Improvements to Kalamazoo Model-1???

[JohnnyCrash]

I'm going to build a Kalamazoo Model-1.

Any thoughts on improvements to this tiny little circuit?

Here's the schematic:







I notice there are NO cathode bypass caps on the 12AX7 or the EL84... the voltage is also pretty low... interesting.

[Frankie]

Originally Posted by JohnnyCrash

I'm going to build a Kalamazoo Model-1.
Any thoughts on improvements to this tiny little circuit?

Cool project.. On mine all I do is turn it up all the way, put a mic just of center of the speaker, hit the record button and have at it.

Of course that is not counting slapping it on the top to make the buzz go away, after you first turn it on.

[zombywoof]

I own a Kalamazoo 2 but am a total idiot when it comes to mods. I did, however, find quite a bit of info on the Kalamazoo Amp Field Guide dealing with tone control upgrades, adding cathode resisitor bypass caps and the like. Once you get rid of the original plug and reduce the hum, these are sweet little amps. That CTS speaker, however, has got to go.

[JohnnyCrash]

I'm building this from scratch - no rebuild or vintage repair :)

[JohnnyCrash]

Well, I ordered all of the parts except for a few here or there...

I'd guess I'll have em here by Tuesday.

I'm thinking bypass caps may be the way to go, but I am curious to hear how it all will sound without them - no bypass caps mean less gain per stage and more output impedance to the next stage.

Any real amp gurus have any thoughts on making a few improvements to this circuit? I'm going to try the original's 1k dropping resistor at R12 (the schem shows a 2.2k).

[jjmantele]

Cathode caps could also be used to increase high end if needed. I use a 0.1 on my "Champo" to do that. More gain too. You could replace the 330K on the output grid with a pot wired as a master. A 250K (audio) and a ~80k resistor could be combined for a master that would have zero affect when maxed. I wonder if 1.5Ks on the preamp cathodes would be "more appropriate?" Especially if cathode(s) will be bypassed with caps.

[mr_hankey]

Aside from a three prong power cord, I think you should just follow the schematic, and then do mods if you're not happy with the way it sounds.

[JohnnyCrash]

Originally Posted by mr_hankey

Aside from a three prong power cord, I think you should just follow the schematic, and then do mods if you're not happy with the way it sounds.

Thats exactly what I'm gonna do!

I'll see how it sounds first, then I'll go from there.

[eyema_believer]

I own a Kalmazoo One. My buddy has had it for a year trying this and that. I think he even went as far as to try different trannys. I know that the last time I talked to him about it, he was mighty thrilled with something he had stumbled on. I shall ask him, and if there is anything exciting, I shall forward that to you.

Peace!

~Shawn

[Jaybird]

I have built a couple of Kalamazoo model 2's from scratch.
http://home.earthlink.net/~olsjm/amps4me/
I would add a line out. This is one fine harp amp. I have heard some guitar through it also and it is pretty cool. If you plan on making the same type of chassis as the origional, you will find that the flex that happens when plugging in can be a problem. I have figured out a way to stop that in the way the cassis is secured to the cabinet. I am sure you will enjoy the amp.

[Tim Swartz]

I've owned and modded several. 220k plate resistor if you want more honk & grind. Cathode bypass caps on preamp and/or output will help juice it up too. But start stock so you have a reference point.

[JohnnyCrash]

Originally Posted by Tim Swartz

I've owned and modded several. 220k plate resistor if you want more honk & grind. Cathode bypass caps on preamp and/or output will help juice it up too. But start stock so you have a reference point.

I'm saving the 220k plate resistors for my Gibson GA-5 build :)

Both will be in tweed Champ chassis and in 1x10" tweed Champ cabinets with a Jensen Neo 10-100 speaker for each. Both will have the same OT iron - Heyboers (the Epi VJr "upgrade OTs" Turretboards.com sells).

I'm definitely just starting stock at first - I may keep them both stock.

[Wally]

Good choice for a build, Johnny. My thought when I plug into a MD. 1 or Md 2 Kalamazoo is 'what's not to like?' I'm sure you will have fun. Let us know what you find with the stock build and what you decide to change...and the results of those changes, please.

[JohnnyCrash]

Originally Posted by Wally

Good choice for a build, Johnny. My thought when I plug into a MD. 1 or Md 2 Kalamazoo is 'what's not to like?' I'm sure you will have fun. Let us know what you find with the stock build and what you decide to change...and the results of those changes, please.

How would you characterise the sound of a Kalamazoo Model-1?

I've never even heard one yet :)

[Wally]

JC, I have only my Md. 2 to compare to a '70 Champ right now. The Md. 1 and 2 are much the same sound. That is a sound that is a bit smoother distorting amp with more compression than that Champ. the Kalamazoo also is more like a Tweed Fender in that it lives in the midrange. The '70 has a bigger bottom end even though the Kalamazoo runs a 10". My Md. 2 is more similar to my '49 Deluxe...just not as big, right? Midrangey singing when pushed...veery thick and harmonically rich. My '57 5F1 has been gone for awhile. I miss her. I remember her sound being more midrangey than the '70 Champ, also. this '70 Champ is hot and rips really well. IT doesn't quite have a comparable amount of compression. The '70 Champ sparkles more than the Md. 2 or the tweed Fenders, to my ear.
The Kalamazoo is understandably very responsive to dynamics, but it never cleans up like the '70 Champ does ...or does so at a much lower volume. The
'70 Champ does a better job of providing and defining the highs and lows. It is a bit more articulate than the Md. 2 or the tweed to my ear.
Thanks for asking. I came back to the shop to work. Instead, I play a freshly set-up Les Paul through 3 nice tube amps just so I can try to explain what my old ears hear and my challenged memory banks can recall. THere goes 30 minutes! hehehehe I love to break a sweat on a guitar while wondering what I am hearing??? By the way, I do remember that when I had my '57 5F1, I liked to chain it to the Kalamazoo. Nice blend of 8" and 10" and the 6V6 with the 6BQ5.

[JohnnyCrash]

Cool...

I can't wait to get this thing built!

[Wally]

Crashmazoo.....