Bandmaster 4 Ohm OT into 8 cab?

[shocki]

My Bandmaster has a 4 Ohm OT. The cabinets I use are just 8 Ohms though. I could upgrade to an OT with an additional 8 Ohm output. I am not sure if I am gaining much by doing this though.

Is it correct that I will loose something like 10W with the wrong impendance? So 30W instead of 40W?

When changing the OT I am thinking about upgraded to a Super Reverb OT BTW. The Bandmaster Reverb has the same Chassis as the Super. So I would not have to drill any holes. I think the bigger OT might get me a tighter bass. Not sure if this is a smart move though

I was thinking about something like that.
http://www.tube-town.net/ttstore/pro...er-Reverb.html

[JoeM]

MAny years ago I did some work on a friends Bandmaster (BF not reverb model). Just for fun we opened the cab wanting to see what speakers were in it. One was blown and had been disconnected. (He got it that way). It had been played for well over 15 years and he never knew it! You mentioned in the other thread it sounds great. Probably not the best way from a theoretical point, but Fenders dont seem to mind the mismatch.

[JoeM]

Oh, just wanted to add - why not another 12" speaker? It's a big sound. My friend did go ahead and replace the speakers, he was really pleased with the results.

[Tage]

Hey to answer your question, yeah that should be a fine transformer. some things to consider though is maybe implementing a way to switch through the new impedances or wiring different jacks as different impedances selections. If it is a blackface amp you will have the internal and the ext. cab jack. or just connect the 8 ohm one. as far as "tighter bass" well you will just have to try it and see, Hammond's are usually overbuilt, more iron, and high quality... and Canadian

Another option would be an edcor 100 watt OT, with a 4-5k primary to 8 ohm secondary, that should net a lot more bass, although I'm on the side of less bass unless your playing bass.

[shocki]

I am still not sure what I am loosing when playing with the impedance mismatch. I would use power I gues. But how much ?

Hammonds are by far the cheapest transfomers here in Germany. Mercury would be at least double or even three times that price. Tubeampdoctor (which I think is Heyboer) is also quite a bit expensive. But I think that is cause TAD is really expensive over here. My friend who is an amp builder favours the Hammond stuff over the TAD stuff.

I will connect the secondary 4 und 8 Ohms to the outputs (not parallel). If I want to hook up two 1x12 cabs (=4 Ohm). I will plug them into the 4 Ohm Load with a external speaker splitting cable. I use the 8 Ohm Output for the single 1x12.

Oh, just wanted to add - why not another 12" speaker? It's a big sound. My friend did go ahead and replace the speakers, he was really pleased with the results.

Of course this would sound great and would equal in 4 Ohms. But I would like to use a light 1x12. I will use an additional 1x12 for bigger stages.

[Regis]

I've been playing dimed 4 ohm Bassmans into 8 ohm cabinets for pretty much thirty years. Never a problem.

[Steve A.]

I am still not sure what I am loosing when playing with the impedance mismatch. I would use power I gues. But how much ?

I think that might be more of an issue with solid state amps. Technically it isn't quite as efficient but it should still get plenty loud.

Steve Ahola

[Alan0354]

I myself never worry about 4 ohm or 8 ohm. I have a few Fender that are 4 ohm out, I use single speaker, two speakers and I never notice that the volume change when it is not perfectly matched even though theoretically you loose power due to mismatch. Don't notice any difference. Also theoretically you change the distortion by changing the load line, but I never notice any difference either. It is only 2:1, I doubt you can hurt anything and I never had problem. If you go from 4 to 16 ohm, then maybe it is a little more different.........which I never tried.

[loudthud]

Back in the 70's I did sound for a bar band with two guitar players. Each used a Blackface Bassman (4 ohm) into a 16 ohm 4x12 Marshall cabinet. Nice distorted sound but not so much volume as to drive the bar owners insane. They came up with the idea before I met them. Reliability wasn't an issue with the tubes available back then.