Bell and Howell 385 Conversion

[CJ]

new kid on the block for the old fart down the street (that's me)

B and H guitar amp conversion, 6V6GT push and pull

boss says "fast and cheap!"
i'm like "really?"

 

[CJ]

got some excess baggage that i don't wanna claim, like the 6V6 osc. and the lamp thingy,

 

[CJ]

i can not confront this in my current state of mind,

so the first thing i do is take a break and grab the biggest cup of designer hi-octane-keep you up til 3 am-cup of coffee i can find, which we took care of in one chug. gota get wired to get this wired.

 

[CJ]

just start rippin and tearin. take it out on the customer.

now we have some breathing room.

 

[shabtek]

ceramic cap city

 

[pucho812]

my buddy has done a few B&H conversions into guitar amps.
As a pure guitar amp without verb or vibrato, they sound really good. Even better if you have the Art Deco B&H cabinets with the fancy woodworked logo

 

[CJ]

that's right.

see what a good cup of coffee can do? 5 minutes and we have a useful platform from which to work.

the customer will be like "what the...who the..., what happened to my antique roadshow amp!"

and i will be all like "plug it in biotch! tell me how you like that jimmy reed tone from the supro super circuit,"

then i will ask him to read the first line of my signature at the bottom of this post...

 

[CJ]

OPT:

 

[CJ]

sq wave

 

[CJ]

configuring the power supply series dropping resistor by simulating 6V6 load with two parallel 10 K resistors so they don't burn up,

no load volts was 550, got a 500 volt cap so no good

with the load and a 180 ohm dropping resistor we drop down to a comfortable 420 VDC

got a 330K 2w bleeder in there lest my medical insurance expires,

 

[CJ]

got the power amp hooked up, drags the pwr supply to 400 VDC, screens at 390.

 

[CJ]

no crossover distortion,

wait, this is cathode bias, class A and all that jive, ain't no crossover distortion, possible,
tubes always conducting, running about 90 ma, tougher on tubes during idle but nice compressed sound with that cathode resistor,

 

[CJ]

transformer ringing at 10 K more pronounced with the tubes as opposed to simple xfmr bench test,

 

[CJ]

sine wave ok, so ready for a two tube preamp/inverter,

 

[Flatpicker]

Funny coincidence, wife and I went to a pizzeria/tavern downtown with some friends a few weeks ago to check out a local country/roots band and the guitar player was playing through one of these that someone had converted for him. It was still in the original Bell & Howell cabinet. I immediately thought, “Why didn’t I think of that”, lol. Sounded pretty cool!

 

[CJ]

done. now a 5E3 tweed Delux, sounds good, 12AY7 for tube 1

 

[ubxf]

I have a 185 Bell & Howell and i was going to work with it but it doesn't have a power transformer so may be not worth it.

 

[CJ]

might have some nice tubes for salvage,

 

[ubxf]

could the output transformer for push pull 25L6 be used with other tubes that work with 6 or 12 v

 

[CJ]

sure, heater voltage don't make no difference,