Simple Aleph 2 transformer question - 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 2nd April 2002, 06:29 PM   #1
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
Default Simple Aleph 2 transformer question

I am ordering some custom toroid transformers for my Aleph 2 monoblocks that I am building. For the transformer, I have the choice of two difference sizes.

Should I get a pair of 1kVA transformers or a pair of 2kVA transformers? I saw that Mr. Pass stated that 1kVA is the minimum. Is there any drawbacks if I go with 2kVA, besides the weight difference?

--
Brian
gte619j@prism.gatech.edu
  Reply With Quote
Old 2nd April 2002, 07:21 PM   #2
Gabster is offline Gabster  Canada
diyAudio Member
 
Gabster's Avatar
 
Join Date: Feb 2002
Location: MTL < QC < CAN
If you going to have a transformer custom made, make sure to check www.plitron.ca, they have a very good selection of toroidal transformers, including standard 1500VA toroidals at reasonable prices (about US$100 each). In fact, this is what I'm planning to use in my Aleph 2 monoblocks.

ciao,
Gabriel
  Reply With Quote
Old 2nd April 2002, 07:25 PM   #3
diyAudio Member
 
Join Date: Nov 2000
2kva is fine.

Drawbacks are price, size and weight(check if you can put them reliable in your enclosure) and larger inrush current when you turn them on (this can be taken care off).

pros are:
Lesser voltage drop and they will probably run cooler.

If the drawbacks are not to much of a problem for you, I would say, get the 2kva's

Regards
  Reply With Quote
Old 2nd April 2002, 07:27 PM   #4
Gabster is offline Gabster  Canada
diyAudio Member
 
Gabster's Avatar
 
Join Date: Feb 2002
Location: MTL < QC < CAN
Sorry but I just realized they only start making 1500VA's at 38Vac...this mess up my plans a little bit.

Can the aleph 2 handle 38Vac (about 54Vdc before bridge and everything)?

ciao,
Gabriel
  Reply With Quote
Old 2nd April 2002, 10:39 PM   #5
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
You could always put some big inductors/choke on your power supply to lower the voltage enough for the amplifier to work.

I am planning on going for the 2kVA transformers. It probably is overkill... 4kVA total for a pair of monoblocks, but that is the life of an engineer.

What is the ideal capacitance per Aleph 2? If I can recall, the production had 4x22,000 uF capacitors. Would it sound better with twice the capacitance? (I will take care of the inrush current for this amplifier, most likely with a relay circuit).

--
Brian
gte619j@prism.gatech.edu
  Reply With Quote
Old 2nd April 2002, 11:47 PM   #6
diyAudio Member
 
Join Date: Mar 2002
Location: Dallas
gents,

The 35V 1500VA from plitron is the reaosn I didn't go with that transformer as it took the supply voltage higher.

Yes the amp will handle it, IF you increase the heastsinking to reject the extra heat. You may have to hack with some other component values but I'd wager its going to fire right up.
__________________
Regards,
W.
  Reply With Quote
Old 3rd April 2002, 02:34 AM   #7
Gabster is offline Gabster  Canada
diyAudio Member
 
Gabster's Avatar
 
Join Date: Feb 2002
Location: MTL < QC < CAN
What if I add power diodes at the input to drop voltage?
  Reply With Quote
Old 3rd April 2002, 03:06 AM   #8
Warp Engineer
On Holiday
 
AudioFreak's Avatar
 
Join Date: Oct 2001
Location: Queensland, Australia
I think you would be better to use big inductors as already suggested above. It'll waste less power and decrease ripple.
  Reply With Quote
Old 3rd April 2002, 03:15 AM   #9
diyAudio Member
 
Join Date: Mar 2002
Location: Dallas
Brian,

Why not just use 2x 650VA Plitorn transformers at 33+33V ???? If you really look at "the one and only"'s advice, he says that you want to have 4x the idle POWER rating of the amp. For an Aleph 2, that means that you want about 1200VA, which is over 1000VA, but less than 1500VA. If 1200VA was commonly available, I'd wager Nelson would say that that's enough. I'm going by memory here, being too lazy to check the Plitron site myself this minute, but I think they have 650VA and 750VA sizes, meaning that if you're going to double up, you don't have to double up on 1000VA loops - you can go with smaller ones quite comfortably.

Jest an idea.....
__________________
Regards,
W.
  Reply With Quote
Old 3rd April 2002, 03:18 AM   #10
Warp Engineer
On Holiday
 
AudioFreak's Avatar
 
Join Date: Oct 2001
Location: Queensland, Australia
625VA not 650VA
  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
mini aleph transformer question wicked1 Pass Labs 3 8th July 2009 11:03 PM
Aleph 3 transformer question karellen Pass Labs 6 17th January 2005 09:48 PM
A simple question for the Aleph 3 owners JEKYLL Pass Labs 6 24th May 2004 07:59 PM
simple transformer question owel Parts 3 12th March 2004 06:41 PM
Newbe v. simple Transformer question jnxw2 Parts 18 22nd September 2002 09:31 PM


New To Site? Need Help?

All times are GMT. The time now is 03:46 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