Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jeff on March 03, 2011, 11:30:26 am
-
I have an old tube record player I want to use as a reverb amp. The amp has two SE stereo channels both four ohms. I'm gonna run a mono signal anyway is there any way two parallel the two SE amps to run off one speaker? I would prefer an 8 ohm load instead of a 2. Can I just put the secondaries of each OT in series and run them to an 8 ohm load? Would I have to put the primaries and tubes in parallel too or leave them?
Is it possible to combine two SE power amps into one speaker load?
-
I suppose it would be ok,but why not use two speakers,one for each channel if you are going to use both sides anyway?Doesn't make much sense just using one speaker when you have a what would be a complex sounding stereo amp.
-
Rewire them so they sound different, and then you can have two different sends giving you two different sounds. Place the speakers in different places in your chamber, and you will have an even more versatile reverb.
Gabriel
-
I know it sounds easier to do it that way. Here's my thinking. The speakers are going to be in a seperate satalite cab so I could move it away from the amp. If I can run them both together I'd get more volume than just one channel and I'd only have to run two wires(one zip) instead of three. Also I wanted to use an 8 ohm load instead of a 2. It might be neat to run it as a two channel and mount one in the satalite and one in the mother cab.
I was wondering if it was possible to make one mono 2.8W amp out of two SE 1.4W amps.
-
if i understand your qustion correctly, you want to use ONE 8 ohm speaker for BOTH channels. if that's the case then yes, strap outputs in series for 8 ohm, strap in parallel for 2 ohm.
--DL
-
I was thinkin'....... Since you have the tubes and everything, how about re-wiring to a PP? Trash the two individual SE OT's, replace with one PP OT. Then you can voice one channel for a Fender-something and the other a Marshall-something! Simple channel switching and you got a cool little project.
Jim
-
Cool idea but I want to recycle the parts I got. Plus I'd have to add a phase inverter tube. Don't have the space for extra tube, cap, resistors etc. Sounds like a whole new project.
I just wondered if this was possible so I could run one line(+/- zipped) instead of 2.
I'll try it out today, get back to ya.
Thanks
Jeff
-
be careful how the OT secondaries are grounded - you could end up shorting one output.
-
Can I just put the secondaries of each OT in series and run them to an 8 ohm load? Would I have to put the primaries and tubes in parallel too or leave them?
Is it possible to combine two SE power amps into one speaker load?
Would never have thought of this :wink:
Since your OT secondaries are electrically isolated from the primary and from each other, it should work. When you place OT 2ndaries in series driving an 8 Ohm speaker, each channel of the amp would be effectively driving a 4 Ohm load. Just like if you paralleled the OT 2ndaries into an 4 Ohm load, each channel would be effectively driving a 8 Ohm load.
cheers,
rob
-
It will work.
The SE iron costs and weighs 3 or 4 times more than one P-P iron of the same bass power. However two irons in the hand (actually mounted and wired) beats one "smaller cheaper" iron in a catalog.
-
Should I parallel the primaries and power tubes?
I was just thinking of combining the two outputs of two SE amps but are you suggesting adding a phase inverter and run it as a push pull?
be careful how the OT secondaries are grounded - you could end up shorting one output.
Good point. They're floating, no ground, so I only have to worry about phase.
-
Thanks for all the help. Finally got it working. I mistakenly forgot to wire the speakers in phase, +to -, when I wired them in series. The terminals were faceing each other and not marked + - and I got them mixed up in my head.
Thanks
Jeff
-
I'd love toknow how this turned out as I have some of the same parts floating around and hadthe very same idea. Been procrastinating, your project has inspired me. How do the OT's in series sound? I pulled a nice old PT and stereo set OT's which we driving 8 ohm ea.
Realized in theory this might work, but was it okay tone wise? Does it have enough bottom end?
How about volume and what you use it for?