Author Topic: Quad 303 transisitor specifications  (Read 704 times)

Offline mygoggie

Quad 303 transisitor specifications
« on: November 13, 2018, 08:36:26 AM »
I am restoring a Quad 303, but need the specifications for the transistor TR104.

Originally it was a U17229, the service manual then replaced it with ZTX504. Subsequently this was replaced by a BC556B. None which I can obtain today.


My problem is that the specs differ and if I can have the specifications of the U17229, I can match this with one of the many online tools. Currently what I have is

RatingZTX504BC556B
Collector - Emitter Voltage-70 VDC-65 VDC
Collector - Base Voltage-70 VDC-80 VDC
Emitter - Base Voltage-5.0 VDC-5.0 VDC

I see a BCW19 has the same ratings but positive values instead of the above negative values. What are the implications of this???

EDIT: Corrected values of the BC556B
« Last Edit: November 13, 2018, 08:50:47 AM by mygoggie »
Herman

~ To heal the soul is to embark on a new journey. ~

Offline DACMan1

Re: Quad 303 transisitor specifications
« Reply #1 on: November 13, 2018, 08:42:19 AM »
Your specs for the BC556B are off. But the good news is that it is still available.
https://za.rs-online.com/web/p/bjt-bipolar-transistors/7619831/
http://www.mantech.co.za/ProductInfo.aspx?Item=65M0878-H

Offline mygoggie

Re: Quad 303 transisitor specifications
« Reply #2 on: November 13, 2018, 08:52:05 AM »
Your specs for the BC556B are off. But the good news is that it is still available.

Thanks, a late night ... used the BC558B values  :facepalm:  Post edited.

Will order on mouser as I have no need for a 100 transistors as min order ...
« Last Edit: November 13, 2018, 08:54:43 AM by mygoggie »
Herman

~ To heal the soul is to embark on a new journey. ~

Offline DACMan1

Re: Quad 303 transisitor specifications
« Reply #3 on: November 13, 2018, 09:04:32 AM »
Thanks, a late night ... used the BC558B values  :facepalm:  Post edited.

Will order on mouser as I have no need for a 100 transistors as min order ...

Mantech should be easier. Communica also has them
http://www.communica.co.za/Catalog/Details/P2297630793

(and of course, if they are the input pair, if you order 100, you could get a more closely matched pair)
« Last Edit: November 13, 2018, 09:06:34 AM by DACMan1 »

Offline marantz123

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Re: Quad 303 transisitor specifications
« Reply #4 on: November 13, 2018, 10:02:43 AM »
The BC556B is a PNP transistor, hence the - values in the spec. Please check in your cct if it is used as a complementary pair with the NPN BC546B. If so, i suggest replacing that as well and matching the pnp and npn hfe within 3% to get the best performance. ( these PNPs tend to have a higher hfe in the gain group (B) anyway) I have modelled the NPN BC546B among other transistors as replacement for some hard-to-get Japanese transistors (2sc and 2sa) and in my experience these Philips/Vishay bipolars are remarkable performers. Have compared them with the lower noise BC550 series as well and the BC546B is still more musical and reveals better detail in stringed instruments...listening tests fair better. The low-noise BC550/560 fairs well in phono stages. Enough rambling....Electrocompt had some in stock. Get both the 546 and 556...in a quantity ( I buy abt 30 at a time normally n they are cheap enough) u may need them later. RS will cost you..but is a last resort.
Good luck.. :thumbs:

Offline mygoggie

Re: Quad 303 transisitor specifications
« Reply #5 on: November 13, 2018, 03:32:13 PM »
The BC556B is a PNP transistor, hence the - values in the spec. Please check in your cct if it is used as a complementary pair with the NPN BC546B. If so, i suggest replacing that as well and matching the pnp and npn hfe within 3% to get the best performance. ( these PNPs tend to have a higher hfe in the gain group (B) anyway) I have modelled the NPN BC546B among other transistors as replacement for some hard-to-get Japanese transistors (2sc and 2sa) and in my experience these Philips/Vishay bipolars are remarkable performers. Have compared them with the lower noise BC550 series as well and the BC546B is still more musical and reveals better detail in stringed instruments...listening tests fair better. The low-noise BC550/560 fairs well in phono stages. Enough rambling....Electrocompt had some in stock. Get both the 546 and 556...in a quantity ( I buy abt 30 at a time normally n they are cheap enough) u may need them later. RS will cost you..but is a last resort.
Good luck.. :thumbs:

No rambling, very valid and interesting information. Thanks! I will make sure that I get both the BC546B and BC556B in quantity and match them like you said as they indeed form a pair.
Herman

~ To heal the soul is to embark on a new journey. ~

Offline Bravick

Re: Quad 303 transisitor specifications
« Reply #6 on: December 11, 2018, 11:10:34 PM »
Try MPSA92. Just turn it 180 degrees, as the pinout is reversed. MPSA42 is the complimentary NPN.

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