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ZTX384/214 Equivalent

M

Mus

pfm Member
ZTX384/214 transistors can be replaced with 2SC2547E/2SA1085E transistors in various Naim boards. But the ZTX ones are c-b-e and the replacements are b-c-e. So you have to twist 2 of the legs around each other to fit them in. While this is no big deal I would rather not, can anybody recommend a suitable ultra-low noise fast transistor pair that's c-b-e?

TIA

Regards,

Mus
 
Originally posted by Paul Dimaline
Could you not mount the transistors on the opposite side of the board?
Click to expand...

Nice idea but, unless my visio-spatial ability has got a bad cold too, I cant see how that would help? The centre leg on one is "b" and on the other it's "c". Mounting on the opposite side of the board transposes "b" & "e" but leaves "c" unchanged? My head hurts now.

Regards,

Mus
 
Richard H has correctly stated 'safest' method if using different pin out devices.

I've done same on my phono cards without problem.

Make sure you use correct length of 'thin' silicon sleeving.

taffyboy
 
Originally posted by colasblue
BC550/560 might be a suitable replacement. Correct or better parameters and correct pin outs
Click to expand...

Excellent, and cheap as chips to boot. Has anybody tried these?

Many Thanks.

Regards,

Mus
 
Mus,

I tried BC550B in the MC five transistor ladder and I didn't like 'em, can't remember quite why so it can't have been too bad, but I found that 2SD786's sounded better (quieter, more fluid). 2SD786's are b-c-e too though.

I've not tried 2SC2547E's.
 
Originally posted by chiily
but I found that 2SD786's sounded better (quieter, more fluid). 2SD786's are b-c-e too though.
Click to expand...

Garf,

Thanks for the recommendation, where did you buy them from? What is its partner called?

Regards,

Mus
 
Mus,

Sadly the 2SD786s are an obsolete part :( I think I was lucky to find about 20 odd in the States. Though I do have a few (not sure how many) of their replacement the 2SC3329, see here for a huge price.

I have been doing a little more digging and I have found a suppier of a variant of the 2SD786, the 2SD-786Q/2SD-786S in the UK, at 24p each +p&p +vat. However being a variant I'm wary of what it's performance may be.

Has anyone out there in possession of the data sheet(s) for the 2SD786, 2SD786Q or 2SD786S to we can nail the differences?

I'll see how many 2SC3329's I have left Mus.
 
WWW.alldatasheet.co.kr is a brilliant place to find datasheets for current devices.

When a device is obsolete there's ususally a good reason, like its an inferior variant of a series and the better one is now available at the same price.

perhaps 2SD787 and 788 might be worth investigating. tey look pretty likely contenders

The 5 transistor ladder is probably the most critical place in the system to get an ultralinear low noise device, but surely there must be a better one around than ZTX214.

Other parts of the circuitry are probably far less crucial.

What do you need the 214 replacement for (or are you just trying to get an improvement)

If you really want a 214 in the signal path then pinch one out of a non critical application (like the output relay circuit) and replace that with a BC550.

Anybody know what Naim now use ?
 
Mus said:
ZTX384/214 transistors can be replaced with 2SC2547E/2SA1085E transistors in various Naim boards. But the ZTX ones are c-b-e and the replacements are b-c-e. So you have to twist 2 of the legs around each other to fit them in. While this is no big deal I would rather not, can anybody recommend a suitable ultra-low noise fast transistor pair that's c-b-e?
Mus
Click to expand...
This response may be a little late but I'm just modding my mc board now. My pair are the 323/3s. On this version the transistor leg holes are splayed tripod-like so its just a matter of orientating the b-c-e 2sd786s. No need for twisting and silicon leg wraps cos there are lots of room.

I couldn't get the complementary 2sb737s and am hoping BC560s will do the job for the few PNP spots.
 
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