Bad Cat Black Cat 30R Low B+

[vintagekiki]

Rectifier select switch

http://schems.com/bmampscom/badcat/badcat_hotcat_30.pdf
BC HotCat 30 rectifier select switch has an additional contact that connects a 100u / 450V auxiliary capacitor in parallel to the 33u / 450V (+ UA) capacitor in the solid state position to repair the filtration due to the increased + UA voltage.
The increased voltage is due to the diodes not having the voltage drop that occurs at the rectifier tube.

http://diy-fever.com/wordpress/wp-content/uploads/2009/12/dual_rectifier.pdf
MB 3ch Solo Head rectifier selection (solid state / tube) is performed similar to BadCat HotCat 30 (page 5)

https://schematicheaven.net/boogieamps/boogie_dualrectifier.pdf
MB dualrectifier rectifier selection (solid state / tube) is performed on the secondary mains transformer. (page 4)

[Helmholtz]

^^ Înteresting. But the 4xEL84 version may have a different rectifier wiring. We need confirmation from the OP.

[bobloblaws]

^^ Înteresting. But the 4xEL84 version may have a different rectifier wiring. We need confirmation from the OP.

The rectifier is as I described, just the 5AR4 with just the two protection diodes.

I'm supposed to get the amp back today. The owner stores this amp in the back of his SUV with no case or cover and it takes a beating. I replaced the standby switch a year and a half ago and he showed me the other day that it had been damaged again. At the time I didn't think it had anything to do with the low B+ but since vintagekiki mentioned standby it will probably be the first thing I look at.

[Helmholtz]

The rectifier is as I described, just the 5AR4 with just the two protection diodes.

I'm supposed to get the amp back today. The owner stores this amp in the back of his SUV with no case or cover and it takes a beating. I replaced the standby switch a year and a half ago and he showed me the other day that it had been damaged again. At the time I didn't think it had anything to do with the low B+ but since vintagekiki mentioned standby it will probably be the first thing I look at.

Thanks.

A standby switch that drops that much voltage should get very hot.

Don't forget that high tube current will pull B+ down. And it will make tubes redplate and age them.

[vintagekiki]

I would ask bobloblaws to draw schematic of power supply BB30R in order to gain insight into the working principle of the circuit power supply and probably the cause of the BB30R failure.

At each switch (and so stby) if it has a poor (cold) solder on contacts or wire, there is a resistance crossing, due to current flow switch becomes hot.
Therefore, before soldering it is necessary previous thoroughly clean and tin contacts of the switch and the wire

[bobloblaws]

I would ask bobloblaws to draw schematic of power supply BB30R in order to gain insight into the working principle of the circuit power supply and probably the cause of the BB30R failure.

With the exception of the differences already discussed it is identical to the schematic in post #1. The Black Cat is well known as a virtual clone of the DC-30.

[vintagekiki]

With the exception of the differences already discussed it is identical to the schematic in post #1. The Black Cat is well known as a virtual clone of the DC-30.

Leave the virtual clone aside. Unnecessary philosophy (... already discussed ...) does not give a positive result.
Schematic in post # 1 that you keep referring to, in the power supply there are no diodes or protection??? diodes only 5AR4 tube.
If you are expecting some solution I would ask you to draw the differences or the actual schematics rectifier the power supply with protection??? diodes.

For your information Matchless DC30 Old Schematic (page 4) has only 5AR4 tube as rectifier (see post #11)

1) Sorry I don't understand what exactly the virtual clone of the DC-30 means.
Is it a real amp, or some program that emulates amp.

[Helmholtz]

May I suggest a compromise?

I understand that the OP is not really motivated to draw an own schematic. OTOH, vintagekiki is very interested in a schematic and I think has some experience in drawing them.
So my proposal would be that vintagekiki sketches a tentative schematic based on the Matchless taking into account the differences reported - and the OP verifies/ corrects the result.

[vintagekiki]

I don't know, maybe I'm wrong.
But all tells me something that bobloblaws has embarked on a custom BB30R, which seems to have ended ingloriously.
From his posts, difference between DC30 and unclear modification cannot be reliably deduced . Therefore, is required schematics for BB30R power supply to identify the cause of low B + and AC ripple.
In order to perform any custom, the amplifier must be in perfect condition and with new (not like new) tubes, which does not seem to be the case.

Whether Matchless schematics can help the user will be known soon.
https://el34world.com/charts/Schematics/files/Matchless/Matchless_Schematics.htm

[bobloblaws]

I don't know, maybe I'm wrong.
But all tells me something that bobloblaws has embarked on a custom BB30R, which seems to have ended ingloriously.
From his posts, difference between DC30 and unclear modification cannot be reliably deduced . Therefore, is required schematics for BB30R power supply to identify the cause of low B + and AC ripple.
In order to perform any custom, the amplifier must be in perfect condition and with new (not like new) tubes, which does not seem to be the case.

Whether Matchless schematics can help the user will be known soon.
https://el34world.com/charts/Schematics/files/Matchless/Matchless_Schematics.htm

I'll tell you what I think. You are a troll. This confirmed it.

"1) Sorry I don't understand what exactly the virtual clone of the DC-30 means.
Is it a real amp, or some program that emulates amp."

I've tried to be polite, including this other time you were breaking my balls,
https://music-electronics-forum.com/...-100-led/page2
...and figured whatever pleasure it gives you to order people around and post gibberish and links to half of the documents on the internet is no big deal to me. But now you're starting to annoy me.

[Helmholtz]

I'll tell you what I think. You are a troll. This confirmed it.

"1) Sorry I don't understand what exactly the virtual clone of the DC-30 means.
Is it a real amp, or some program that emulates amp."

I've tried to be polite, including this other time you were breaking my balls,
https://music-electronics-forum.com/...-100-led/page2
...and figured whatever pleasure it gives you to order people around and post gibberish and links to half of the documents on the internet is no big deal to me. But now you're starting to annoy me.

Sorry, I think you are not being fair to VK.
He is a valuable member here, who often provides hard to find schematics. I am sure his intent is always constructive, trying to help. But please consider that English is not his native language, so some misunderstanding happens. Did you ever try to participate in a foreign forum?
I actually think he deserves more likes.

[vintagekiki]

I'll tell you what I think. You are a troll ... ...

Thank you!

I read it somewhere.
Road to hell always has been paved with good intention.

[bobloblaws]

Sorry, I think you are not being fair to VK.
He is a valuable member here, who often provides hard to find schematics. I am sure his intent is always constructive, trying to help. But please consider that English is not his native language, so some misunderstanding happens. Did you ever try to participate in a foreign forum?
I actually think he deserves more likes.

I appreciate all that.and if you read the link to the the Roland Cube thread I told him I appreciate his willingness to help me out. But the subtext is that he is pushy and overbearing and has a "my way or the highway" attitude. That is not cool.

[vintagekiki]

But please consider that English is not his native language, so some misunderstanding happens.

Translation is machine (as as).
It is not a literary expression, technically quite well understood.
Thank you for understanding
vk

[Helmholtz]

Translation is machine (as as).
It is not a literary expression, technically quite well understood.
vk

Maybe not always. In my experience translation machines (german-english) are rather poor and sometimes the results are ridiculous. I don't use them.

What do you think about my proposal above regarding the schematic?