| whit3rd <whit3rd@gmail.com>: Jan 11 03:21PM -0800 On Thursday, January 10, 2019 at 7:24:54 PM UTC-8, Fox's Mercantile wrote: > 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. Oh, then the 'easiest' solution I'm aware of is a pogo pin soldered in a BNC fitting, and a lathe-job threaded tube, 3/8-27 to 38-32, to mate the threads. I'm not sure I've ever encountered 3/8-27, but I have taps for 3/8-24./ -26. /-32 |
| whit3rd <whit3rd@gmail.com>: Jan 11 03:37PM -0800 On Thursday, January 10, 2019 at 7:24:54 PM UTC-8, Fox's Mercantile wrote: > The Amphenol button connector is 3/8-27 pitch. Is this about the connector depicted here <https://archive.org/details/Amphenol/page/n5> at the top left of page M-6 ? |
| Fox's Mercantile <jdangus@att.net>: Jan 11 06:22PM -0600 On 1/11/19 5:37 PM, whit3rd wrote: >> The Amphenol button connector is 3/8-27 pitch. > Is this about the connector depicted here <https://archive.org/details/Amphenol/page/n5> > at the top left of page M-6 ? Yes. 5/8-27 Industry standard. -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com |
| etpm@whidbey.com: Jan 11 04:46PM -0800 On Fri, 11 Jan 2019 15:21:54 -0800 (PST), whit3rd <whit3rd@gmail.com> wrote: >Oh, then the 'easiest' solution I'm aware of is a pogo pin soldered in a BNC >fitting, and a lathe-job threaded tube, 3/8-27 to 38-32, to mate the threads. >I'm not sure I've ever encountered 3/8-27, but I have taps for 3/8-24./ -26. /-32 Lots of people who aren't machinists or who work with lamp fittings could easily think that a 1/8-27 straight pipe thread is 3/8-27. This is because 1/8-27 straight pipe thread has a major diameter of .394" to .390", which is only .019" to .015" over the major diameter of a 3/8 thread. And as sloppy as some threads are made, especially the threads on lamp fittings, the mistake is even easier to make. I have had more than one person ask me to either tap holes for 3/8-27 or if I knew where to buy a tap for that thread because they had no luck looking in catalogs or online for the elusive 3/8-27 tap. Eric |
| Fox's Mercantile <jdangus@att.net>: Jan 11 08:23PM -0600 >>>> that search string... >>> Except....A UHF connector is 5/8-24 pitch. >>> The Amphenol button connector is 3/8-27 pitch. CORRECTION The Amphenol button connector is 5/8-27 pitch. -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com |
| Fox's Mercantile <jdangus@att.net>: Jan 11 09:11PM -0600 On 1/11/19 8:36 PM, Martin C. wrote: > I have never seen such a connector, but have read that the shell > thread is the same as a a PL259. > Could a common PL259 to BNC adaptor be modified? They are NOT the same. The common UHF connector is 5/8-24. The Amphenol button connector is 5/8-27. -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com |
| etpm@whidbey.com: Jan 11 09:14AM -0800 On Thu, 10 Jan 2019 14:19:27 -0800 (PST), whit3rd <whit3rd@gmail.com> wrote: >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. Thanks for the edifying reply. Some time back I wanted to use the mains power as a frequency standard when adjusting a generator. I was worried about connecting my 'scope directly to 125 volts so I used a 12 volt out step down xmfr. The wave form was really distorted. So I guess this was a perfect example of the xmfr being made in a way that was unsuitable for audio. Thanks Again, Eric |
| whit3rd <whit3rd@gmail.com>: Jan 11 03:07PM -0800 > when adjusting a generator. I was worried about connecting my 'scope > directly to 125 volts so I used a 12 volt out step down xmfr. The > wave form was really distorted. That can happen because of saturation and remanence: the addition of a load on the low voltage side (like, a light bulb) will help greatly. The best small-signal audio transformers are potted in protective shells, in order to prevent strain on the magnetic laminations (which makes the magnetic core do those nonlinear things). |
| Phil Allison <pallison49@gmail.com>: Jan 11 03:34PM -0800 > >Audio transformers are most efficient when made from very thin laminations of > >soft iron, ** Soft iron has not been used since the days of Michael Faraday. Thin laminations of silicon steel is the norm. > when adjusting a generator. I was worried about connecting my 'scope > directly to 125 volts so I used a 12 volt out step down xmfr. The > wave form was really distorted. ** You exaggerate. .... Phil |
| Phil Allison <pallison49@gmail.com>: Jan 11 03:36PM -0800 whit3rd wrote: > audio transformers are potted in protective shells, in order to prevent > strain on the magnetic laminations (which makes the magnetic core > do those nonlinear things). ** Where does this utter drivel come from ??? .... Phil |
| whit3rd <whit3rd@gmail.com>: Jan 11 03:41PM -0800 On Friday, January 11, 2019 at 3:36:18 PM UTC-8, Phil Allison wrote: > > strain on the magnetic laminations (which makes the magnetic core > > do those nonlinear things). > ** Where does this utter drivel come from ??? From a guy with a Ph.D who did a bunch of magnetism studies. When unloaded, power transformers have lots of undesirable signal-handling features. |
| Phil Allison <pallison49@gmail.com>: Jan 11 04:21PM -0800 On Saturday, January 12, 2019 at 10:41:18 AM UTC+11, whit3rd wrote: > > ** Where does this utter drivel come from ??? > From a guy with a Ph.D who did a bunch of magnetism studies. ** Really ?? Has he got a web site - I could do with a good laugh. > When unloaded, power transformers have lots of undesirable signal-handling > features. ** More and worse drivel than the last lot. Give up - you have NO clue about audio or mains transformers. ... Phil |
| etpm@whidbey.com: Jan 11 04:37PM -0800 On Fri, 11 Jan 2019 15:07:21 -0800 (PST), whit3rd <whit3rd@gmail.com> wrote: >audio transformers are potted in protective shells, in order to prevent >strain on the magnetic laminations (which makes the magnetic core >do those nonlinear things). I had no idea! But I should have. So if I had loaded the xmfr down some the wave form would have more closely resembled a pure sine wave. Because of the tube amp I bought I have got the bug a little to learn about audio stuff in general and tube stuff in particular. I ordered a B&K Precision 4100 function generator last night and when it gets here in a week or so I'll be hooking up the TEK 465B to an audio xmfr, and some others, to see how the waveform gets distorted with frequency, voltage, and waveform. Thanks, Eric |
| Jeff Liebermann <jeffl@cruzio.com>: Jan 11 10:46AM -0800 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 Perhaps it would be interesting to see what's in a commercial tape head cleaner? GC Electronics Magnetic Head Cleaner Kinda looks like alcohol (ethanol) is safe. <http://www.gcelectronics.com/order/msds/116.pdf> Ethanol 86.8% Methanol 4.5% Acetic Acid Ethyl Ester 1.1% 2-Pentanone, 4-Methyl- 1.0% Solvent Naphtha 0.4% (Petroleum), Light Aliph. Hexane 0.4% 2-Propanol,2-Methyl- 0.11% Benzene, Methy- 0.05% Cyclohexane 0.001% Other 5.7% MG Chemicals 407c Audio/video head cleaner <https://www.mgchemicals.com/products/cleaning-products-for-electronics/cleaners/specialty-cleaners/audiovideo-head-cleaner-407c> It says "Safe on Plastics". The composition is somewhat different from the GC head cleaner. <https://www.mgchemicals.com/downloads/msds/01%20English%20Can-USA%20SDS/sds-407c-l.pdf> 67-63-0 propan-2-ol (IPA) 50% 107-83-5 methyl-2-pentane 15-25% 96-14-0 methyl-3-pentane 5-10% 79-29-8 dimethyl-2,3-butane 5-10% 75-83-2 dimethyl-2,2-butane 3-7% 110-54-3 n-hexane 1-2% -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| Jeff Liebermann <jeffl@cruzio.com>: Jan 11 10:55AM -0800 On Thu, 10 Jan 2019 08:55:55 -0500, Pat <forums@greensdomain.com> wrote: >a symptom of dirty tape heads? Drop outs - yes. Loss of highs - yes. >Static? Sounds more like a bad connection or static electricity being >generated somewhere. There's quite a bit to be found using Google search on the topic: <https://www.google.com/search?q=tape+head+static+electricity> The motion of the mylar tape backing over the resin filled head tends to build up a static charge on the tape. Metal reels and tape cartridges will discharge most of this, but plastic reels and collect static. In high tech tape backup drives, such as LTO type drives, it is possible for the static electricity to fry the heads. <https://www.streetdirectory.com/travel_guide/116367/data_recovery/sony_lto_tape_storage_media.html> "The working of the MR head is very much disturbed by the static electricity, and the MR head can be destroyed even by a minute static charge electricity." -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| thekmanrocks@gmail.com: Jan 11 09:45AM -0800 Tim R: Are there buttons or switches on that Fisher amp for selecting pairs of speakers? |
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