Tube Compressor repair Questions

I'm Repairing my Gates Sta-level. To start, I'm putting tones through the unit and tracing them through the components. A few of the caps (.1uf) I'm getting major oscillation (sound like a tremolo effect) @ (anything below) 280Hz. I figure I'll replace those first... everything on the compressor is Original.

Any thoughts are welcome..

I`d be tempted to look at changing the electrolytics before doing anything with the signal caps.

I agree with Rob. Low-frequency "motorboating" like what you describe is often a symptom of dried-up filter caps. There should be no need to replace the coupling caps unless they've become leaky.

could be vca tube gone bad, upsetting balance. polyester type caps rarely fails.

Thanks guys; I really appreciate your thoughts (this forum Rocks!), I checked the electrolytics as you suggested and they are not holding their Capacitance at all.

Now I have to figure out how to fit new caps in the unit; those Old 10-15-15 mfd & 20-20 mfd caps were a nice for saving space.

Probably more questions to come...

Thanks again
:guinness: :sam: :guinness: :sam: :thumb:

New Sensor in NYC offers a limited selection of new, multi-section can caps. Perhaps they have one that will fit your needs.

http://www.newsensor.com/

Can caps here:

http://www.tubesandmore.com/new/scripts/silverware.exe/catalog@d:/dfs/elevclients/cemirror/ELEVATOR.FXP?PAGE=SUBCAT&SEARCH_TREE01=CAPACITORS&SEARCH_TREE02=MULTISECTION&SEARCH_TREE03=FP

..you could look into motor start/motor run capacitors. they're relatively inexpensive and available in those values..

photo flash caps too would work Wil

Wilebee

thanks guys,

Vibroworld will custom make them... I sent them an email to see what the prices are like.

looks like a good place.
check it out.

http://64.225.39.49/parts/tech15.html

One of other thing...

I'm also Cloning the Sta-level (after I repair the original). I have all the parts except for the chassis. Where can you buy a nice heavy duty steel chassis?

http://www.par-metal.com/

I tried to remove the insides of a big can-cap and it was a huge waste of time. The entire inside surface had a layer of tar and the paper is so compact that its impossible to remove this stuff. I drilled, dug, soaked, burned and nothing worked.

It burned with a green flame, it was quite odd.

But some don't have the tar, and I guess its quite easy.

cannikin, could you elaborate a little on the Gates Sta-Level? It seems that if you are planning to clone the unit you really dig its sound. What do you use it for? After having nearly completed my GSSL project I'm starting to look for a new project, but I really want to do tube stuff again, so this might be interesting for me as well! Thanx for any comments.

[quote author="martthie_08"]cannikin, could you elaborate a little on the Gates Sta-Level? It seems that if you are planning to clone the unit you really dig its sound. What do you use it for? After having nearly completed my GSSL project I'm starting to look for a new project, but I really want to do tube stuff again, so this might be interesting for me as well! Thanx for any comments.[/quote]

I've used the Sta-level in other studios and it sounds great on Low frequency instruments. The engineer put the Gates on a Guitar track I did and it beefed it up.. after that I was sold - I reach for the Gates as the first option when I track guitars.

dave-

there is a mod out there to speed up the release time, if you are building one up from scratch Id look for that one and incorporate it into your build, better attack and release times on that unit turn it from a one trick pony into something really useful.

dave

Hey guys;

I got my hands on a 15-15-15 mfd 475V Multi Cap.

The original calls for 15-15-10 mfd.

I can use a 15-15-15

Right? any considerations to think a about.

[quote author="soundguy"]dave-

there is a mod out there to speed up the release time, if you are building one up from scratch Id look for that one and incorporate it into your build, better attack and release times on that unit turn it from a one trick pony into something really useful.

dave[/quote]

I'll take a look around thanks.

when I redid my federals, I upped the cap value and the voltage out of the power supply went up and the circuit wasnt digging it at all. When I put the spec'd value back in, everything was cool. Id try it out and keep that in mind if you have problems. I imagine this typee of thing is fairly circuit specific but its helpful for me to hear about others pitfalls, so there ya go.

when you finish yours let me know, Id love to come and check it out!

One cool thing you could do, if you dont need it rack mounted is to build it into a table top hammond steel box and set it up like you would a guitar amp, that might be really cool.

dave

[quote author="cannikin"]The original calls for 15-15-10 mfd.

I can use a 15-15-15

Right? any considerations to think a about.[/quote]
The difference in value is small (and smaller than the typical tolerances), so no problem.

Best regards,

Mikkel C. Simonsen