Dukane Power Amp> Guitar Amp?

[Arn C.]

I have this old tube amp:    DUKANE  1A435B POWER AMPLIFIER 50W ,  I was wondering what would be a good preamp that I could build that would compliment this amp.   It's intended use would be for guitar.   I noticed it has auxillary ouput connections for 6.3 volts and also B+.  I will assume this is so I can connect a tube preamp to the existing power from the transformer.

Any suggestions would be appreciated.

Thanks!
Arn C.

[John Lyons]

Hey Arn

Are you wanting to redo this guy as a guitar amp...just adding a tube or two to to make a preamp inside?

It depends on what kind of amp you want to end up with. Clean, overdrive or...

What tubes are in there right now? (pre and power)

John

[Arn C.]

Well,  I really just want to make a good complimetary preamp, possibly tube or possibly sollid state.   I already have an amp case with 12" speaker that I took this out of.  I made a tube MIC preamp a lonnng while ago that did not have enough volume.  So then I made the carlsboro preamp and I could only get one channel to work.   But, that was a log while ago. 
First thing is I have to recap the amp, real noisy,  I also may replace the resistors as the resistance has jumped up considerably on all of the resistors.   

I am wondering if the ROG amp simulation circuits would have enough out put as a preamp push the tube amp or would I have to add something out to get a bigger signal?

So, a tube preamp is not out of the question, but I am also interested in using ROG type circuits if possible.

Thanks for any and all input!
Arn C.

[JonFrum]

Regarding the amp itself, a Google search comes up with Sean Weatherford, who posts at ax84.com. He owns one, or did in the past. He's a knowledgeable guy, and may be able to answer questions. As far as a preamp, you need one with sufficient output to drive the power tubes. Depending on the power tubes, that may be 15-20volts coming out of the phase inverter. I doubt an amp sim is what you want - a preamp that will put out a few volts is more like it.

[John Lyons]

I think the best thing would be to make a full amp out of it. Something simple like the fender AB165 schematic. Clean with maybe a hint of oververdrive. This way you can use the thing as an amp by itself. Then build the ROG stuff to you hearts content. Putting the ROG stuff in front of a clean tube preamp will get you a great sound.  It's just that there are some issues with joining fets and tubes with voltages and noise...it gets complicated. I'd start with a simple amp. Once it sounds good clean and full you can make some FX to go with it.

John

[petemoore]

 DUKANE  1A435B POWER AMPLIFIER 50W
  See if you can figure out the power supply for the preamp first, it was possible for me to tap off a Dynakits PS to power a Vox AC 30 type tube preamp, it had tube sockets as connectors in the front panel, one of them said Vsupply [or something and measured 390Vdc]. The 'preamp circuit itself [-PS] was about the same as wiring a 9v distorter.
  Whether the PS of the 435 can be tapped to supply a pre is something worth looking in to, don't get yer expectations high yet, but if possible, this would take alot of the gruntwork out of the equations of building and transporting it.

[Arn C.]

The service literature says: "auxillary power 225 volts DC @7.5ma; 6.3 voltsAC@1.4amps, B+ and filament power for audio preamplifier..."

So, yes all set up for a preamplifier.   Anyone know of a good tube preamp for guitar?  I know there are many out there.  Just can't decide what would sound the best.   I like clean, also a little overdrive or extra gain.   I would love to have this for bluesy and rock sounds.          I have many pedals to use with this amp for other sounds.  It doesn't matter if the preamp has a lot of wiring or not, looking for the sound not the complication of it. 

Thanks again!
Arn C.

[petemoore]

The service literature says: "auxillary power 225 volts DC @7.5ma; 6.3 voltsAC@1.4amps, B+ and filament power for audio preamplifier..."
  Excellent ! This simplifies things.

So, yes all set up for a preamplifier.   Anyone know of a good tube preamp for guitar?
  VOX AC 30 [AC 30 TB]
  Fender [pick one]
  add name brands look up the schematics and compare preamp designs.
  I would get something going mostly 'clean', alot can be done @9V to add grit and dirt,
  I would want to 'hear' mostly the output section first, with less 'pre' distorted.
  I kind of lump 12ax7 distortions as like...distortions, similar to transistors, but more tubey sounding. 'Regular' [er...old style, cleanish] preamp of course can 'do clean, so allowing a wider range of clean to dirt can be dialed in.

[JonFrum]

You might want to go to ax84.com and check out the P1eX and HO preamps. A lot of people have built them, so you can get plenty of help. If you get %^&*y, you might want to try a Dumble preamp - it has a nice overdrive sound that's great for blues. It's also a more complicated build.

http://ampgarage.com/forum/index.php?sid=daea9cd3a0755e8f9956fbc86aa8e717

[Arn C.]

Thanks everyone for your help! 
This place is always GREAT!

Peace!
Arn C.