Is there a CPT-002B replacement option?

[Sl1pm0de]

Thank you in advance. I bought a Capcom Big Blue cabinet that didn’t come with a CPT-002B transformer. I have not been able to find one so I am hoping to find another option.

Does anyone know the output the transformer provides to the QSound board so I can try to spec a possible replacement? Does anyone know of a direct replacement that I could purchase? If you have an extra CPT-002B for sale, please let me know. I would be happy to purchase it.

 

[nem]

Output is 14VAC.

 

[Sl1pm0de]

Thanks. Do you know how many mA? Would this be a good replacement?

https://www.surplussales.com/item/_tp/aba-202.html

 

[Big_P Big_p]

14VAC is right and it probably needs to be able to provide at least 2.5A and maybe more. From my understanding some people have had trouble getting the amp to work with anything but the original transformer. From looking at the q-sound amp I think your best bet would be a 120VAC to 14VAC toroid transformet (but i have not been able to find one) as the version of the amp that came in the big blue has a wave rectifier to turn the AC to DC (the 12v version does not and only accepts 12v DC). There are a few 120VAC to 15VAC toroids around that may work. It dosen't look like the extra volt would be an issue but you would be a guinea pig and I can't say I am 100% sure it won't cause problems. If you looked hard enough you may be able to find a 14V toroid. I thought a toroid transformer may be the best bet because they are more efficient, produce less heat and provide inherent EMI shielding, as well as cause minimal signal distortion, produce low mechanical humming, and have only small off-load losses, which is all good stuff for audio circuits.

 

[xodaraP]

Could you bypass the rectifier and just run the amp on DC power?

 

[Sl1pm0de]

I wonder if this is an easier route. I do have a CPT-003A transformer. It’s 220v. How would I convert the 120v cabinet power to 220v for the CPT-003A and then connect that to the QSound amplifier?

 

[Sl1pm0de]

Could you bypass the rectifier and just run the amp on DC power?

This could possibly be an option too.

 

[Big_P Big_p]

I wonder if this is an easier route. I do have a CPT-003A transformer. It’s 220v. How would I convert the 120v cabinet power to 220v for the CPT-003A and then connect that to the QSound amplifier?

Something like this in between the power in and the Capcom 220v (but it probably only needs to be 5A and an EL transformer into the original Capcom C transformer would probably be ok) but it's an expensive option https://www.surplussales.com/item/_tp/mt3000ds.html

Could you bypass the rectifier and just run the amp on DC power?

Yep definitely an option as the capcom amp boards are identical it's just that the 14VAC board has the rectifier where as the 12v DC board has an inductor in place of it. However you would need to add the smoothing inductor to the q-sound amp and no one has worked out its value. You can probably use a fairly wide range of values as its only for smoothing but it probably needs to be there.

This is the cheaper and probably better option but your power supply would need to be able to provide enough amps on the 12v line to cover whatever you have running off it already plus an additional 2-3A.

See schematic and photos. D1 (the black rectifier package) would need to be removed and a smoothing indicator (coil) put across pin 1 and pin 2 of D1. The you just supply 12v to pin 1 (check that in the schematic notes working from memory) and the speaker gnd is the amps gnd.