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Fw: [Amps] Boycott New Chinese linear Amplifier
PA3DUV
The blood pressure is rising ;-)
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Cheers, Dick PA3DUV ----- Original Message -----
From: "Administrator" <amps@...> To: <amps@...> Sent: Wednesday, October 04, 2006 10:08 PM Subject: Re: [Amps] Boycott New Chinese linear Amplifier I told you morons to stop this thread. Nothing techinical here. Am I going to have to throw you all out of here. The list founder told me to clean up this mess and I will. |
Re: 3 - phase HV supply
PA3DUV
开云体育Moin Peter,
?
Mains goes 5 volt down from 440 to 395, measured on
the transformers primary terminals.
?
The plate transformer is over 45 kg, I lift it with
my chain come-along and a sling around it.
Concerning the 2nd harmonic: I never measured that
but did not receive complaints so far from guys listening in the 20 meterband
while I was working DX on 40 ;-)
?
Cheers, Dick
PA3DUV
?
?
?
|
Chortle of the Week
Phil Clements
A post on the AMPS reflector that got by the censor today was from
Bob, W6TR; the thread was about the copying of the AL-811 amp in China. "Isn't it time to bring the curtain down on this thread? Copying an Ameritron amplifier is like trying to perform a hemorrhoid transplant." Bob W6TR This made my day! (((73))) Phil, K5PC |
Re: Hi-pot tester
Hsu
Hi,Guillermo,
I think your square wave generator's freqence is too high?the ignition automotive coils's is iron not ferrite, the frequence must below kilo hertz 73! Hsu u may be in the good direction; I did not tried with TV flyback transformers, but did once some experiments with old ignition automotive coils, excited with a square wave generator and a darlington transistor amplifier. I could never get more than 400 volts pk-pk. With 13.8V supply. The circuit was not optimized also due to lack of time for another tasks, but I think one could get better results. More experimentation is in order here. Best regards Guillermo - LU8EYW. Recent Activity 17New Members 1New Files Visit Your Group Y! GeoCities Share Your Resume Show off your talent and skills. Y! Toolbar Get it Free! easy 1-click access to your groups. Yahoo! Groups Start a group in 3 easy steps. Connect with others.. |
Re: Hi-pot tester
GGLL
Hsu, you may be in the good direction; I did not tried with TV flyback transformers, but did once some experiments with old ignition automotive coils, excited with a square wave generator and a darlington transistor amplifier. I could never get more than 400 volts pk-pk. With 13.8V supply.
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The circuit was not optimized also due to lack of time for another tasks, but I think one could get better results. More experimentation is in order here. Best regards Guillermo - LU8EYW. Hsu escribi: Thanks! will |
Re: Hi-pot tester
Hsu
开云体育Thanks!?will
?? All Neon
tranformer there has been replaced by Switching power supply.Old
transformer
?isn't?easy to get now.?There is
another important reason,I often ?purchase? NOS tubes,
so,
?it needs battery operated.
? 73! Hsu
?
|
Re: Rotary Switches
pentalab
--- In ham_amplifiers@..., jmltinc@... wrote:
Rocket 88 (remember those?). I can't hi-pot a switch online.if no no specifications are known or the switch has no identifying marks?### pretty tough. You can see and download ALL the detailed specs of Multi tech switches at..... industries.com/Default.htm ### Centralab JVC series switches are used in alpha.. and a lot of other amps. ### You can look at contact surface area.. and also space between contacts... contacts to rotor etc. Figure on 9 kv per 1/4" 4.5 kv per 1/8" etc. ### B4 u get too carried away.. you have to figure whether u want a PI- PI-L... how many KW.... how many bands, shorting or non shorting switch... how many KV on anode of the tube etc. ### for 8877.... 3-500Z's.... etc.... a model #86 will work fine. For 4-1000's... YC-156's 3000/6000 A7 triodes... and also big tetrodes.... 1-3 wafers of the model 88/85 will work. ### for mono band amps.... u don't require a bandswitch of course.....ditto with heavy duty roller inductor's. ### My buddy had a 1969 Delta 88 oldsmobile..... stupidest thing he ever did getting rid of it..... 455 cu in V-8... globs of torque ! Jim VE7RF |
Re: Hi-
On Oct 4, 2006, at 3:25 PM, craxd wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:The problem is not that the tubes are faulty, it's that some designers of amplifiers ignorantly chose to ignore C-feedback. Less negative is not necessarily positive.RF design engineers from many companies ranging fromGuffaw. The clue word here is "many" because he fails to list the ...... chortleiciousA participant in a discussion can not be the censor of theYes, it has stunk since someone re-appeared on Amps after several ...R L Measures, AG6K, 805.386.3734 r@..., , rlm@..., www.somis.org |
Re: Hi-
Mike Sawyer
开云体育Will said: "Positive with respect to the cathode you mean? Terman calls
it less negative, see below." ?
I remember that thread. Even a simpleton like me understood what you were
saying and the point you were making. I often beleive he did this to demonstrate
his arguementative skills, (which I didn't think too much of).
Mod-U-Lator, Mike(y) W3SLK |
Re: Hi-pot tester
craxd
Hsu,
Most of the smaller commercial ones at around 4-5 kV use a neon sign transformer. Those are not that heavy, nor big either. It's according to what you have available there, but any sign company can get you a used transformer cheap. You may have to use a doubler or tripler, it's according to the output voltage of the transformer. These are pretty low current, maybe 5 mA or so. It doesn't take much. Best, Will --- In ham_amplifiers@..., "Hsu" <Jbenson@...> wrote: and W6CW,But I do not want use ac transformer. it is two heavy and need AC main power.I have some junk B/W andClour TV FBT, I think if I can be use in this project. I have a quertion, How much current the hi-pot tester shouldsupply?The another function of tester is burning of the "junk" between two electrode,it needs more current. 73! Hsu |
Re: O.T. The "other" list ...aka .... Tom R @%&H
pentalab
--- In ham_amplifiers@..., GGLL <nagato@...> wrote:
Admin. Anyway, I left the list.members.... ### Total number of new members is climbing daily. ### I find it amusing that Rauch designed that 3 x 811 amp........ [who in their right mind would actually design and build a 3 x 811 amp these days is beyond me].... then say it has a buncha drawbacks... and needs to be improved ? #### considering Rauch designed nearly everything MFJ sells.... including ant tuners with..get this Delrin Rod forms that melted with 900 w [I guess they don't test anything]..... and considering Rauch brags about all the Ameritron amps he designed. [all of em]..... if that was me who designed any of that stuff...... I'd make damn sure nobody ever found out who I was.... I'd be embarassed ! ### I'm told he was also involved with Dentron + Heath ?? Dentron, imo... never produced a single linear that was any good. IMO.... some of this stuff being passed off as "linear amps"... is not engineered at all..... it's ill conceived. ### For not much more $$$.... "they" coulda added simple things... like a stnadby/operate switch on the heath's... grid/cathode 3agc fuses... HV fuse... step start, safety protection diodes.... real xfmr's, etc..... and ended up with a much better built... "product". ### Go to Tom's website sometime. His AL-1500 looks nice..... SO does the pix of the YC-156 10 kw+ output "medical amplifier" in his workshop... complete with taps for 160-10m ! ### what's he gonna do with a HB "medical linear"..... do a little diathermy on 14.175 Mhz ? ? later.......Jim VE7RF |
Re: 811 debacle
On Oct 4, 2006, at 2:34 PM, craxd wrote:
I know it's poor form to talk about another group, but I haveThe amazing thing about Boss Tom is that he knew that I had previously used the censor bypass mailing list on three occasions to counter being censored, yet he went ahead and censored me. Clueless? R L Measures, AG6K, 805.386.3734 r@..., , rlm@..., www.somis.org |
Re: O.T. The "other" list
craxd
Guillermo,
The thing is, he blamed either Rich or one of use for doing it! I'm also not satisfied he didn't do it. He could have been using an alternate e-mail of his at the time, and after all the heat, he said this to cover it up. Best, Will --- In ham_amplifiers@..., GGLL <nagato@...> wrote: Anyway, I left the list.screw. About this messagethe chinese quality of tubes and amplifiers, the thread include Am I goingfrom "the administrator": clean upto have to throw you all out of here. The list founder told me to this mess and I will." |
Re: I hate the input network
craxd
Hsu,
Take a look at the link below. The amps uses a broadband input tune network that I'd think could be used for the cathode the same as it is on the grid in this one. It wouldn't hurt to give it a try. It is set up with an attenuator in this one, but could be modified I think. I've not looked at the schematic in a while, I just remember somewhat that they done. Best, Will --- In ham_amplifiers@..., "Hsu" <Jbenson@...> wrote: network for matching transistor driver. it need at least six coils and 12 relays or switchs and someadjusting work.why throw them off my linear amplifier? The problem:if without input network,its driver will unmatched.Innegative cycle, the input impendance will becuume very big, it is a bigest problem.Even in positive cycle, there is a problem, input capacitance, so the input impendance is not "pure" resistance,if no much more tube in parallel. If we design a GG Push-pull amp, the problem should be solved. Thepush-pull design only have 1/4 input/output capacitance in same tube' amount.The onventional P-P design must with resonator in plate tank. But I think it can be replace by a wideband P-P RF transfoemer, insecondary, wen can add a Pi net work.Certainly, we can use the transformer adjust the proportion of primary and secondary,let input impendance to match with the transitor driver. It is a good idea? |
Re: 811 debacle
On Oct 4, 2006, at 3:02 PM, craxd wrote:
This is too good to be true, from the admin;Indeed. Rich got the blameno Rich has been spoofing the admin, youTom Rauch is W8JI's worst enemy. R L Measures, AG6K, 805.386.3734 r@..., , rlm@..., www.somis.org |
Re: Hi-
craxd
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
design community that include Eimac, Siemens, ETO, Henry, and Ameritron.""recognized amplifier experts", and this according to a guy who says that Ni-CrNearly Perfect Amplifier", which appeared in the January, 1994 issue of the> magazine. The article outlined things which a perfect or nearly amplifier would have. Examples were step-start to limit inrush-I,T/ R, R/T switching that was Faster than that of transceivers in ordera glitch resistor in the HV+ lead to limit peak-I during an anomaly,> improve heat transfer. The article apparently lit the fuse of Tom Rauch, W8JI, (MFJ-Ameritron) and the even shorter fuse of Dickprobably since MFJ and ETO were major advertisers in QST, this got QST'sanalysis. I didn't figure he did by some of the stuff he has said. One can tell if someone has actually been taught something, or just trying to quote things they've heard or read from unreliable sources. I highly doubt he's ever did any actual research either. I know what that's like as I'm still doing it on transformers and power supplies. I've been doing it now for about two years straight. I'm still finding out new things that I hadn't seen in other works. responsible engineers from every major tubeThe only person from a tube mfg that he got to go along with his It would about have to be as i've read the photocopy of your letter from Eimac. who told QST's Paul Pagel that Eimac's Chief SpecificationsEngineer, Willis B. Foote was not authorized to tell me that gold-sputteringcondition. That would be a salesmans tone so as not to make ones think the tubes were faulty. RF design engineers from many companies ranging fromGuffaw. The clue word here is "many" because he fails to list the No problem! With air in the tube, the grid can go positive provided that theThis all over Tom trying to argue that a control grid couldIt can and definitely does so in a grounded-grid amplifier during Positive with respect to the cathode you mean? Terman calls it less negative, see below. Unconnected the space charge could cause the grid to become slightly negative or to where equilibrium is achieved between it and the cathode. The way I read it, the ions cause the space charge to increase from the cathode toward the grid. In the Radio Engineers Handbook, 1st edition by Terman, on page 316, sub-section 13 is listed; "Effect of Gas Upon Tube Characteristics" which is quoted below; "Very small traces of gas in vacuum tubes affect the characteristics adversely in a number of ways as a result of the positive ions produced in the tube by collision between the gas molocules and the electrons flowing to the anode. The positive ions travel in the opposite direction from the electrons, and normally end their existence by falling into the cathode or negative control grid. Electrons that bombard the cathode tend to destroy the emission of thoriated-tungsten and oxide coated cathodes. Positive ions collected by the negative grid result in grid current, which limits the resistance that may be inserted in series with a negative grid, and which also introduces noise. Positive-ion currents to the grid limit the d-c resistance that may safely be placed in series with the control grid and the cathode, because the voltage drop that such a grid current produces across the resistance has a polarity that makes the grid less negative than would otherwise be the case. Thus if the tube begins to liberate gas, with resulting positive-ion grid current, the grid becomes less negative, thereby increasing the space current. This increases the number of positive ions produced, and will cause additional grid current, and still greater reduction in the negative grid potential. If the resistance in the grid circuit is high enough, this process can become cumulative, and in some types of tubes can easilyresult in the destruction of the tube as a result of excessive plate current caused from loss of grid bias. The maximum resistance that is permissable to place in series with the grid electrode depends upon the grid characteristics and the method of obtaining bias. It is of the order of several megohms in small tubes used for voltage amplification at audio and radio frequencies. With small power tubes, such as the output tubes of radio receivers and public address systems, the allowable grid resistance is much less, particularly if a fixed bias is employed in the grid-cathode circuit, since self-bias provides an automatic protection against excessive increase in plate current". End Quote. thecan't beIt may be less negative than the cathode, or one 10v.grid is neg. 1490v (to ground), the grid potential is positive It does not matter a whit what the grid-chassis potential is, the Correct. However, in the way voltage is defined, it has a positive or negative polarity, and this is measured from ground or 0 Vdc by its definition. One side of 0 is negative, and on the other side of 0 is positive. Since the current through the tube is from the B+ supply, and the chassis ground is generally the B-, then by definition, the grid is never positive when tied to the chassis or B-. However, I know to measure this, it is measured between the cathode and grid, not the ground and grid. That's why I always agree the same as Terman described it, less negative. It could never be positive in respect to it, especially ifTying the grid to the cathode is a whole nuther ballgame, Will. I know this. Remember him saying a grid couldHe's assuming gas ionization between the positive anode and the oscillation. During the parasitics debate, trying to explain why no gas could be found in tubes that had popped their grid fuse, he To Toms theory, in the emortal words of John Wayne, "Not hardly". wide... truth.open kind, where there is no censor-librorum/moderator/ ...A participant in a discussion can not be the censor of theIn other words, he was hanging me out to dry to look like a foolThat's why Richard George reasoned that Tom was most likely the Yes, it has stunk since someone re-appeared on Amps after several years of absence. book.Well, that was it, I started by-passing him According to this nameless admin, he booted all of us out.
Best, Will |
Re: O.T. The "other" list
GGLL
Well, apparently it was a spoof message, not sent by the Admin. Anyway, I left the list.
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Best regards Guillermo - LU8EYW. GGLL escribi: It appears that the administrator of "the other" list loose a screw. About the chinese quality of tubes and amplifiers, the thread include this message from "the administrator": |
I hate the input network
Hsu
开云体育The ?GG?linear is very popular
? it need at least six coils and? 12 relays
or switchs and some ?adjusting work.why ?throw them off my linear amplifier?
?? The problem:if without input network,its
driver will unmatched.In? negative cycle, the input impendance will becuume
very big, it is a bigest problem.Even in positive cycle, there is a problem,
input capacitance, so the input impendance is not "pure"?resistance,if?no much more tube in parallel.
? If we?design a GG Push-pull?amp, the
problem should be solved.?The push-pull design only have?1/4
input/output?capacitance in same tube' amount.The onventional P-P design
must with resonator in plate tank.
? But I think it can be replace by a wideband P-P
RF transfoemer, in secondary, wen can add a Pi net work.Certainly, we can use
the transformer ?adjust the proportion of primary and secondary,let input
impendance to match with?the transitor driver.
??? It is a good idea?
?????????
73! Hsu my linear amp? resonance |