Hi all,
For this amplifier I'm building, I need 4 2SJ162s and 4 2SK1058 output transistors. I can get these for about $40, or I can get these as "quad matched pairs" for $88.
My question is it worth the extra cash for them to be matched? I don't know enough about amplifiers to realise how much difference there could possible be using individual transistors, some of which may vary compared to others.
Many thanks,
Alex
For this amplifier I'm building, I need 4 2SJ162s and 4 2SK1058 output transistors. I can get these for about $40, or I can get these as "quad matched pairs" for $88.
My question is it worth the extra cash for them to be matched? I don't know enough about amplifiers to realise how much difference there could possible be using individual transistors, some of which may vary compared to others.
Many thanks,
Alex
Hi,
I hope you mean $40 (£25) for the set of eight.
If you are only buying 4pair you will have little opportunity to match.
I bought 16pair for 4 projects and was left with one (out of the 32) that had a significant Vds mismatch. The current in this FET is measurably greater than it's partners. I suspect it runs at a higher temperature, both Tc and Tj. I hope I cannot hear it.
I hope you mean $40 (£25) for the set of eight.
If you are only buying 4pair you will have little opportunity to match.
I bought 16pair for 4 projects and was left with one (out of the 32) that had a significant Vds mismatch. The current in this FET is measurably greater than it's partners. I suspect it runs at a higher temperature, both Tc and Tj. I hope I cannot hear it.
Hi, thanks for the replies.
Yes I do mean $40 for eight ($88 for a set of eight that are all matched). The online site i was looking at to get the matched 4 pairs is http://www.tech-diy.com/LATFET.htm . They also stock other matched transistors that i need too.
It's hard to find a source for these chips, there are a few people selling them on ebay at £4 each, but I had a bad feeling these might be mixed and matched and badly matched.
If i went for the $40 for eight, would it be worth me getting an extra pair just incase one had a significant Vds mismatch like you encountered? It would be handy to have a spare pair for any failures I suppose.
Lastly, I'm assuming these are pretty good output transistors if you bought 16 pairs of them
Many thanks,
Andy
Yes I do mean $40 for eight ($88 for a set of eight that are all matched). The online site i was looking at to get the matched 4 pairs is http://www.tech-diy.com/LATFET.htm . They also stock other matched transistors that i need too.
It's hard to find a source for these chips, there are a few people selling them on ebay at £4 each, but I had a bad feeling these might be mixed and matched and badly matched.
If i went for the $40 for eight, would it be worth me getting an extra pair just incase one had a significant Vds mismatch like you encountered? It would be handy to have a spare pair for any failures I suppose.
Lastly, I'm assuming these are pretty good output transistors if you bought 16 pairs of them
Many thanks,
Andy
Buy 8, and if there's anything wrong with them harass this guy =>
www.diyaudio.com/forums/member.php?s=&action=getinfo&userid=1925
Jack has pretty neat measuring gear, he's bound to deliver you nicely matched specimens.
(don't mind his odd avatar, he's from New Jersey)
Idea : you could ask Jack if he's able/willing to match the Renesas/Hitachi devices at a specified drain current.
On the other hand, if someone who's likely to have designed more amplifier circuits than any other tells you not to bother ?
In church you have to sit on your knees and wait for lightning to strike as a sign. Overhere, you just yank the Pass chain at the right moment.
www.diyaudio.com/forums/member.php?s=&action=getinfo&userid=1925
Jack has pretty neat measuring gear, he's bound to deliver you nicely matched specimens.
(don't mind his odd avatar, he's from New Jersey)
Idea : you could ask Jack if he's able/willing to match the Renesas/Hitachi devices at a specified drain current.
On the other hand, if someone who's likely to have designed more amplifier circuits than any other tells you not to bother ?
In church you have to sit on your knees and wait for lightning to strike as a sign. Overhere, you just yank the Pass chain at the right moment.
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