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Re: Hsu
To be honest with you guy... stay away from it.
i Know 4 owner of LA-4000, 3 got home for major repair + modification.? The last one i dont know i never spoke with the owner but i bet is power board will fry very soon. YU Lang the owner of AMPTEC, is not listen at all...not very helpfull ...he not came back to my email as i told him all the bad design he do on this piece of junk :) The way he keep the amp running using power divider on 240 volt is getting hot very fast and blow very quick. Glitch resistor value is to low and not limit often current when flashover occur...the board trace goes in smoke each time. IMD is ridiculous...even at 1500W. Screen voltage is well regulated so i am thinking IMD is from tube.? 4CX1500B swap will be possible but very expensive ...? much more better amp is around and make here with full service support. Dont waste a buck on this. This is my opinion.. Guillaume VA2NA |
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International shipping of Amplifier question L4B and a NIB HF-2500 Commander
I need to ship a Drake L4B to a ham in VK6 land. The quotes I found from FedEx DHL etc are totally nuts. The buyer isn't in a hurry but somehow we have to get the shipping to something reasonable. So I thought where better to find out than from the Ham Amplifier group? So where do we get reasonable deals.
One other question. I also have a brand new in the box Commander HF-2500 with a serial number on it of 0475. It has never had a plug connected to the power cord. Yes I am selling off a local SK's ham equipment for the widow. SK is Jule Franke W9TQA link to the sales AD on QRZ.com All help appreciated. Email to me k9uwa@...? thanks 73 John k9uwa |
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Re: Hsu
¿ªÔÆÌåÓýThanks Lou.Hsu was a great contact. He helped me out on many occasions, when it came to sourcing good quality stuff from China. Not only that, I reckon he is a very decent and honest person. As I mentioned, I had a question for him the other week and the email has gone unanswered, so far. I hope everything is ok with him. Cheers, Alek. On 25/06/2019 6:55 PM, Gudguyham@... [ham_amplifiers] wrote: Hsu and his partner who sold the HF 2013 amplifier back in 2013 had broken off the partnership and his partner went on to start the Amptech company. ?Hsu was supposed to come to Dayton in 2013 to show off the HF2013 manual and auto tune amps. ?About a week before the Dayton show Hsu ?gas bypass surgery and couldn¡¯t make Dayton. ?The amps were here in the US waiting for him. ?The manual tune was to go to a friend of mine as he had already paid for it. ?Subsequently my friend finally got the amp some months later. ?The amp had issues that I had worked on and at the time I was in contact with Hsu as he shipped me parts. ?Since that time I haven¡¯t heard from him. ?Far as I know after the split with his partner he hadn¡¯t done much with amps. ?I have to admit that he was very good at supplying parts needed to get that amp working again. ? -- From sunny Binningup Family Businesses: SP Electrical. The Velvet Fox. Smart Design Electrical. Perth Interiors. |
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Re: Hsu
VA2NA? did an? extensive IMD? write up on the Amptec? LA4000,? back? on Oct 22, 2017.? ? It's Item #15, under
'files'? on this site.? Uses? 2 x FU-728's....and? runs? 4 kw output.? ?Appears? to be a clone of a manual tune? OM-4000.? ? ?Amptec? version? is? $3.5 K.... vs $6.1 K? for the OM-4000? version. AFAIK,? amptec? is? still? HSU's? company..... but perhaps? VA2NA? can comment.? Jim? VE7RF? |
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Re: Hsu
Hsu and his partner who sold the HF 2013 amplifier back in 2013 had broken off the partnership and his partner went on to start the Amptech company. ?Hsu was supposed to come to Dayton in 2013 to show off the HF2013 manual and auto tune amps. ?About a week before the Dayton show Hsu ?gas bypass surgery and couldn¡¯t make Dayton. ?The amps were here in the US waiting for him. ?The manual tune was to go to a friend of mine as he had already paid for it. ?Subsequently my friend finally got the amp some months later. ?The amp had issues that I had worked on and at the time I was in contact with Hsu as he shipped me parts. ?Since that time I haven¡¯t heard from him. ?Far as I know after the split with his partner he hadn¡¯t done much with amps. ?I have to admit that he was very good at supplying parts needed to get that amp working again. ?
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On?Tuesday, June 25, 2019,?Alek Petkovic vk6apk@... [ham_amplifiers]??wrote:
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Re: W6WRT SK
I talked with Bill a few times and even bought some of the stuff he no longer had the time for.
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I hated to see he's gone. There are fewer and fewer of the knowledgeable left and few with any knowledge joining. I know we all had to start somewhere, but I still say my Novice exam required more theory than the present Extra exam. 73, Roger (K8RI) On 6/21/2019 1:21 AM, Randy randy@... [ham_amplifiers] wrote:
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Roger (K8RI) |
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Re: W6WRT SK
¿ªÔÆÌåÓýWell, shit. Another good one gone. RIP Bill. 73 Randy KZ4RV On 6/20/2019 5:31 PM,
jim.thom@... [ham_amplifiers] wrote:
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Re: W6WRT SK
I?m sorry to see this. Did have a number of
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QSO?s with Bill. RIP OM de Jim SM2EKM Den 2019-06-20 kl. 23:31, skrev jim.thom@... [ham_amplifiers]: Saw this on.... 'amps'...posted? by? Rob,? K5UJ. |
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Re: True RMS AC Ammeters ?
Trus? rms? voltmeters work really good with? ratty waveforms.? ?They will handle anything you throw at em...including? sawtooth, square waves, and loads of harmonics.??
True? rms? ac? ammeters, good ones, have? 1%? accuracy? > 100Amps.......and? 2% accuracy? for? <100 Amps. I still have not heard? back? from Wilbac..who makes my various panel meters.? Jim? ?VE7RF.? ?? |
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Re: True RMS AC Ammeters ?
What precision do you want?
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For what you probably want, I would think a true RMS volt meter of a known accuracy within a couple % and a known resistance should suffice as measuring the calibration, but.the problem with true RMS volt meters is how do they handle a not so clean wave form. The problem with the moving vane current meters, as I understand it, is accuracy and I believe they are also the cheapest I don't know where they stand as far as repeatability. I use a 3KVA line conditioner that develops a clean and regulated, true sin wave for the 120 VAC stuff in the shack. (2 computers and two transceivers) They could be calibrated against a precision Power Supply or in series with a precision A meter using clean DC. OTOH I don't remember any inexpensive way to measure how well they do against a ratty RMS wave form. It's been a very long time since I did measurements traceable to the NBS After 33 years I'm not sure if I can remember how I did all of that. 73, Roger (K8RI) On 6/13/2019 9:52 AM, jim.thom@... [ham_amplifiers] wrote:
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Roger (K8RI) |
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Re: True RMS AC Ammeters ?
W2xj
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On Jun 12, 2019, at 9:46 AM, jim.thom@... [ham_amplifiers] <ham_amplifiers@...> wrote:
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Re: True RMS AC Ammeters ?
¿ªÔÆÌåÓýA few years back, on some FB group I belonged to at the time, I
forget which, somebody posted a picture of a large industrial
transformer, I'll guess it was maybe 10' square and 8' tall, I
really don't remember, but YUGE compared to a residential pole
pig. It was old, and had definite discoloration of the paint in
some areas, not in others. I didn't follow his point of posting, so I asked him why an old
xfmr would discolor in some areas, not in others, and many years
after installation. He said that, being in an industrial area,
there were lots of machines using solid-state switching at high
power levels, creating all sorts of transients and weird currents
that the design of the old xfrm never anticipated. Obviously, some of that garbage would escape back out into the neighborhood HV lines. And back into our homes. So, yeah, no. Not gonna be easy to get the RMS value of garbage.
73 Randy KZ4RV On 6/13/2019 4:10 AM, 'Roger (K8RI)'
k8ri@... [ham_amplifiers] wrote:
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Re: C-L-C update
¿ªÔÆÌåÓýSomewhere, AG6K is smiling... 73 Randy KZ4RV On 6/10/2019 11:05 PM, Jim Strohm
jim.strohm@... [ham_amplifiers] wrote:
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Re: True RMS AC Ammeters ?
<The garbage coming off the power line, as well as "in house" appliance? <generated trash doesn't give us much better.? The old Amp meters can? <give us effective amps based on heat and those don't care what the? <waveform looks like. <73, Roger (K8RI) ##? apparently, the only type of? AC? AMMETER? ?that? indicates? true? rms? current (regardless of? wave form)? is the Moving Iron type.? ? ?Dunno if my 3 x panel meters? are moving iron? type..or not.? I'll? try and dig up info from the meter? maker.? ##? Mine all use a 5:1? current xfmr torrid....? ?with one conductor? passing through the torroid? hole.? I use a 0-75A? for the? fil of the? 3cx3000a7.? ? ?And a? 0-100? A? ?for the fil of the 3x6? fil.? The 3rd is a 0-150A, used for the pri of the plate xmfr.? ## 2 wires? from current xfmr..... over to the respective panel meter.? ##? I'll? test this all out.? ?Current on both? fi? xfmr? sec? are? resistive of course.? ? Its the plate xfmr pri? ?I'm? concerned about.? Jim? ?VERF ---In ham_amplifiers@..., <k8ri@...> wrote : The garbage coming off the power line, as well as "in house" appliance generated trash doesn't give us much better.? The old Amp meters can give us effective amps based on heat and those don't care what the waveform looks like. 73, Roger (K8RI) On 6/12/2019 9:46 AM, jim.thom@... [ham_amplifiers] wrote: |
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Re: True RMS AC Ammeters ?
The garbage coming off the power line, as well as "in house" appliance generated trash doesn't give us much better.? The old Amp meters can give us effective amps based on heat and those don't care what the waveform looks like.
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73, Roger (K8RI) On 6/12/2019 9:46 AM, jim.thom@... [ham_amplifiers] wrote:
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True RMS AC Ammeters ?
? If? you look? at the? distorted waveform coming out of the FWB, FWCT, FWD, it typ consists of high, peak pulsed? currents.... when a C filter is used.? ? Like? 15-24A on peaks....and only? 1.5? to? 1.7 msecs in duration? at the bottom....as? seen on a scope.? ?Same deal on both the sec..and pri? of the? plate xfmr.? To measure primary? AC current on the? plate xfmr,? ?you really require an? TRUE RMS? AC? Ammeter.? ? I hadn't? even thought of that anomaly, when? installing a? 0-150A? panel mount? ? AC? AMMETER.? ? Did some research, and if using a NON rms ammeter? on the primary of a? single phase plate xfmr...with a FWB / FWD /? FWCT rectifier? and C?? filter, the non rms meter? can indicate as much as 40%? on the low side ! The plan is to compare the panel meter to a Fluke true rms clamp on ac?ammeter.? Even with all that, you still have the issue of Power factor. True rms??Volts? X? true RMS? amps?=?True??VA power,? not??true?watts.??One of the ham fellows sent me a pix of his? spectrum analyzer display, depicting the odd? harmonics of the? 60 hz input...of a plate xfmr and FWB +? high? C? filter.? ?The? 3rd and also 5th? (180 hz + 300 hz) harmonic is the worse, then the 7/9/11+? drops like a rock.? ? With? full? wave rectification, the harmonics are always odd.? A half wave rectifier produces only even??harmonics.? What? would be interesting is to measure peak AC current on the pri.? ? ?Then? compare to software results.? Jim? ?VE7RF |
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Re: C-L-C update
<Henry had been using the resonant choke PS since before many on here were?
<born and they worked fine until the resonating cap developed leakage and the? <value changed. <The transformers were old design high impedance and used 866A, 872A, 8008,? <575A, or equivalent/similar in xenon such as 3B28, 4B32. <Nobody ever complained about hum (harmonics) in any ham mode or AM broadcast? <use even after the transformers were the modern design and retcifiers were? <SS. <The 8K 600V drop is only for key down and at 9% regulation is no big deal.? <For intermittent loads the dynamic regulation is much better and could be? <improved with a bit more output C. <I dont understand what all the fussing is about these days. <Carl ##? Points? well taken, but it's not? 1954 anymore.? ?I see that? Henry radio still sells the? resonating caps on their website,? ?$120.00? ?Made by? HEC.? ? The? 8K uses? 2 of em? for? 60 hz.... and 3 of em for? 50 hz. That's a lot of? $$$, just for some resonating caps.? ? 300 watts? CCS? for the bleeders? is a bunch, but a requisite when using choke input.? ? Toss in the cost of the choke, + resonating caps...... and a low Z plate xmfr sec +? high C filter cap makes? more sense.? Put the? $$? where? it should go.? ##? I used? 816's...and the bigger? 866? back in the? day.? But you had to wait a few minutes for the mercury to vaporize.? ?The B+ output came off of the? CT? of the? fil xfmr that ran the? rectifier tubes...so a special HV? fil xfmr was used. . Peak plate xfmr? sec? current was low, so a high? Z? plate xfmr could easily be used.? IE:? high sec? dc resistance.? ? ##? The only mode where? 100 / 120hz? ripple..and harmonics are an issue is Broadcast FM.... and that's? when using single phase power.? ?Without the added? ?C-L-C? tacked onto the? output of the resonant choke, the? B+? supply won't meet? the FCC ..... 'AM? noise spec'....applied to? broadcast? FM.? ?The typ? resonant choke already has a cap on the output, so adding? one additional choke + 2nd cap is not a big issue.? ? ?FM is the only mode where the TX is operating full bore? cxr, whether modulated..or not....and plate current is max at all times.? ?During speech pauses, or between program material is when? you will hear any? ripple...or? ?ripple harmonics.? ?Typ? FM? consumer RX's? are good from 50-15 khz....and with a local? 100 kw erp? FM? station? across? town,? you? would hear em .?? ##? That's all a? moot point for? ham use.? ##? One slight advantage of the 127 lb dahl choke is..... unlikely some bozo will steal it.? Later.... Jim? ? VE7RF? ? ? |
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Re: C-L-C update
Henry had been using the resonant choke PS since before many on here were born and they worked fine until the resonating cap developed leakage and the value changed.
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The transformers were old design high impedance and used 866A, 872A, 8008, 575A, or equivalent/similar in xenon such as 3B28, 4B32. Nobody ever complained about hum (harmonics) in any ham mode or AM broadcast use even after the transformers were the modern design and retcifiers were SS. The 8K 600V drop is only for key down and at 9% regulation is no big deal. For intermittent loads the dynamic regulation is much better and could be improved with a bit more output C. I dont understand what all the fussing is about these days. Carl ----- Original Message -----
From: jim.thom@... [ham_amplifiers] To: ham_amplifiers@... Sent: Tuesday, June 11, 2019 9:47 AM Subject: Re: [ham_amplifiers] Re: C-L-C update <I've seen mention on this list of Rauch trying to blow himself up doing something with resonant chokes, but I <wasn't privy to the actual event. What was the story there? <73 <Randy <KZ4RV ## simple really. His choke resonated at aprx 117hz- 119hz..with just bleeder load. Once the real load was applied, the choke XL drops a tiny bit... and resonance freq increases a bit. Once it hit 120 hz... with a load on it, all hell broke loose. ## He was using the classic resonant choke - filter cap config.... like henry radio and collins used...except they resonated on the high side of 120 hz.... which increases in freq even more..with max load. ## In the above resonant choke - cap config, the resonant choke is getting hammered by 60% ripple, coming out of the rectifiers. And the ripple freq coming out of the rectifiers is 120 hz...or 2F. ## Think of how parallel resonant traps work on a triband yagi. You end up with extremely high peak V on the capacitor section of the trap....and extremely high current flowing through the coil. When the sign wave flips polarity, you get a huge back emf from the coil..which charges up the cap. The cap then discharges through the coil..producing high currents through the coil. It just goes back and forth forever ( with power applied..and a big load). ## The other issue with the classic resonant choke - Cap setup is the B+ is only .9 X xfmr sec. Henry radio used a 6000 vac sec on it's 8K ultra....fed into a FWB.... then into the resonant choke - cap filter..and a big 300 watt bleeder. The 8 K ends up being just 6000 X .9 = 5400 vdc.... no load. Which drops down to 4800 vdc with a 1.25A load. 6 kw dc input..and 3.5 kw rf output. So it drops 600 vdc... which is nothing to write home about. ## A 3600 vac sec with a FWB..or a 1800 vac sec and a FWD would have done the job... and a C input filter. ## Put the $$$ into the xfmr.... not a choke. Gotta run, a ton of stuff going wrong this AM. Jim VE7RF --- This email has been checked for viruses by AVG. |