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Wawasee Black Cat Mobile Tube Amp. Good or bad?
- Thread starter 70cst
- Start date
Does not look like an amateur radio amplifier to me..............
........................and your point is????????????????
If you look at the top of the page, you will see: Amateur Radio Related>Amplifiers.
The Black Cat is a POS CB amplifier, NOT an amateur amplifier.
Show some class guys.:headbang
If you have been reading my post...you would see that I am looking for an early 70's amp for show in my restored 70 C10.
Some people need to relax and chill out.
I agree show me some class.
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that squeealin P.O.S wont win you any friends.unless your high end hearing is gone and nobody else uses cb in your area.
the inverter whine is obnoxious and those amps splatter like crazy.if its just for a show unit thats fine as it would be "period correct".
its a pile of junk to operate though.
the inverter whine is obnoxious and those amps splatter like crazy.if its just for a show unit thats fine as it would be "period correct".
its a pile of junk to operate though.
Granted, a Black Cat ain't no Alpha but it is funny how so many assumed since it was CB it had to be class C, nothing but a splatter box and a worthless inverter supply. Here is a bit of info for you. Almost every tube amp made for the band back then was actually over biased closer to class A than class C.
The reason was simple, it's easier to just ground the cathode when keyed than to add a zener to reduce bias. Splatter box, really? Would he be better with a pair of unbiased transistors? With respect to the DC to DC converter for the HV, every piece of mobile 2-Way gear prior to 1967 from Motorola to RCA used this method without issue. You only hear it on the air if the filter caps dry out.
The reason was simple, it's easier to just ground the cathode when keyed than to add a zener to reduce bias. Splatter box, really? Would he be better with a pair of unbiased transistors? With respect to the DC to DC converter for the HV, every piece of mobile 2-Way gear prior to 1967 from Motorola to RCA used this method without issue. You only hear it on the air if the filter caps dry out.
you ever run one of those?
that inverter squeal is nasty even if you remote the supply in the trunk.
you also would not want the bill for the 8417 tubes to keep it alive.nor 2n1522's when it drags your 50 amp alternator down.let voltage go down and poof! dead transistors.take this from someone who worked in a shop and saw plenty of these.
"swings" like crazy but splatters like hell.
keep for historical purpose or display.
that inverter squeal is nasty even if you remote the supply in the trunk.
you also would not want the bill for the 8417 tubes to keep it alive.nor 2n1522's when it drags your 50 amp alternator down.let voltage go down and poof! dead transistors.take this from someone who worked in a shop and saw plenty of these.
"swings" like crazy but splatters like hell.
keep for historical purpose or display.
Of course I ran them and serviced them. Motorola Motracs, Afterburner, Black Cat, all the old marine HF AM gear, even every radio from the Currier 23 by ECI to the Rat Shack mobile / bases used this. I could see if the voltage dropped significantly this would cause the frequency of the inverter to drop and draw more current through the inductive transformer. Anything that was built decent and ran with the right fuse would handle that lack of voltage. I know the commercial 2-Way gear did not blow up when they left the ignition on and the battery ran low. They used like 4 of those switching transistors on each of the two side heatsinks to run a 100 watt TX. Extreme overkill.
This is just a method of producing B+. Once the DC is filtered and applied to the amp, it has no effect on splatter or swing. It's also worth noting it takes a lot less filter cap to remove ripple from 400 hz than the 60 or 120 hz you would get off the AC line B+ supply. If you heard obnoxious buzzing from one of these supplies you probably just needed to tighten the four bolts on the transformer core to stop the laminates from vibrating at the operating frequency. That would cure the problem 90% of the time. Don't get me wrong, this would not be my first choice today but the operator is looking for period correct gear that is usable in this vehicle.
This is just a method of producing B+. Once the DC is filtered and applied to the amp, it has no effect on splatter or swing. It's also worth noting it takes a lot less filter cap to remove ripple from 400 hz than the 60 or 120 hz you would get off the AC line B+ supply. If you heard obnoxious buzzing from one of these supplies you probably just needed to tighten the four bolts on the transformer core to stop the laminates from vibrating at the operating frequency. That would cure the problem 90% of the time. Don't get me wrong, this would not be my first choice today but the operator is looking for period correct gear that is usable in this vehicle.
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the biasing caused the splatter.
yes inverter supplies are fine when designed right.
the black cat ran around 1 khz.nothing you tighten will shut it up.
i had a amp that got its b+ from a dynamotor.was in a box in the pickup bed for noise.
sounded like a power saw when you keyed up.
yes inverter supplies are fine when designed right.
the black cat ran around 1 khz.nothing you tighten will shut it up.
i had a amp that got its b+ from a dynamotor.was in a box in the pickup bed for noise.
sounded like a power saw when you keyed up.
But the biasing is nearly in class A. Ever look at the schematic for these amps? Relay grounds cathode through choke when keyed. That makes the tube conduct well before RF is applied.
If you stop and think about it, the only way to make sound of any type is vibration. Of all the parts in the power supply, only the transformer can produce vibrations due to it's magnetic field.
I've never met a transformer I could not quiet down but some did require more then tightening of the four bolts. Once I had to dip the transformer in polyurethane and another time I dripped crazy glue into all of the laminates. Sometimes you even have to add a shim between the windings and the core to stop vibration.
I think I bought one of those at a garage sale for $10. It did not even have a tank circuit. I think the tube was coupled to the coax connector through a blocking capacitor and a small coil. Took out all the phones in the house, when I tried to use it on 10m FM.
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