Make: Bell P/A - Model: Carillon '35'

Just got this thing..It's a tubed PA amp...

Since I'm thinking this won't be good for any mic pre stuff (guessing), I'm going the guitar amp route, (maybe)..

Haven't had very much time to fool with it, yet... Hoping for some schematics on chassis, TBD...

Here are some relevant links on the exact model or EXTREMELY similiar (little to no info for these, on the web)...

http://groups.google.com/group/alt.guitar.amps/browse_frm/thread/3b258f5e9f073bc9/e6fd6a9f411deece?lnk=st&q=6L6GC+bell&rnum=4&hl=en#e6fd6a9f411deece
"My dinosaur egg is a Bell Carillon Model 35-A 35 watt amplifier with:
2 RCA 6L6GC's
3 12AX7's (two DOA)
1 12AV6
3 HI-Z microphone inputs
1 aux phono input
4 - 8 - 16 ohm speaker connections

The front panel has 7 knobs:
Mic 1, 2 and 3
Program
Master
Bass
Treble
(I would want to add a midrange.)
The amp was mfg. by Bell P/A Products at 1209 N. Fifth St. Columbus, OH
43201 "

http://www.radioattic.com/attic.php?sellerId=38#38029

"Bell Carillon Amp
Six tube 35 watt monoblock P/A amp with two 6L6GCs, three 12AX7s and 12AV6. Rebuilt with new capacitors and fresh tubes. Very powerful with excellent treble and bass response. Nice clean case and chassis. $195.00. (0038029)"


Here's what I'll be following:
http://www.rru.com/~meo/Guitar/Amps/PA2Guitar/pa2g-notes.html
http://www.rru.com/~meo/Guitar/Amps/PA2Guitar/index.html

Here's a link to the sister thread @ homerecording.com's forum:
http://homerecording.com/bbs/showthread.php?t=201096

Pics!!!

Ugh.. No schematic

Can anyone comment on the whether it would be realistic to make this into a guitar head?

Thanks

P.S. I'm not getting any sound out of it at the moment... Still trying though..

I'd bet a dollar it'd make a great guitar amp. I actually have pursued a similar project with a 20 watt Bell PA amp that fell into my possession. It doesn't have as much high end as I'd like, but it is a loud and crunchy mofo.

Things that are probably the case: the input is probably not that well suited to a guitar, and the tone circuit is probably not that great either.

I would suggest tracing out the circuit--you don't really need to worry about the power supply, just trace the audio section. If you haven't done this before, it might help to download a few amp schemos off the internet (I think Fender has a bunch on their site now, & there are various other sources as well.)
Here's my slightly flawed schem for my Bell amp:
http://home.att.net/~giuseppe_poteet/tr_tubeschem.pdf
There's a thread about it somewhere in the archives.

The other thing about looking at other guitar amp schems is that in addition to giving you a reference for tracing the circuit, it can also show you areas where the Bell circuit might be improved.

I'm no expert on these matters, but I'm slowly learning, & maybe some of this will help.

Also, tube datasheets here:
http://www.tubedata.info/

Good luck
Tom

I have yet to relace a Bell PA but you can pretty much turn any PA amp into a guitar amp. Here is what I would do with that Bell:

1. Forget about that 12AV6. You're going to focus on the 2x 6L6's and 3x 12AX7's

2. Find a guitar amp schematic for an amp that you like that shares the same tube layout. I'd say 60's Blackface Fender or Marshall Plexi would be a good start.

3. Figure out from the stock Bell circuit where each of the wires from the transformers are going and what they are doing. You're only going to reuse the chassis, sockets and transfomers here for sure, though you may be able to recycle some of the wiring and passive parts as well. You will NOT be reusing the Electrolytic Caps or Pots. Even if they work fine now you're setting yourself up for early failure by using old parts there, though reusing the carbon comp resistors and non-lytic caps would be a good idea if possible.

4. Gut the whole thing and rewire it according to your new Fender/Marshall circuit. You can leave stuff that will be the same or similar alone if you want. If it has a circuit board lose that shit and go point to point.

5. For the input you can go 2 channel parallel like the old amps or instead use the first two stages in series (and maybe a footswitch to take the extra stage in and out of the path) ahead of the stack like new amps.

6. You have just enough pot locations already for the classic guitar amp layout of: Gain 1, Gain 2, Hi, Mid, Lo EQ, Master Vol, and Presence Controls. Of course you're also going to have to put 1/4" jacks on the back to replace the screw on mic connectors for the input as well as the weird sockets for the output. Use switching type 1/4" jacks so that when there is a not a cable plugged in it shorts to ground. The input jacks should fit right in the holes that are already there and for the output you should drill out the mounts for the speaker sockets and remove the octal bases. Replace these holes with octal block off plates and drill out a hole for the 1/4" in the center of the plate.

7. Depending on the output taps for the transformer you may have a bunch of taps you don't need. For guitar you're never going to need more than 4, 8, and 16 ohm taps. Most people can get away with only two of these three so decide on how you want the output jacks to work. On amps like this that I relace I like to have one or two output jacks setup in parallel with the hot leg of the jack hooked up to a wire with a open spade end that you run out of the case to the screw on the tag strip. This allows you to select the load with the wire, very simple. A lot of PA amps used this kind of stup already. Any output taps that you don't use should have the wire ends covered with shrink tubing and bundled up, you don't want the end to short out on the case so make sure its sealed up well with the tubing.

8. Replace the ungrounded AC cord with a grounded three prong one and connect the ground wire to a power transformer mounting bolt. If you're output transformer is center tapped (most likely it is) put a switch between the center tap and ground, this will be your standby switch.

9. Its likely that this amp uses a cathode biased setup with little or no negative feedback. Keep this and don't go for any exotic biasing if it doesn't already have a negative bias supply tap on the power transformer.

10. Rock out! These PA heads make great guitar amps and are each unique in their own ways. Because they are using different iron than the circuits you're cloning (or tweaking) of course they will have their own sound. Good luck!

Hey... Thanks!!!

Check out my thread over at diyAudio.... I've added some detail over there...

http://www.diyaudio.com/forums/showthread.php?s=&threadid=90325

I'm gonna re-read all of this a few times before I comment further...

Thanks again...

I can't seem to find any Marshall Plexi that uses the 6L6... Except the JTM45 re-issue:

http://72.14.203.104/search?q=cache:lpf5k9w6UrIJ:www.legendarytones.com/marshallshoppers1.html+marshall+plexi+6l6&hl=en&gl=us&ct=clnk&cd=1&client=firefox-a

Am I missing something?

Since you're relacing it anyway you can use pretty much any Octal power tube that you want as long as it doesn't overload your output transformer. I wouldn't mess with KT88's or 6550's, but EL34, 6L6, KT66, 5881: these guys should all work. If you use EL34's like most Marshalls you just have to wire it for it since it has an extra control grid. If you want to maintain the 6L6's you could just use the preamp circuit from a marshall and the power circuit from the Bassman which the original Marshalls were designed after anyways. Since you're designing the amp you can do whatever you want.

Jesse

I expect this a pretty dumb question, but..

What limits the number of input circuits you can have? Is it possible to build the power circuit using the 2 x KT66 and then have a Bassman 6G6-B input, a Super 100 style input, a AC30 style input, and let's just say an Orange AD30 input?

Like I said, dumb question... I'm almost positive that is possible, is it feasible though? I wouldn't expect that the inputs would mimic their originally acclaimed tone.. I do think it would at least they'd be mildly influenced, though.

?????

Thanks for all your help!! :thumb:

If you had more preamp tubes you could set up some kind of independent switching preamp circuits. A lot of modern Mesa/Boogies use a topology like this I think. Really, since this is your first amp build I would keep it as simple as possible. I've had more time to think about your project and in light of your inexperience it would be best not to get too deep into something too complicated and wind up with a pile of parts instead of an amp. You know the old saying K.I.S.S. (keep it simple stupid)? Keep it simple. Do you have a schematic for this guy? Looking at the original schematic and redrawing into to the circuit you want will save you a lot of headaches once you get started.

Do the following and you will have a badass amp for guitar:

1. Replace the electrolytic caps (usually in an old amp any cap above 1uF (1MFD) is an electrolytic. Since you've already plugged it in you've probably ruined any chance of saving them by reforming so just go ahead and replace them all. You might have a hard time finding the metal can type electrolytics so I would say just get a JJ multi section like this: http://www.tubedepot.com/cp-jj-40-20x3-500v.html In the power supply here its okay to go with a bigger value in the filter capacitor, it will actually improve bass response with the higher capacitance.

2. Leave the design of the power amp and driver section alone. You're only going to mod the pre-amp section. The driver tube is the preamp tube closest to the power tubes.

3. Leave the design of the power supply alone.

4. Mod only the preamp section. The biggest problem with the preamp section in there is that it doesn't have the right kind of EQ for guitar and its designed for Hi-Z mic inputs. While this will work for guitar its not optimized. As it is set up it is wasting one of the gain stages and has a 12AV6 that is of no use. Leave the heaters hooked up as they are (the wires going to pins 4,5 and 9 are the heaters. Rewire the two 12AX7's in the preamp style that you want and there you go! Do this first and see what you come up with. If for some reason you don't like the outcome you can always mod it further but this should be a good first project.

Notes: Remove the tubes before you do any soldering. For desoldering you need some small pliers for pulling out bits of wire and a solder sucker or a desoldering braid for removing solder. I find the sucker works better for me. Check and double check your soldering before turning it on the first time. Expect it to sound weird when you first turn it on, make sure it is hooked up to the right speaker load and let the amp warm up for a least an hour or so before you even plug anything into it for testing. You have to let the amp stabilize itself before you amplify anything. If you wind up with hum you may want to make sure its set up with star grounding, thats where all the grounds connect to the chassis in only one place (the ground lug of the input jack usually). You may also want to center tap the heaters if they are not already, but worry about this stuff only if you have hum. Oh yeah, discharge the can capacitors before you touch them and don't work with the amp plugged in. If you don't know the proper discharging techniques study it before you dive in, you don't want to die building an amp!

Great reply!!

Okay.. I'll start by getting the schematic... It's on Sam's Photofact, for 15 dollars... I'll update the thread when I know more...

Thanks :thumb:

lol... Check this ad out...

http://cgi.ebay.ch/Bell-Carillon-35-A-Amplifier-6L6-New-tubes_W0QQitemZ250033094894QQihZ015QQcategoryZ10171QQcmdZViewItem