I bought a Kalamazoo model 2 off Craig list. Seller said it needed work. That was an understatement. The 47 k resistor off the input jack was broken. No problem there. Soldered it back on. The multicap was removed. Three caps were soldered in its place, a 10uf, 10uf , 450v each and a 22 uf 500v. I didnt have a 20 which is spec but I had a 22, I doubt it will make much difference. The chassis was covered in dust. I believe that this amp came from a dumpster. When I took it out of the box, the cabinet virtually disintegrated. The top came right off and the sides broke. The speaker baffle was separated from the frame. The speaker itself I discovered was missing the dust cap. I don't know if the speaker works or not. After using alcohol, vinegar, and nail polish remover, I managed to get most of the dust off. Then I hit it with some electrical component cleaner. Now it looks shiny new.
I hooked up another speaker. There was little to no hum. I think once I get the grounded power cord on there it will improve more.
Since I never played a zoo until tonight, I wasnt sure about whether the tremolo was working, it appears to be a very subtle control. I did notice that the frequency appeared to oscillate when I was not playing. I assume it works somewhat. I did not replace the tremolo cap 10uf 25 v.
Can anyone tell me about what to expect on the tremolo sound and how prevalent the sound is. Also, should I swap out this tremolo cap.
Can anyone also recommend a speaker.
I noticed that the zoo sounds a little like a champ but less airy and basey. The sound was pleasing.
Last Edited by blueswannabe on Apr 03, 2013 3:56 PM
hi - You're lucky that resistor broke (should be 4.7K, not 47K?) - usually repeated stress from front panel flex transfers through the resistor and breaks the solder lug from the tube socket. Then you have to replace the socket which is a lot more work!
The 10uF cap in the tremelo circuit usually deteriorates and the tremelo effect will weaken. A good sign of this is that when you turn the tremelo knob up to higher frequency it will die all together. Replace that cap and it should recover to full depth. Occasionally one of the 3 orange drop caps in the circuit will go bad but that is very, very rare. ---------- /Greg
Hi Greg, thanks for reply. The broken resistor was R1 (yellow purple orange). I was surprised the tube pin did not break first becasue the resitor wire is pretty stiff. To repair, all I did was take some wire from another reistor and used it to sister the two together with solder.
I'm gonna swap out that tremolo cap as it does appear to be weak to my ears and your description.
With regards to the 20uf 450 cap. I used 22uf 450 as that was what I had available. I know your big on keeping it spec. Do you think that will cause a discernibale difference?
I was able to test the speaker and it does work, it just needs a dust cap and maybe some rubber cement to touch up two barely perciptible pin holes in the cone. I have touched up some 1955 Jensen P10R's this way with good result. Although those had more prominent tears. The zoo speaker voice coil which appears to be made of aluminum has a slight tear. I was thinking of either leaving it alone or hitting it with a dab of silicon sealant. DOes anybody know if I shoudl do anything?
I can't answer that because the zoo is new to me. I was expecting a more pronounced change in the tone. But again, I don't know if it's the trem cap that needs replacement ( which I will do anyway based upon what I have read and Greg's comment), nor do I know how the trem is supposed to sound. I know it oscillates the signal. It seems similar to a reverb in theory. But I could be wrong on both counts. I would defer to some die hard zoo users.
I use my tremelo for certain applications. Like if I'm covering an organ part in a song, or trying to add an ethereal tone to something. What I've found is the MOST fun application however, is bringing up the volume on my amp and mic, setting the tone at its lowest, and then moving my mic around in front of the speaker. Changing the angle of the mic face in relation to the speaker can produce a theremin-like sound with the oscilated feedback. :-)
@blueswannabe
You asked for a recommendation on a speaker? My first response would be an Eminence Lil Buddy. But if you want to get as close as possible to the original speaker's sound, I'd try a Weber Signature Alnico. ----------
Hawkeye Kane
Last Edited by HawkeyeKane on Apr 03, 2013 2:28 PM
Wow, had time to play the zoo without a cabinet. All I can say its dam good harp amp. Tremolo works. Nice little Leslie type effect. Quiet at idle and plenty loud.
I think the speaker is on the way out, can anyone suggest a close sounding substitute.
Last Edited by blueswannabe on Apr 03, 2013 6:11 PM
Sorry, I meant to respond last night, but I was doing it on my phone, and I had to jump to my fatherly responsibilities.
Glad to hear your trem works. Last night I was gonna answer you by saying that tremolo intensity/depth can vary from Zoo to Zoo. The speed is pretty much the same on all of them. But Greg will even tell you that Model Two's can have subtle differences to their trem depth.
My usual settings if I'm using the Zoo by itself are: Volume 7 or 8, Tremolo off, Tone between 1 and 4, and I adjust for tonal differences between different songs. When I run the line out and use my Alamo along with it, Volume goes to 5 on both amps, bass and treb are zeroed out on the Alamo, and the Tone on the Zoo still gets adjusted accordingly.
In terms of the speaker, I would still say a Weber alnico of some kind will get you closest to the original CTS's sound. ----------
Great amp. Cheaply made but well conceived. I'm not crazy about EL84 typically. I have an epivalve junior that makes a slight ringing sound. The tube is good, it must be the design or circuit or transformers, who knows. The zoo outperforms the epi and there is no ringing to my ears.
Also, I noticed that it is feedback resistant. Another plus.
Now have to build a pine cab with plywood baffle since the old cab and baffle are crumbling. I'm sure the tone will continue to improve with the cab.
I had the same problem with my Zoo cab. Let's face it, particle board that's pushing 50 years old is very liable to be falling apart depending on the amp's history of treatment. I built my own new cab from scratch out of solid red oak. The resonance the oak gives it is pretty noticable now. I like it a lot.
----------
Hawkeye Kane
Last Edited by HawkeyeKane on Apr 04, 2013 12:13 PM
Like the redwood cab. The person who is going to help me build the cab suggested thin plywood like 3/8 It's 3 sheets sandwiched together). I said no because I wasn't sure about resonance. He was thinking to maintain it's lightweight characteristics. I suggested pine for classic design and resonance.
@Greg, thanks for info on cap. I will say this I should have taken your advice early on for amp selection - like 4 years ago.. ALso, any suggestions on a speaker that is a good substitute for the zoo speaker that maintains the same quality sound. Would you agree with one of the following alnico speakers from Weber, the signature series 10 (smooth cone), the signature series 10S (ribbed cone), or the vintage series 10A125-O (smooth cone). Which of these get me closest to the original speaker. I was thinking the Sig Series 10. Does anyone know. Thanks.
Last Edited by blueswannabe on Apr 04, 2013 2:41 PM
bloozefish asked about folks using the trem on a 'zoo2. I don't use mine, nor on my other amps with trem. The few times I've tried it, I felt that I wanted to directly control any pulsing effect in real time with my own vibrato. The mechanical felt like I was "locked in" to a certain pulse rate. On the other hand, I do like the theramin idea! I'll have to try that!
(Oh, and be careful about speaker size in the little 'zoo -- I can't recall details but I know I had trouble with some big 10" -- can't recall now if it was the depth or other parts in the way -- so that observation was very little help to you!!)
Last Edited by TetonJohn on Apr 04, 2013 3:18 PM
Pine should work well...or birch. I used oak for the durability since I use the amp a lot. The red color actually comes from the stain I used. Here's what it looked like before the stain.
Right now, the only bits of the original cabinet still on the amp are the feet and the back panels. The handle is actually a leather Ampeg model I got from Mojotone. Makes it a lot easier to grab than the original vinyl strap.
I know there was a cat on eBay who was selling pre-made birch cabinets for M1's and M2's, but I can't find him now. Are you gonna build your cab to the original cab specs or put your own spin on it? I've even seen a couple Zoos rebuilt into 2X10 cabs before.
@Teton
What kind of mic do you use with your Zoo? I should probably tell you that the only mic I've made the theremin effect with is my Peavey Cherry Bomb. So if you're using some kind of similar bullet with a roughly similar element design, it should work the same way as mine does. But if you're using a crystal/ceramic bullet, or a stick or vocal mic, it might be a different ballgame.
----------
Hawkeye Kane
Last Edited by HawkeyeKane on Apr 05, 2013 7:03 AM
I was thinking to make the cabinet about 1-2 inches taller to allow for more speaker choices and better clearance. I will keep everything else the same. Gonna try to tolex it myself and new grill cloth.
What peakers do you guys have in there?
Last Edited by blueswannabe on Apr 05, 2013 9:24 AM
I love my Zoo, have the original cts in it. The previous owner bought a Weber SIG 10F but never tried it and sent it with the amp. I'm curious so I tried it after five minutes I put the original speaker back in because it was to dark for my taste. The speaker performed exactly as descripted on the weber site. ---------- Violence is the last refuge of the incompetent. Isaac Asimov
I also still have my original CTS in mine. I also have a Lil Buddy that I've tried in it a couple times. I like the sound it produces too, but as it's been established in this thread by more than one person, the original CTS 10's of Zoos are a major factor in their distinctive sound.
One other thought I had for a different speaker choice....God, I can't believe I'm actually gonna say this....since CTS speakers were rather inexpensively made back in the day, perhaps a Jensen P10R, P10Q, or Jet Blackbird would be a close present day comparison. Jensen speakers today ARE NOT Jensen speakers from 40 years ago after all. Greg, have you ever seen or heard a Zoo with a Jensen reissue in it? Can you comment on it?
HK asked what mike I use w/'Zoo. Last time, it was a Greg H. w/Brush crystal! -- full on Greg H. kit!! So, I did just try the "theramin" thing (with a current production GB) -- yeah, fun -- a bit hard to control, but with some practice who knows!? Thanks for the tip -- will drive my wife crazy!
I have a Zoo-2 clone built (very well) by our own MJ, and it has one of the newer made-in-Italy Jensen P10Rs. I've been meaning to get around to replacing it with a Weber Sig 10 or 10A125-O, but I've noticed something lately...
That Jensen is starting to sound really good after a looong break-in time. I'm quite surprised and really pleased at how it's now sounding.
