Will new caps change my eq. range or tone?

[jcarpenter]

I own a an Old Jess Oliver G400R amp head. I think its an early 70's model. Anyway I got it used for about 250.00. I already replaced a bad 6u7 preamp tube and I had a three prong grounded cord installed. The last thing I need is to get the reverb working.

I also hate the sag of the 5u4. I may change to a GZ34 for less sag and more head room.

So my question is should I do the cap change because its due? Can I get away with changing the rec. tube without the cap change. As far as the power tubes and other preamp tubes I want to stay with those.

If the amp is powering up okay should I just fix the verb and change the rec tube? I have modded things and ended up ruining an already good sound because I was expecting a good tone to improve or magnify to a great tone. Most of the time I end up dissapointed regreting the whole thing plus shelling out $$$ for the work and parts. I am tring to show some restraint here but the amp is from the 70's and its due and needs work.

Or should I leave well enough alone.

[hasserl]

Well you've got 30 some odd years on the caps, which is about twice the designed life span I believe. They may be operating just fine, but on the other hand they may be getting ready to let go now. Have you taken a look at them, sometimes you can see evidence of leaking electrolyte, and/or bulging of the cap. Even if they look perfectly fine they may not be.

Re changing to a 5AR4 rectifier, the increase B+ level may exceed the max voltage rating of the original caps. But even if it doesn't, you'll be stressing them with even higher voltage levels as they are at the end of their effective lifespan. I don't know that that's a great idea.

Changing the filter and cathode bypass caps shouldn't result in a great change in tone, as long as you stick with original capacitance values, and as long as the stock caps aren't in such bad shape that they are not performing correctly, which means they should be changed regardless.

Bottom line, change them. There really is no downside to it and there is plenty of potential downside if you don't.

[jcarpenter]

Thanks i am going to map guy today.