Yellow Mullard OC44

[Smeddling]

Hi Everybody
Today I was given 6 of the subject transistors. They were 'harvested' from a board found in a skip!
I have tested them on my DCA 55 an all look good. Two measure around 40 and the other 4 measure 85, 102, 110 &180. Leakage is no more than 35uA.
I understand that these transistors were used in the Rangemaster.
My questions are:
Are they genuine?
Is there another circuit (fuzz/boost) that these will be good for?
Does anybody know the difference between the yellow and black transistors?
Are the yellow ones particularly unusual/ scarce?

Cheers all

[Electric Warrior]

They sure look like the real deal and measure just as expected.
Some of the black variants hardly leak at all and I think not all of them cover such a wide range of hfes. Other than that it's just a visual thing.

You could try them in a Fuzz Face. Most of your transistors should be gainy enough to bias well despite the low leakage.

[dfx_pedalpcbs]

Genuine defo. What a find!

In my experience the yellow jacket ones are normally a bit lower hfe than the black equivalent. These can sell for £10 to £15 each on the ebay last time i checked.

[Smeddling]

Thanks folk.
I think I'll have crack at a rangemaster circuit and a fuzz face then 👍
Cheers

[dfx_pedalpcbs]

What was the board from any identification marks on it?

[Smeddling]

What was the board from any identification marks on it?

I didn't find the board personally. It was possibly a radio as the guy who skipped it converts old radios into fancy lighting. I've told him to give me the guts in future, just in case!

[kaycee]

Thanks folk.
I think I'll have crack at a rangemaster circuit and a fuzz face then 👍
Cheers

As you have 3 transistors left, might I suggest the Selmer Buzz Tone. It runs at 3 volts from 2 AA batteries, but is plenty loud enough. An added emitter bypass cap of 22uf on Q1, switchable, makes it a boost and a proper fuzz. I have found these very forgiving of tolerances in transistors.

[aron]

I just built a Fuzz Face using some of the OC140/CV7112 that I had left. Sounds great!

[Smeddling]

As you have 3 transistors left, might I suggest the Selmer Buzz Tone. It runs at 3 volts from 2 AA batteries, but is plenty loud enough. An added emitter bypass cap of 22uf on Q1, switchable, makes it a boost and a proper fuzz. I have found these very forgiving of tolerances in transistors.
[/quote]

Thanks Kaycee. What sort of gains are required Q1-Q3?
Cheers

[kaycee]

I usually run lowest to highest gain. Ideally, something around 60 - 90 for Q1 and then 90+ in the last two.

[mozz]

Want to trade for any SFT352's?