Dyna Comp Transistor Equivalents

rhandy gaye · Post by **rhandy gaye** » 14 Dec 2010, 04:08

hi, i hear ya.

i've built some great radios over the years that started life as fuzz pedals.

DrNomis · Post by **DrNomis** » 21 Dec 2010, 01:36

I built a "Deluxe Dynacomp" from a Schematic that I got from Mictester,I used BC549C Hi-Gain,Low Noise NPN transistors with an average gain of about 600,and they worked fine for me,they are fairly common,and cheap too....

You can buy them from Jaycar Electronics....

snmavronis · Post by **snmavronis** » 18 Mar 2011, 20:50

I just got the remaining parts I need including the 2SC1849's from Small Bear. My father is going to e-mail me instructions later on how to make a transistor tester to determine NPN or PNP and where the emitter base collector is. In the meantime, I know these are NPN transitors but can anyone confirm the pinout? Here is thow the 2SC1849 is labeled on the flat side:

C1849
R 50

Here's an illustration for how my MPS5172 NPN transistor is mounted. This is why I need to figure out the pinout for the 2SC1849 that I just got to be sure:

snmavronis · Post by **snmavronis** » 18 Mar 2011, 21:48

[EDIT] I just found this Asian datasheet on the 2SC1849 / 2SC1850 - http://jp.ic-on-line.cn/IOL/datasheet/2 ... 951106.pdf

If this is true to the ones I got from Small Bear then I am safe with my PCB layout. Can anyone confirm if they also got some from SB too?

DrNomis · Post by **DrNomis** » 18 Mar 2011, 22:08

I've built a "Deluxe" Dynacomp, using parts avalible nowdays, the transistors I used were all BC549c with an average gain of about 640, the BC549c is a low-noise NPN Silicon bipolar transistor, equivalent to a BC109c, according to my transistor data books, they seem to work fine.....

They have a CBE pinout....

snmavronis · Post by **snmavronis** » 18 Mar 2011, 22:14

DrNomis wrote:They have a CBE pinout....

Thanks that may work if these are not a center base configuration. CBE or EBC doesn't matter since I can just turn them around as long as I determine the emitter side. When my dad gives me is transistor tester schematic I'll share it here someplace. The only thing a meter will tell you is if the base is in the center or not.

DrNomis · Post by **DrNomis** » 18 Mar 2011, 22:20

snmavronis wrote:
DrNomis wrote:They have a CBE pinout....
Thanks that may work if these are not a center base configuration. CBE or EBC doesn't matter since I can just turn them around as long as I determine the emitter side. When my dad gives me is transistor tester schematic I'll share it here someplace. The only thing a meter will tell you is if the base is in the center or not.

No worries, if you have any problems just let me know....

snmavronis · Post by **snmavronis** » 19 Mar 2011, 01:22

Well I did some testing on the 2SC1849 using a digital meter in diode test mode. I read how the relationship of the emitter to collector is such that the voltage drop is 'slightly greater' between the emitter and base than between the collector and base.

First though I used a simple diode test to verify that the leads on my meter were positive and negative as labeled. Then I determined where the base was and that it was an NPN transistor. I don't want to go into all the details here but learned how by watching several YouTube videos and reading websites like this one - http://www.allaboutcircuits.com/vol_3/chpt_4/3.html

Refering to the pinout number order in the graphic below with the postive (+) base already determined to be in the middle, and using the negative (-) lead testing the voltage drop between pin 1 and 2 was 1.025 and the drop between pins 3 and 2 was 1.014 making pin 1 the emitter side. This behavior was also verified with known NPN transistor MPS5172 that has an EBC configuration that measured E=1.038 vs C=1.030 using the digital meter diode test. The difference between E and C isn't much but it was consistant every time.

Anyway I hope my test method is good enough to go with, otherwise you're invited to my transistor BBQ!

snmavronis · Post by **snmavronis** » 22 Mar 2011, 14:03

FYI, I got an email reply from Steve at Small Bear Electronics where I bought my 2SC1849 transistors:

Looking at the front with the leads pointing down, from left: E B C. Same as your drawing.