AX100 100W Aleph-X Monoblocks - Page 55 - 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 12th July 2008, 11:00 AM   #541
diyAudio Member
 
Join Date: Mar 2008
i just wanted to to hear the sound ....as i heard aleph3.....wonderfull man you try to make one aleph-3...

here is the pic...of aleph x..
  Reply With Quote
Old 12th July 2008, 11:14 AM   #542
Account Disabled
 
Join Date: Jul 2008
Quote:
Originally posted by space2000
i just wanted to to hear the sound ....as i heard aleph3.....wonderfull man you try to make one aleph-3...

here is the pic...of aleph x..
Hi space2000

alephx more heat than aleph3 so more$$$$$ to build it
I cant make aleph because is no good, keep $$$ to buy
class-b musical fidelity amp class-b 25dC at full power COOL


  Reply With Quote
Old 12th July 2008, 01:03 PM   #543
daly41k is offline daly41k  United States
diyAudio Member
 
Join Date: Feb 2007
Location: Phillipsburg, New Jersey
Default aleph1.2 to AX100

Hi GL, I hope that your summer is going well! I got some jfets from Erno Borbely all matched and ready to go to begin a new board to install in my previous AX140 (based on measurements).

I have done a few upgrades to your original cirucuit and I would like to get an opinion from you on the input design.

I have upped the xformer to 2kva to reduce hum, this has helped as the tranny noise was reduced by half and now is not heard at the listening position but can be heard if you are standing near the amps. This is ok because a low noise plitron would cost more than my entire project to date. The amps have worked flawlessly driving my line array tweeters and if I did anything more to them I would play arround with the input offset on one amp (go through the matching mosfet ritual again).

This winter I want to try the j-fet inputs. The question I have is that you have ac coupled the inputs. My DEQX speaker correction, digital crossover, and room correction preamp has been modified/upgraded by the factory and now includes output balanced signal transformers. My entire system is dead quiet and no dc offset anywhere. My Pass 350.5 for the mid/bass only measures <3mv on the output. I also have 40uf caps in the +/- output lines to roll off the signal to protect the tweeters from the 50-100mv of dc output from the XA140's (rolls off the signal at 100hz, the DEQX digital crossover is set for 2700hz at 48db/octave.

My question would be with the DEQX having no dc offset at all will I need those expensive PP caps on the input? I know you made a comment somewhere in this thread that the circuit was more stable with the AC coupling. Did you ever come to a conclusion on that point or are you just enjoying the sounds. My hobby progects have been on hold since the Prime Minister at home has had me busy and I have been travelling a lot plus working out. Sometimes a beer in the yard on a hot day beats being inside.

Let me know what your opinion is? dave
  Reply With Quote
Old 12th July 2008, 05:01 PM   #544
diyAudio Member
 
Join Date: Dec 2002
Location: Illinois, USA
Default Re: aleph1.2 to AX100

Quote:
Originally posted by daly41k

My question would be with the DEQX having no dc offset at all will I need those expensive PP caps on the input? I know you made a comment somewhere in this thread that the circuit was more stable with the AC coupling.
I think the caps are required. But if you'd like to leave them out, I suggest first putting in some cheap caps and measuring the voltage across them while the circuit is running. If you measure zero volts and it stays zero, I am wrong and the caps are probably unnecessary.

Jeremy
  Reply With Quote
Old 13th July 2008, 12:10 AM   #545
diyAudio Member
 
Join Date: Mar 2008
Default Successfully build aleph-X.

Hi,

I have build aleph-x successfully. There was a distortion cause by the input wrong placement.

I need a bit help from you guys.

I just connected DVD output to Aleph-x (+in) and (GND). It is working fine with no distortion at all. But I am not sure is this correct.

For input connection of aleph-x as I am driving from DVD player to aleph-x.

Pls tell me is this correct way.

(DVD player + out) goes to (+ in Aleph-x)
(DVD player GND out) goes to ( GND Aleph-x)

How about aleph-x ( input)? Should I keep just open?

Thank you for your help. very clean sound.

Best regards
michael
  Reply With Quote
Old 13th July 2008, 12:25 AM   #546
diyAudio Member
 
macka's Avatar
 
Join Date: Dec 2001
Location: Australia
It will work better if you ground the negative amp input .

But what we have been telling you is you will need to put a capacitor in both the negative and postive input on the amp to minimise DC offset.

Ian
  Reply With Quote
Old 13th July 2008, 06:41 PM   #547
diyAudio Member
 
Join Date: Nov 2006
Quote:
Originally posted by macka
It will work better if you ground the negative amp input .

But what we have been telling you is you will need to put a capacitor in both the negative and postive input on the amp to minimise DC offset.

Ian
hi, Ian

what value for this input capacitors..

now im using 100uf bipolar is this ok?

and.. is it possible to have - (minus) Diff DC offset?

when i measure diff DC offset on my aleph X with no input signal sometimes DC offset showing 40mv to -15 for the + side.
and 60-100mv for the - side..

is it normal? and do they have bad effect?

abs DC offset are about 30mv for left and 100mv right channell

thank you
  Reply With Quote
Old 13th July 2008, 09:56 PM   #548
diyAudio Member
 
macka's Avatar
 
Join Date: Dec 2001
Location: Australia
Depends on how well everything like the input pair are matched.

Ian
  Reply With Quote
Old 16th July 2008, 07:00 PM   #549
gl is offline gl  United States
diyAudio Member
 
Join Date: Dec 2003
Location: Sierra Foothills - California
Hi Dave,

Wow! I go away to Toronto for a week and suddenly this thread roars back to life after weeks of dormancy!

As you guessed, I have been listening to music for the most part. I have not been doing any experiments on the AX100J since my last posts on the subject. My experiments have been confined to a UGS based line amp which is coming along well and sounds very nice. I have talked about that earlier as well.

I read only one question in your post and that is in regard to the input coupling caps. My recommendation is to include them. I recall one or more people stating that they could be removed if you were using balanced inputs where the driving device had equal impedances on both legs. I have not tried this even though I now have the new line amp driving the AX100J's in balanced mode.

So far my summer has been consumed with travel and home repairs too - snow damage to the deck, and next month a new roof goes on. So audio is taking a back seat here too.

Regards,
Graeme
  Reply With Quote
Old 19th July 2008, 02:58 PM   #550
daly41k is offline daly41k  United States
diyAudio Member
 
Join Date: Feb 2007
Location: Phillipsburg, New Jersey
Default aleph 1.2 to xa100

GL, thanks, I will try it first with some caps in place and take the suggestion of measuring across the caps and if no dc is present then I will try the circuit with out. I am also going t dress up the chasis so these beauties will be welcome in the house. I have been listening to them for about a year now with no problems.
One mono unit runs slightly hotter than the other but I have been too lazy to drag it back to the test bench and readjust the bias on the hotter unit. I will keep in touch with you as I proceed.
Have a great summer and don't fall through the roof. dave
  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 04:52 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