X100 backengineered here - Page 11 - 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 3rd June 2001, 02:36 AM   #101
diyAudio Member
 
promitheus's Avatar
 
Join Date: Jan 2001
Location: Germany
Petter thatīs cool !!!
Wish I could do the same.
Tell us more on your impression and how things go.
The best of luck.
Ilias
  Reply With Quote
Old 19th June 2001, 10:08 PM   #102
diyAudio Member
 
Join Date: Jan 2001
Location: Scandinavia
Default Status report and matching of FET's result

I have gotten PCB's and expect to start building input stages this weekend. Sorry about taking so long, but I must say my experience with home PCB making and etching was not a good one. Pro's do it better -- thanks!

Today I matched my batches of IRF610 and IRF9610. Each population was 30 units. I am not sure whether they were all from the same lot codes (I did not bother to check this)

Out of each lot, I was able to select 10 pairs that were all matched to within 5mV at the chosen 30mA (clue -- look at the diagram on page 1 ....), no problem!

Out of the p-types I got 7 pairs to less than 1mV. Range was .18V, SD: 0.057V, Mean 3,52V

Out of the n-types I also got 7 pairs to less than 1mV. Range was .37V, SD: 0.089V, Mean 3,92

I realize this is all somewhat academic since I was not able to control temperatures perfectly, but it demonstrates the point that pairs are easy to match up. Besides, these units were inexpensive.

I am eager to test my output transistors which will be more interesting since I am looking for larger sets, but I also have a population of 60.
  Reply With Quote
Old 20th June 2001, 06:01 PM   #103
diyAudio Member
 
Join Date: Jan 2001
Location: Norway
Removed...

[Edited by McKajVah on 06-21-2001 at 04:48 PM]
  Reply With Quote
Old 20th June 2001, 06:58 PM   #104
grataku is offline grataku  United States
diyAudio Member
 
Join Date: Dec 2000
Location: -
McKaj,
you should be very careful about posting this type of things on a public forum. Much like underage drinking, smoking weed, and your parents having sex this is something that everyone knows it happens and everyone does it (but me, the illegal stuff that is) but you just don't talk about it. And if you don't know about it means you shouldn't be told.
Itsy bitsy piece of advice: remove the post.






  Reply With Quote
Old 20th June 2001, 07:48 PM   #105
jam is offline jam  United States
diyAudio Member
 
jam's Avatar
 
Join Date: May 2001
Location: Auburn, CA, USA
McKajVah,

Grataku has a point.

Intellectual property should be respected.



[Edited by jam on 06-20-2001 at 04:40 PM]
  Reply With Quote
Old 1st July 2001, 11:49 PM   #106
hifi is offline hifi  Sweden
diyAudio Member
 
Join Date: Mar 2001
Location: sweden
how is it going? i want som results posted!!!

;-)

/micke
  Reply With Quote
Old 2nd July 2001, 05:48 AM   #107
diyAudio Member
 
Join Date: Jan 2001
Location: Scandinavia
Smile Patience ...

My apologies for the lack of progress on this thread.

Current status is that I have but for some missing parts (resistors) that I will get today or tomorrow, I have completed input stages for two channels. I have not done any PSU work yet, but this is going to be more traditional anyway and should not prove to be a problem. Since I made my PCB so tight, it has been somewhat of a challenge to fit all the parts. I had to revert to placing components on both sides of the PCB -- some of this was planned for, but not all, and without plated through holes ... I also had not anticipated that form factor of high quality components such as capacitors is not always a choice (OS con's for example, not available in radials). I am still quite happy with the layout.

My hope is to make available simple measurements (gain, frequency response) before July 4, but I am not at all certain that I will make this deadline. If I do miss it, there will be a delay until July 16 or so, but then I might be able to make distortion measurements as well.

Bear in mind this is for input stage with dummy load only.

If the results are good, I should be able to have the amps fully built relatively quickly.

Petter
  Reply With Quote
Old 25th July 2001, 11:12 PM   #108
diyAudio Member
 
Join Date: Jan 2001
Location: Scandinavia
Thumbs up OK then!

Status: Working prototype of input stage!!!!
(This means that 90% of the work is done -- this is the innner loop of the drawing in the first post of this thread, and the only section requiring adjustment and real design work, a breakthrough that has been coming for a lOOOONG time now).

After 2 days in the lab, it turns out that my prototyping board is working after all! The identical sister is not working, probably a blown FET or fried resistors -- I did have some smoke in a resistor set. When you are working with +-50V supplies (and no ground), it is quite easy to fry things. Very strange that I did not fry more stuff. I did choose to start of with my best matched FET's and as such I was relatively brave (or foolish). Due to space limitations (overoptimization) and very very high voltage rails (by choice) I really would want a little more cooling. If I fail that, I will add a small fan (to the prototype set).

So, I have sinusoidal balanced in, with sinusoidal balanced out, and significant gain. About 60V pk-pk output with "configurable behaviour" -- add more voltage, get more output swing. This is a one-gainstage design. Output stage will just provide power. When you read this, you now know what I have been aiming for -- a configurable power amp. Add more juice to the output stage and suck out more power, for example 4 times as much. 99% of the time you are in low power mode with low heat + high class A drive in output stage. 1% of the time you are in high power mode with low class A drive ("low" compared to commercial products with normal price tags).

I have not tested with load yet, but hooking up to a power stage will be a lot of fun. I noticed that i had dropoff in gain at around 10KHz, much too low. I really should consult with the specs of the originals for comparison.

I also need to verify stability -- the circuit needs to be completely in balance. A word of construction advice, use mathed devices in equivalent roles -- ie bottom 4 current sources match up, top two match up -- inverted cascode probably not important but why not -- input devices a resounding YES! your best pair.

When building, set up current in top sources first with a high quality current meter measured after the inverted cascode. Then set up bottom sources to half that value -- before stuffing board completely. Complete and adjust outer lower pair for correct output voltage -- will probably be way out of balance and relatively insensitive and suddenly swing over really fast -- this is actually in line with my simulations that you may recall I had trouble with once I switched to real devices.

Also when building, use a triplet of resistors to set up all your trimpot turns (15 in my case) to be in your desired window (1 resistor drawing most of the current in paralells with a trimpot + a series resistor). I have about 1 turn per .08mA on the current sources ... I have an Excel spreadsheet which uses linear optimization methods to solve this (untrivial) problem. I call this a less than trivial problem because I gave up after 40 minutes with pen and paper and did the job in 5 minutes in Excel .... Of course there are 2 solution sets and 3 unknowns -- when I was in college, I probably would have done it for the exercise. Now I have other things to do.

Now, I need a place to host the pictures so I can put them up on this board. Anyone care to host it for me and provide a URL? Nothing incriminating here ... Send me an email through the system.

Petter

  Reply With Quote
Old 26th July 2001, 12:32 AM   #109
diyAudio Member
 
Join Date: May 2001
Location: Tasmania, Australia
Hi You can host the pics at my web site if you wish.

regards

Anthony Holton

http://www.aussieamplifiers.com
  Reply With Quote
Old 26th July 2001, 08:32 AM   #110
hifi is offline hifi  Sweden
diyAudio Member
 
Join Date: Mar 2001
Location: sweden
im just curios....how much do your circuitry differ from the X original?..

/micke
  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
Help needed: Firing up the Aleph-X100 Blitz Pass Labs 86 22nd September 2010 09:09 PM
Fisher x100 rudy129 Parts 0 11th February 2008 01:32 PM
Aleph DIY x100 and Wilson Audio-low impedance problem. elviukai Pass Labs 11 9th March 2006 06:36 PM
Has anyone heard of the SPL-X100 speaker? Matttcattt Car Audio 1 11th December 2003 02:58 PM


New To Site? Need Help?

All times are GMT. The time now is 11:25 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2