开云体育

Mine went from Hammond to DigiKey and then was shipped to me.

Well, that's no surprise. Don't run any more than 30% of maximum power in FT8 mode. That goes for radios and amplifiers. Stick to that and you'll never have a problem. 73, Alek VK6APK.

I just read through the entire manual. https://www.alpharfsystems.com/wp-content/uploads/2016/05/Alpha_78_Operating_and_Technical_Manual.pdf On data modes, like FT-8, that amplifier HAS to be

FT8 is a 100% duty cycle mode and at some point depending on wire size and physical size of the toroid it will at some point overheat. ?It it overheats too much the permeability of the core itself

Hi, Last week my Alpha 78 stopped working. I found the windings of the L5 was burned. I rewinded the toroid with new wires. Now, it is working. I checked the temperature after transmitting on 80

DigiKey sells the Hammond transformers, but does not stock them. They are ordered through DigiKey, and then shipped direct from Hammond. First, you look up the listing of Peter Dahl transformers:

Agree 100% Jim. I've got some nice little 3-amp FWB rectifiers. I'll toss the single diode and stick an FWB in, along with a fresh cap. -- 73, ~Alan

It's two boards. One for control & the other for bias voltages. http://www.ifwtech.co.uk/g3sek/

Are there more than one set of boards: i.e., are you selling multiple sets of boards for multiple amplifiers?? Or is this just one amplifier-set of boards? TNX, Steve K0XP

Boards are 95% assembled and configured for 4-250A tubes. If you plan on using different tetrode tubes, you'll need to do the math outlined in the printed manual I'm including. Includes R14 wire-wound

I bought one last year from? them,10 week wait and total cost was about 1K.? ?? 73s Bob W5RG

How do you find the Peter Dahl transformer listings on Digi Key? Or any US seller? Trying to find the price to decide on a tube switch for an Alpha 76PA 3-tube amp. 73, Dave, w6de Sent: 1 March,

I would toss the 1/2 wave rectifier......and replace it with a FWB.? ? Then bond the negative to the chassis.? ?A 1/2 wave rectifier is abt the stupidest thing I have ever seen.? You end up with

That’s true, once you bias the cathode instead of the grid you no longer need a negative voltage. Lou Sent from the all new AOL app for iOS

Hi Louis, Thanks for the reply.? As I said, I can't see where the polarity change would create any problem, and sounds like you've had the same experience. Appreciate the info! -- 73, ~Alan

Alan, lately that’s all I do with the FL2100 and SB200 amps. ?I do solid grounded grids on both. ?Change to cathode bias doing away with those awful grid resistors . ?I change to a low v current

Yessir!? Hammond Mfg. and DigiKey are great resources. I've ordered a couple of their Peter Dahl transformers, and they make a first-rate product! Pricing was fair enough, and they shipped

Howdy Folks, A quick question (and maybe a stupid question... but): Can anyone see any issues in reversing the polarity on the key-line circuit (from "positive ground" to "negative ground") on the

Here, some updates. This is the beginnings of the elaborate chain drive assy. 2 x more chains, yet to be installed, plus tensioner's....( for the vac tune + load caps). Note on the big model 90

What does it say on the SN on the dahl / Hammond xfmrs ??? ? Dahl / Hammond told me that it is NOT a SN, but the actual date code. I bought 2 of the dahl FWB rectifier assy's....just when dahl