2SC2526 & 2SA1076 replacement

[Pilot Mariner]

Hi - Can anyone suggest an equivalent or replacement for these complementary pair transistors, from a Pioneer SX-D7000 amplifier, which can be obtained from RS or Farnell.

Cheers

[G6ONEDave]

I misread the request, as it can be read either that the transistors can be supplied by RS and Farnell, it also can be read that equivalents are required. Anyway the type that you require have not been manufactured for a long time now. You will probably have to modify the heatsinking to take TO220 style devices, as opposed to the original 2 hole mounting of the originals, which are now obsolete. The originals are listed in various data books and a replacement with similar electrical specification could be in TIP, BD, MJ, MJE, 2SC and 2SA ranges.

Dave

[Pilot Mariner]

Thanks Dave for answering.

Maybe I should have made my post a bit clearer.

I am repairing a horrendous Pioneer SX-D7000 tuner amp for a forum member. The 2SC2526 and 2SA1076 output transistors on one channel are S/C and are virtually unobtainable or very expensive. I was therefore looking for electrically equivalent transistors as replacements that I could use, and sneak them onto my works daily RS or Farnell order (hence the RS/farnell reference).

In the end I have fitted a MJL3281A/MJL1302A combination. I could still use the original fixing clip and holes to retain the TO-264 style packages on the heatsink.

I am now ready to let the smoke out, but I am trying to devize a way of powering up safely without all my hard work going up in smoke.

(I have also repaired the power amp board, fortunately I had the components for that close to hand).

Mark

[dave cox]

I don't think you could do any better than the MJL3281A/MJL1302A

[paulsherwin]

A traditional lamp limiter should prevent a major disaster. Start with a 40W or 60W lamp. You should see a bright flash as the smoothers charge up followed by a very dim glow until the amp starts doing some work. Obviously if the lamp stays brightly lit, switch off and investigate.

[Pilot Mariner]

Yes Paul, that was my thinking also, but would I be better breaking into the secondary side with 2 lamp limiters on the split phase supply. Could there could still be enough energy in the primary to cause damage on the secondary circuit with a primary limiter?

Thanks Dave for confirming my choice of replacements.

This amp has come to me after a previous repairer gave up on it, (don't think it's a forum member) unfortunately he omitted to fit one of the insulating washers on the output transistors. When I switched it on it blew up 2 good 2sc2526/2sa1076 combinations together with numerous components on the preamp board, hence my taking care powering it up after the rebuild. I could kick myself for not checking.

Mark

[paulsherwin]

The limiter should prevent the transistors from going overcurrent for long enough to stop them going bang if you switch off promptly. There are no guarantees of course.

[Valvepower]

Hi,

A while back I did a repair on a 1980’s Trio power amplifier with cooked 2SA/2SC TO3 transistors and I replaced them with MJ TO3 parts (sorry, can’t remember the exact numbers though) with no problems. Although, I did keep an eagle eye open for any spurious oscillations and suchlike though, however there appeared to be none.

My trusty ‘ole Variac is my friend when powering up the solid-state power amplifiers

Quick heads up here… Whilst talking ‘old’ transistors the Sanken STD03P and STD03N are going end of life, so it may be prudent to pop some in the toy box as there are no direct equivalents for these kiddies

Terry