Carlsbro Cobra 90 KB preamp circuit diagram

[hennep]

I'm still not used to the fact that camera's are getting better and my eyes are getting worse.
Now that I have made a photograph, I can see that there is a dot between the 2 and the 5.
Without magnification I thought it said: T2-5A
If it is T2.5A then it makes sence and I can get myself some 2.5A fuses.

carlsbro_fuses.jpg

There are 2 fuses, connected between the transformer and the rectifiers.
I don't know the exact moment when the fuse has blown, probably when the amp was switched on.
I guess the fuse slowly degraded during many years of service.

[J M Fahey]

Fine.
Please remember that the "T" at the beginning is important, meaning "(T)ime fuse" , a.k.a "Slow Blow" and you must order them that way.
A regular fuse will easily burn on the turn on thump, so get the proper ones.

[Lars]

Hi. I know this is an old tread, but never the less.
I also have a Carlsbro Kb90- and I have some diagrams for the amp as well. See Attachments
My amp has a wery strange problem. Perhaps somebody has an idea. It plays well for 6-7 hours and then it turns unstable, the sound comes and goes and at last it is totally gone. I can turn it off and after 15 minutes I can have it running for 30 minutes without problems. I have allready tried with contact spray and have been through Allmost all meldings. Does anyone have an idea where to look ?

[nickb]

Try changing all the controls one at a time when this happens and carefully record the effect each has on the problem. This should give some clues as to where the problem might be.

[Lars]

Thanks nickb. This is a good advise and I will try to remember it next time it happends.
The problem is that it never happends when I am testing- probably because my wife complains when I play it lout for hours :-)
It would be really nice to have a 4 Ohm 100W resistance to use as a load for the first 6 hours. Perhaps I should try to find one
I have found some more Carlsbro Cobra KB 90 diagrams. See Attachements.

[J M Fahey]

Cool !!
This is the Cobra 90 Bass version.
Now we only need the guitar one to complete the trio
I visited England in '86 (same year of this version) and **everybody** used them live, they were in every Pub band backline .... yet nobody acknowledged it.
Simple, good, reliable, but the snobbish mentality "I'm driving a cheap car but "my other" car is a Mercedes" killed them.
They were the British equivalent of Crate and Peavey but "nobody famous used them", so ....

The PA/Kb line looks like an HH knockoff.
Which were *the* popular Club/Pub PA.