Bogen Challenger Coversion

[jbouche]

Has anyone here ever coverted a Bogen Challenger, or something similar, into a guitar amp. What is required?

Thank you,
Jay

[JohnnyCrash]

Which model is it? What tubes does it use?

Should be easy enough.

[jbouche]

I am going to have to get the info from my brother. It is a project that he is undertaking. I did see the unit this weekend. It looks as though it is from the 50's. It had a grey hood, dark red chassis, and large silver dollar sized cream colored knobs . It had 2 6L6's and a 5U4. The preamp tubes I did not recognize one(or two of the numbers). I will try to get more info.

Thanks,
Jay

[jbouche]

I called my brother for the info, and he said that there was a very helpful soul that he ran across on ebay who sent him the information he needed. Thanks for the willingness to help. That's what I really dig about this forum. There are lots of knowledgeable and good people here. On the FYI side, for Johnny Crash. I went to school at Fullerton College right there on Chapman Ave.(the other Chapman Ave.). I worked for Moody music back in the day and played the Orange circuit in the 80's Joshua's ( The Marquis), Goody's, Manhattan's, Jezebel's etc. Good times! I even made an appearance at the Brea Tavern. How is the music scene in Orange these days? The Rock Box and Band West-do they still exist? There was another rehearsal hall in Garden Grove, but the name escapes me. I was just curious.
Thanks,
Jay

[JohnnyCrash]

Originally Posted by jbouche

I called my brother for the info, and he said that there was a very helpful soul that he ran across on ebay who sent him the information he needed. Thanks for the willingness to help. That's what I really dig about this forum. There are lots of knowledgeable and good people here. On the FYI side, for Johnny Crash. I went to school at Fullerton College right there on Chapman Ave.(the other Chapman Ave.). I worked for Moody music back in the day and played the Orange circuit in the 80's Joshua's ( The Marquis), Goody's, Manhattan's, Jezebel's etc. Good times! I even made an appearance at the Brea Tavern. How is the music scene in Orange these days? The Rock Box and Band West-do they still exist? There was another rehearsal hall in Garden Grove, but the name escapes me. I was just curious.
Thanks,
Jay

I remember Moody Music!

I don't think Band West is around anymore. There is a cool place off of Raymond over near Orvac (great for some parts by the way).

I was playing in the scene in the mid '90s and into 2001. I've been on a gigging break in OC for a while (did a few L.A. gigs though). The scene used to be cool, now IDK, I'm a little out of the loop.

[jbouche]

I appreciate the update.

Thanks,
Jay

[jh45gun]

I am converting over A Bogen 65 watt tube head now

[jbouche]

I would not mind seeing some pictures. Either in progress or finished would be great if you can.
Thanks,
Jay

[jh45gun]

When I get a chance I will its been on the back burner for a month or so I did some work to it but not much.

[jh45gun]

Correction I thought my Bogen was 65 watts its actually 60 its a MX 60 I have not messed with it for a while so I forgot. I also misplaced my copy of the sams folder/schematic I had on this so now I have to make a trip to the city next to ours and get a copy from the library.

[Gunny]

Every time I see a Bogen conversion thread on a Forum, I issue this safety warning. Using a voltmeter, check all the screws on the rear mounted terminal strip to see if there is high voltage DC present. If there is, kill the power, drain the caps and disconnect the component connected to that screw.
Nothing worse than reaching around behind an amp and getting zapped. Bad design on Bogen's part.
If this doesn't apply to your model of Bogen, then there's no problem.

[jh45gun]

Good info to know Gunny evidently that does not apply to my model. I found my schematics again ( Yee Haw) and the speaker terminals are hooked up directly to the Output Transformer.

[jh45gun]

Jbouche I forgot to post this earlier but Schematic Heaven has several Bogen Conversions using their challanger 20 amps coverting them to guitar amps.

http://www.schematicheaven.com/hifi.htm

[Radspin]

I had a Bogen Challenger tube PA head that was around 20 watts (can't remember the model number). It had screw-on mike terminal inputs and I used a 1/4-inch-screw-on adapter to plug my guitar into it (from Switchcraft; lord knows where you'd find those now). I turned the min input volume to 10 and used the master volume to regulate the overall volume. It sounded fantastic--but I sold it because I had about 10 amps in my house and didn't really need the Bogen. I've heard a few other Bogen amps and they all sounded great--I'd be willing to bet that your conversion will sound great also.

[jh45gun]

Yea it sounds OK now but I suspect after I replace a few more caps it should be better yet or at least more trustworthy. :) Mine is interesting as it has 3 rectifier tubes. GZ34/5ar4s though mine has one 5u4 in it and instead of the 7027A tubes the Schematic shows 7027A output tubes. Mine was supposed to have 7581 output tubes I know as it is factory written on the chassis. Mine has been converted over to 6l6 output tubes might be why it has a 5u4 as one of the rectifiers? (Just guessing on that unless some one put one in cause they did not have a 5a44??? Anyway here is a copy of the post I wrote earlier on it and what I plan to do.

OK I am replaceing the caps in my Bogen MX60 PA head as I can afford them. It is a different amp in the respect it has like 3 different cap sections for voltages with two 40 MF caps that supply the highest voltage (530 V source) off the rectifiers that I replaced as a start. They were cardboard cans which I replaced with a newer style two lead Electrolitic. The Amp has 3 Gz34 rectifiers though one has been replaced with a 5U4. The next filter section utilizes a 4 section can that some amps use 20 20 20 20 or a 20 20 10 10. Mine uses the latter can that supplies a 440 V source a 410 V source and a 370 V source and a 200 V source. Then there is a 4 cap can that has four 5 MF sections that supply some lower voltage sources 3 @ 90V and one at 75 V and several other Electrolitics that need replaceing like in the bias circuit. 9 caps all together and two of them are the 4 multi cap cans. So it has a lot of caps to replace. The other thing I had to do is replace the Low Impedence Cans with plugs jumpered for high Impedence in the sockets the low impedence cans use. The Schematic shows how to do it and the plugs are a octal size 9 pin socket. I only replaced two of them for now and left two channnels low impedence. The amp is 60 watts so it has lots of power though this amp is a bit less as it is supposed to use 7581 output tubes though this one is running 6l6s. Maybe that is why the 5u4 was put in instead of a GZ34? Amp with just the two 40 MF caps replaced sound better so far and with my Digitech RP 80 plugged into it using the EQ and adding some verb and other effects it sounds good. Of course I am expecting even better with the replacement of the other caps. So if ya can pick one of these up cheap with a few mods they make a good tube amp. I have to add a 3 prong cord yet too. The amp is a 4 channel amp with a Master Volume and bass and treble controls. It is rated at 60 watts. Lots of clean headroom. It sounds good as is but adding a few pedals or a multi pedal to get effects and more EQ really makes these amps shine.

[Scott S]

The first tube amp I played through was my Dad's Bogen MO-100A (SS-rectified, 4x8417 with a 7247/12DW7 voltage amplifier/PI). By the time he got it, it had already overheated its power transformer and fried two of the four 8417's, but it managed to run on the two remaining ones. Sounded alright, but not very exciting (not much gain, and no tone controls).

- Scott

[jh45gun]

This Bogen has bass and treble controls and at 60 watts has more than enough power.

[Rich_S]

Here's my web page describing an extensive conversion, Bogen CHB20A to 18 Watt Lite II.

http://richardstevens.home.mindsprin...tar/index.html

[bdgregory]

I've converted a few Bogens so far (though I'm still fiddling with the voicing. This paper is a good place to start reading:
http://www.geofex.com/Article_Folders/old2new.htm

and this paper expands on the original, and is also very helpful:
http://www.netads.com/~meo/Guitar/Am...a2g-notes.html

Finally, google is your friend. There's a fair amount scattered around various fora. I've found it's very easy to do a simple recap job, and add some i/o jacks, then use a pedal for the voicing. They take pedals quite well and you can get done very cheap and easy this way. The 6L6 based amps work great.

[bdgregory]

Rich, I just had a chance to see your CH20 conversion - very nice work. You've given me some inspiration on some of my challenges. I particularly like your face plate solution, and your retro cabinet.

[electrorocket]

..

[scantron81]

my favorite amp.I have a ch-35.