Help with a bogen schematic

[flicker180]

folks, i'm in need of some help regarding a particular Bogen K-15 schematic.

I'm trying to assemble a parts list for redoing/upgrading all caps, etc. in the amp and am a little confused on a couple of things...

since the schematic is copyrighted, i cannot post it online, but would be happy to email it to anyone who can help.

thanks,

dave

 

[TheAmpNerd]

Sure you can post it online.
As long as you aren't charging for it.
AND
As long as it is for educational purposes
or learning, or for people to help you out.
AND
you cite your source and give
proper notice as to who the copyright
owner is....so others
know who created it etc,
there should be no problem.

OR
not that I would know, but I've heard of
videographers and photo people flip it 180
degrees and it is a whole
'nuther piece of art/work.

You aren't worth the time
and the effor to sue.

Unless you are like Kazaa or some other place
like that.

NOW,

Patents or trademarks are a whole 'nuther story.

PM Sent.

 

[flicker180]

it's from Howard Sams & Co and they're kinda anal retentive about having a 20.00 schematic and service manual floating around...that being said, i'll post a link up in a few seconds.

oh, and i never got your PM, AmpNerd.

dave

 

[flicker180]

ok, schematic is here:

http://www.flickerdown.com/forsale/k-15.pdf

thanks for any help, guys.

dave

 

[TheAmpNerd]

Originally posted by flicker180
dave

Dave,

Got it. So, how can we help?

It gives you the parts list.
It should be a piece of cake.

 

[flicker180]

well, i'm a little iffy on some of the symbols preceding the electrolytic capacitors in the CAP. column...any clarity there?

additionally, i'm also wondering about having higher voltage ratings on the Fixed Caps? i'm assuming the 400v rating is nominal voltage and that a 600v rating would just increase the threshold without changing anything.

dave

 

[TheAmpNerd]

Originally posted by flicker180
well, i'm a little iffy on some of the symbols preceding the electrolytic capacitors in the CAP. column...any clarity there?

Dave,

Those symbols refer to the actual lug on the multi section
capacitor. They have imprints on them so you know
how to wire them up. If you look at the lug side
of the cap you will see them.

C1 is dual multisection cap
C2 is a quad multisection cap

Each symbol represents a corresponding lug
on the actual cap.

I would imagine that even though the dual cap
only has two lugs, when you look at it, you will
still see the other symbol(s) even though there isn't
a lug there.

additionally, i'm also wondering about having higher voltage ratings on the Fixed Caps? i'm assuming the 400v rating is nominal voltage and that a 600v rating would just increase the threshold without changing anything. /B]

Not a problem. You can always go up in voltage rating
of caps. That is you can always put a higher rated
cap in a circuit. So if the circuit calls for 400 V caps,
you can put in a 600 V cap.

 

[hasserl]

Originally posted by flicker180
well, i'm a little iffy on some of the symbols preceding the electrolytic capacitors in the CAP. column...any clarity there?

additionally, i'm also wondering about having higher voltage ratings on the Fixed Caps? i'm assuming the 400v rating is nominal voltage and that a 600v rating would just increase the threshold without changing anything.

dave

Those symbols are actually imprinted on the cap can itself to show you which terminal they are referring to. A triangle, a square, etc. Look right on the cap near the terminals and you should see them. The number refers to the micro farrad value.

The voltage rating on the caps refers to the max voltage they are designed to operate at. If Bogen used 400v caps originally you can be assured that the rating is high enough for the circuit. You could use a higher rated cap, say 630v, if you wanted to, and that would not be deterimental. But you would not want to go with a lower rated cap.

But why change them anyway? They are probably fine. I would change out the electrolytic filter caps, but I would go with the stock coupling and tone caps. Unless you wanted to experiment with different types. But try the stockers first to see how it sounds.

That is unless you're going to gut it and start all over. In that case you might want to consider changing the circuit completely, using some classic amp as a base.

 

[flicker180]

i've got 2 K-15s and an M330A on the way.....

one K-15 will stay stock
one K-15 will get a comp upgrade and/or new circuit (matchless lightning? 5F6? who knows?)
and the M330a...well, i dunno yet.



dave

 

[flicker180]

i'll also post a worklog as i go through 'em...they're good learning amps for this kinda thing so....hehehe.

dave

 

[TheAmpNerd]

Dave,

Have fun, be safe enjoy.

If you haven't taken it apart yet,
hasserl has a good point.

Do the electrolytics first then
give it a try. so you know how
it sounds.

Then change the caps in
stages, have listen and see
what it does.

This is also helpful from a trouble shooting
stand point. If the amp doesn't work
you limited the change to only that one
stage you worked on.

If you do eveyrthing at once and the amp
doesn't work...well that will either be more
educational or you'll get pissed and toss the amp.