More Power for ZEN - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 8th October 2001, 11:44 AM   #1
diyAudio Member
 
Join Date: Sep 2001
Location: Europe, Slovenia
Hi you all!

Ive recently finished my version of ZEN Revisited. It worked great first time started and I enjoy its sound almost every day. No hum. Very stable. Sounds good to! Thanks to Mr. Pass Ive also got rid of that noisy bump in the speakers when powering on.
Ive placed the transistors on very large heat sinks, which are at the same time the sides of the Al box. Large enough to comfortably keep my hands on them.
Since there is some extra room for heating I was thinking about adding some power to the amp. Is this possible? And if it is, how can be done?

Regards
  Reply With Quote
Old 9th October 2001, 06:11 PM   #2
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
The stock Zen amp runs the output transistors at
about 25 watts, which is a figure that I have found
over the years to be absolutely reliable. The
manufacturers of these devices tout figures up to 150
watts or so, which I find to result in very unreliable
operation. Somewhere in between is a region where you
might find acceptable reliability with only an occasional
failure.

Given good heat sinking, I think you could probably
take the devices up to 50 watts, resulting in 20
watts worth of output for the amp, without seriously
compromising reliability.

Alternatively, you can parallel (matched) devices and
take the power up arbitrarily, which will be the subject
of a future Zen project.

Also alternatively, you can use the Aleph current source
and double the efficiency of the circuit, which would
double the output with the same dissipation, and if you
also allowed for 50 watts per device, you could easily
get 40 watts. This project has already been done, and
is being prepared for publishing.

There are yet other ways to increase power, many of
which are on a schedule for projects, but we don't want
to overlook an easy and very good sounding one: Build
4 stock Zen channels, and run them as two set of parallel
bridged into the load. This has to be driven balanced,
but it gets you 40 watts and sounds just terrific.
  Reply With Quote
Old 10th October 2001, 07:32 AM   #3
diyAudio Member
 
Join Date: Sep 2001
Location: Europe, Slovenia
Many thanks for your kind answer Mr. Pass. The idea of balanced driven ZENs is worth giving a try I can see many of your goodies are still to come. That is good and thanks again for sharing!

Regards
  Reply With Quote
Old 12th October 2001, 02:37 PM   #4
peted is offline peted  United Kingdom
diyAudio Member
 
peted's Avatar
 
Join Date: Feb 2001
Location: U.K. - S. Oxon
Gema, my Zen Revisited does 50W/chan into 4ohm - parallel channels. Nelson (thanks due again) is taking this to the next level - fully balanced - nice

I established current and voltage swing requirements into my speakers (by listening to real music & scoping), turned out it needed 50V rail, 4A bias per stage. It'll be less into 8ohm. And (this is the fun bit!) BIG heatsinks. I'm using 250W Exicon MOSFETs from Profusion. These are twin chipped versions of their 125W devices and so far seem happy at 128W - heatsinking is everything with these desgins. The high bias also brings down distortion.

The result manages to both play loud and sound nice. Heating bill will be lower too this winter I'm sure!

Check my site for the rest of the story.

Cheers

Pete
  Reply With Quote
Old 12th October 2001, 03:28 PM   #5
diyAudio Member
 
vdi_nenna's Avatar
 
Join Date: Oct 2000
Location: PA, USA
Blog Entries: 1
Send a message via Yahoo to vdi_nenna
Question Balanced?

Wait a second. What's this? Balanced Zen?

How many Zens channels did you build to get a stereo set?
  Reply With Quote
Old 12th October 2001, 04:04 PM   #6
diyAudio Member
 
Join Date: Aug 2001
probably four....two/ch running parallel,, one big piece of hardware you've got there.....
  Reply With Quote
Old 12th October 2001, 05:05 PM   #7
diyAudio Member
 
vdi_nenna's Avatar
 
Join Date: Oct 2000
Location: PA, USA
Blog Entries: 1
Send a message via Yahoo to vdi_nenna
Yes, but if you look at what NP wrote:

but we don't want to overlook an easy and very good sounding one: Build 4 stock Zen channels, and run them as two set of parallel bridged into the load. This has to be driven balanced,

2 sets of parallel bridged...that sounds like 4 amps for one stereo channel. Parallel one stereo Zen, then bridge another set, right? Is that 8 channels for a stereo setup?

I don't know, someone learn me right here!

Vince
  Reply With Quote
Old 12th October 2001, 05:12 PM   #8
peted is offline peted  United Kingdom
diyAudio Member
 
peted's Avatar
 
Join Date: Feb 2001
Location: U.K. - S. Oxon
Quote:
Originally posted by Nelson Pass
<snip>but we don't want
to overlook an easy and very good sounding one: Build
4 stock Zen channels, and run them as two set of parallel
bridged into the load. This has to be driven balanced,
but it gets you 40 watts and sounds just terrific.
Vince, ref NP above: I think Nelson means 4 Zens per channel, i.e. bridged paralleled stages, for double the votlage swing but that means you also need double the current capability. A lot of hardware indeed! Guess it comes down to how easily you can create the heatsinks!

I went parallel (still unbalanced) only to drive a 4ohm load - built 4 of the critters - amazing how much quicker the last ones are to build over the first one!

Pete
  Reply With Quote
Old 12th October 2001, 05:42 PM   #9
diyAudio Member
 
vdi_nenna's Avatar
 
Join Date: Oct 2000
Location: PA, USA
Blog Entries: 1
Send a message via Yahoo to vdi_nenna
Man. That's what I thought. How's the bridge/parallel sound over a single set? Probably a better lower freq.

You guys ever hear of Bob Lubwig? His main mastering room uses something simular, but his Cello amp's put out 1000w for the neg. side and 1000w for the pos. signal. All going to a set of very large EgglestonWorks monitors. They stand on a concrete slab that goes down to granite. A really sick room!

Some other guy heard about it too.
http://www.audioreview.com/reviews/S...uct_7220.shtml

Thanks for the info.

Vince
  Reply With Quote
Old 13th October 2001, 12:48 PM   #10
diyAudio Member
 
promitheus's Avatar
 
Join Date: Jan 2001
Location: Germany
First of all yeah I think NP means 4 Zens per channel. 8 for a stereo amp. But also I think he meant to bias all of them higher for better quality. I think its a great idea. Mr. Pass when is the new website up? I cant wait for the new stuff. :-)
  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
40A 250V Schottky Power Diodes- Has anyone use in Power Amp to replace Diode Bridge? dtm1962 Solid State 10 15th September 2011 07:38 PM
LTspice tool for power amp power supply component evaluation andy_c Software Tools 2 23rd August 2009 05:10 PM
Power transformers versus amplifier output power..what is your option? destroyer X Solid State 38 9th May 2009 05:23 PM
Amplifier 3000 Wats Rms Power + Smps Higcht Power Bestiality MARAVILLASAUDIO Class D 1 5th November 2004 04:06 PM
power output calculations, rated power and required power output metebalci Tubes / Valves 7 22nd February 2004 05:49 PM


New To Site? Need Help?

All times are GMT. The time now is 05:05 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