Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Pass Labs This forum is dedicated to Pass Labs discussion.

Mezmerize DCB1 Building Thread
Mezmerize DCB1 Building Thread
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 March 2015, 02:06 PM   #1521
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by Joel Wesseling View Post
...................Looking for Matched quads of 2SK170-BL.

How many pieces would I need to buy, to come up with 2 matched quads?
I see 50 Pieces for $33 and 20 for $13, on ebay..
..................
I measured many hundreds of lsk170.
I found lots of matched pairs which I sold on at low cost. All the b grade are sold. I still have a grade and c grade in swap meet.

But I did not find any matched quads.
Matching requires both Id and transconductance to be equal.
This is a very sensitive measurement and the chances of getting a quad set seem by my experience to be very low (zero quads from 300pairs)

However,
if you are ONLY selecting by Idss and completely ignoring gm, then it is very easy to select by Idss, so easy it is recommended regularly and by many to DIY.

You don't need to pay the exorbitant prices I see being asked for selected Idss pairs.
Out of a batch of 100 devices you will get at least 40pairs to better than 1% of Idss. The remaining pairs are likely to be better than 5%
= virtually no wastage.
__________________
regards Andrew T.

Last edited by AndrewT; 3rd March 2015 at 02:10 PM.
  Reply With Quote
Old 3rd March 2015, 10:08 PM   #1522
Dennis Hui is offline Dennis Hui  Canada
diyAudio Member
 
Join Date: Aug 2002
Location: Toronto, Canada
Mezmerize DCB1 Building Thread
Quote:
Originally Posted by Salas View Post
Lower THD due to higher Yfs and narrower bandwidth due to higher Ciss. About DC offset, matched Idss criterion stands the same although such high Yfs JFETs tend to be even more temperature susceptible than K170.
Thanks for the info Salas! I'll stick with 2sk170.

Cheers,
Dennis
__________________
We are fearless amplifier builders. A little heat doesn't scare us at all.
- NP 2002
  Reply With Quote
Old 9th March 2015, 07:06 PM   #1523
zibra is offline zibra
diyAudio Member
 
Join Date: Nov 2011
New owner here. Which resaistors exactly got most influence in sound? how many of them are most important?

Click the image to open in full size.

I found 4 at output but see 8 of them

http://www.audiocircle.com/index.php?topic=85001.0

Last edited by zibra; 9th March 2015 at 07:11 PM.
  Reply With Quote
Old 9th March 2015, 07:54 PM   #1524
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Mezmerize DCB1 Building Thread
The 220 Ohm ones are the more influential. Found in two pairs left and right to the output relay towards the PCB's center.
  Reply With Quote
Old 9th March 2015, 08:08 PM   #1525
zibra is offline zibra
diyAudio Member
 
Join Date: Nov 2011
220R you meant? Next are 220k and least important 1M?
Thank you. In that case Ill try 4x220R and see if I hear difference first.
Is there any tolerance of value? Can I use 200R or 180R?

Last edited by zibra; 9th March 2015 at 08:17 PM.
  Reply With Quote
Old 9th March 2015, 08:28 PM   #1526
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Mezmerize DCB1 Building Thread
The front row pairs near the PCB's edge flanking the signal output connector have two 220K and two 1Meg ones. Those are in parallel to the signal and less important. The 220R (Ohm) ones are in series to the signal, hence more important. All in all those eight are the only ones related to the L & R signal paths. You can use 200R instead of 220R.
  Reply With Quote
Old 9th March 2015, 08:30 PM   #1527
zibra is offline zibra
diyAudio Member
 
Join Date: Nov 2011
Superb, thank you for explanation. Ill try Caddock first.
  Reply With Quote
Old 9th March 2015, 08:32 PM   #1528
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Mezmerize DCB1 Building Thread
Alright. What type of resistors you got there now? Have you listened to it already and in what kind of system?
  Reply With Quote
Old 9th March 2015, 08:41 PM   #1529
zibra is offline zibra
diyAudio Member
 
Join Date: Nov 2011
Im not in hurry yet Just info for future.
Bought it assembled already and it looks like Takman metal film resistor.
DCB1->renovated Dynaco ST35->DIY speakers ScanSpeak 2608/913000 + Visaton AL130
Not ready now for changes though.
  Reply With Quote
Old 9th March 2015, 08:48 PM   #1530
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Mezmerize DCB1 Building Thread
Consider sinking the MOSFETS for manning it up to 200mA at a point also.
  Reply With Quote

Reply


Mezmerize DCB1 Building ThreadHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
FS : F3 PCB + PSU - Hypnotize - Mezmerize - LightSpeed korben69 Swap Meet 16 21st June 2013 06:52 AM
WTB Mezmerize PCB 3GGG Swap Meet 3 16th January 2011 09:15 AM
My XXLS Subwoofer building thread... harrisni Subwoofers 9 28th October 2007 08:21 PM
Fave song from SOAD 'Mezmerize'? PeteMcK Music 6 8th March 2006 03:12 AM
Gainclone building thread based on BrianGT's boards meat Chip Amps 752 8th August 2004 06:25 AM


New To Site? Need Help?

All times are GMT. The time now is 12:31 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki