Search found 461 matches

by emrr
Thu Apr 19, 2018 8:09 am
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 32
Views: 4206

Re: Dielectric Absorption

clipped in near the tube cathode. Physically near, but in series with the grid in the drawing, the one other reference I checked was a direct heated circuit and there the battery is in series with a resistance between ground and grid, not in series with signal. I haven't messed with these circuits ...
by emrr
Mon Apr 09, 2018 5:57 pm
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 32
Views: 4206

Re: Dielectric Absorption

Found the Mallory grid bias cell and holder. I get a brief 0.3-0.4V reading. 2M4 DCR and climbing. I don't trust those readings.

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by emrr
Thu Apr 05, 2018 10:29 pm
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 32
Views: 4206

Re: Dielectric Absorption

In the 90s, my hamfest tool kit contained a 9V battery and a simple DMM to characterize unknown film caps found in the wild. The basic procedure was to charge the unknown cap for five counts, short it for one count, and then measure the recovery voltage. After some training with known samples, the ...
by emrr
Wed Apr 04, 2018 9:12 am
Forum: The Peabody Lounge
Topic: RIP Frances Lloyd
Replies: 4
Views: 439

Re: RIP Frances Lloyd

Nice to see the history of it.
by emrr
Wed Apr 04, 2018 9:07 am
Forum: Build
Topic: Redco Audio Wire and Cable
Replies: 6
Views: 778

Re: Redco Audio Wire and Cable

Yep. I ordered one of three panels from the, got it in about 2 months. Ordered the final two later, they'd not kept the design even though I'd told them there were more coming, and I've got nothing.
by emrr
Thu Mar 29, 2018 5:47 pm
Forum: Build
Topic: Meanwell Single, Bipolar and Triple Output Switching Power Supplies for Audio Projects
Replies: 17
Views: 1798

Re: Meanwell Single, Bipolar and Triple Output Switching Power Supplies for Audio Projects

I've used a bunch of the Meanwell RS-25-48 for phantom, with an RC filter after it. Not been a problem that I've detected. They are adjustable over a small range, so you can land voltage at a best spot for the range of load expected.
by emrr
Thu Mar 29, 2018 5:42 pm
Forum: Build
Topic: Redco Audio Wire and Cable
Replies: 6
Views: 778

Re: Redco Audio Wire and Cable

They are currently on my shit list for failing to deliver 2 custom connector panels 9 months after pricing them and taking my CC. Occasionally they make promises when bothered, usually they don't respond.
by emrr
Tue Mar 27, 2018 8:53 am
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 32
Views: 4206

Re: Dielectric Absorption

I need a Duracell 504 15V and found that Exell were making a lot of vintage battery replacements. I don't suppose there is enough of a demand for those but Exell is a good resource. http://www.exellbattery.com/ Last I looked a few years ago there wasn't a source I could find for those discontinued ...
by emrr
Tue Mar 27, 2018 7:48 am
Forum: Pro Audio Design
Topic: Dielectric Absorption
Replies: 32
Views: 4206

Re: Dielectric Absorption

It had not grown anything. Here's an article about those bias cells: http://www.antiquewireless.org/uploads/1/6/1/2/16129770/09-the_mallory_bias_cell.pdf I really don't know the mechanisms at play in the old caps. That particular piece I would easily believe was powered on most of 1939-1988 in a rad...