No, use only the O rating. ONSEMI 2SA1943OTH and 2SC5200OTU are good, they have TO-264-3 package. Mouser numbers 512-2SA1943OTU and 512-2SC5200OTU
Well if you drilled them TO-3P your past that selection point. I would still go for O rating, bought from a reliable source.
@mainframe99 From the Toshiba 2SC5200N datasheet
https://eu.mouser.com/datasheet/2/408/2SC5200N_datasheet_en_20150512-1799632.pdf
Using continuously under heavy loads (e.g. the application of high temperature/current/voltage and the
significant change in temperature, etc.) may cause this product to decrease in the reliability significantly even
if the operating conditions (i.e. operating temperature/current/voltage, etc.) are within the absolute maximum
ratings. Please design the appropriate reliability upon reviewing the Toshiba Semiconductor Reliability Handbook
("Handling Precautions"/"Derating Concept and Methods") and individual reliability data (i.e. reliability test
report and estimated failure rate, etc).
Ensure that the junction temperature does not exceed 150.
https://eu.mouser.com/datasheet/2/408/2SC5200N_datasheet_en_20150512-1799632.pdf
Using continuously under heavy loads (e.g. the application of high temperature/current/voltage and the
significant change in temperature, etc.) may cause this product to decrease in the reliability significantly even
if the operating conditions (i.e. operating temperature/current/voltage, etc.) are within the absolute maximum
ratings. Please design the appropriate reliability upon reviewing the Toshiba Semiconductor Reliability Handbook
("Handling Precautions"/"Derating Concept and Methods") and individual reliability data (i.e. reliability test
report and estimated failure rate, etc).
Ensure that the junction temperature does not exceed 150.
In the BOM, there are cells containing the text "See note =====>", but I can't find the note anywhere in the excel file...
Often you only have to look in the next column of the spreadsheet labeled "description" where you will find a selection criterion, from there pick the appropriate part value at the left from the column labeled "value".
Hi guys, in order to come up with a matched pair of transistors how many of them do I need to buy?
The problem is that if I need 6 matched pairs, I have to buy a LOT of transistors and it seems a huge waste of money to me...correct me if I'm wrong
And even then, what do I do with the remaining transistors?🙁
The problem is that if I need 6 matched pairs, I have to buy a LOT of transistors and it seems a huge waste of money to me...correct me if I'm wrong
And even then, what do I do with the remaining transistors?🙁
I usually buy 10 of each and use the closest matched ones and then I have a few spares if problems arise. The outputs aren't as critical to match.
Hi folks, has anyone got any spare drilled Heatsink sheets for the pcbs, I'm building an Ef4 if that makes a difference.
Hi everyone.
Do we really REALLY need to go through transistor matching for output devices and drivers? I'm asking because I made some cost estimates and it really makes the cost of the project skyrocket. At 2.50$ per device (minimum!), say I need to buy 30 PNP output devices and 30 NPN devices to come up with 4 matched pairs (and I think I'm being tight). It makes a total of 150$ PER CHANNEL. It means a total of 300$ only for output devices.
Then, we have to match drivers.
Then we need to shell out additional money to buy a suitable matching rig.
And in the end I'll be left with a lot of transistors which I know I'll never use again.
Do we really need to splurge 500$ or (very likely) more just for transistor matching? I didn't see anyone mentioning this cost in this thread...
If I could just buy the required number of transistors and be happy with it I would really appreciate it.
Do we really REALLY need to go through transistor matching for output devices and drivers? I'm asking because I made some cost estimates and it really makes the cost of the project skyrocket. At 2.50$ per device (minimum!), say I need to buy 30 PNP output devices and 30 NPN devices to come up with 4 matched pairs (and I think I'm being tight). It makes a total of 150$ PER CHANNEL. It means a total of 300$ only for output devices.
Then, we have to match drivers.
Then we need to shell out additional money to buy a suitable matching rig.
And in the end I'll be left with a lot of transistors which I know I'll never use again.
Do we really need to splurge 500$ or (very likely) more just for transistor matching? I didn't see anyone mentioning this cost in this thread...
If I could just buy the required number of transistors and be happy with it I would really appreciate it.
I didn’t bother to match any transistors in the build except for the ones it tells you to in the build guide -Q1,2,3,4. The amp performs perfectly and I posted measurements a while back to prove it.
You don’t need to match.
You don’t need to match.
@andreax1985
Please refer to this post
https://www.diyaudio.com/community/...son-of-badger-suggestions.369758/post-6897975
Please refer to this post
https://www.diyaudio.com/community/...son-of-badger-suggestions.369758/post-6897975
Thanks Stuart. Comparing the THD measured using unmatched transistors (reported in the post you addressed me to) to the THD reported in the build guide, is it correct the say that the use of matched pairs will reduce THD by a factor of 5 to 7 with respect to a unit with unmatched pairs?
No, I would not make that comparison.
There are many things to consider when interpreting the results.
The initial measurements were taken with a QA-401 and distortion magnifier. That combination is not able to measure as low as our current devices. So its quite possible that we were just measuring the measurement set-up.
The other things is those early measurements were taken without some of the tweaks we have made since those initial measurements were taken. For example the feedback trace tweak.
So you're amplifier will preform just fine if you don't match anything. But if suggest that you look at my list below and consider matching the transistors shown. How far you go down the list is up to you.
1. Q1, Q2
2. Q3, Q4
3. Q5, Q6
4. Q105, Q106
5. Q107, Q108
6. Output Transistors
I think many of the builders did not match the output transistors, and you can save yourself some serious money for other components or projects. I myself bought six NJW3281G and six NJW1302G and they where actually pretty close without matching. I also went for 55v rails, a modest 600VA transformer and all 64v caps, saved myself some money. And you know what ? It is still the best amp I ever had.
When buying @ Mouser Farnell et al. 10 parts will usually cost at much as 8. So buying 10 outputs when I need 6 or 8 is an obvious choice. Concerning the LTP, CAS and CM, buying min. 10 each might be the best value for $$ quality update around.