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MapacheRaper
Joined: Feb 15, 2018 Posts: 166 Location: Spain
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
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Posted: Thu Aug 09, 2018 1:27 am Post subject:
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that the measurements move slightly is partially due to temperature changes...
You will like to rest the trannies a while in their circuit before you measure them... whenever you touch them the voltage will change ad then it takes some time to settle to the ambient temperature...
I have build the transistor matcher from Elektrouwe, the linke was posted here and found that many of my matched transitors via the method you like to use showed some discrepancies... either i was to stupid to do it properly, my DVM not being the best suited for it, or i wasn't waiting long enough for them to settle...
with the circuit by elektrouwe you also have to wait until they settle, but i find it quiet easier to match with them and you can also get pretty close detailed readings your typical average DVM wouldn't be capable to show...
Only disadvantage, you'll need an oscilloscope...
MAybe Ian Fritz can tell you more, guess he's sometimes still visiting here and can expalin again or say what i/we did wrong, then hopefully getting it then. _________________ https://soundcloud.com/bastian-j |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24081 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Thu Aug 09, 2018 1:36 am Post subject:
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You really need the zener diode as it makes the reference voltage needed for the measurement. And also do use a 5v1 one, as around that zener voltage the zener's temperature dependency is as small as possible. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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JovianPyx
Joined: Nov 20, 2007 Posts: 1988 Location: West Red Spot, Jupiter
Audio files: 224
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Posted: Thu Aug 09, 2018 6:06 am Post subject:
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Knowing who Ian Fritz is, I'd say that there are no components in this circuit that can be casually eliminated including the zener diode. _________________ FPGA, dsPIC and Fatman Synth Stuff
Time flies like a banana. Fruit flies when you're having fun. BTW, Do these genes make my ass look fat? corruptio optimi pessima
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MapacheRaper
Joined: Feb 15, 2018 Posts: 166 Location: Spain
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Posted: Thu Aug 09, 2018 6:09 am Post subject:
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@wackelpeter
I ordered an DSO150 osci, but it was DOA. I´ll be getting one in other moment, thought. I´ll check the matcher. Thanks!
@bluehell. I´ll search for the zener. Thanks for the explanation! |
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gabbagabi
Joined: Nov 29, 2008 Posts: 651 Location: Berlin by n8
Audio files: 23
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MapacheRaper
Joined: Feb 15, 2018 Posts: 166 Location: Spain
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Posted: Fri Aug 10, 2018 5:53 pm Post subject:
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That´s a sweet idea. I have a bunch of zeners coming, but maybe Im breadboarding this so I can finish some building
I will try with a 50k pot
Thanks g.gabba! |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
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Posted: Fri Aug 10, 2018 10:42 pm Post subject:
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I wonder how much influence a mismatch in the Zeners would have on the measurements… At least i'm unaware if there is some difference of a few mV in the Zeners and if it's too marginal to care of.
Well my guess is that it is not much or has effectively no effect on the measurements, but i'm not Pretty sure. _________________ https://soundcloud.com/bastian-j |
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AlanP
Joined: Mar 11, 2014 Posts: 746 Location: New Zealand
Audio files: 41
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Posted: Sat Aug 11, 2018 12:04 am Post subject:
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http://www.dragonflyalley.com/synth/images/TransistorMatching/ianFritz-transmat0011_144.pdf
For clarity -- that schematic shown on this thread is misleading as hell.
When matching transistors, do it while watching a mildly boring movie. Leave five minutes after you've placed a transistor to measure it.
10 stick transistor in socket
20 wait 5 minutes
30 measure transistor
40 put transistor on some tape with a note of it's reading
50 get a new transistor
60 goto 10
Also, leave your reference transistor in there permanently. All your measurements will be with that one as a reference. |
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gabbagabi
Joined: Nov 29, 2008 Posts: 651 Location: Berlin by n8
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Posted: Sat Aug 11, 2018 12:45 am Post subject:
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RUN MATCH.BAS |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
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Posted: Sat Aug 11, 2018 2:20 am Post subject:
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AlanP wrote: | http://www.dragonflyalley.com/synth/images/TransistorMatching/ianFritz-transmat0011_144.pdf
For clarity -- that schematic shown on this thread is misleading as hell.
When matching transistors, do it while watching a mildly boring movie. Leave five minutes after you've placed a transistor to measure it.
10 stick transistor in socket
20 wait 5 minutes
30 measure transistor
40 put transistor on some tape with a note of it's reading
50 get a new transistor
60 goto 10
Also, leave your reference transistor in there permanently. All your measurements will be with that one as a reference. |
don't you have to switch the trannies in their sockets to get the difference in your measurements??? means trannie which was sticked into socket a must be sticked then into socket b and the other trannie vice versa? due to the nature of that we don't have an ideal=equal reference voltage at both trannies? So you have to substract delta UBE 1 from delta UBE2 to get the mismatch of the trannies? _________________ https://soundcloud.com/bastian-j |
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AlanP
Joined: Mar 11, 2014 Posts: 746 Location: New Zealand
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Posted: Sat Aug 11, 2018 3:33 am Post subject:
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Naw, leave Q2 permanently stuck. Just endlessly replace Q1 and measure. |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Sat Aug 11, 2018 5:45 am Post subject:
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yep okay, was a bit off my mind... it's of Course way easier and much more useful to just swap the probes of the DVM... _________________ https://soundcloud.com/bastian-j |
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MapacheRaper
Joined: Feb 15, 2018 Posts: 166 Location: Spain
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24081 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Mon Aug 13, 2018 2:12 am Post subject:
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That is a good solution too - great you got it working :-) _________________ Jan
also .. could someone please turn down the thermostat a bit.
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MapacheRaper
Joined: Feb 15, 2018 Posts: 166 Location: Spain
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Posted: Mon Aug 13, 2018 3:53 am Post subject:
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gabbagabi
Joined: Nov 29, 2008 Posts: 651 Location: Berlin by n8
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MapacheRaper
Joined: Feb 15, 2018 Posts: 166 Location: Spain
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Posted: Mon Aug 13, 2018 1:55 pm Post subject:
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