NAD

BluJu

So yesterday I went to pick up my new amp.

I am now the proud owner of a Fender Bassman 59' reissue.

I picked it up of our recording engineer after playing it a few times in studio and falling in love.

Unfortunately this amp is a total backbreaker (the reason I got rid of my twin reverb and my marshall) so will probably stay cozy at home while my Trusty Blues Jnr comes along to the gigs.

May give it some excitement here and there. Got a gig on Sat night at rumours so will put the Bassman through it's paces there.

It is also very loud (even though currently running on 2 power tubes as opposed to the usual 3).

What tubes should I put in that will make it break up early?

Will post pics this evening.

Psean

Nice one man!

BluJu wrote: Will post pics this evening.

You better...

warrenpridgeon

Nice! I am considering getting a small, lower watt, tube amp... Playing in church I don't really get to crank my 40watt...

ezietsman

BluJu wrote: It is also very loud (even though currently running on 2 power tubes as opposed to the usual 3).

The 59 RI is supposed to have 6 tubes: 3x 12ax7 preamp, 2x 6L6 power and 1x 5AR4 rectifier tubes. Are you really running it with only a single power tube? I don't believe this is wise. You can pull half the power tubes if it has pairs, you can't (or probably shouldn't) use half of the last pair. Its a push-pull amp (like most others), it needs at least two power tubes to work right.

I guess you'll need an attenuator ?

BluJu

ez wrote:
BluJu wrote: It is also very loud (even though currently running on 2 power tubes as opposed to the usual 3).
The 59 RI is supposed to have 6 tubes: 3x 12ax7 preamp, 2x 6L6 power and 1x 5AR4 rectifier tubes. Are you really running it with only a single power tube? I don't believe this is wise. You can pull half the power tubes if it has pairs, you can't (or probably shouldn't) use half of the last pair. Its a push-pull amp (like most others), it needs at least two power tubes to work right.

I guess you'll need an attenuator ?

Well the tube on the far left of the 2 power tubes are there. Then there is an open slot, must be for the 5AR4?

ezietsman

BluJu wrote:
ez wrote:
BluJu wrote: It is also very loud (even though currently running on 2 power tubes as opposed to the usual 3).
The 59 RI is supposed to have 6 tubes: 3x 12ax7 preamp, 2x 6L6 power and 1x 5AR4 rectifier tubes. Are you really running it with only a single power tube? I don't believe this is wise. You can pull half the power tubes if it has pairs, you can't (or probably shouldn't) use half of the last pair. Its a push-pull amp (like most others), it needs at least two power tubes to work right.

I guess you'll need an attenuator ?
Well the tube on the far left of the 2 power tubes are there. Then there is an open slot, must be for the 5AR4?

Nope. That is the rectifier tube which provides the DC voltage for the rest of the amp to work, without it there will be no sound. I think your amp is limping along at this point. You'll probably clearly hear the difference when you crank it just a bit for some overdrive, between one and both tubes in.

MikeM

Ez is right. It's bad to run it like that.. It wouldn't work without a rectifier tube, so the tube that is in is probably biased wrong and seeing the wrong load and a heap load of other stuff.

BluJu

Thanks fellows. What replacement tubes do you suggest I go for?

MikeM

Whatever you can get your hands on ? Folks on the forum are often fond of JJ. I've had decent experience (Although not for many years) with Electroharmonix and Tung Sol. Also heard good things about TAD 6L6s

BluJu

It is definitely the rectifier tube that is missing which leads me to believe that a solid state rectifier was probably installed.

bottledtone

Its actually okay to pull valves. Some guys have run 100watt amps on 1 output valve. Been stories of guys finishing gigs with valves that had fallen out and finding they really dug the tone. Yeah, would be inbalance, but bias won't change if it is a fixed bias, and no issue with load.
Some amps have fuses on the cathodes, so if the valve dies and pulls too much current, it will be taken out of circuit for you to finish gig.