Modded Fender Bassman 135 - Value?

[pbassnut]

I just got back home from trying it out and it didn't sound very good at all. I was skeptical of it, but was compelled to check it out because it was so cheap and he was throwing in a Mesa Boogie 1x15 for another hundred bucks if you bought the amp and it wasn't too long a drive for me to go audition it. I think the mods more or less ruined it because it made it lose warmth (it sounded like a dry and thin solid state circuit, only with tube distortion), the classic Bassman tone was MIA and it actually diminished the depth and headroom. I wouldn't waste your time with it.

 

[kbakerde]

I just got back home from trying it out and it didn't sound very good at all. I was skeptical of it, but was compelled to check it out because it was so cheap and he was throwing in a Mesa Boogie 1x15 for another hundred bucks if you bought the amp and it wasn't too long a drive for me to go audition it. I think the mods more or less ruined it because it made it lose warmth (it sounded like a dry and thin solid state circuit, only with tube distortion), the classic Bassman tone was MIA and it actually diminished the depth and headroom. I wouldn't waste your time with it.

OH WOW!!! Well thanks for the report.

 

[gimp]

Indeed! Saved me the drive.

 

[BassmanPaul]

"not be much different", I don`t agree, it`s a substantial audible difference.
modded amps are a crap shoot no doubt about it, sometimes though you can get a gem that was modded by someone who knows what they`re doing.

Believe what you will.

If YOU like the result then enjoy it for what it is and don't let logic get in the way!

 

[taurus1]

Believe what you will.

If YOU like the result then enjoy it for what it is and don't let logic get in the way!

I trust my tech, but more importantly my ears and recording equipment.
if it makes you happy theorizing why you think I`m wrong, don`t let reality get in the way.

 

[will33]

I just got back home from trying it out and it didn't sound very good at all. I was skeptical of it, but was compelled to check it out because it was so cheap and he was throwing in a Mesa Boogie 1x15 for another hundred bucks if you bought the amp and it wasn't too long a drive for me to go audition it. I think the mods more or less ruined it because it made it lose warmth (it sounded like a dry and thin solid state circuit, only with tube distortion), the classic Bassman tone was MIA and it actually diminished the depth and headroom. I wouldn't waste your time with it.

Well, tjere's the answer....too bad.

My favorite thing about bassmans is their warm but still pretty clean tone, before you get into any real grit. Anything done that makes that tone louder is good, anything that does not is bad...simple as that.

I still think some lowend highpassing and/or tweaking of the bass control could help them out, but apparently, just taking a bunch of parts out and sticking the wrong power tubes in there without the required mods to run them is not the path to success.

There's a guy on here somewhere who had a Houston tech do some sort of mod to the lowend/bass control that helped the output withoit losing the tone. Have to dig through some old posts and PM's.

 

[BassmanPaul]

I trust my tech, but more importantly my ears and recording equipment.
if it makes you happy theorizing why you think I`m wrong, don`t let reality get in the way.

I don't my brother, it's the more than fifty years of repairing, designing and building tube amps that colours my thinking. They still taught tubes, well valves, when I went to engineer skool. <sigh> Soooo long ago! I was young then. Sniff, sniff

 

[B-string]

I don't my brother, it's the more than fifty years of repairing, designing and building tube amps that colours my thinking. They still taught tubes, well valves, when I went to engineer skool. <sigh> Soooo long ago! I was young then. Sniff, sniff

Did they only have the four pin tube bases back then?
I know we used to be on good terms

 

[taurus1]

I don't my brother, it's the more than fifty years of repairing, designing and building tube amps that colours my thinking. They still taught tubes, well valves, when I went to engineer skool. <sigh> Soooo long ago! I was young then. Sniff, sniff

well you could school me six ways from Sunday then, respect.

 

[Steve Dallman]

I modded my Bassman 100 years ago to use 6550's. I added a filament transformer, rewired the sockets, changed the bias to separate bias adjusts for each tube, and added two fans...one supplies air to the inside of the chassis, and the other blows on the tubes. I got this amp from a prison, and the musicians there had been removing parts for years to keep other amps running. There wasn't much in it but a stripped board, the transformers and the sockets. I also increased the B+ filtering significantly.

I wired the bass channel into an Ampeg type, with baxandall bass and treble. It sounds fantastic. The normal channel is a London Power design, sort of Fender but the tone stack is tuned down an octave, I added a mid slope. The gain structure is different, with a sensitivity control and a volume. No master needed. In place of the master, I put in a resonance control which decouples the NFB at low frequencies.

I have another Bassman 100 so I could compare them. The stock 100 was not loud enough for gigging, and ran out of headroom fairly early. The modded 100 has plenty of headroom, far more than the stock one. The London Power preamp is pretty close to the Fender, but is more versatile. The Ampeg channel is just great. It sounds deeper and fuller with more clarity and a more 3-D tone.

I've rewired some Bassman 50's to use 6550's along with increasing the B+ filtering. They all still sounded like Bassmans, but the increased headroom turned these amps into giggable machines. The only problem is that to remove a power tube, the chassis has to be pulled. With the 50's, a fan wasn't needed. It got no hotter.

One bass player used a Twin Reverb with no speakers in it, for his bass head. He too was running out of headroom. Same 6550 mod + filtering and he was thrilled.

The tone with all was an improvement over the 6L6's. Tighter, bigger, more solid, but still with the warmth you'd expect from a Bassman.

I am going to rewire my other Bassman 100 but not the same. I'll wire it for use with either 6L6's or EL34's or both. I'm looking for something different from it. I wouldn't mind getting some grind from it, and using it along with the 6550 head.

 

[will33]

Now that ^^ is something more along the lines of what I was hoping the OP had stumbled into. Don't lose the tone, just beef it up enough to be able to cover more/louder gigs.

 

[beans-on-toast]

When I consider buying at an amp that has mods, I look at the chassis to see if any holes have been drilled, I check out the transformers to see if they are original. Of course condition is important as well.

An amp like the Bassman 135 is built with an eyelet board. It is easy to undo any modifications that were performed, assuming that the transformers and chassis are original. Sometimes the amp is gutted. The original eyelet board is removed and replace with a new one. Some people don't like the ultra-linear output transformer and change them to convert the amp into a blackface Bassman. So it is important to determine to what extent the amp has been modified and if the original parts are available.

So I think that the price really depends on what was done to it. $250 for a good working modified 135 Bassman amp is not unreasonable. A hacked amp is another story.