Quad 34 transistors - UK Vintage Radio Repair and Restoration Discussion Forum

valveaudio · 28th Apr 2016, 2:28 pm

Please ignore previous thread, wrong type number.

The Quad 34 schematic shows BC214C PNP and E5270 NPN transistors.
I think I could use BC556/558 and BC550 to replace these, any advice or comments on this?.

Thanks
Trevor

stevehertz · 28th Apr 2016, 7:02 pm

Having just done a spot of web searching, as I see it (far from conclusive!) the former can be replaced with a BC557 and the latter a BC549.

Just out of interest, I recently had a faulty 2SC1571 in a receiver I was working on, and until the proper replacement arrived (BC184L) I used a basic, general purpose 2N4401 just to 1) prove that the trannie was faulty and 2) just to see if I could hear anything amiss. The set worked fine with my 'rogue' 2N4401 fitted! Of course I fitted the BC184L when it arrived. But it just goes to show, maybe we stress too much sometimes when fitting replacement transistors. Of course you have to be aware of over running trannies by voltage or current, but there you go, in my case that totally 'wrong' trannie worked fine.

paulsherwin · 28th Apr 2016, 7:50 pm

See https://en.wikipedia.org/wiki/BC108_family.

The BC182/3/4 are electrically identical to the BC547/8/9. The BC212/3/4 are identical to the BC557/8/9.

Ed_Dinning · 28th Apr 2016, 9:13 pm

Hi Gents, note that these BC182/ 212 types come with different pin-outs (K & L types). identify the pin outs first and bend legs if they are not correct.

Ed

28th Apr 2016, 2:28 pm	#1
valveaudio Hexode Join Date: Feb 2006 Location: Diss, Norfolk, UK. Posts: 386	Quad 34 transistors Please ignore previous thread, wrong type number. The Quad 34 schematic shows BC214C PNP and E5270 NPN transistors. I think I could use BC556/558 and BC550 to replace these, any advice or comments on this?. Thanks Trevor

28th Apr 2016, 7:02 pm	#2
stevehertz Dekatron Join Date: Sep 2011 Location: Rugeley, Staffordshire, UK. Posts: 8,831	Re: Quad 34 transistors Having just done a spot of web searching, as I see it (far from conclusive!) the former can be replaced with a BC557 and the latter a BC549. Just out of interest, I recently had a faulty 2SC1571 in a receiver I was working on, and until the proper replacement arrived (BC184L) I used a basic, general purpose 2N4401 just to 1) prove that the trannie was faulty and 2) just to see if I could hear anything amiss. The set worked fine with my 'rogue' 2N4401 fitted! Of course I fitted the BC184L when it arrived. But it just goes to show, maybe we stress too much sometimes when fitting replacement transistors. Of course you have to be aware of over running trannies by voltage or current, but there you go, in my case that totally 'wrong' trannie worked fine. __________________ A digital radio is the latest thing, but a vintage wireless is forever..

28th Apr 2016, 7:50 pm	#3
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,945	Re: Quad 34 transistors See https://en.wikipedia.org/wiki/BC108_family. The BC182/3/4 are electrically identical to the BC547/8/9. The BC212/3/4 are identical to the BC557/8/9.

28th Apr 2016, 9:13 pm	#4
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Quad 34 transistors Hi Gents, note that these BC182/ 212 types come with different pin-outs (K & L types). identify the pin outs first and bend legs if they are not correct. Ed