Kalamazoo model 2 or Vox ac4, which to build?

[Dennis Perusse]

Hello,


Hey quick one for you. I'm almost done with building a firefly amp and I'm just getting the feelers for the next project. Now their are two amps I'd like to build but not sure which one to do. Since I don't have the funds to do both at the same time I'm gladly putting this decision up to everyone to help me along here. So do I build a Kalamazoo Model 2 or do I go about and build a Vox ac-4?

For those who remember my thread a while back I took the Kalamazoo model 2 schematic and did a layout of it as well as did some small changes to it. So if I were to build that I'd do it in that manner with all of my ideas for updates to the original circuit. But after seeing Andyfromdenver's vox ac-4 build from a dead pathfinder amp I realize that I like that amp too. Both are a challenge for me as I've now only build two tube amps. With the Kzoo model 2 amp I'd be able to get a decent build thread going since no one has built this type of amp with a turret board. Plus I'd be able to get my brother to give me a hand with the cabinet as he's good with woodworking so I'd be a fun family project.


But with the vox ac-4 build it would be in a territory that I'd never been before. Where I've built a champ amp and now the firefly amp I've noticed that vox's are a different kind of beast. Plus having to research the vox ac-4 as I want to know as much as humanly possible about the amp so I can be somewhat faithful to the circuit too.
So let me know your opinions on this matter as either one would be fun to do.


Dennis

[andyfromdenver]

Hey D :)
I'd be jazzed if you built an ac4 and used a different OT than the Mercury Mag, so we can compare differences. I'd be glad to chime (vox joke) in and help if you get stuck. I noticed a couple British options:
http://livinginthepast-audioweb.co.u...p=xfrmrclassic
re: the OT, they mention the small size of the original copy and suggest as an option, a larger suitable replacement. Could be really cool!

Sounds like you've already put lots of effort into the Kalamazoo though...

[Dennis Perusse]

Andy,


True I have put some effort in the Kzoo model 2 but the interesting part is is that I don't know if my layout would work. That's one of the reasons why I'd love to attempt the Zoo 2 over the AC-4. My brother also has in his tube stash a Nos ef86 tube which I know I could have if I attempt the AC-4 project. Both amps offer a lot of promise in terms of being built. The Kalamazoo model 2 amp since their are those on this list who mentioned that they'd like to see a modernization of it. I know that Robster wanted to do a model 2 and was very encouraging in what I was attempting. Also Greg Heumann from Blows Me Away Productions expressed an interest should I get around to building one as he rebuilds/restores them for sale.

Then their is the AC-4. I've been a big fan of the Beatles and have always enjoyed the sound of a vox. Hearing the song Taxman off of Revolver and you can hear that british bite that the vox has. And after seeing your version of it from the bones of the Pathfinder amp I really am interested in building one. Especially since your version of the layout would be cool to look at building off of a schematic is very hard for me at this point and time. One site to look at in terms of vox repairs is this place.

http://www.chambonino.com/work/vox/vox16.html

This guy is an amp repairman in England who does some amazing work. A definite site to look at for those wanting to learn more about various amp repairs. Check it out. :-)

But like I mentioned before...decisions, decisions...and I need more input before I start anything. Heck I still have to finish up my firefly amp first. ;-)

Dennis

[drf64]

I've built a Kalamazoo Model 2 and liked it. I had to experiment with the values of the trem caps and I never did get to a range of speed that I liked, but the amp otherwise was very nice. I never did anything more than just get the chassis complete. IIRC I used a 5E3 eyelet board.

Good luck. I think you'll like either one.

dan

[Dennis Perusse]

Dan,


Do you have any pictures of the eyelet board for that amp. I'd love to see that.


Dennis

[hackworth1]

That Kalamazoo Schematic looks like fun. I vote for Kalamazoo.

http://music-electronics-forum.com/a...oom2schem.jpeg

[drf64]

Originally Posted by Dennis Perusse

Dan,


Do you have any pictures of the eyelet board for that amp. I'd love to see that.


Dennis

I will check if I have any. I have moved since I built it a few years ago and it's still in a box some where. If I can't find any pics I'll try to find it and snap a few. It is a nice little amp that breaks up at low volume.

I also exchanged emails with the guy who who has posted a lot of Kalamazoo amp info. I don't recall his name but he's a great guy. I told him I was actually thinking about naming the amp and taking pics, but since he had posted the schematics I wanted his permission to link to his site, give him credit, etc. He was pretty happy about all of that. Alas, I built the amp but never got it in a cab. And then I got away frome amp building and took up farming. Life is an adventure.

dan

[Lunchie]

Although im a fan of vox, i actually dislike the AC4, so i would say the Kali

[Dennis Perusse]

Okay then, the Zoo model 2 it is. I've already secured an actual Kalamazoo model 2 chassis so that'll be coming to me soon. My goals then are to do these things;

1. To do a modern take on the Kalamazoo Model 2
2. To use a turret board instead of True Point to Point wiring.
3. To also show my steps so others can build one if they like it. This expands not only my own knowledge but a chance to put my foot in the wet cement of how I want to do things as a project.
4. To also include my brother to help me on the cabinet. Can't think of a better family project than that. :-)
5. Also to include costs as well as a template layout for others to work from.


So when I get my firefly amp project done I'll start getting stuff together for a build list. Special thanks to everyone who has answered my questions as well as given me encouragement in this. It is very much appreciated. :-)

Dennis

ps I still plan on venturing into the land of vox-ville but I'll do that afterward. :-)

[andyfromdenver]

DP, I read the info on that link, and he prints a customer testimony about how after servicing the vox ac4 it had more "clarity" and "presence". I'm going to email him. If I can make a couple tweaks to mine to get that, it's going to be awesome!! I think the stock circuit just has a slight "blanket over the speaker"muddiness or flatness of eq thing happening that needs to be changed. Hopefully he gets back to me.
Also, if the Kalamazoo ends up being cool, I may make one too with some spare transformers that I think would be suitable.
Time to get on the build for you; better wrap up the firefly!!! :)

[Dennis Perusse]

Andy,


He might get a hold of you, or he might not. Where he lives in England and he runs some odd hours you might hear from him. I contacted him via snail mail as, at the time, he wasn't accepting any email due to his workload. I got a hold of him about one amp he built that he said he was going to post a circuit at his site. Well, he didn't get around to posting it online and yet I'm not sure if he'll send it to me via snail mail. Not sure. Give it a try, though, you might be lucky and he'll send and email to you. His sight is fascinating, especially since he rewinds his own transformers too. :-) Give it a shot, and let us know if you hear from him at all.

Dennis

ps It's gonna take me a while before I put together the zoo 2 as I'm in the process of securing an actual chassis from my friend Greg. Plus I'm gonna need to figure out my actual layout and clean it up to size it up for the amount of g-10 board that I'll need. That and where my brother is going to do the cabinet for me I gotta bug him for a few things too. But when I do the build thread will commence. :-)

[Jaybird]

I have built a few Kalamazoo clones both model 1 and model 2. I built them PTP not using an eyelet board as the original Kalamazoo is PTP. I think the tremolo on the Model 2 is fantastic. I owned an ac-4 and did not like it. Too thin for my taste. I would recommend the Kalamazoo.

[TNO]

The Model 2 is just about the best single-ended amp ever.
IMO.

Go with 30-10-10 on the filters for more headroom and better bass response.

[Robster]

I have a Kal model one at the moment I just fixed up with new caps and a Jensen speaker. If you need cabinet dimensions let me know.
Rob

[Dennis Perusse]

Hello,

Robster: Greg over at Blows Me Away Productions gave me the dimensions for the cabinet so I'm set there. I am going to have to modify them a bit since the chassis is going to have to be deeper to accommodate the g-10 board that will be going in. Most likely that'll change the dimensions of the cabinet slightly. Not so much the height or the length but the depth of the cab only. He also got for me a model 1 chassis so I have reference points for when I build this thing. :-)

TNO: I'll try those values when I get all of my parts together. Where my brother is going to make the cabinet for me it's gonna take a while. My garage is a complete disaster area right now so that's gotta get cleaned first. Plus I'm still debugging my firefly circuit and this heat that we've been having has made progress slow. :-(


Dennis