Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

Use this form to submit comments directly to the Asylum moderators for this forum. We're particularly interested in truly outstanding posts that might be added to our FAQs.
You may also use this form to provide feedback or to call attention to messages that may be in violation of our content rules.

You must login to use this feature.

Inmate Login

By default, logging in will set a session cookie that disappears when you close your browser. Clicking on the 'Remember my Moniker & Password' below will cause a permanent 'Login Cookie' to be set.

Moniker/Username: The Name that you picked or by default, your email. Forgot Moniker?	Examples "Rapper", "Bob W", "joe@aol.com".
Password:	Forgot Password?
	Remember my Moniker & Password ( What's this?)

If you don't have an Asylum Account, you can create one by clicking Here.

Our privacy policy can be reviewed by clicking Here.

Inmate Comments

From:
Your Email:
Subject:

Message Comments

Original Message

RE: Hopefully, Mr Fraker will join us, as you suggested....

Posted by tube wrangler on March 14, 2013 at 08:30:36:

Hello, Winston.

In the past, Jupiters have had reliability problems, so techs are afraid of them.

Perhaps the new Jupiters are better now. My own approach-- to everything-- is total reliability first, everything else second, but not avoided-- one just works a little harder, using only "bulletproof" parts. Dynamicaps aren't perfect-- you can pull or melt the leads off of them. Handled right, they don't fail, once installed and run correctly.

Never put them somewhere where they will be heated.

A company that always sells super-reliable caps is REL-- Reliable Capacitor. I also use many of those.

You can always try any combos you like to try, however, but be careful about using anything questionable at voltage-- or swing-voltage possibilities that are getting fairly close to the cap's published ratings. Stay a long ways away from those ratings!

That's from my point of view as a customer demand supplier-- for your personal work, you can probably fry a few caps and not ruin your world.

Spectral overlaps do occur where parallelling of a cap that doesn't fit into the mix-- disturbs that mixe's proper operation. Happens everyday with DIY folks. It also happens to experts because cap manufacturers are always changing their caps. This is normal human progress- changing things. You just work with the new stuff until IT works, or get something that does work.

It's an Art-- you can't calculate much of it and get stellar results. You have to use sensitive equipment elsewhere in the system, and you take advantage of good test equipment where it can be effectively used. An example is identifying those sonic overlaps with a Spectrum Analyzer.

Once you have the industrial or DIY experience, you'll know what the preamp is doing anyway, so test equipment will become mostly a way of looking (somewhat-- all test equipment is limited) at what you're already hearing and noting.

The Spec. Analyzer will also identify unwanted oscillations mostly caused by wiring, physical placement problems with components, and layout problems.

Sometimes, manufacturers apply oscillation-quenching circuits or parts (an example is the use of a series resistor at a grid input, etc.)-- sometimes referred to as a "grid stopper". You may see things like this in a piece of equipment.

The existence of such items in audio equipment is proof that the designer gave up before the equipment was designed and built right, and "fixed" his problem with a gimmick.

You have to work around, or eliminate these things when working with existing equipment before you can just add capacitors-- and expect the results that the best caps can deliver.

---Dennis---