Making a Fender bandmaster Reverb louder with upgrades, any suggestions???

[Slobrain]

Hello all,

I wanted to ask if anyone has ever upgraded the OT and PT in a 70's bandmaster reverb? This is the bigger cabinet head for the reverb pan. I'm wondering if I can fit in a bassman OT to up the watts on this amp? I'll probably need to upgrade the PT and choke too. Then add a SS rectifier as well. Heck, maybe put in a Twin reverb OT if I could...

I'm wanting up the clean output for pedal use and will run this head thru a 2x12 cab using celestions. I know I'll have to replace all the filter caps too but fitting in bigger PT and OT trannies is my concern. These amps are going kinda cheap still considering that bassman heads on ebay are now at $600.00 where I used to get them at $200.00 to $300.00 some years back.

I like the band masters but never working on one of the Bandmaster Reverb type. Just not sure about the space factor.


Thanks

SLO

[Raybob]

Great amp. I own a '69. All I've done to it was to 'blackface' it to AB763 Super Reverb. I didn't change anything else because I like it as is, but there is room for a Bassman OT which would give more headroom. You could also go with diodes for the rectifier. If you really want to hot rod it, you could run 6550s or KT66s if you had a PT with a little more current, but I'll bet you'll be happy with just the OT swap and SS rectifier.

[Slobrain]

Thanks for the info RayBob,

I will probably use some 5881's since they sound great and are cheap. I have run different power tubes in Fenders but always fall back to the 6L6 or 5881 for tone.


The bandmaster is on its way and hopefully it will sound good like many other old fenders I have had in the past. I have been thinking about getting a combo cab built for it though but not sure if I want to do 2x10 or get the Super reverb type cab but do 2x12 instead of 4x10. I never really was a fan of 10 inch speakers, especially in combo cabs...

Slo

[txstrat]

Actually to get more headroom out of the amp, more speakers would be a better choice than beefing up the transformers.
As far as I'm concerned I like the Jensen 10'' more than the 12'' cause they have a tighter bass response. A 12 will sound sloppy instead IMHO.
And the 10'' Jensen ceramics are definitely louder. Look at the specs.
Just my 2 cents

[Slobrain]

Thanx for the info Txstrat, which Jensens would sound loud but a good tight low end? I've tried some celestion 10's from avatar but they sounded cold and mild lows with no punch.

What model Jensen 10 would you say sound the best for all around rock guitar with lows that match a 4x12 cab?

Slo

[R.G.]

Changing speakers to ones which have 6db more output efficiency is like doubling the power of your amp.

[JoeM]

I dont think 10s are going to give you the lows you want if you're thinking along the lines of a 4X12 cab. I'd keep the amp in the head cab and get a 2X12 cab with efficient speakers. (at least)

[txstrat]

Thanx for the info Txstrat, which Jensens would sound loud but a good tight low end? I've tried some celestion 10's from avatar but they sounded cold and mild lows with no punch.
What model Jensen 10 would you say sound the best for all around rock guitar with lows that match a 4x12 cab?
Slo

I'm using several amps with Jensen C10Q and some with C12Q. The 10s have definitely a tighter bass response and more punch. They also deliver enough low end IMHO.
I don't think 10s lack low end by design. Just the opposite. Look at different bass cabs. They usually have a 15'' or two or four 10s.
I mean the 10s wouldn't be used for bass cabs if they lack low end by design.
Sure, all speakers sound different, and I really dig the sound of them Jensens.

[akimball442]

The answer to your original question is basically 'yes.' But a TR transformer really won't do you that many favors. Certainly not enough to justify the cost. A Bassman head transformer however, would most definitely extend and clean up the bottom end. My primary gigging amp is a somewhat modified 68 Bassman head. It's GREAT. The Bandmaster definitely does not have the bottom end of the Bassman... it was a 'bass' amp after all....

On the Bassman, I modded the 'bass' channel as basically a 5f6A preamp complete with the cathode follower, since the extra tube was available. I used the deep switch to select between a .68 and 25uF cap. Adds a nice thump and twang to the bottom end of a telecaster without getting distorted when I want clean. It also doesn't get 'farty' with humbuckers, although my LP has fairly low output as humbuckers go, and I've never tried anything hotter than that. I keep the amp at right around 5, which is just on the verge of breakup (I A/B this amp with an AC30 + boost for crunch). The 'Normal' Channel is your standard Blackface circuit. The other 50W Fender amps seem to crack up a little sooner than the Bassman. Since the basic Blackface circuit pretty much a Blackface circuit, I have to conclude that the transformer is the reason for the difference.

Also worth mentioning is another minor mod I did to the tone stacks on the Bassman. This is worth mentioning because you will also not have middle controls on the Bandmaster head.

I play Fenders with the mid controls cranked. Your mileage may vary, but I prefer that sound. You can pretend you have a middle control cranked up by removing the typical 6.8K middle resistors and replacing them. The 5f6 has a 25K middle pot. I subbed a 22K resistor for that. A Twin or most other blackface amps with middle controls use a 10K middle pot. So I used a 10K resistor.

Increasing the midrange has the effect of increased gain, although actually it just makes the tone stack less lossy.

Ultimately as previously mentioned, LOUDER is going to come from different speakers, but you can get a little cleaner longer with the Bassman OT and bumping the mids a little.

Good luck, and long live easy to mod Fenders!

[Ronsonic]

Going to a Bassman output tranny is a fairly reasonable and sensible mod. ATMO, anything more isn't. Yeah, you could build a Twin in there if you wanted, but why. A Dual Showman would be the answer to that question. As big and scary as those are, they are even more of a bargain in this the 21st Century.

[1ampman]

My opinion would be a Bassman output, Diodes for rectifying, larger filter caps and most important speakers with large magnets which will stay cleaner and be higher output than smaller magnets. BUT, Bandmaster Reverbs are going for a nice high price and you could buy a Dual Showman Reverb at the same price. Once you mod your amp the value goes down. So now you have 25 ideas and the choice is yours! Life is good.....

[Chuck H]

and most important speakers with large magnets which will stay cleaner and be higher output than smaller magnets.

Yeah dude... Big magnets rule man. Real loud and stuff.

[Silvertone Jockey]

Old thread but I have a 69 TFL 5005D Bandmaster Reverb chassis mounted in a Twin cabinet and I'm running a twin output transformer. I also tried a transformer from a tube organ that was in between stock and the twin output iron in physical size but the Fender iron sounds much better. I'm running it into a single 8 ohm speaker and the other is hooked up to my Silvertone 1484 (also with a larger output iron) running both amps in stereo feeding the twin cab speakers. My 1484 has a good sounding reverb with a short decay and mixed with the Fender long decay verb it sounds amazing in stereo. It's the rig in my avatar picture