EBS Drome Bass Combo

[chrissss1111]

Hi eveybody

Could you possibly have EBS Drome Bass Combo 150W schematics (the old one, blue edition)
especially power amp section
It's very hard to find on web

thanks in advance

Chris

[Jazz P Bass]

A Swedish amplifier.
Ask them: Contact us | (ebssweden.com)

[chrissss1111]

A Swedish amplifier.
Ask them: Contact us | (ebssweden.com)

I wrote them
unfortunately I had no response from EBS Support :-(

[chrissss1111]

Power MOSFETs:
2x 2SK2221
2x 2SJ352

Power Supply: +/- 53V

guts:
https://ibb.co/BB0TWqs

[chrissss1111]

ok the problem is solved

[J M Fahey]

1) nice amp but heatsinking looks barely adequate, isnīt there a small fan hidden somewhere?

2) donīt have it, but in general MosFet amp designers didnīt go wild and used the generic Hitachi circuit suggested in datasheet.

Compare it to yours side by side, you might get lucky.

Notice how basic circuit repeats:







I have found this all over the place, with minor variations.

[chrissss1111]

1) nice amp but heatsinking looks barely adequate, isnīt there a small fan hidden somewhere?

There is no fans
the heatsink is cooled by speaker air from inside cabinet
the more power the more moving air generated by speaker cone (EBS Silent Cooling System)

[g1]

ok the problem is solved

What was the fault, and how did you solve it?

[chrissss1111]

What was the fault, and how did you solve it?

There was a big POP in speaker after turning off
I adjusted DC offset and bias current of output MOSFETs
now is way better