Aleph-X builder's thread. - Page 4 - 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 20th February 2004, 05:44 PM   #31
MikeW is offline MikeW  United States
diyAudio Member
 
MikeW's Avatar
 
Join Date: Sep 2002
Location: North of Boston
Default OK

The heatsinks will get hot only 50-60 deg. C. If it gets to 70 it is a good idea to shut it down. It will also depend where you put the switch.
__________________
MikeW
  Reply With Quote
Old 20th February 2004, 10:44 PM   #32
diyAudio Member
 
Join Date: Sep 2001
Location: Salt Lake City
Thanks Grey for the biasing tips. My resistirs are 1% tolerance but I think I'll still take a few minuites and read em all and see exactly what I've got here. I'll probably start off using the .25 ohm jobs. I suppose I can always adjust the operating current slightly from there anyway.

Larry,
I reccomend building a regular Aleph first so you can get used to matching fets adjusting bias and such. They are still just about the best thing going out there. From what I've read the AX sounds a bit brighter and packs a bit more slam than a same size Aleph. I'm about to find out....hopefully this weekend.......

Mark
  Reply With Quote
Old 20th February 2004, 11:35 PM   #33
diyAudio Member
 
Join Date: Jul 2002
Location: Seattle
Hi Mark: I may take your advice, just to get another success under my belt after the ZenV4. My previous effort, an A-75, is sitting on the shelf awaiting my return to fix it after screwing up the power leads to the output stages at the very last minute (what a dummy thing to do). I actually did quite a lot of Vgs matching of devices for that and got some very tight groupings of all three Q types, especially the IRF230 and IRF9230 output devices. Still have quite a few of those matched devices and have mulled over the idea of using them, like Peter D., in an X. As Nelson recently suggested, I gave them about 5 seconds of test time, but made sure they were all about room temperature first.

As elsewhere posted in this forum, the pot adjustments on the A 75 were a little twitchy too. When I go back to the project, I am going to use multiturn pots to make it easier. I think if I do the X I will go that route with it too. Those blue and white Bourns (or whatever) single turn jobs are for the birds. Seems like the X (like the A 75) is hard enough to set without dealing with a balky pot too.

thanks for your comments. I may take the easy way out on this next project. Don't know yet.

Larry Wright
Seattle area
  Reply With Quote
Old 20th February 2004, 11:55 PM   #34
diyAudio Member
 
Join Date: Sep 2001
Location: Salt Lake City
Larry,

I agree with you on the single turn Bourns stuff. I deal with so many things in the field that have single turn that should be 10 turn....it gets frustrating sometimes. I am using Bourns 10 turn on my X's

Mark
  Reply With Quote
Old 21st February 2004, 02:50 AM   #35
diyAudio Member
 
kilowattski's Avatar
 
Join Date: Aug 2003
Location: Long Island, New York
Default Capacitors

Howdy Gents,

I am getting parts together to start my Aleph-X in parallel with finishing my Zen IV. I would like to start by designing the power supply. I will design a board for the rectifiers and capacitors. I would like to use a good quality snap-in capacitor. The rails will be +15V and -15V and I would like to do a CLC filter with 47,000uF cap, 3 mH inductor and 47,000uF. Could anyone recommend a capacitor manufacturer? I would like to use better components. Would you recommend 105 degree caps? Thank you in advance.
__________________
-----------------------------------------------
Kilowattski
  Reply With Quote
Old 21st February 2004, 04:39 AM   #36
diyAudio Member
 
Join Date: Sep 2001
Location: Salt Lake City
Well, I definately know that Igor would have his power supply located VERY close to the incomming power meter thats for sure.... Perhaps you could do the first X with a 3 phase primary on the power transformer

Mark
  Reply With Quote
Old 21st February 2004, 04:45 AM   #37
Thunau is offline Thunau  United States
diyAudio Member
 
Thunau's Avatar
 
Join Date: Mar 2001
Location: PA USA
Today I ordered a couple of dual secondary 16V transformers rated at 17.5A each secondary (they were only $45.00 each). Was it a sound purchase? I would like to use four devices per board. The AX spreadsheet tells me I can only get about 29W in 8Ohm with these and 15W in 4 Ohm. I would like to bias a bit higher but with lower supply voltage. Can I do something to the power supply to drop the voltage a bit? The spreadsheet suggests that the actual voltage at the Fets is a bit higher than the secondary. Maybe I should go with eight devices per channel. What's the concensus?
Sorry if the questions are a bit basic. This is my first amp. I did a few DIY speakers before but this is a new territory.
__________________
"Most people just say what they know, the wise ones know just what to say."
  Reply With Quote
Old 21st February 2004, 06:08 AM   #38
grataku is offline grataku  United States
diyAudio Member
 
Join Date: Dec 2000
Location: -
The spreadsheet is off actually, on my amp (built, tested and presently being used) it's more like 50 W/8ohms with an adjusted 50% ac current gain.

In other words, if that's what u want to built you got a pretty good deal.
  Reply With Quote
Old 21st February 2004, 07:43 AM   #39
diyAudio Member
 
CheffDeGaar's Avatar
 
Join Date: Feb 2003
Location: This Universe, I think
Default Re: Resistors and Capacitors

Quote:
Originally posted by Mark A. Gulbrandsen
Thanks Grey for the biasing tips. My resistirs are 1% tolerance but I think I'll still take a few minuites and read em all and see exactly what I've got here. I'll probably start off using the .25 ohm jobs. I suppose I can always adjust the operating current slightly from there anyway.
Mark
Hi Mark,
As Grey said, with 1% tolerance, you'll be fine, even without measuring them. To be overkill, I'd chose resistors of twice the original value in 1% tolerance, and paralell 2 of them (or 3 with three times the value, etc... - I used 4 //ed ). Two advantages here IMHO : a larger saftey margin re. dissipation and stability, and the couple of resistors will average the total resistance value in all the places they will be used, leading to a better match between resistances values all over the amp. I felt better this way, with all the time I spent closely matching the mosfets

Quote:
Originally posted by kilowattski
Could anyone recommend a capacitor manufacturer? I would like to use better components. Would you recommend 105 degree caps? Thank you in advance.
Hi Guy,
I "usually" use Panasonic TSHA snapin caps. 105C rated (mandatory in this use IMHO, longer life), can be easily sourced (Digikey), and very robust. Try to bypass each cap with a small film cap (100nF/MKF), and you're in

Hope this helps
__________________
/Cheff - Falling feels like flying, until you hit the ground
  Reply With Quote
Old 21st February 2004, 11:03 AM   #40
diyAudio Member
 
Brian Donaldson's Avatar
 
Join Date: Jan 2003
Location: Texas, Love it or leave it
Hey Mark, I like you three phase idea. In my new house, my listening room backs up to the attic, and I was considering an auto parts AX. I could use the radiator and electric fan from a front wheel drive car and I even thought about using a electric motor to spin a car altinator instead of huge transformers. You can vary the output voltage by the feild voltage and the output is three phase if you connect straight to the stator and make your own bridge. It may take some surgery to convert from delta to wye. Even without capacitors, rectified three phase from a car alt only has like 15% ripple and would be much higer frequency (like 2000 hz) meaning much less needed capacitance.
Hummmm. This idea needs more developement. I could build an ugly as $hit frankenamp and have it out of sight on the other side of the wall in the atic (I have a 2' x 6'8" door right next to the amps home) and it wouldn't offend the wifes sence of decor.
  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



New To Site? Need Help?

All times are GMT. The time now is 11:54 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