Heathkit SB-220

[paws264]

To Goldengohper in my best "Kung-Fu Master's Voice"

"Grasshopper", many many summers ago, when people wore pajamas and lived life slow, there were no BIG tubes that put out 5 to 10 thousand watts available to us.

we had to use 4-65's and 4-125's. We also use a new tube called 4x150 (you know it now as the much improved 4CX250 family) long before the 4-400 / 3-500 Z came out. These are the 60's and 70's that I am talking about.

We finally got ahold of some 3-1000's and were able to move away from the multiple tube amplifiers and, surplus 8874 and 8877's became available, this is the late 80's

Now a days, if you can afford it, you buy yourself one or two big tubes and be done with it.

I know that you really don't give a shat about the history of Homebrew Amps but, you have to be aware of why those multi-tube jobs are still around and being supported.

.

 

[Bassbug]

Just out of curiosity. For higher wattage output instead of using the five or six 3-500Z tubes what kind of modern tube would put out 10.000 watts? :Wavey

 

[kswitchdr]

Just out of curiosity. For higher wattage output instead of using the five or six 3-500Z tubes what kind of modern tube would put out 10.000 watts? :Wavey

3cx3000a7,3cx6000a7,4cx10000,4cx15000

 

[kswitchdr]

Just out of curiosity. For higher wattage output instead of using the five or six 3-500Z tubes what kind of modern tube would put out 10.000 watts? :Wavey

3cx3000a7,3cx6000a7,4cx10000,4cx15000

 

[Bassbug]

Thanks, kswitchdr for the info.

 

[paws264]

To Goldengohper in my best "Kung-Fu Master's Voice"

"Grasshopper", many many summers ago, when people wore pajamas and lived life slow, there were no BIG tubes that put out 5 to 10 thousand watts available to us.

we had to use 4-65's and 4-125's. We also use a new tube called 4x150 (you know it now as the much improved 4CX250 family) long before the 4-400 / 3-500 Z came out. These are the 60's and 70's that I am talking about.

We finally got ahold of some 3-1000's and were able to move away from the multiple tube amplifiers and, surplus 8874 and 8877's became available, this is the late 80's

Now a days, if you can afford it, you buy yourself one or two big tubes and be done with it.

I know that you really don't give a shat about the history of Homebrew Amps but, you have to be aware of why those multi-tube jobs are still around and being supported.

.

Paws I agree with you about the days of old...just mentioning 5 in parallel tough to balance each tube for output. Was I right about the blown up tube?

Actually, the fourth tube from the top (the one closest to the plate choke) had the top of neck of the tube blown apart. I think that the inside lookings of the bottom tube was an optical illusion, I have more pictures around somewhere.

On a multiple tube amp with directly heated cathodes, balancing RF feed input is just a matter of luck; because tubes are a voltage amplifing devices and the imputs are in parallel, all tubes SHOULD get the same feed, if you are lucky. Does that mean all tubes will put out equally, only individual cathode current reading could tell.

I built a six tube 4CX-250B amp that was cathode driven (indirectly heated), in order to balance the operation of the tubes, each cathode return had a normally-closed female phono jack that I used to monitor the individual tube currents. I had a built-in Zero to 1000 milliamp meter with a male plug.

I had a controllable bias supply to the control grid of each tube which, I used to control the plate/cathode current. Ran like a dream.

Totally off topic, well not really:

Anyone every seen an Anderson Golden Falcon with 8908 Tubes? It's got 1 X 3 X 6 and is doing 1600 on my 43P.

 

[CDX-007]

125w in, to ONE 4-1000A @ 7kv = 3500w pep OUT!

...and it glows

 

[North Texas Mudduck]

bass bug give me an email
i send you some pics and just maybe have a 3 tuber or 5 tuber laying around
warwagon555@yahoo.com

 

[Toll_Free]

Just out of curiosity. For higher wattage output instead of using the five or six 3-500Z tubes what kind of modern tube would put out 10.000 watts? :Wavey

3cx3000a7,3cx6000a7,4cx10000,4cx15000

A 3CX4500 would do what your asking, and to it for years.

A 3000 tube will do 8 to 10 grand.

My 4CX5000R box does 22 grand. It's rated at 6000 watts dissipation. This is fresh-tube. I run 180 watts into it, and get near 18 grand out. 4 watt CB gets me *gulp* 400 of the most cleanest watts around.

--Toll_Free

 

[Toll_Free]

Anyone every seen an Anderson Golden Falcon with 8908 Tubes? It's got 1 X 3 X 6 and is doing 1600 on my 43P.[/color]

I did a couple mod's to them at Cat Dillon's YEARS ago. I can't say that he didn't do any like that, but we did a few up there.... Wow.

--Toll_Free

 

[Toll_Free]

Yup, that was a picture of it on the way in the door, like Nomad said, consideration has to be given to the heat dissapation thru the socket connections expecially when you are dealing with 90 amps at 5.0 volts (that's 450 watts of heat just to light the tubes!).

The heat generated is because of the finger stock used, and the inherent resistance from the pin's of the tube and the fingerstock itself.

Want to see your tube socket temp drop? Solder the fils connections, instead of using the silver to make the connection.

--Toll_Free