Hi, Anyone have the scoop on the 1mA meter movement used in the Alpha 77. Just want to understand the internal resistance, without having to pull mine apart, again! There has been some suggestion tha
My 77D(x) had sat for many years unused when it came to me, its a very early s/n but still a great amp. Initially the blower was horrendously noisy. Finally I pulled it out and stripped it down. Low
I have never seen an overlay for an Alpha amplifier. I have seen them for Heathkit amplifiers but never seen one advertised for an Alpha. Given the general value/cost of Alpha amplifiers I'm not sure
Hi, I have a nice big Motorola power supply battery charger unit. Comes from an MSR2000 system and can provide 13.8v at 30A. Has lots of electronics for battery charging, monitoring, alarms, etc. Wou
Hi, Is that with the HT switch in the CW or SSB position?. If the CW position it sounds about right. If in the SSB position and HV, Ip and Ig all look normal then I can only assume he has an amp with
Try building a tube amp, from all new parts, no pulls, surplus or nos, bet that will be just as, if not more expensive. Everyone selling a built amp, or a kit, expects at least some profit. Tube amp
That's a good breakdown, I hadn't realised, until I re-read the website, that the PSU is INCLUDED! Really is quite a good deal. A 1500 watt, RTTY contest capable amp for a bit over US$3k. A Pi, fans
I have an Ameritron choke to go in my 77D, just need that bag of round tuits! The Ameritron choke is not a panacea however. Used in the Alpha 78 there is a nasty fire starting resonance when operatin
I had the same problem with my early 77D, so early the fwd ad rfl meter is open wired on tag strips, no pcb. I just replaced the diodes, seems they have a finite life. Likely you have a similar probl
I don't think the 8877 will be to lively with a mere 2400 volts on its pip. That new transformer will need to up the HT a fair bit. Filament volts, 8877 5 volts, 8874 6.3 volts, 3CX800 13.5 volts. Ma
Hi Ken, I don't know that exact switch well but probably big enough to be possible that you can drill out the rivet then replace the contacts with some from an otherwise unsuitable wafer, think that'
I read also that the K4 internal PA will also support pre-distortion at some point. Now being a software radio and being Elecraft it might not have this on first shipment but being a software radio a
I have 2 Henry 2K Classic amplifiers and in both of them the tube filaments are most certainly in parallel. A Dark tube, noted on both, was caused by slight loosening of the filament grips in the soc
If the amp was stored in damp conditions it is possible that moisture may be the culprit. You could try baking the choke in a low oven for a good period of time (?). That would be sure to expel any m
Except when they dont. Case in point, 3 tube Alpha 78, and probably 76 or similar rf decks, where you want real all band coverage. The Ameritron choke is naturally self resonant around 11 point somet
Carl, Did you notice any effect on 10MHz. When I put an Ameritron choke in my 78, which I agree fits just fine, it was okay but went bang on 10Mhz. Had I the time then I would have investigated movin
Hi, Yes, understood it is 200 watts in US, here it is 1kW for advanced licence with high power permit hence the interest. I wonder if anyone has done any work on a suitable choke for true 160-10 oper
Dennis, I have here two of this exact amplifier, actually the export model but I believe transformer differences aside they are the same. I agree the blower is indeed quite noisy, though airflow I fi
I think it might fit, just about, There is about 73mm clearance from the tops of the 8874's to the cabinet of the 78. The 8877 measures about 43mm taller than the tiny 8874. so there would still be a
The third option of course is homebrew. If you are in a position to be home building a 3CX3000A7 amplifier I would not think this to be a major hurdle and of course there is much info available on th