Thanks anyway.

Regards,
  Reply With Quote
Old 11th August 2004, 03:02 AM   #65
fab is offline fab  Canada
diyAudio Member
 
fab's Avatar
 
Join Date: Mar 2004
Location: Canada
Quote:
Originally posted by jtcc1015

...I was simply trying to explore all the aspects of the issue before I start making modification to my system.

Thanks anyway.

Regards,
You can increase the value of feedback DC blocking cap and the value of DC blocking input cap as well. It will preserve more the phase accuracy at 20 Hz if you choose a -3db corner frequency at less than 0.2 Hz for example. Check the 20Hz square wave with an oscilloscope to convince you. This will however not increase dramatically the bass response but only slightly. The problem is maybe your low corner speaker frequency point is a little too high. That is why a "loudness" control designed for low frequency compensation can help. It can also compensate for poor bass response of some recordings. Personnally I use a variable loudness control in my preamp in the feedback path like on this post of this thread:
http://www.diyaudio.com/forums/showt...125#post359125
see post #7 attachment.

Good luck

Fabien
  Reply With Quote
Old 23rd September 2004, 05:09 AM   #66
diyAudio Member
 
acenovelty's Avatar
 
Join Date: Aug 2004
Location: SF Bay Area
The simplest tweek for more bass is to re-examine your bias current setting. Raising it to 125, 150 or 200 etc. will give more bass, but the heatsinks have to take the resultant temperature rise. 'Course, maybe your speakers just ain't puttin out what you expect. I have 2 double barrelled and 4 120W Leach amps driven from a Lexicon CP3 and have nothing but pleasure from them. A pair of subwoofers is driven by one 300 W Leach amp and I seldom increase the volume control beyond 1/4th of the possible gain. And then my speakers have been built to produce what can come out of a Leach amp. But that's a different subject. An amp that seems "weak" can more often be traced back to the power supply and the capacitors that provide the juice for your sound. It would seem from your specs that you have an adequate power supply, but.........
Take a look at this site for a really good power supply design:

http://zero-distortion.com/start.htm

go to the Designing your own power supply section.

After that, maybe you'll want to think about becoming a speaker builder. You can make better speakers than those Mark Levinson boxes.

Prosit
  Reply With Quote
Old 24th September 2004, 08:12 AM   #67
diyAudio Member
 
Join Date: Jul 2004
Location: the 3rd rock from the Sun
Thanks for your advise. I shall give it a try.
  Reply With Quote
Old 25th September 2004, 04:47 AM   #68
diyAudio Member
 
Join Date: Jun 2004
Location: Indore , India
acenovelty is very right ,

The following written by him makes lot of sence ;-

1," The simplest tweek for more bass is to re-examine your bias current setting. Raising it to 125, 150 or 200 etc."

2, "An amp that seems "weak" can more often be traced back to thepower supply and the capacitors that provide the juice for your sound. It would seem from your specs that you have an adequate power supply, "
__________________
RL
  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
My Leach Amp Clone (LEACH 150) panson_hk Solid State 32 22nd May 2014 11:25 AM
High Current Leach/leach super amp bowdown Solid State 41 2nd March 2011 02:15 PM
anyone have leach PCB? ilyash Group Buys 2 7th September 2007 10:36 AM
Leach Superamp vs Leach 4.5 Samuel Jayaraj Solid State 4 26th October 2002 09:20 AM
Leach amp vs super Leach amp supernet Solid State 0 21st February 2002 10:16 PM


New To Site? Need Help?

All times are GMT. The time now is 10:17 PM.


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