PDA

View Full Version : Bassman vs Bluesbreaker, etc


hobageeba
05-14-2008, 03:14 AM
So I know that the Marshall Bluesbreaker is based off of the Tweed Bassman circuit, but what would you say the difference is tonally? I've got a Bassman LTD right now and I'm not happy with it for several reasons. The top end is too harsh, the low end is a bit too loose, and it's too loud. Would a bluesbreaker be an improvement on any of those areas?

I'm also looking to put together a kit but am only finding the 18 watt "mini bluesbreaker"s. How do those sound compared to the regular bluesbreakers? Has anyone put together any of the kits offered out there? Any recommendations? Oh, and is a JTM45 basically a bluesbreaker minus the tremolo? Maybe I can put together a JTM45 kit and throw it in a bluesbreaker cabinet since I don't care for tremolo on amps. Thanks!

hobageeba
05-14-2008, 01:10 PM
That's interesting. I guess because the Bassbreaker is 30 watts I figured it would have a bit less headroom and breakup nicely at a more reasonable volume. I've never had the chance to directly a/b the same head with a 10 inch speaker vs a 12 inch speaker so to be honest, I'm not really sure what the difference between 10's and 12's are.

mbetter
05-14-2008, 01:33 PM
That's interesting. I guess because the Bassbreaker is 30 watts I figured it would have a bit less headroom and breakup nicely at a more reasonable volume. I've never had the chance to directly a/b the same head with a 10 inch speaker vs a 12 inch speaker so to be honest, I'm not really sure what the difference between 10's and 12's are.

The Fender Bassbreaker was a really cool amp, I wish they still made them.

pjrhd28
05-14-2008, 01:43 PM
Couple of insights:

1. I know the ORIGINAL circuits are similar (if not the same), but I'll be darned if I've ever heard a good Marshall (or clone) Plexi or JTM 45 sound like a vintage or clone Bassman. The Marshall side just seems so much more aggressive, brighter, and chimier (especially clean).

2. If you 're looking for JTM 45's , check out the Germino website and the soundclips. They seem spot on.

3. The difference between the EL-84 18 watt powered Marshalls (or clones) and the EL-34 (or KT-66) ones are night and day to my ears. The 34 or 66 ones have the chime but also have so much more "whoomph"; they also stay clean longer for that Hendrix clean tone.

re-animator
05-14-2008, 02:32 PM
I think a bluesbreaker (in the right cab/speaker combo) will fix what you don't like about your bassman.


To me, at low volume they actually sound quite similar, but when they get cooking they start to get a little different. You can definitely tell they'er in the same family.... they've got that singing characteristic, while still being raunchy and rude for chords, and cleaning up nicely with the guitar volume.


The seminal bluesbreaker designs are 2x12 closed back w/ alnico speakers (clapton tone), and 4x12 closed back with ceramics (pete townshend). Either configuration will give you a more solid, thumpy low end with some soft presence roll-off, especially with greenback speakers.

bosstone
05-14-2008, 02:37 PM
I have never heard both amps in the same room at the same time but I would say they have a lot of similarities. I would put both of them way up my list of the top 10 best sounding vintage combos ever made. I passed on a Bluesbreaker for $1,000.00 in 1984. I thought it was too expensive at the time and I was really into my new Boogie MKIIC+. Back then few of us had more that one gig amp. I regret not buying that amp more than any amp that I ever considered buying.

hobageeba
05-14-2008, 03:11 PM
The seminal bluesbreaker designs are 2x12 closed back w/ alnico speakers (clapton tone), and 4x12 closed back with ceramics (pete townshend). Either configuration will give you a more solid, thumpy low end with some soft presence roll-off, especially with greenback speakers.

I thought that the bluesbreaker combo was born out of Clapton's urging for a combo...Are you saying use the JTM45 head with a 2x12 closed back cab? Or is there some for of the combo that has a closed back...Does anyone know if the bluesbreaker is as crazy loud as a 5F6A bassman? I'm guessing it's more comparable to an AC30 volume-wise, which would be nice because I have an AC30 and can handle it's volume.

Russorama
06-10-2008, 09:12 PM
Hmmm....I have a RI Bassman LTD and my highs are not harsh at all. Have you given the speakers time to break in? (How long have you had the amp)? I really love my Bassman......really, really do! It's cleans are simply delicious and who needs reverb with those wonderful 4x10's chiming so sweetly? The thing loves any pedal. I do keep my bass set at anywhere from 0 to 3 1/2 or 4 depending on the guitar and pickups.
I wonder if retubing with KT66's and rebiasing might do what you want without changing amps altogether....I mean they are a very similar circuit right? I'm assuming that would be do-able (but get advice on that from someone more knowledgable than I before you go doing it). Again, I read lots of guys say their Bassman's are too bright and really you just need to give the speakers lots of time to break in and then they sound great! (Mine has the new Jensens).

re-animator
06-10-2008, 09:20 PM
I thought that the bluesbreaker combo was born out of Clapton's urging for a combo...Are you saying use the JTM45 head with a 2x12 closed back cab? Or is there some for of the combo that has a closed back...Does anyone know if the bluesbreaker is as crazy loud as a 5F6A bassman? I'm guessing it's more comparable to an AC30 volume-wise, which would be nice because I have an AC30 and can handle it's volume.


Weird.... in my experience the AC30 is the loudest of those 3 (with blues at least). The Bluesbreaker in a 2x12 with greens is probably about as quiet as a bassman, maybe a little quieter since greens are really low efficiency.

bigeasy
06-10-2008, 09:40 PM
the two original amp head designs are very similar. The output transformers, 6L6 vs. KT66 and a bit more negative feedback on the JTM45 where really the only original differnces. When you start talking about speaker configurations (makes a big difference), and Marshall going to EL34s, and more bright caps, that's when things go in different directions.

I've built both and currently run a JTM45 in my line, and some of the other amps in my line are based off of the 5F6A circuit as well.

From what you have described, I would guess your harsh top end is coming from Jensen RI 10's that I personally don't care for. I think your loose low end may be from the GZ43/5AR4 rectifier.

Personally I would replace just two of your speaker (leave the other two out) with higher powered weber speakers (10A150, 2x 4 ohm speakers to get you back to 2 ohms). Then run a solid state rectifier, and make sure your bias isn't too high.

This will give you a warmer (smoother) tone, and will tighten up your bass response.
That's a lot less than buying another amp, and you can always sell the webers if for some reason you wanted to.

But having said that, I'd love to sell you an EDS45...

Earl (bigeasy)
Schreyer Audio

JimiStiff
06-11-2008, 03:47 AM
That's interesting. I guess because the Bassbreaker is 30 watts I figured it would have a bit less headroom and breakup nicely at a more reasonable volume. I've never had the chance to directly a/b the same head with a 10 inch speaker vs a 12 inch speaker so to be honest, I'm not really sure what the difference between 10's and 12's are.

i guess my bassbreaker has 45 watts...but recently i can handle it's volume very well. i have jumpered the two channel which gives me a nice break up with my tele or HB Guitars.

sxt
06-11-2008, 05:39 AM
great thread - I'm waiting on a jtm45 clone ....

ROKY
06-11-2008, 07:51 AM
Weird.... in my experience the AC30 is the loudest of those 3 (with blues at least). The Bluesbreaker in a 2x12 with greens is probably about as quiet as a bassman, maybe a little quieter since greens are really low efficiency.

This makes sense to me .

es137p
06-11-2008, 04:18 PM
you should try the Victoria 45410, its like a real Bassman, The reissue Fender's really aren't, too clean and bright.

billstets
06-11-2008, 04:49 PM
I recently built a Metro JTM45 kit, and I love it. However, that circuit is known to have very very piercing highs in the bright channel, and very flubby bass when pushed. It's just the way it is with that circuit, and since it is based off the Bassman, I am not surprised that the Bassman has these issues.

I've already done two mods to the circuit to try to fix these issues. I changed the V1 cathode cap to a much lower value (changed to 10uf from 330uf) and I changed the capacitor across the bright channel volume pot from 500pf to 100pf. These mods made a big difference, and they are very commonly done to JTM45s. I am content with the brightness now, but I would still like the bass to be a little tighter when the amp is distorted, so I might try one or more further modifications to tighten bass. Still, I really liked the amp in its stock form, and like it even better now the way I have modified it. I just have to remember that the low end is a little loose when pushed, and I avoid playing certain things. My Kingsley D30 is my main amp, and I don't have these kinds of issues with that amp at all, but the JTM45 is a fun amp to have as a back-up and alternative to the D30. I get some great tones from it!

These kinds oif mods could probably be done to your Bassman for a very reasonable price. The parts are a few dollars, and it's very quick for an experienced tech (which I am not) to do. You just swap a couple of caps.