KRIS BOOMER amplifier

[unit_399]

I've been wanting to run a tube amp and have the opportunity to buy a KRIS BOOMER Amplifier from a seller in Colombia. I downloaded the manual. Single 6JG6 driving three 6LQ6. The unit works, and is in good condition, but the seller lives over 700 kilometers round trip from our farm.

I don't have a lot of experience with KRIS amps and need some advice. Are these good amps quality-wise ?? It's box stock, so other than replacing the electrolytics what else might it need ??I have plenty of NOS Sylvania tubes. The price is right, but I don't want to drive all that way for an amp that is so-so quality and performance-wise.
Anyone got experience with these ??

- 399

 

[nomadradio]

Anyone got experience with these ??

Build quality is not bad. At least this model has a 12-Volt relay with a transistor to key it. Tube-type keying circuits are an abomination.

Input is not tuned. You'll want to remedy that. Also, has zero grid bias. You will definitely want to remedy that. We found that turning the carrier down enough to sound good will make the tubes run hot with zero bias. Turning the carrier high enough to fix that will just sound wrong.

A minimal design, contains not one part that doesn't serve to tickle the wattmeter.

I would classify it as a good starting point, but not a polished end product.

73

 

[Dmans]

Unit_399,
This thread is a very similar chassis to the 1 driving 3 you are contemplating. It might be good information to look at-might not.

https://www.worldwidedx.com/threads/kris-600-ssb-new-project.235284/#post-645134

73
David

 

[loosecannon]

Hi 399,

here is a link to my kris power pump project that you helped me with a few years ago.

the schematic i drew shows it modified to eliminate the driver tube, and with bias and the tuned input added. those were done with Nomad's help.

https://www.worldwidedx.com/threads/kris-power-pump-upgrade-restoration.183792/

hope these pics help give you some ideas as i imagine your amp is similar.
LC

 

[unit_399]

Thanks, guys. Just the kind of info I was looking for. Looks like Luz and I will be taking a long drive this weekend. The guy that has the amp bought it new in the States decades ago with plans to run it here. But he couldn't pass the license test and is afraid to bootleg. Government is tough on pirate stations because of the drug situation. So it has really never been used too much at all. He has some other cb stuff I want to check out too. Thanks again. 73s.

- 399

 

[Dmans]

Unit_399,
I hope it pans out for you!

73
David

 

[nomadradio]

Next time I'm at the shop I should see what notes I took from the last "straight 3" conversion we did. For that matter, I remember taking the fourth tube socket and simply wiring it in parallel with the 3 final sockets to make a straight 4. Might not have been this model, but there should be notes about component values for a tuned-input PI or L network. Might even find some pics.

73

 

[Pioneer621]

Were there a couple versions of the Boomer? I have one that looks like the one in post #1, but it only has two tubes, just an empty hole where a third socket looks to have never been installed. Uses a pair of 6JU6 output tubes. Got this one for $20 years ago at a local hamfest from a fellow CBer that happened to be there. Needed caps, but otherwise wasn't too bad for the price.

 

[Dmans]

Kris did have a couple different versions.
A "Boomer"-2 tube A/C, a "Boomer" 12v 2 tube, two different versions of the "Big Boomer" 1 driving 3, a "600SSB" 1 driving 3, a "Power Pump" 1 driving 2, "Mach 3B" "Mach 3 Plus 3" and there may be others.

73
David

 

[Pioneer621]

I didn’t know about the 12v version, but am familiar with the Big Boomer and others. Guess I was just wondering if they had a few revisions of the same model name like the D&A amps. Like a 2 tube Boomer, then a 3 tube Boomer with a driver, etc, but still just the Boomer name. I have only seen the 2 tube and the schematic I was familiar with was 2 tube only. Unit_399 stated it was a 3 tube with a driver and after I thought about it I actually wasn’t sure if Kris had a few versions of the same model. I know the Big Boomer was similar, as was others, but technically different model names. I had presumed the one pictured in the OP was just a 2 tube, but peaked my curiosity, none of this adds much to the thread other than me being curious.

 

[Dmans]

More info here.
http://www.cbtricks.com/Amp/kris/index.htm

73
David

 

[nomadradio]

Found some pics of a Mach 3+3 amplifier this brand. Shows the new bias wiring under the chassis, but not much else. No written notes in the archives here.

73