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I’ve found this amp on reverb for a friend. he was in search of a Deluxe Reverb for a while then I came across this on a month ago.
I wanted to get him one with the original components and the speaker. it had an ugly red speaker when it came to me. and we were lucky to find the original Jensen C12Q with a like-new cone. the cones are the characters more than the magnet to me.
the speaker came from ’66 fender amp. it’s period correct and sounds great after my speaker tech re-glue the voice coil and damper. there was a play between the frame and the magnet. he fixed it of course. I love vintage C12Q as much as vintage Jensen P12Q and P12N
My interest in fuzz pedal came from JMI Tone Bender III reissue which belongs to a friend. this pedal has 3 of OC75 glass tube transistors.
And, unfortunately, My Sola Sound Bum Fuzz came with 3 of NPN transistors while OC75 is PNP type. then found this web page with germanium and silicone transistor lists
There are 26 of germanium NPN transistors from the data sheets
2N1302, 2N1304, 2N1306, 2N1308,
OC139, OC140, OC141
NKT713, NKT773, NKT774, NKT781
Black glass tube NPN transistors are OC139, OC140, OC141 from them.
OC75 is like this according to this web page on alltransistors.com
Type Designator: OC75 (PNP)
Maximum Collector Power Dissipation (Pc): 0.125 W
Maximum Collector-Base Voltage |Vcb|: 20 V
Maximum Collector-Emitter Voltage |Vce|: 20 V
Maximum Emitter-Base Voltage |Veb|: 10 V
Maximum Collector Current |Ic max|: 0.01 A
Transition Frequency (ft): 0.1 MHz
Collector Capacitance (Cc): 50 pF
Forward Current Transfer Ratio (hFE), MIN: 55
And, for OC139, OC140 is
Vcb: 20 V / 20 V
Vce: 20 V / 20V
Forward Current Transfer Ratio (hFE), MIN: 40 / 75
I’m going to try OC139. simply beccause, OC139 is cheaper than OC140 on ebay. and I’m wondering how Transition Frequency differences work with Fuzz. I’ll update in a few weeks
I just tried 9V battery trick for 50’s Fender Champ 5F1 and Deluxe 5D3. and the speaker wiring turned out being reversed. both of them still have the factory wiring.
And, both of them move backward (to the magnets) when they wired 9V + to the white wire, and – pole to the black wire.
They mostly say there is no absolute speaker phase unless they are in the same cabinet. at the same time, many people say the speaker cones move forward when they hooked up in the right direction with 9V battery.
Fortunately, 9V battery didn’t kill my 8″ Champ speaker, nor 12″ Deluxe speaker. but I’ve read some cases this trick killed their speakers.
I’m not sure with 50’s and 60’s Jensen speaker’s correct phase. but, I started to believe Fender hooked them up this way. I’ve seen only 2 cases. and will update if I come across any Jensen speaker with different phase.
I see two of ACY41 germanium transistors on the board.
Grabbed this off ebay for a great price. two hundred something in USD. it sounds great and quite different than my Bum fuzz and old Sola Sound fuzz pedal a friend has.
but, it has an issue. it rattles on high level. I’m sending back this back to British Pedal Company.
BF champ AA764
the voicing of stock 8″ speaker is quite different to 50’s Oxford 8EV. I guess this stock speaker came from Oxford as well but I could be wrong.
I replaced the stock 25uf 25v power tube cathode bypass cap to 47uf.
it came with stock Amperex buggle boy which is still alive and kicking and GE 6v6gt. only the rectifier tube has replaced at some point.
stock speaker is on the right side.
I came across this tweed princeton a couple of days ago. it had more than few issues with the pots, electrolytic caps, wires, grounding, input jacks and one of the resistors.
and it sounds beautiful like a win instrument with the new components.
Researchers at the Massachusetts Institute of Technology (MIT) and Harvard Medical School have teamed to develop a novel tattoo ink that can show your body’s health changes.
The novel ink consists of biosensors that react to changes in the tissue fluid and make the skin an “interactive display”. So far, researchers have investigated four biosensors that respond to three types of body information, changing their colors.
As the pH-value increases, the color changes from violet to pink, an increasing sodium content is seen as a bright green under UV light, and blue becomes brown when the glucose level increases.
This animation from a video of the researchers shows how such a tattoo might look like:
Especially for diabetics, a tattoo with ink that reacts to an altered glucose level could be useful. They have to prick their finger with a small needle if they want to measure their blood sugar level – usually several times a day. This procedure can be painful in the long run and can lead to small scars.
You can read more about this innovative technology here: https://www.media.mit.edu/projects/d-Abyss/overview/