3/4-stage Aleph 2 - 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 16th January 2007, 02:13 PM   #1
Sony is offline Sony  Europe
diyAudio Member
 
Join Date: Sep 2004
Location: Europe
Default 3/4-stage Aleph 2

Hello!

Instead of following the main plans on building an Aleph 2, I was wondering if I could make the necessary arrangements to make it a 3-stage or a 4-stage amplifier (instead of 2-stage), wouldn't this result in:

+ Lower distortion.
+ More precision.
+ More low-end control.
- A some how less "natural" sound.

Could I be right? Could this be an interesting way to go?

Thanks and regards
  Reply With Quote
Old 16th January 2007, 02:26 PM   #2
moe29 is offline moe29  United States
diyAudio Member
 
moe29's Avatar
 
Join Date: Dec 2002
Location: Florida
Send a message via AIM to moe29 Send a message via Yahoo to moe29
Check out the Aleph 0, may be what you're thinking of.
  Reply With Quote
Old 16th January 2007, 10:22 PM   #3
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
This is one of those ideas that has me scratching my head. Yes, it can be done--just make sure that the signal reaching the output stage is roughly 3-4V above the negative rail and that the feedback mechanism is more or less intact so the output biases decently--but why? It kinda negates the whole point. It's like taking a Ferrari to a tractor pull. Can a Ferrari pull weight? Yes, but that's not what a Ferrari is for.
While increasing the NFB might arguably increase low end control, I'm not sure I'd go so far as to say that it increases precision, whatever that might mean. Yes, with enough feedback you can hit any reasonable distortion target, but at what price?
If you're dead set on trying to increase the gain, the easiest way would be to start at the front end, perhaps with larger load resistors (reduce bias current through differential to compensate), or perhaps to use an active load. You could use devices with more gain than the IRF9610. If you're willing to accept lower closed loop gain, you can just increase the NFB on the circuit as-is. That one would be easiest and fastest, assuming that your preamp can make up the difference.

Grey
  Reply With Quote
Old 17th January 2007, 01:42 PM   #4
Sony is offline Sony  Europe
diyAudio Member
 
Join Date: Sep 2004
Location: Europe
Grey, thanks for all the great tips.

The Aleph 2 in its original form sounds really good when driving easy loads. On hard loads, it fails - lack of control on the bass spoils the all sonic picture.

I would like to build an amplifier that would make a difficult speaker (large 4-ways floorstanding, with low sensivity, low impedance curve peaks, very demanding woofers) sing exactly as the Aleph 2 when driving an easy load...

Probably, I should look at a difference topology...
  Reply With Quote
Old 17th January 2007, 02:07 PM   #5
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
Time to biamp. Use the Aleph for the mids and high frequencies.

Grey
  Reply With Quote
Old 17th January 2007, 02:57 PM   #6
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally posted by Sony
Grey, thanks for all the great tips.

The Aleph 2 in its original form sounds really good when driving easy loads. On hard loads, it fails - lack of control on the bass spoils the all sonic picture.

I would like to build an amplifier that would make a difficult speaker (large 4-ways floorstanding, with low sensivity, low impedance curve peaks, very demanding woofers) sing exactly as the Aleph 2 when driving an easy load...

Probably, I should look at a difference topology...

old mighty Treshold,some of Krells (100?) or Pass X........as Grey sez-for biamping
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 17th January 2007, 05:08 PM   #7
Sony is offline Sony  Europe
diyAudio Member
 
Join Date: Sep 2004
Location: Europe
Indeed, I have one great case of success in bi-amp configuration!

Yet, I have used identical amplifiers.
When using different topology amplifiers for bi-amp (like Aleph and X or Aleph and Krell), appart from the need of equalizing the gain of the two amplifiers, won't there be problems on:

- Amplifiers out of phase?
- Amplifier circuits total lenght introduces an audible signal-delay?
  Reply With Quote
Old 17th January 2007, 06:29 PM   #8
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Neither of those should be problems.

  Reply With Quote
Old 17th January 2007, 09:01 PM   #9
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
The only significant source of delay is the crossover itself...not the amplifier(s). Note that this is true regardless of whether the crossover is active or passive. Replacing a passive crossover with an active one will not be a problem.
The amount of phase shift will depend largely on the slope you choose, whether 6dB/oct, 12, 18...etc. So if phase shift is of concern to you, you might explore that route. There are also phase shifting circuits you could try if you really want to move things around.

Grey
  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
What phono stage for aleph p1.7 freakyone Pass Labs 13 1st March 2009 05:22 PM
Upgrading Aleph from 3 to 2 gain stage Sony Pass Labs 1 17th January 2005 09:29 PM
DVD + aleph analog stage? george a Pass Labs 8 3rd February 2004 11:27 AM
2-stage aleph reinhard Pass Labs 2 29th May 2002 10:49 AM
Aleph L vs. Balanced Zen line stage diy student Pass Labs 4 10th January 2002 09:04 PM


New To Site? Need Help?

All times are GMT. The time now is 02:40 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