Always SUNNy in...

[Isaac]

Kustom (in charcoal sparkle tuck n' roll) X1-18B

Never heard of it. Post pics, please!

[bigobassman]

Hey Isaac,

Those cabs were made maybe for a couple of years and apparently not many were made or survived.  I've been around gear for nearly 50 years.  Been to countless guitar shows over the years as well and had never heard of one until about 2 years ago.  Saw my first pic of one about a year ago and this is the only one I've seen in person.  It's similar to the folded horn design of  Acoustic Control Corp.'s 301 and 360 cabs of the early thru mid 70s.  In fact, some of these Kustom cabs were powered cabs (like the 360 ACC) and the head mate had a jack to use with the powered cab giving a lot of power and sound using 2 of these cabs.  I've obviously never seen a powered cab since mine is not.  After spending Saturday taking it apart, I've discovered the original speaker is a 4 ohm 18" CTS.

Anyway,  I've got some more rehabbing to do to it.  I've taken pics all the way and when I'm finished, I'd love to share. 

[Isaac]

Cool.

I repaired a friend's 361 a few years ago. That was bittersweet, especially for him, as he needed it repaired in order to sell it.

[PB Blaster]

Not to hijack my own thread back... ;-{) but the OOPS guy dropped off 38 lbs of vintage D140's yesterday so I set about to test what was going on in the cab. I assume it's ok to run it open back, for speaker testing?

The top speaker, the Altec 421A, actually sounds pretty good. It's probably fine, just a little on the honky side for me, and of course it farts out pretty good anything north of the 5th fret on the low E string. The head is really the problem as far as distortion goes, it's a dream up to five, starts to get a little ragged after 6, and worse after that.

I did experiment some with leaving it on 5 and cranking the bass, with fairly good results, but still need more volume. Maybe sometime down the road get the head worked over for gobs of clean volume, maybe KT88's?

Anyway, the lower speaker, the 412-8H, sounds a bit frazzled. It's probably what I was hearing in the cab that I didn't like.

Out to the shop to open the box on the JBL's in a bit. Too cold to be outside working on machinery, or at least that's my excuse?

Here's the inside of the cab, and a quickie shot of the amp yesterday evening. Looks better in person ;-{) Condition wise, the tolex is pretty amazing, the head is very clean, the cab looks like it's been around... I'm resisting the temptation to wash the grillecloth while the speaks are out (done this before with great results). I probably won't, it's really a perfect match to my relic P Bass this way.

[bigobassman]

Sorry about the thread detour PB Blaster.  If you're looking for rattles or similar things and need to see or touch inside the cab, open back is OK.  But for performance and sound testing, much better to have the back on and tight.  It's amazing how much difference that will make.

Give me a shout on the 421A status.

That is a fantastic looking rig.  I think that you'll find the performance greatly enhanced once you service that head.  On the cab, check for evidence of missing insulation on the side(s.)  It should be lined on all sides including the back for maximum performance.  Not sure about the tubes.  I've not had to buy any in recent years, but I've heard pretty good reports on the JJs.

Very cool looking Fender bass and will be a great match to the Sunn rig.

Looking forward to the report with the JBLs!

[EdBass]

Sorry about the thread detour PB Blaster.  If you're looking for rattles or similar things and need to see or touch inside the cab, open back is OK.  But for performance and sound testing, much better to have the back on and tight.  It's amazing how much difference that will make.

+1
It's certainly a PITA to mess with all those screws, but it indeed makes a night and day difference.

[Isaac]

Switching to KT88's isn't going to gain you very much. Remember, doubling power is only a 3 dB gain, and going from 6550's to KT88's won't get you anywhere near that much. The small Sunn heads are 60w, maybe 80w with solid state rectifiers. They just aren't going to blow the doors off their hinges.

[EdBass]

Switching to KT88's isn't going to gain you very much. Remember, doubling power is only a 3 dB gain, and going from 6550's to KT88's won't get you anywhere near that much. The small Sunn heads are 60w, maybe 80w with solid state rectifiers. They just aren't going to blow the doors off their hinges.

+1
More speakers will make a far more dramatic difference than anything you can do to the amp itself, an additional 215 cab with another set of JBL's will get you that 3 dB gain Isaac mentions as well, but unlike the possibility of doubling the power of a 60 watt Sunn, the gain available with a matching cab is indeed attainable.

Going to a SS rectifier, and beefing up the power supply caps can get you some more headroom allowing the amp to get a smidgen louder before breakup and noticeably tighten up the bass response, but again as Isaac posts the difference between 6550's and KT88's in that circuit would be negligible at best.