[Amps] home brew amp

[Charles Farr]

My Dad, built several amplifiers, one was a pair of 813s. During his 
career in the Air Force, he belonged to MARS, and a lot of parts came 
through that system. My brother, W6IJ, and I spent a lot of our time at 
the Travis AFB MARS station. We cut our ham radio teeth there. Learned 
the code, basic electronics. Ham radio became the "thing" that us boys 
did together.

I remember coming home from overseas and seeing the 813 amplifier. It 
was UGLY, a real hodge-podge of repurposed former military cabinetry. It 
was reasonably safe, but the power supply was another thing. He had it 
under the table and the components were exposed. The bleeder resistor 
was exposed on top of the power supply where if you weren't careful, you 
could get your feet in a perilous situation.

I couldn't stand for that and while I was home on leave I built a cover 
for the power supply. Dad just couldn't see the need for it. His premise 
was that he was the only operator, knew the power supply was there and 
so he didn't think it was a big deal.

That amp worked very well, and offered switchable biasing for AB2 and C 
class. Dad, WQ6H, loved CW, so it HAD to have class C capability.

That amp/power supply had a 115 VAC transformer in it, so it dimmed the 
lights throughout the house when he keyed it. Luckily, our nearest 
neighbors were about a 1/4 mile away. Nonetheless, I'm pretty sure they 
all knew when Dad was on the air. TV was unwatchable  in our house when 
the rig was operation.

These days, we're pretty spoiled by advances in technology, both in ham 
radio and in TV. The advent of cable and satellite has made the 
likelyhood of interference much less of a problem.

Chuck, W6AJW




On 01/13/2017 11:42 PM, Fuqua, Bill L wrote:
>    As a teenager I too built unshielded amplifiers.
> I just wanted to get results and then do something else.
> I got my general in 1962 or 63. don't recall.
>   My first HB rig was a 6AG7,6L6 and pair of 6146Bs on CW. I then went to SSB with a CE 10A which drove my
> 6146Bs, and later I made a amp with a pair of 813's and then went to a pair of grounded grid 250th tubes.
> The HB transmitter was shielded but the amps were not.
> 73
> Bill wa4lav
>
> ________________________________________
> From: Amps [amps-bounces at contesting.com] on behalf of Russ Williams via Amps [amps at contesting.com]
> Sent: Friday, January 13, 2017 10:36 PM
> To: Arnie Pfingst; amps at contesting.com
> Subject: Re: [Amps] home brew amp
>
> Arnie,  thank you for posting this.  I am glad to hear there were others whose audio came into the neighbors stereos and scrambled TV reception.  I didn't have the opportunity to become a ham during my school years, so I went the CB route and built 11 meter sweep tube amplifiers from my high school junior year, 1973 and forward, finally getting my novice ticket in 1985.  I am still building today and play with regens and am sorting out a 4-400A 6 meter amp I built a few years ago.73,RussKW6T
>
>
>        From: Arnie Pfingst <arnie123 at hotmail.com>
>   To: "amps at contesting.com" <amps at contesting.com>
>   Sent: Friday, January 13, 2017 3:13 PM
>   Subject: [Amps] home brew amp
>
>
>
> I've been reading about how several people on here built an amp and how it works or doesn't work
> I had my General Lic. before I graduated H.S (1972). I thought I was good with electronic design and knew everything about building stuff.
>
> My station was all, Heathkit SB 300 receiver, SB 401 transmitter, SB 600 speaker, monitor scope, antenna tuner, EV desk mic, and phone patch.
>
> Not bad for a kid just out of High School. I thought the only thing missing was an amplifier. My dad suggested I build one, (he worked CW in the spark gap days his call was 9ccj)
>
> so I did.
>
> I found a pair of new 813 tubes on the old 40 meter swap net, and scrounged all of the the parts needed for a separate power supply that sat on the floor.
>
> When it was done, I think it put out about 500 watts into a wire. I got my WAS and WATV in one weekend!!! (worked all stereos, and worked all TV) I was proud of my accomplishment,
>
> it all worked. Shielding? i didn't have money for that so the tubes just sat on top on the chassis directly in front of a small blower. My dad was ready to
>
> kick my ass for doing this after he had words with most of the neighbors. My point is to encourage people to continue building and TRYING things.
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