I'm back to good ol' transistor matching frenzy. I found a stash of NJL0302/0281 pairs with quite some mismatch in Hfe. NPNs are in the range of 80-90, PNPs are between 110-130. I thought DMM method is throwing me off, so I built the rig for measuring with LM317 current source into collector with Ice=100mA and Vce 19V, but got the similar result as with DMM on few tested NPNs. Is my stash useless?
Hi zdr,
Those matches are fine. It's nice if you can match the NPN against the PNP transistors, and that difference isn't nearly as bad as some other transistor types. So match the PNP to themselves and do the same for the NPN parts.''
-Chris
Those matches are fine. It's nice if you can match the NPN against the PNP transistors, and that difference isn't nearly as bad as some other transistor types. So match the PNP to themselves and do the same for the NPN parts.''
-Chris
I made a simple rig to inject 1ma base current, and then measured voltage drop across 10R collector resistor. While hfe does go up significantly, it seems that transistors already matched by hfe with dmm do not deviate much from each other at higher currents. How reliable is dmm hfe marching anyway?
Are these caps any good for this amp:
http://www.kemet.com/Lists/ProductCatalog/Attachments/388/KEM_A4029_ALC10S.pdf
http://www.kemet.com/Lists/ProductCatalog/Attachments/388/KEM_A4029_ALC10S.pdf
I do not know the KEMET capacitors (I myself am using NICHICON on this position), but KEMET capacitors have a good reputation!
Keep in mind though: the capacitors you are looking for are part of the FC-100 backend PSU. Any "good" brand (Nichicon, Panasonic, Vishay, Epcos, …) will do the job.
I wish you good luck with your FC-100 - Rudi
Keep in mind though: the capacitors you are looking for are part of the FC-100 backend PSU. Any "good" brand (Nichicon, Panasonic, Vishay, Epcos, …) will do the job.
I wish you good luck with your FC-100 - Rudi
This Slit Foil Capacitor are old BHC, now owned by Kemet. I think is excellent choice, if diameter (35mm) is suitable in your PCB.
Here are some "audiophile" hype about Slit Foil technology 🙂
It's a good choice, for sure!... (by my point of view)
Here are some "audiophile" hype about Slit Foil technology 🙂
It's a good choice, for sure!... (by my point of view)
If you go to custom PSU board, I can highly recommend this: CRC Power Supply by Project16
It's suitable to customization, universal pitch for filter capacitors and etc. A lot of good option here, even if you stay with original design (IMHO, it's excellent for back end of FC-100)
It's suitable to customization, universal pitch for filter capacitors and etc. A lot of good option here, even if you stay with original design (IMHO, it's excellent for back end of FC-100)
Thanks, but I will keep the original pcb design as much as possible. I divided it in two boards to keep the cost low, but they are made to be easily attachable to each other.
I'm planning to use wire wound resistors at the outputs, Vishay LVR-5 0.1 ohm 1%. Is that a good idea?
https://www.vishay.com/docs/30206/lvr.pdf
https://www.vishay.com/docs/30206/lvr.pdf
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For sure, looking good... Or Ohmite WH series (bit smaller)
pinnochio have a good success with Ohmite
Other option to stay with "original" from BOM, MPC74. I think is good enough...
Hi zdr,
If you can find the "plate resistors", they are non-inductive. They also make non-inductive wire wound resistors. These are always prefered over the standard wire wound types. Something like the TE Connectivity SQMW series parts. They are radial resistors, so there is very little exposed metal lead. I forget if they fit this PCB or not, but I always try to use these types. The plate resistors are available on Ebay last time I looked. One of the very few times I will recommend shopping on Eeekbay.
The normal inductive resistors can make some designs oscillate, but even if those don't, the non-inductive type will buy you some extra phase margin. That's always good.
-Chris
If you can find the "plate resistors", they are non-inductive. They also make non-inductive wire wound resistors. These are always prefered over the standard wire wound types. Something like the TE Connectivity SQMW series parts. They are radial resistors, so there is very little exposed metal lead. I forget if they fit this PCB or not, but I always try to use these types. The plate resistors are available on Ebay last time I looked. One of the very few times I will recommend shopping on Eeekbay.
The normal inductive resistors can make some designs oscillate, but even if those don't, the non-inductive type will buy you some extra phase margin. That's always good.
-Chris
Actually, even though the title says "wirewound", they are actually metal strip up to 5W - see the data sheet.
LVR05 LVR-5 5 0.005 to 0.3 1, 3, 5, 10 Metal strip
I have these already in the drawer, that is why I ask.
Margins were given sufficient derating to not oscillate , with " caveman" resistors. I would guess with non inductive types , miller caps could be reduced , unity gain could be pushed higher. But , specs are already superior
to overpriced Pass / Curl B$. get as "Anal" as you want.
PS - we even oriented ( the one layer inductor to be opposed to the nearby traces) and suggested 2 layer cancelling OP inductors , so ... "junkbox" components will still make for a superior amp.
I notice , the commercial sector on this forum is both condescending and slightly hostile towards me. Expected. ---- $$$$
Edit - I am true blue DIYA , they troll the forum for $$ , Jason might not like that opinion.
Slewmaster was "breaking point" "redneck teck " triggering ... - CONTACT US – Virtual Zero Audio Store is so far ahead of esoteric (Pass/curl/self ??) designs . They with $$ , produce relative
junk. Welcome to the new order.
OS
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Hi,
After a nice experience with the Quasi ( Very simple quasi complimentary MOSFET amplifier ), I am planning to try this other semiconductors amplifier before to return to my vacuum tube habitudes 🙂
I have already Thermal Track transistors, but I cannot find the 2SA1360 and the 2SC3423 from Toshiba, I have seen that a Chinese company Inchange Semiconductor Company( Inchange Semiconductor Company(ISC) ) is producing them, they are not fake, but I don't know if the specifications are exactly the same and I would prefer the original ones 😀
Did you have a suggestion where to find genuine parts ? I already contacted joshvi ( VAS transistors for sale 2SA1360Y/2SC3423Y,2SA1209S/2SC2911S and KSA1381E/KSC3503E ) but didn't get an answer yet... In case there is no availability is it possible to replace them with other parts ?
The problem is the same for the 2SK170B but I understand that it is possible to use LSK170B from Linear Systems however it is not available from large distributor like Mouser or Digikey ?
Thanks and rgds,
Marc
After a nice experience with the Quasi ( Very simple quasi complimentary MOSFET amplifier ), I am planning to try this other semiconductors amplifier before to return to my vacuum tube habitudes 🙂
I have already Thermal Track transistors, but I cannot find the 2SA1360 and the 2SC3423 from Toshiba, I have seen that a Chinese company Inchange Semiconductor Company( Inchange Semiconductor Company(ISC) ) is producing them, they are not fake, but I don't know if the specifications are exactly the same and I would prefer the original ones 😀
Did you have a suggestion where to find genuine parts ? I already contacted joshvi ( VAS transistors for sale 2SA1360Y/2SC3423Y,2SA1209S/2SC2911S and KSA1381E/KSC3503E ) but didn't get an answer yet... In case there is no availability is it possible to replace them with other parts ?
The problem is the same for the 2SK170B but I understand that it is possible to use LSK170B from Linear Systems however it is not available from large distributor like Mouser or Digikey ?
Thanks and rgds,
Marc