2N555 replacement transistor - UK Vintage Radio Repair and Restoration Discussion Forum

TimothyStuart · 21st Jun 2021, 2:30 pm

I am renovating a B&O Master 610 tuner/amp and need to replace the 2N555. From various threads I have read that I can use a AD149 but I am wondering are there significant differences that should concern me? I would greatly appreciate some guidance please.

G6ONEDave · 21st Jun 2021, 5:48 pm

I'm making a calculated guess here but I think you mean a 2N555 and not SN555, as the latter is more likely an 8 pin timer chip.

The specs in the Towers international Transistor Selector book for 2N555 are; PNP Germanium, TO3 package, VCB 30v max, VCE 30v max, VED 15v max, Ic max not given, TJ 90C max, P TOT 40WC, FT 150K min, COB not given, HFE 50 mn, HFE Bias 500mA, equiv ASZ16 and 2N1536.

Specs for AD149; PNP Germanium, TO3 package (same pinout as above), VCB 50v max, VCE 30v max, VED 20v max, IC 3.5A max, TJ 100C max, P TOT 27WH, FT Min 200K, COB Max not given, HFE 30 mn, HFE Bias 1A, equivs same as above.

Hope this might be of help.

Dave

TimothyStuart · 24th Jun 2021, 10:31 pm

Many thanks Dave. Yes I did mean 2N555

Station X · 25th Jun 2021, 9:01 am

Thread title edited.

Cruisin Marine · 25th Jun 2021, 9:12 am

According to old Equivalents Guide:
AD149IV, ASZ16, TI3027, 2N1536

Restoration73 · 25th Jun 2021, 9:31 am

AD143 work well and new old stock can be found e.g.

http://markhindes.easywebstore.co.uk/AD143_AG1LI.aspx

21st Jun 2021, 2:30 pm	#1
TimothyStuart Triode Join Date: Jan 2021 Location: Hove, East Sussex, UK. Posts: 20	2N555 replacement transistor I am renovating a B&O Master 610 tuner/amp and need to replace the 2N555. From various threads I have read that I can use a AD149 but I am wondering are there significant differences that should concern me? I would greatly appreciate some guidance please.

21st Jun 2021, 5:48 pm	#2
G6ONEDave Octode Join Date: Dec 2019 Location: Owston Ferry, North Lincolnshire, UK. Posts: 1,704	Re: 2N555 replacement transistor I'm making a calculated guess here but I think you mean a 2N555 and not SN555, as the latter is more likely an 8 pin timer chip. The specs in the Towers international Transistor Selector book for 2N555 are; PNP Germanium, TO3 package, VCB 30v max, VCE 30v max, VED 15v max, Ic max not given, TJ 90C max, P TOT 40WC, FT 150K min, COB not given, HFE 50 mn, HFE Bias 500mA, equiv ASZ16 and 2N1536. Specs for AD149; PNP Germanium, TO3 package (same pinout as above), VCB 50v max, VCE 30v max, VED 20v max, IC 3.5A max, TJ 100C max, P TOT 27WH, FT Min 200K, COB Max not given, HFE 30 mn, HFE Bias 1A, equivs same as above. Hope this might be of help. Dave __________________ Quote "All is hyperthetical, until it isn't!" (President Laura Roslin, Battlestar Galactica)

24th Jun 2021, 10:31 pm	#3
TimothyStuart Triode Join Date: Jan 2021 Location: Hove, East Sussex, UK. Posts: 20	Re: 2N555 replacement transistor. Many thanks Dave. Yes I did mean 2N555

25th Jun 2021, 9:01 am	#4
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: 2N555 replacement transistor Thread title edited. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

25th Jun 2021, 9:12 am	#5
Cruisin Marine Octode Join Date: Jul 2018 Location: Worthing, West Sussex, UK. Posts: 1,005	Re: 2N555 replacement transistor According to old Equivalents Guide: AD149IV, ASZ16, TI3027, 2N1536

25th Jun 2021, 9:31 am	#6
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,801	Re: 2N555 replacement transistor AD143 work well and new old stock can be found e.g. http://markhindes.easywebstore.co.uk/AD143_AG1LI.aspx