Good amp, bad cab

5F6-A

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I have a great JTM45-esque PTP amp (e.g. Mullard, GEC and Philips NOS valves, real mustard caps, great transformers, F&T filter caps in vintage correct values) with a couple of extra features (i.e. cathode bias switch, Frondelli Master volume, FX loop). The amp is a beast. I have some Heritage series Celestion Greenbacks in a 2x12" cab. However, I suspect that the weak link is the cab. It's an open back 2x12" of unknown origin (NOT plywood but some sort of cheap and nasty stuff). A bit ugly too. I'm toying with the idea of getting a good custom made cab to house the otherwise fab G12M and G12H 55 Celestion speakers as I suspect the cab is not up to par with the rest of the rig.

Has anyone got direct experience of something similar (i.e. good amp and speakers but bad cab)? Is it worth saving up to get a good cab? Thanks!

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5F6-A

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Honestly, just close the back.It will add bass and mids.. Changing the wood wouldn't make a huge difference as I've used many cabs and generally speaking some of the best were homemade plywood cabs..
Thanks! This is not plywood.
 

freefrog

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Yep, the cab can make a big difference... are your drivers "frontloaded" or "backloaded", BTW?

Woods, shape and volume are obviously to consider here but personally, I wouldn't hesitate to think "out of the box" and I wouldn't discard happy accidents: I've modified some pine boxes sold as furniture for 25 Euros each and it made excellent 1X12 cabs...
 

JeffH66

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I also think closing the back will make a big difference. I took my Marshall JCM 800 4x12 Cab to Scott Splawn’s shop in Dallas NC when I lived in Charlotte and he told me the best thing I could do to improve the sound of the cab was to upgrade the quality of the wiring to heavy duty guage wire, which your cab could use, and to put a heavy duty, solid birch ply back on the cab.

I had the cab in at the time to have the grill cloth changed and I had him upgrade the wiring while he had it too. My plan was to go back and have the new back put on, but I ended up having to move before I could get it done. I have also heard that putting some insulation inside the cab around the speakers and then closing the back can help the sound.

I think with a little work you can make that cab sound a lot better, and look better, for a lot less than buying a top quality new cab, even an empty one.
 

HogmanA

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I don't think there is such a thing as a 'bad' cab: only cabs that don't sound like you want them to.
The guitar amplifier industry is so uninventive and stuck in its ways since the 70's when it comes to speaker enclosures.

By closing the back on that cab, you would probably lose bass (for me, a good thing in your setup).

My favourite cab is 2x12, less deep than yours, closed back and very old, resonant pine ply. It interacts with the speakers at relatively low volumes, and cuts bass, which is great for recording.

I agree with the happy accident philosophy.

One of my best sounding wacky experiments (and best sounding cabs ever) was a open back 2x12, deeper than yours, made into 4x12 by mounting the speakers in the sides, facing 90 degrees away from the front speakers, with a lot of 10mm holes drilled in 4 concentric circles - maybe 4 circles of 12 holes each to form the baffle.

Actually, just remembering it from nearly 20 years ago makes me determined to make another like it.
 

el84ster

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Maybe I missed it, but what do you hear that’s lacking or you’re not liking?

Sometimes these problems are easy to figure out: your amp was really meant to mate with a closed back, birch cab. Successful amp companies put an awful lot of research into making them sound best, plus the ears or many pro musicians during the design process.
So often we can solve these problems by going back to the full intended design.
 

tzd

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Get a 2x12 cab from VBoutique USA to put your speakers in, you won't regret it!
 

HogmanA

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Maybe I missed it, but what do you hear that’s lacking or you’re not liking?

Sometimes these problems are easy to figure out: your amp was really meant to mate with a closed back, birch cab. Successful amp companies put an awful lot of research into making them sound best, plus the ears or many pro musicians during the design process.
So often we can solve these problems by going back to the full intended design.

As intended? Open or closed?
8_12_Marshall_Cab.jpg
 


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