[sdiy] Looking for advice about powered reference monitor problem

[Shawn Rakestraw]

Hello,

Sorry, I know this is slightly off-topic, but still relative to music.
Hopefully it is not out of line.

I have a pair of 15+ year old Event 20/20 bas v2 reference monitors. A
couple months ago, I began to notice that one of them was operating at a
significant difference in volume and it would gradually increase in volume
until normal again. So it initially sounds like the audio is panned to the
right, but gradually becomes centered again over the period of 5 to 15
minutes.

I bought a new pair of Adam monitors (one of them had a weird noise problem
right out of the box) and I decided to replace the electrolytic capacitors
in both of my old Event monitors. I was happy because swapping the
capacitors seemed to fix the problem. I returned the Adam monitors and
re-employed my old trusty Events.

After a week or so, now I am noticing the same one having the same issue
again. At power up, it takes about 5 minutes to come up to normal volume.
It seems odd to me that the problem disappeared after the cap swap and now
is returning.

I know this is a pretty general question, but I thought someone might know
exactly what to check.

I don't have a schematic, but I can tell you there is a giant toroidal
transformer that sends power to a single circuit board with 2 amplifiers,
one for an 8" speaker and the other for the tweeter. It seems like both
speakers suffer from the same volume attenuation problem. The capacitors I
replaced were 2 big 10000 uF where the power enters the board and 7 100uF
in the amplifier section. There is a bass and treble section, as well as a
gain pot.

Thanks to anyone that may offer some advice.

- Shawn

[image: 20201111_153537.jpg]
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20201119/de24476c/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 20201111_153537.jpg
Type: image/jpeg
Size: 602118 bytes
Desc: not available
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20201119/de24476c/attachment.jpg>