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Tim R <timothy42b@aol.com>: Jan 11 06:26AM -0800 MIDI in and out confuses me though.   I've never been able to get it to work except by trying it both ways.   Weird thing on this Fisher amp. Putting in headphones (and it's a 1/4 inch jack) disconnects speakers automatically. There's no way to have both room sound and headphone sound. Still it's nice to have this working again.

dansabrservices@yahoo.com: Jan 11 06:29AM -0800 On Friday, January 11, 2019 at 9:26:30 AM UTC-5, Tim R wrote: > MIDI in and out confuses me though.   > I've never been able to get it to work except by trying it both ways.   > Weird thing on this Fisher amp. Putting in headphones (and it's a 1/4 inch jack) disconnects speakers automatically. There's no way to have both room sound and headphone sound. Still it's nice to have this working again.   This is a very common setup. I have received units with no sound that turned out to be a failure of the headphone jack. Without the headphones, the jack shorts the signal line to allow it to continue to the amp. If the jack does not short, then no sound. Rare, but I have seen it a number of times over the years.

Dave M <dgminala at mediacombb dot net>: Jan 10 04:49PM -0600 If you don't mind buying from Chinese sellers and waiting a month or so for delivery, Ebay item 113114727770 is what you're after if you don't have the tooling for a crimp style connector (Ebay # 323326819341). Or, you could get several of these (Ebay # 392106541719) with the BNC already assembled onto the cable, Just cut off the banana plugs and solder your mic connectors onto the cable.   Cheers, Dave M

whit3rd <whit3rd@gmail.com>: Jan 10 06:59PM -0800 > Most of my vintage testers have those old style 5/8" screw on MIC > connectors. I have considered changing all of them to BNC     Don't you want a UHF BNC adapter? Take a look at images.google.com with that search string...   The UHF center socket takes a banana plug, so putting a ground banana compatible post next to the coax connector can let you use a dual-banana-to-BNC as well.

Jim Mueller <wrongname@nospam.com>: Jan 11 03:21AM On Wed, 09 Jan 2019 20:03:29 -0600, tubeguy wrote:   > Or, is there another method to accomplish this?   > Yes, I could solder on the chassis type BNC connectors, but they would > lack shielding at the connector.   You can remove the spring from the mic connector and drill the opening out enough to remove the plating. Then take a single hole style BNC connector and file the threads down until it fits in the mic connector. Solder a wire onto the center of the BNC and feed it through the hole in the mic connector. Then solder the BNC into the back of the mic connector and solder the center contact. That's how I made mine. It avoids having to come up with an unusual size tap.   -- Jim Mueller wrongname@nospam.com   To get my real email address, replace wrongname with eggmen. Then replace nospam with expressmail. Lastly, replace com with dk.

Fox's Mercantile <jdangus@att.net>: Jan 10 09:24PM -0600 On 1/10/19 8:59 PM, whit3rd wrote: > that search string...   > The UHF center socket takes a banana plug, so putting a ground banana compatible post > next to the coax connector can let you use a dual-banana-to-BNC as well.   Except....A UHF connector is 5/8-24 pitch. The Amphenol button connector is 3/8-27 pitch. Unless you consider cross threading a feature, they are not compatible.   -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

tubeguy@myshop.com: Jan 10 11:44PM -0600 On Fri, 11 Jan 2019 03:21:22 GMT, Jim Mueller <wrongname@nospam.com> wrote:   >the mic connector. Then solder the BNC into the back of the mic >connector and solder the center contact. That's how I made mine. It >avoids having to come up with an unusual size tap.   I was holding both parts in hand and thinking about doing something like that, except my thought was to epoxy the BNC into the Mic connector. (of course making sure they fit tight so there is a good connection on the ground side).   There have been lots of great suggestions in this thread!

"pfjw@aol.com" <peterwieck33@gmail.com>: Jan 10 11:58AM -0800 Some "Stuff":   Acetone (C3H6O) will attack spolyester resin, many two-part epoxies, ABS plastics, polystyrene, some forms of nylon, lacquer, shellac, unstabilzed celluloid and superglue.   Denatured Alcohol (C2H5OH)is ETHANOL with some other ingredient added to render it unfit for consumption. Typically that "other" is wood alcohol/methanol.   "Rubbing Alcohol" (C3H7OH) is, typically some mixture to include isopropyl alcohol, water and any number of other ingredients, including scents and lubricants.   "Wood Alcohol/Methanol/Stove Fuel" CH3OH) will attack a range of plastics.   https://www.plasticsintl.com/chemical-resistance-chart   A few actual facts do help speed the discussion along. Not to be snarky even a little bit, as I was somewhat surprised by the sensitivities of some things on the list.   Peter Wieck Melrose Park, PA

dplatt@coop.radagast.org (Dave Platt): Jan 10 11:55AM -0800 In article <5f4955a0-fad8-4e2a-b6d7-8ab62e8f6f54@googlegroups.com>,   >> The heads are metal. No worries about hardening. Who told you there >> was oil in rubbing alcohol? It's alcohol and water. Period.   >I forget the official standard for it, but it contains rather more than water & alcohol. Looked it up last year.   "Rubbing alcohol" is addressed by several different USP standards.   "Isopropyl Rubbing Alcohol USP" is defined as 70% isopropyl alcohol (plus or minus a couple of percent) by volume, the remainder "water, with or without suitable stabilizers, perfume oils, and color additives certified by the FDA for use in drugs." So, even drugstore isopropyl alcohol can have components other than alcohol and water.   "Rubbing Alcohol USP" (without the word "isopropyl") is ethanol, water, denaturants (e.g. sucrose octaacetate or denatonium benzoate), "with or without color additives, and perfume oils."   Some commercial rubbing alcohol used to contain lanolin, to help keep the skin from drying out; I don't know if any still does.   If you don't see the term "USP" on the label, then whatever you're buying may not comply with the USP standards I mentioned.   Outside the US things are even more complex; British "surgical spirit" is methylated spirit (ethanol denatured with methanol), castor oil, diethyl phthalate, and methyl salicylate ("wintergreen oil").   (Relevant information cribbed from the Wikipedia article on rubbing alcohol, and the newdruginfo.com links which cite the USP definitions).   For electronics cleaning purposes such as tape-deck heads, I prefer to buy technical-grade isopropyl alcohol. My local Frys carries the Puretronics brand ($9/quart).

"pfjw@aol.com" <peterwieck33@gmail.com>: Jan 10 12:29PM -0800 Adding to Dave's post - a bit of history:     "In 1906, President Theodore Roosevelt signed the Pure Food and Drug Act into law. The law elevated the public health role of the United States Pharmacopeia because it defined a drug as "all medicines and preparations recognized in the United States Pharmacopeia (USP) or National Formulary (NF)," and defined adulterated drugs as those referenced in the USP and NF but differing from "the standard of strength, quality, or purity" specified in the two compendia. The practice of labeling medicines with the letters "U.S.P." or "USP" became more prevalent. In 1938, the Food, Drug and Cosmetic Act reaffirmed the role of the pharmacopeia and expanded its role to include USP standards for labeling and packaging. "   Peter Wieck Melrose Park, PA

tubeguy@myshop.com: Jan 10 03:10PM -0600 On Thu, 10 Jan 2019 08:07:13 -0000 (UTC), gregz <zekor@comcast.net> wrote:   >supposed to have oil to prevent skin drying too much. Most don't. Isopropyl >or ethyl cleans heads.   >Greg   I have used isopropyl alcohol all my long life for audio and video heads. Works well.....   Acetone is very harsh and will melt plastic and remove paint. I will not use it for this....

tabbypurr@gmail.com: Jan 10 08:42PM -0800 On Thursday, 10 January 2019 20:08:06 UTC, Dave Platt wrote:   > For electronics cleaning purposes such as tape-deck heads, I prefer to > buy technical-grade isopropyl alcohol. My local Frys carries the > Puretronics brand ($9/quart).   We generally use BP & BSes rather than USP. So the answer depends to some extent on where the enquirer is.     NT

Paul Drahn <pdrahn@jodeco.com>: Jan 10 12:36PM -0800 > curious. I am very happy with the way my tube amp sounds. > Thanks, > Eric   The capacitance of the windings will limit the high frequency response. Perhaps the best will have the secondary wire in parallel with the primary wire. Never had one to take apart.     Paul

whit3rd <whit3rd@gmail.com>: Jan 10 02:19PM -0800 > I see really expensive audio output and power transformers for sale > as well as cheap ones. And lots of folks really want older ones > because they are better than the new crop. So what is the difference?   The core of a transformer has laminations, because a solid metal lump would have electrical conduction losses (eddy currents) to cause large heat losses (and reduce output efficiency). A power transformer has thick laminations (60 Hz losses are small anyhow, but at 60 kHz, that would be inefficient), and a switchmode transformer is made of high-electrical-resistivity ferrite (at 60 kHz, the size can be small, though such a low-magnetization material wouldn't be great for lower frequency power).   Audio transformers are most efficient when made from very thin laminations of soft iron, which is a more expensive construction than is used for either 60 Hz or 60 kHz power transformers. It just has more small parts.

Look165 <look165@numericable.fr>: Jan 10 11:30PM +0100 The parasistic elements. (copper, iron...).

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