Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Effects => Topic started by: Rontone on February 22, 2022, 11:09:14 am

Title: Copicat Super IC Overhaul Repair
Post by: Rontone on February 22, 2022, 11:09:14 am

I have a pile of old Copicats I have been going through, next on the list is a Super IC model, in bad shape

Missing its motor/transformer, roller arm and a few other bits

Caps have burst and have a nice crust on them

Luckily I have new tape heads for this model, and a spare motor from an older model,


I have attached a schematic

So my spare motor has no extra winding to power the board, looking at the schematic I think I will need a 28v transformer with a centre tap to hook up

Is that correct? I wondering if I can get it to fit in there just next to the motor

Also it will need a 3 core mains lead fitting, I have seen it is ideal to add a transformer on the output signal to isolate it,

Does this have to be a 1:1 small Trans, will it have to be a certain impedance, I have seen some 10k:10k on ebay I could mount on a board and stand it off the chassis somewhere

Title: Re: Copicat Super IC Overhaul Repair
Post by: jojokeo on March 26, 2022, 01:05:13 pm

Quote from: Rontone on February 22, 2022, 11:09:14 am

So my spare motor has no extra winding to power the board, looking at the schematic I think I will need a 28v transformer with a centre tap to hook up

Is that correct? I wondering if I can get it to fit in there just next to the motor

Also it will need a 3 core mains lead fitting, I have seen it is ideal to add a transformer on the output signal to isolate it,

Does this have to be a 1:1 small Trans, will it have to be a certain impedance, I have seen some 10k:10k on ebay I could mount on a board and stand it off the chassis somewhere

Yes, appears to be a typical bipolar power supply set-up for older opamp chips w/ 28v CT transformer. The other output/isolation transformer appears to be CT as well on the schematic.

Title: Re: Copicat Super IC Overhaul Repair
Post by: Rontone on March 26, 2022, 02:41:29 pm

Thanks, I will look at some 28v transformers to power the board

Quote from: jojokeo on March 26, 2022, 01:05:13 pm

The other output/isolation transformer appears to be CT as well on the schematic.

Did you mean in the top right of the schematic? If so that is a pot core inductor on the oscillator board [the picture is from a different unit but same type of oscillator]

Title: Re: Copicat Super IC Overhaul Repair
Post by: Rontone on March 26, 2022, 02:54:42 pm

Would one of these types of transformer work, if the two 0V are joined, does it become a CT?

Title: Re: Copicat Super IC Overhaul Repair
Post by: jojokeo on March 26, 2022, 03:01:30 pm

Can't say for sure on the PT without a schematic/pinout for it? But I'm guessing you might? Test it first...

Title: Re: Copicat Super IC Overhaul Repair
Post by: Rontone on March 26, 2022, 03:08:06 pm

Here is the wiring diagram from the datasheet