sci.electronics.repair@googlegroups.com

Google Groups

John Robertson <spam@flippers.com>: Dec 30 02:31PM -0800 On 2019/12/28 2:50 a.m., John-Del wrote:   > Alibaba lists the STK0055N for about $12 shipped:   > https://www.aliexpress.com/item/32820841800.html   > The one review said it worked...   That Alibaba one sure looks authentic! Well, maybe not so authentic... Like a poor copy of a copy...   Ali Baba and the 40 thieves is the full name of the original book if I am not mistaken...and an interesting name choice for a company!   John :-#)#

John-Del <ohger1s@gmail.com>: Dec 30 03:04PM -0800 Ali Baba was the good guy. The 40 thieves were, well, thieves. Ali Baba learned the secret phrase that the thieves used to gain entrance to a cave where they stashed their loot (as I recall).

John Robertson <spam@flippers.com>: Dec 30 03:12PM -0800 On 2019/12/30 3:04 p.m., John-Del wrote: > Ali Baba was the good guy. The 40 thieves were, well, thieves. Ali Baba learned the secret phrase that the thieves used to gain entrance to a cave where they stashed their loot (as I recall).   True, he only stole from the thieves...which makes him the good guy...(?).   John ;-#)#

John-Del <ohger1s@gmail.com>: Dec 31 05:03AM -0800 On Monday, December 30, 2019 at 6:12:22 PM UTC-5, John Robertson wrote: > > Ali Baba was the good guy. The 40 thieves were, well, thieves. Ali Baba learned the secret phrase that the thieves used to gain entrance to a cave where they stashed their loot (as I recall).   > True, he only stole from the thieves...which makes him the good guy...(?).   > John ;-#)#     In a Robin Hood sort of way I guess. I'm 62 and read the story only once, and that was when I was in second or third grade, so I don't recall the particulars - but my recollection was that Ali Baba was the good guy.

etpm@whidbey.com: Dec 30 09:23AM -0800 On Mon, 30 Dec 2019 06:52:40 -0800 (PST), "jfeng@my-deja.com"   >Is it a mono or stereo amp? If stereo, is the noise identical in both channels? Can you hear suspicious noises coming directly from the electronics (like crackling from the transformers)? In the absence of any diagnostic linformation, my knee-jerk reflex is to suspect the coupling condensers, followed by the cathode bypass and power supply filters. When you have the noise, try freezing one component at a time using freon spray. If you have an oscilloscope, does the noise show up on the power supply b+? These things do not have very many components, and you ought to be able to divide and conquer. The amp is stereo. The noise is coming from one side only. I'll post more info in another post. Thanks, Eric

etpm@whidbey.com: Dec 30 09:29AM -0800 On Mon, 30 Dec 2019 05:01:07 -0800 (PST), "pfjw@aol.com"   >Good luck with it - you will likely need it.   >Peter Wieck >Melrose Park, PA The amp you linked to is not my amp. My amp has no solid state devices except for the bluetooth module. But it is obviously separate from the amplifying electronics as it only connects to the input through a relay. Check out the link: https://www.doukaudio.com/el34-tube-integrated-amplifier-hifi-stereo-pure-class-a-power-amp-p0025-p0025.html This amp is similar but does not have the bluetooth module. Eric

"pfjw@aol.com" <peterwieck33@gmail.com>: Dec 30 01:33PM -0800 Same suggestions, although a bad Russian tube is no surprise whatsoever. Jeff is linking you to a reasonable site, however.   Peter Wieck Melrose Park, PA

etpm@whidbey.com: Dec 30 01:56PM -0800 On Mon, 30 Dec 2019 13:33:24 -0800 (PST), "pfjw@aol.com"   >Same suggestions, although a bad Russian tube is no surprise whatsoever. Jeff is linking you to a reasonable site, however.   >Peter Wieck >Melrose Park, PA I already have a really nice isolated auto transformer with a meter. The amp does draw a little more than 50 watts. I measured it when I made up the buck xmfr power supply for it. If the 5u4 tube starts to conduct much different than 80 volts what does that mean? Eric

John Robertson <spam@flippers.com>: Dec 30 02:54PM -0800 > hour and a half drive away. > Thanks, > Eric   Hi Eric,     Look for flashes of light in any of the tubes - that would be serious and that tube(s) needs immediate replacement.   When your amp again misbehaves try unplugging the inputs to it. Still have loud noise?   Then unplug the two 6N9 tubes, one at a time to hear if that makes the noise go away. These are the phase splitter tubes for the four output tubes if stereo. Two EL84Bs if mono.   At least that is what I would do...   John :-#)#

tabbypurr@gmail.com: Dec 30 07:58PM -0800 > hour and a half drive away. > Thanks, > Eric   Most likely cause is a bad connection somewhere. The fault is most likely after the volume ctrl, though it might be on a secondary supply line. Connections can be prodded with something insulating. A resistor in series with the speaker would keep the volume & Pdiss down. Keep an eye on supply current that it doesn't get excessive during fault.   A failing tube, cap or carbon resistor are also possible. Less likely deteriorating insulation. Comparing the voltages in the 2 channels while it faults might help home in on where it's going awry.     NT

Fox's Mercantile <jdangus@att.net>: Dec 30 10:14PM -0600 > Most likely cause is a bad connection somewhere.   Thank you Captain Obvious. If you had read the entire thread, you would have seen that it was a defective EL34. Please try to keep up.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

etpm@whidbey.com: Dec 30 09:12AM -0800 On Sun, 29 Dec 2019 17:34:08 -0800, Jeff Liebermann <jeffl@cruzio.com> wrote:     >You'll probably also need a spindle speed tachometer. Something like >this: ><https://www.ebay.com/itm/332908532113> I'll need to check my VFD to see if it can be jumpered to output 120 volts. I couldn't remember if more voltage would cause more current. Thanks. Since my son is doing light duty work with the lathe 1/2 HP should be fine. And the motor he is using now is 1/2 hp. It's just a standard single phase induction motor though. The washing machine motor has a tach so that's covered. If I can get the existing VFD to work out of the washer. Cheers, Eric

etpm@whidbey.com: Dec 30 09:15AM -0800 On Mon, 30 Dec 2019 05:08:34 -0800 (PST), "pfjw@aol.com"   >Do check that the motor is well-and-truly 3-phase, however.   >Peter Wieck >Melrose Park, PA As I stated in my post I do have already a VFD that would work except that I think it only outputs 120 volts. And the motor nameplate says on it that it is a 3 phase induction motor. The voltage and frequency are listed as being variable. But Jeff L. suggested that it may be jumperable so I will need to check the manual. I didn't even think it may be able to output 120 volts. Cheers, Eric

Michael Terrell <terrell.michael.a@gmail.com>: Dec 30 07:28PM -0800 > https://www.automationdirect.com/adc/shopping/catalog/drives_-a-_soft_starters/ac_variable_frequency_drives_(vfd)/micro/drive_units/gs2-21p0?gclid=CjwKCAiA3abwBRBqEiwAKwICA90933xWXOub4tqOEwtiM2NTBIQOIMPluf5Adgkwgq4LVLq26XmkxxoCZ6kQAvD_BwE   > Only one of many options.   > Do check that the motor is well-and-truly 3-phase, however.     So called 'High efficiency' washers have them, and so do some window Air conditioners. They eliminate the need for a fancy gearbox and they can reverse direction easily. A smaller motor can be used in some cases. Variable speed is used to reduce energy use on smaller loads.

etpm@whidbey.com: Dec 30 09:45AM -0800 Well, I peeked inside the amp and took off the transformer covers. There are indeed 3 transformers. From what folks have said I half expected to find some sort of weights under the xmfr covers because the amp is so heavy. Nope, just copper and iron. Inside the amp are no solid state devices but for the Bluetooth module, which connects to the input through a relay. So the amp switches automatically between inputs depending on whether the Bluetooth module is recieving a signal. On to the tubes. I turned the amp on again last night and just listened. After a while, maybe 45 minutes, I heard a crackle. Looking carefully at the tubes I noticed that one of the EL34 tubes was glowing brighter at the top than the other EL34 tube. There is a mica disc in the top of the tube and a little of the filament protrudes through a small hole in the mica. And this is what was glowing brighter. I tapped the tube and heard the noise coming out of just the left speaker. Tapping the right side tube produced no noise. I though that maybe one tube was getting more voltage than the other so I waited for things to cool down and then swapped tubes. The same tube got brighter but was now on the right side. So the tube must be bad because the problem travels with the tube and the same tube gets brighter no matter which side it is plugged into. So, anybody have suggestions on tubes? I'm not an audiophile. My hearing isn't good enough. I don't think matched pair tubes would make any difference to me ears. But I can hear well enough so a fairly high quality tube set would be desirable. And I do think I should get a pair so that they will hopefully last tghe same amount of time. Thanks, Eric

Fox's Mercantile <jdangus@att.net>: Dec 30 12:11PM -0600 > So, anybody have suggestions on tubes?   <https://www.tubesandmore.com/products/el34b-valve-art>     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Trevor Wilson <trevor@rageaudio.com.au>: Dec 31 05:21AM +1100 > pair so that they will hopefully last tghe same amount of time. > Thanks, > Eric   **Sure. Dump it and buy a decent solid state amp. Almost anything will be far more reliable and better sounding. Why bother with a cheap, Chinese tube amp?   -- Trevor Wilson www.rageaudio.com.au

etpm@whidbey.com: Dec 30 10:50AM -0800 On Tue, 31 Dec 2019 05:21:03 +1100, Trevor Wilson   >**Sure. Dump it and buy a decent solid state amp. Almost anything will >be far more reliable and better sounding. Why bother with a cheap, >Chinese tube amp? Because I like it. It sounds good. People spontaneously comment on how good it sounds. Not how it sounds almost as good as a solid state amp. And I like tubes. Are you grumpy today? Eric

etpm@whidbey.com: Dec 30 12:50PM -0800 On Mon, 30 Dec 2019 12:11:47 -0600, Fox's Mercantile <jdangus@att.net> wrote:   >On 12/30/19 11:45 AM, etpm@whidbey.com wrote: >> So, anybody have suggestions on tubes?   ><https://www.tubesandmore.com/products/el34b-valve-art> Thanks Jeff. I may order them today. Trevor at Rage Audio just raged at me and told me to throw away my tube amp. I wonder if the heat Down Under is getting to him? Eric

Trevor Wilson <trevor@rageaudio.com.au>: Dec 31 09:27AM +1100 >> be far more reliable and better sounding. Why bother with a cheap, >> Chinese tube amp? > Because I like it. It sounds good.   **How do you know? Have you compared it to a decent, inexpensive solid state amp? Are you certain that it is not simply acting as an expensive, unreliable filter?   People spontaneously comment on > how good it sounds.   **How would they know? By a very considerable margin, loudspeakers and room acoustics, dominate the sound of a system. All amplifiers, unless they are faulty (like cheap, shitty tube amps) sound very similar. Particularly to listeners who have little of no familiarity with the system.     Not how it sounds almost as good as a solid state > amp. And I like tubes.   **Well, I guess we're different. I like my system to provide a close illusion of the original musical event. No tone controls and no (audible) distortion. If that result can be achieved with tubes (and it can, but it costs a lot), then great. SS does it cheaper and more reliably.   > Are you grumpy today?   **Well, yes, but that's another story. I'm very angry with my global warming denying government. I'm stuck with the morons for a few more years. Just as Americans are stuck with man with the intellect and maturity of a 10 year old boy for POTUS. Still, there is hope. Not much though.   I suggest you try a decent, inexpensive SS amp. Dump the tubes. Good tube amps do sound pretty damned good. Trouble is, they are REALLY expensive. For budget sound systems, SS does it better.     -- Trevor Wilson www.rageaudio.com.au

Trevor Wilson <trevor@rageaudio.com.au>: Dec 31 09:29AM +1100 > at me and told me to throw away my tube amp. I wonder if the heat Down > Under is getting to him? > Eric   **34 degrees here in Sydney today. Not too bad, but the smoke from the bushfires (and the bushfires themselves) is taking it's toll. Depressing stuff. This is going to be our future.   -- Trevor Wilson www.rageaudio.com.au

etpm@whidbey.com: Dec 30 02:34PM -0800 On Tue, 31 Dec 2019 09:27:29 +1100, Trevor Wilson   >I suggest you try a decent, inexpensive SS amp. Dump the tubes. Good >tube amps do sound pretty damned good. Trouble is, they are REALLY >expensive. For budget sound systems, SS does it better. On the 1st Satuday in August I will be roasting my 25th pig. It's an annual party. Why don't you fly up and camp out? We have 10 or 12 wooded acres. I have an extra tent. It's a good party and you can listen to my shitty tube amp and grouse about it while we grouse about our shitty "leaders". I'm sure the amp will sound better than Trump. Eric

Trevor Wilson <trevor@rageaudio.com.au>: Dec 31 09:43AM +1100 > listen to my shitty tube amp and grouse about it while we grouse about > our shitty "leaders". I'm sure the amp will sound better than Trump. > Eric   **Thank you, but no thanks. Pork is not a meat I like to eat.   Have you tried a decent, but inexpensive SS amp?   I'd rather listen to, well, ANYTHING, but Trump.   -- Trevor Wilson www.rageaudio.com.au

John-Del <ohger1s@gmail.com>: Dec 30 03:02PM -0800 > pair so that they will hopefully last tghe same amount of time. > Thanks, > Eric     The Russians make pretty good EL34s these days, but I prefer the old 6CA7s. I still have a small stash of those left.

Trevor Wilson <trevor@rageaudio.com.au>: Dec 31 10:06AM +1100 On 31/12/2019 10:02 am, John-Del wrote: >> Thanks, >> Eric   > The Russians make pretty good EL34s these days, but I prefer the old 6CA7s. I still have a small stash of those left.   **Me too. I have a bunch of those steel, MIL-Spec ones.   -- Trevor Wilson www.rageaudio.com.au

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com.