Hartke 3500 issue

[BassCajon]

Hi there.
This is regarding one of the older versions.
So it's not really noticeable when played hard, but there is a slight fuzz or "unclean" sound when I play the strings lightly.
It really bugs me and i'd like to figure out the issue.
If it helps, it seems to be more present with the master vol turned up. I don't think that the tube needs replacing because I turned the tube preamp knob to 0 and still heard this sound..
I also know its not the speakers because I tried another amp head.

I know all of this is pretty vague, but thanks for any help in figuring this out.

[Bass_Pounder]

May just need a good cleaning.............

Spray some electronics cleaner in all the knobs and work them through. Also spray the cleaner in all inputs/outputs and run a 1/4 cable in and out of them a few times.

[BassCajon]

Well, the knobs/EQ all work quietly and I don't think the inputs are the problem either.
Theres just this light fuzz in the background of my note and it's coming from somewhere in the amp.. Like I said, it's more present with the master turned up but it's audible at all settings.

[Bass_Pounder]

Originally Posted by BassCajon

Well, the knobs/EQ all work quietly and I don't think the inputs are the problem either.
Theres just this light fuzz in the background of my note and it's coming from somewhere in the amp.. Like I said, it's more present with the master turned up but it's audible at all settings.

A slight distortion/fuzz can be caused by oxidation in the effects loop.

Also, you could try opening it up and cleaning all the wire harness/ribbon cable connections.

[BassCajon]

Interesting. Well, I have it open.
How can I clean the oxidation in the effects loop?
I know how to clean oxidizing on input jacks pretty well but can you be a be more specific?
And what would be the best way to clean the harnesses?

[Bass_Pounder]

Originally Posted by BassCajon

Interesting. Well, I have it open.
How can I clean the oxidation in the effects loop?
I know how to clean oxidizing on input jacks pretty well but can you be a be more specific?
And what would be the best way to clean the harnesses?

*AS long as you are comfortable* poking around inside (be careful though)......................

The effects loop can be cleaned just like other ins/outs. Spray some contact/electronic cleaner in there and work a 1/4 cable in/out for a while.

For the wiring, I do it by disconnecting it, spraying some cleaner on the connection, then placing it back together/apart a few times to ensure that the connection is clean and making good contact.

[levis76]

I assume it does it with both preamps, compressor off, eq off, and contours at 0. Could possibly be caps starting to go, I mean these amps are getting up there in age and yours are probably the stock caps. Electrolytic caps are typically good for 10-15yr, some last longer and some last much less depending on use, environment, and quality of the cap itself. They aren't hard to replace if you know how to desolder/solder without burning your amps boards up. Hardest part about it is finding proper replacements. Not sure if the power transistors would fail slowly like this, they usually just short and pop, but I could be wrong. I'm sure an internet engineer will be along any moment to explain why we are all wrong and stupid. I got $5 that says it'll be billfitzmaurice.

[Rickett Customs]

I bet you Larry Hartke could get you in touch with one of his guys.....

(201) 680- 8153

[Stumbo]

Originally Posted by Rickett Customs

I bet you Larry Hartke could get you in touch with one of his guys.....

(201) 680- 8153

+1

Larry 201-680-8153 Cell anytime