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Cosmo!

Started by G.G., October 29, 2012, 04:54:47 PM

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G.G.

Hi Folks,
Here is my Cosmopolitan I finally got boxed up. It's a 'Bean-etched PCB and I ended up using a Russian MP38A for the Ge transistor spot and a 2N3565 leftover from my CSOD in the Q2 spot. I had expected this to be way too high gain to use on a regular basis, but it turns out to be very flexible and sounds pretty great no matter how it's set up. Bumped my Yellow Shark off the board, which I didn't think would ever happen.  ;D




midwayfair

White sparkle and black aluminum. So classy! Very nice build.

I just finished another cosmo with an MP38A. Those are great transistors that suddenly became VERY hard to find.

G.G.

thanks Jon! Last time I checked I noticed Gordelux didn't have any more, I suddenly became really tight-fisted with the ones I have. BTW, what hFE's are you getting with yours Jon? I was asked about that and it seems like most of mine are in the 300s, but the one in my actual pedal is around 170. 300 seems kind of high, just wondering if I'm metering those right.

pickdropper

The PPP sparkle white is such a cool color.  I have one here in 125b size that I've been waiting to use.  Just gotta find the right project.
Function f(x)
Follow me on Instagram as pickdropper

Bret608

This is a really cool color combination! Never would have occurred to me if left to my own devices. Cool transistor combination as well. I finished mine not long ago, and I find it just makes me want to play more.

Have you been testing your transistors with a DMM? Recently, in the electronics lab at the college where I work, I took a 2n1306 ge tranny and tested it in both this high end test unit that looks almost like a piece of rack gear and just a plain old multimeter. In the former, I was getting hfe of about 80, and in the DMM it was well over 200. That was educational!  :D 

midwayfair

Quote from: G.G. on October 29, 2012, 06:16:14 PM
thanks Jon! Last time I checked I noticed Gordelux didn't have any more, I suddenly became really tight-fisted with the ones I have. BTW, what hFE's are you getting with yours Jon? I was asked about that and it seems like most of mine are in the 300s, but the one in my actual pedal is around 170. 300 seems kind of high, just wondering if I'm metering those right.

That seems really high. Maybe a calculation mistake?

I only had two over 70, and maybe three under 40. Most were in the 50s. I really, really like low-gain transistors, so I was really happy with them.

I really regret not buying 50 of them instead of just 20. It was only an extra $10 or so, I should have just bit the bullet. I really didn't expect them to run out so quickly, though. He said he had a couple thousand in May.

G.G.

OK, looked into it a bit more and I'm metering them wrong. I was just plugging them into the DMM, which doesn't take leakage into consideration. I was surprised they were that high, lol!

Yeah, I wish I would have bought a box of them too.  I haven't hit a bad one yet.

chromesphere

#7
Nice build!! Love the finish!

Quote from: midwayfair on October 29, 2012, 07:18:41 PM
I really regret not buying 50 of them instead of just 20. It was only an extra $10 or so, I should have just bit the bullet. I really didn't expect them to run out so quickly, though. He said he had a couple thousand in May.

Hey Jon / G.G. not sure if maybe he relisted some, but found this and thought you might like to see it!

http://www.ebay.com.au/itm/MP38A-Germanium-NPN-Transistors-USSR-1980S-QTY-45-/160910593904?pt=LH_DefaultDomain_0&hash=item257704cf70

EDIT: also if you want more or if they sell, i'd message gordelux, i've seen him sell out of models, then relist lots more, so he's probably got a surplus.
Good luck!


Cheers
Paul
Pedal Parts Shop              Youtube

midwayfair

Quote from: chromesphere on October 30, 2012, 02:42:49 AM
Nice build!! Love the finish!

Quote from: midwayfair on October 29, 2012, 07:18:41 PM
I really regret not buying 50 of them instead of just 20. It was only an extra $10 or so, I should have just bit the bullet. I really didn't expect them to run out so quickly, though. He said he had a couple thousand in May.

Hey Jon / G.G. not sure if maybe he relisted some, but found this and thought you might like to see it!

http://www.ebay.com.au/itm/MP38A-Germanium-NPN-Transistors-USSR-1980S-QTY-45-/160910593904?pt=LH_DefaultDomain_0&hash=item257704cf70

EDIT: also if you want more or if they sell, i'd message gordelux, i've seen him sell out of models, then relist lots more, so he's probably got a surplus.
Good luck!


Cheers
Paul


Score! Just bought them and some low-gain PNPs for Percolator experiments.

G.G., let me know if you want a dozen or so, 45 is probably more than I'll ever need.

chromesphere

Orsum Jon, glad you got them :D
Paul
Pedal Parts Shop              Youtube