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.

Babelfish M25, SissySIT - general building tips and tricks
Babelfish M25, SissySIT - general building tips and tricks
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 24th January 2019, 07:13 PM   #341
Russellc is offline Russellc  United States
diyAudio Member
 
Join Date: Mar 2003
Location: midwest
Babelfish M25, SissySIT - general building tips and tricks
Quote:
Originally Posted by Zen Mod View Post
naah

rims on mountain bike , ya Dodo .....

For what it's worth, mine are 27 inches.
__________________
Pass B-1 preamp, Pass BA3 preamp, Pass F-5 Amp, Pass F-6 Amp, Pass BA-3 Amp, Pass M-2 amp, Pass Aleph J amp, Pass Pearl 2 Phono pre Tekton Enzo, Altec A7, Econowave JBL 2235H & B&C CD
  Reply With Quote
Old 26th January 2019, 04:29 AM   #342
dBel84 is offline dBel84  United States
diyAudio Member
 
Join Date: Jul 2006
Location: midwest USA ~ WI
Quote:
Originally Posted by Zen Mod View Post
power it up , .......

wait few mins , calming your breathing
no kidding - I kept waiting for something to release the sacred faerie dust

but at least I think I have identified the problem - no 5V to power the HALL effect chips , looks well soldered and the correct orientation, so I will have to explore a little more.

The offset cannot be zeroed but I can get it down to 300mV, the bias settles at 2.6A, the 2K Iq pot has no effect which makes sense given that the opto has no voltage to work with - I measure -0.9V and -.5V at pins 3 and 4.

Both rails at approximately 24 - positive rail looks like it is pulling down a little more than negative rail

I only left it on long enough to do some troubleshooting , very odd that both channels are behaving the same ( although not tested this time - only tested right channel )

..dB
  Reply With Quote
Old 26th January 2019, 05:45 AM   #343
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Babelfish M25, SissySIT - general building tips and tricks
you see what's happening when you are raping pcb with connectors not meant to be mounted here ?

I don't now which of traces you broke , but see - have you positive rail reaching 7805 (most likely you have) , does 7805 is having 5V out .......

in fact , first check is there continuity between 7805 out and Hall, pin 8
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 26th January 2019, 02:07 PM   #344
dBel84 is offline dBel84  United States
diyAudio Member
 
Join Date: Jul 2006
Location: midwest USA ~ WI
Quote:
Originally Posted by Zen Mod View Post
you see what's happening when you are raping pcb with connectors not meant to be mounted here ?
ouch - no violation intended

Click the image to open in full size.

they actually work very well but I can appreciate that they are not your preference.

While troubleshooting the right board, I tested the left - it again has no ability to lower Iq but voltage across 0R1 comes up at 150mV with 200mV offset and slowly drifts up to 200mV. I can easily zero offset which remains at +- 1mV and the gate voltage measured at the 100R gate resistor is -4 for the SIT and -4.2 for IRFP9240.

Just giving the right board another piece by piece review and then will assess it. I "think" it might be a poor via contact - lower trace did not appear continuous with upper trace and I had not flooded the solder through the board - now corrected.

..dB
  Reply With Quote
Old 26th January 2019, 02:22 PM   #345
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Babelfish M25, SissySIT - general building tips and tricks
Quote:
Originally Posted by dBel84 View Post
........

While troubleshooting the right board, I tested the left - it again has no ability to lower Iq but voltage across 0R1 comes up at 150mV with 200mV offset and slowly drifts up to 200mV. I can easily zero offset which remains at +- 1mV and the gate voltage measured at the 100R gate resistor is -4 for the SIT and -4.2 for IRFP9240.

......

..dB
so , you're saying that you can set Iq to 2A (but no less) and you can set DC offset ?

obviously you have specific pair of outputs ....... 200mV is on the verge of voltage window for opto-bjt I tested for

so - either looking for mosfet with greater Ugs , or slightly increasing one or both resistors from rails to opto-bjt (R16,R17)

or just leave it on 2A , fine with me
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 26th January 2019, 04:51 PM   #346
dBel84 is offline dBel84  United States
diyAudio Member
 
Join Date: Jul 2006
Location: midwest USA ~ WI
Quote:
Originally Posted by Zen Mod View Post
so - either looking for mosfet with greater Ugs , or slightly increasing one or both resistors from rails to opto-bjt (R16,R17)
the right channel now appears to be working too - gate voltages of -3.2 V and the HALL chip is seeing 5V

BUT - still same behavior - starts up at 1.5A and slowly ramps up - this side gets to 2.6A and I cannot s=zero offset completely.

@ZM - how much would you recommend increasing R16/17 ? take them up to 3K2 or even higher?

..dB
  Reply With Quote
Old 26th January 2019, 07:14 PM   #347
sontero is offline sontero  Italy
diyAudio Member
 
sontero's Avatar
 
Join Date: Sep 2010
Location: Cagliari - Sardinia
since the Sissy is really an amp that sounds wonderful I decided to refine his qualities. I thought of placing in key points of the circuit where the signal passes some valuable component.
I added the components one at a time to understand how much weight they had in the final result.
then R1 = Vishay z-foil (TX2575), R2 = Caddock MK132, R20 R21 R-flying = Dale RN55.
But the biggest impact on sound was the comparison between capacitors. I was intrigued by ZenMod's suggestion to adopt the old Philips MKC in polycarbonate in parallel to the Silmic II ...... and as I had a pair of 4.7uF Clarity Cap CSA I put them in competition.
having listened carefully to the coupled Silmic + MKC he won tremendously. I invite everyone to try ..... I think nobody will repent.
I am very satisfied at this point .... great sound
Attached Images
File Type: jpg mkc+silmic.jpg (125.5 KB, 142 views)
File Type: jpg clarity CSA.jpg (243.9 KB, 140 views)
  Reply With Quote
Old 26th January 2019, 07:18 PM   #348
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Babelfish M25, SissySIT - general building tips and tricks
Quote:
Originally Posted by Zen Mod View Post
........ or slightly increasing one or both resistors from rails to opto-bjt (R16,R17)

or just leave it on 2A , fine with me
of course that I made a typo - I meant R18 and R19

I would try to increase them both (if you can center DC offset with standard values) to first standard value

so - 43 to 47K , 36 to 39K

for test , lifting one leg and putting 4K7 in series (to each( will do the job

what are Ugs values of outputs in that other channel?
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  Reply With Quote
Old 26th January 2019, 07:44 PM   #349
noelectrix is offline noelectrix  Europe
diyAudio Member
 
noelectrix's Avatar
 
Join Date: Dec 2006
Location: leipzig germany
Quote:
Originally Posted by sontero View Post
the coupled Silmic + MKC he won tremendously
Hi Sontero, do you know where to get the MKCs (what value?) in europe?

best
stefan
  Reply With Quote
Old 26th January 2019, 08:48 PM   #350
sontero is offline sontero  Italy
diyAudio Member
 
sontero's Avatar
 
Join Date: Sep 2010
Location: Cagliari - Sardinia
Quote:
Originally Posted by noelectrix View Post
Hi Sontero, do you know where to get the MKCs (what value?) in europe?

best
stefan
hi Stefan
look this from Bulgaria:
2 x NOS 1.0uF 1uF 250V Philips Chicklet MKC 341 HQ Axial Polycarbonate Caps | eBay
  Reply With Quote

Reply


Babelfish M25, SissySIT - general building tips and tricksHide 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
3D Modeling Tips and Tricks Patrick Bateman Multi-Way 13 14th March 2019 02:58 AM
PCB tips and tricks - Part 4 AndersHa Construction Tips 5 28th March 2016 11:26 PM
How To Solder Tips and Tricks Eddiegnz1 Tubes / Valves 21 20th December 2013 09:52 AM
Tube Tips/Tricks for beginners SamK2012 Tubes / Valves 10 19th November 2012 12:12 PM
Couple of tips/tricks peace brainerd Everything Else 0 10th April 2006 03:57 PM


New To Site? Need Help?

All times are GMT. The time now is 07:00 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki