Tweed Bassman cabinet

[osing]

Howdy,


I am planning on building a 5F6-A tweed Bassman and want to build the cabinet myself. I am curious if anyone here has seen a vintage Bassman and could tell me whether it used solid pine boards or if it used laminated pine (i.e. several narrower boards glued together). I remember seeing some wide pine boards at Home Depot, and I do not believe they were laminated. I think they are called "Select" or "Premium". Those have no knots.


Any thoughts if the Home Depot boards would be a good choice? Other suggestions?

[sluckey]

I can't talk specifically about the Bassman but I have a 1957 Harvard amp. It has wide pine boards. Looks like cheap Ponderosa pine including big knots.

I would prefer glued up boards because they will be straighter, less cupping, and more stable. Look closely at the HD boards. I would not be surprised if they are glued up.

[SILVERGUN]

Those premium select pine boards at HD are not glued, and I usually have to sort through a bunch of 1x12s to find a couple straight ones. (they do have some laminated "project panels" but I have seen those glue joints come apart so I shy away from those)
 
They are usually about 20%+ heavier than the knotty pine and almost twice the price. Other than that, I like them for cabinet builds.
 
Not sure if you've seen this, but hope it helps:

[sluckey]

Those premium select pine boards at HD are not glued

Glad you saw this thread SG. I had forgotten about your recent experience with pine boards.

[thermion]

I've had terrible experience with new growth pine boards from the big box...like they warp in both directions simultaneously over time.?. Total crap, I guess you have to kiln dry/ press this stuff to make it work?
If you can (re)source some old dry long leaf pine, say from a home demo, I think you'll be better off. Or possibly some of that reclaimed, super dense river bottom stuff.
The glue work on those laminated boards will fail at some point, I wouldn't bother with it.

[SILVERGUN]

Those premium select pine boards at HD are not glued

Glad you saw this thread SG. I had forgotten about your recent experience with pine boards.

Yeah sluckey and osing, I've bought a bunch of the select pine boards this year.
Luckily I have about 6 HD's within 15 miles so I had lots of stock to choose from and I won't settle for bending, twisting or cupping at all when I'm spending $24 for an 8' 1x12 of pine
 
You have to take your time to find a "perfect" piece, and even then, if you leave it in the heat you can expect it to warp pretty quickly....the extra weight is a direct result of the increased density of those boards as compared with the knotty pine. I can easily push my fingernail into the cheap stuff about a 1/8" with little resistance.
I usually go right from the store to the saw so I don't run into problems by the time I hit the dovetail jig.

[tubenit]

I have built some fairly nice looking cabinets over the years out of hardwoods such as mahogany, sapele, and maple (including figured maple).  Those are left uncovered allowing the wood to show.

I think the best sounding most resonant warm cabinet I ever built was 11-ply plywood. It didn't have open areas between the plys that I could tell. Very light weight and very resonant. I covered it with cloth backed vinyl.  I don't understand why it had such a rich warm resonant tone but it did. Wasn't the amp, it was the cab as I could run another amp into that cab and get the same resonant tone.

I am not a big fan of pine cabinets because of knots and warping and twists in the wood. Just a personal preference as obviously there are more great pine cabinets out there then any other wood approach (probably).

IF I am going to tolex or vinyl over it,  I personally like the higher quality plywood.

With respect, 10thtx

[osing]

Thanks everyone!


Silvergun, are you saying that if you find a straight board that as long as you start working on it right away you minimize any chance of warping and cupping after the fact? Is it perhaps not nearly as likely to warp once it has been finger jointed and glued together in a cabinet since movement is severely restricted?


Also, if those boards are 20% heavier/denser, I wonder how much that affects the sound? I have read quite a bit about the great sound of vintage Bassman amps, and some claim the cabinet is a big part of it. Not sure if using denser pine would make and audible difference on a new build?


I love some of the exotic wood cabs people have built, and someday I might try it, but first things first!

[sluckey]

Silvergun, are you saying that if you find a straight board that as long as you start working on it right away you minimize any chance of warping and cupping after the fact? Is it perhaps not nearly as likely to warp once it has been finger jointed and glued together in a cabinet since movement is severely restricted?

I always wait a day before working on a project with 'furniture grade' joinery. This allows the wood to acclimate to temp/humidity in my shop which is very different from the air-conditioned climate inside HD.

Quarter sawn boards will be much more stable than flat sawn boards. Look for those. There won't be many in a pile at HD but you can usually find a few.

[SILVERGUN]

1) Silvergun, are you saying that if you find a straight board that as long as you start working on it right away you minimize any chance of warping and cupping after the fact? Is it perhaps not nearly as likely to warp once it has been finger jointed and glued together in a cabinet since movement is severely restricted?


2) Also, if those boards are 20% heavier/denser, I wonder how much that affects the sound? I have read quite a bit about the great sound of vintage Bassman amps, and some claim the cabinet is a big part of it. Not sure if using denser pine would make and audible difference on a new build?

1) Yes, I usually start on it right away because I try to catch it before it changes shape. I've watched them change drastically in just a few days, and have even returned one because it was just unacceptable. When you're trying to get dovetails to fit perfectly it can be frustrating (finger joints, not so bad)
Like sluckey said, one day is good,,just don't leave em out in the shed in the summer for a week.
 
2) Yes, all wood/species will sound a little different (like tubenit mentioned) and he has a ton more experience than me so listen closely to his recommendations on tone.
BUT, sound is also subjective, and guys who own original bassman's wouldn't want you to think that your newly built 5F6-A could possibly sound half as good as their vintage seasoned furniture.
 
I did read somewhere where Gerald Weber was talking about how he could hear a big difference in aged wood, and would only make his amps with that...but he is trying to create demand in a tough market, and charge a premium price for a premium amp.
 
Speaker selection will have a much greater effect on your tone than the type of wood used.

[osing]

Thanks again guys, I appreciate your inputs as always.


Silvergun, while I have your ear, could you give me some practical advice regarding the finger joints. In an ideal world, I would think they should be fairly tight, but does that make it difficult to get enough glue in there to make a permanent bond? This will be my first shot at doing finger joints, and although I will try on some scrap pieces first, I'll probably end up with joints that are either too tight or too loose. It would be good to know what to strive for, though. I saw a youtube video a while back of the 65 Amps shop, and the owner was bragging how tight their CNC cut joints were, to the point where glue almost wasn't necessary as they stayed together when he threw a cab on the floor :-)


Also, how do you go about cutting out the openings on back panels as well as the areas on top where the controls are located? I am thinking I would draw out the shapes on the wood, then use a cutout saw and get close to the lines, and finally use some files and sandpaper to get it perfect. However, I have seen some folks use hole saws. Any advice?

[SILVERGUN]

Osing,
I'm no expert on finger joints as I've only had to do them once due to the fact that the work-piece was too wide for my dovetail jig. I'd rather have them nice and snug before glueing, and add some finish nails with a nail gun if I was worried about the glue bond. If you're covering it with tolex then the nail holes won't bug you.
Everytime I set up to do joints, I always practice on scrap wood a few times, so once I get those joints tight I know I'm ready for the big time.
 
For the back panels, and top control cutout, I'd use a router and a template (that you'd make ahead of time), that way you will get some practice with your router.
I'd do the top control cutout (including round-over) before I actually assembled the box. It'll probably take a couple attempts to get it just right.
 
YouTube is full of guys who are much better with good wood practices than me, and the other gentlemen on this thread make me look like a birdhouse hack.
 
The only way I get good results is if I put everything else completely out of my mind, and don't rush to get done.
 

[osing]

Hi guys,

So I am almost done with my Bassman cab - I just have to do the roundover and some sanding. I will be using a 1/2in radius roundover bit along the outside edges.  However, where I am not so sure is the rounding of the cutouts on the two back panels. Since they are only 1/4in thick, I don't see how easily I can use a roundover bit - the guide bearing needs something to run along which leaves little room for any rounding.  I would be curious what others have done on their builds.

[sluckey]

Use a guide bushing mounted in the router baseplate.

[osing]

Sluckey,

I am struggling to envision how that would be done. I have never used guide bushings but rather only bits with bearings attached at the end. With a bushing attached to the baseplate, would you basically need to guide the router along a template with the back panel below the template so that the cutting part of the bit can do its work?

[sluckey]

Sorry, You would also need a template. But you can make a 1/4" thick template with the same cutout as the back panel. Tape this to the back panel using double-sided carpet tape and use your ball bearing bit.

[osing]

Thanks Sluckey. I actually made templates out of 1/2in MDF to make it easier to make the back panels in the first place so I can just use those. I'll play around with some scrap wood tomorrow before I try on my actual back panels, but I think I get what you're saying now. Thanks!

[osing]

I was able to complete the roundover on the back panel cutouts using Sluckey's suggestion and am happy with the results! I used a 1/4in roundover bit on the cutouts and then a 1/2in bit on the cab itself.

Any thoughts on whether to go with t-nuts for the speaker mounting, or are the double threaded screws with nuts a better choice (like the baffle board screw that Doug sells, see link below)?
http://hoffmanamps.com/MyStore/perlshop.cgi?action=template&thispage=AmpTrim&ORDER_ID=588888640

[sluckey]

Nice job! I like T-nuts and double threaded screws with kep nuts. I don't really have a preference. Double threaded screws are a tad easier to install.

How thick is your baffle? How does it attach to the cab?

[osing]

Thanks Sluckey! Maybe I will give the double threaded screws a shot. My only concerns with those are somehow poking holes in the speakers when installing them, but they look easy to install and probably are less likely to fall out between the baffle and grille cloth (which is my one concern about the t-nuts :-)


I should have mentioned that the baffle is just held in place by some painter's tape for the photo. I still need to order mounting hardware as well as tweed covering and grille cloth (I need to do some research on those, though, as I don't know how much material is needed nor have I ever tried applying it. The baffle is 3/8in baltic birch, I could not find the 5/16in that I believe the original bassmans might have had, but I figured 1/4 in would be too weak. Hopefully, the 3/8in will work out.

[osing]

Howdy again,


I finally got my hands on a 5F6-A chassis, and when I hold it up inside the raw cabinet (i.e. no tweed yet), I am noticing that the 2nd input jack of the Normal channel likely will not fit inside the radius of the cutout. I did take into account the fact that the tweed will force the back panel and thus chassis out a bit towards the back, but even then the fit seems too tight. Since the cabinet is still unfinished, I should be able to file away at the rounded corners a bit and make it work. I wonder, though, has anyone else had problems using the 1 1/4 in radius for the panel cutout as shown in the drawing posted earlier by Silvergun? I am thinking a 1in radius might be better.


Also, while I have your ears, do you guys typically apply any sort of finish to the bare pine inside the chassis (i.e. the part that will remain uncovered)? Do you lacquer or apply any other finish to the tweed itself?


Finally, does anyone know what the 3rd screw on the top panel of the Bassman in this pic is for? I understand the two chassis mounting screws, but what is the screw to the right of the handle near the edge when looking from the front?


http://www.andrewsamplab.com/Amp%20Photo%20Gallery/1959_tweed_bassman.htm


Thanks!

[HommeMarrBuckley]

That is a fine looking cab!  Well done sir.
Very tight/precise finger joints--I surely would have broken one of those off.
I wouldn't worry or waste time with the interior of the cab.  It won't be seen.
What did you use on the exterior of the cab?
Any ideas for speaker choice?  some Jensen P10s
Going with floating baffle?
Take your time.  You have done a great job so far. 

[osing]

I bought some tweed but have not applied it yet. To be honest, I am not looking forward to it and have some research to do first as I have done it before. Wish me luck!


As for speakers, I have been pretty happy with the Weber speakers in my Super Reverb. I have been using one each of 10A150, 10F150, 10A125 and 10F125 but then trying to determine which are my favorites. I am leaning towards two 10F125s and either two 10F150s or two 10A150s. If you look in the videos section of this forum, you can see a video I made trying to compare the various combinations of speakers (in pairs - I have it wired so that I can run any combination of pairs at 4 Ohms with the OT Set to 4 Ohms). However, from what I have read, people seem to like the 10A125s in the Bassman, so I don't know that I can assume what sounds good to me in my Super Reverb will necessarily sound good in a Bassman.


The baffle will be floating with two screws at the top and two at the bottom.


Any thoughts on what that third screw I mentioned above is for?  Anyone lacquer their tweed?

[sluckey]

Found this...

"Yes, they mounted a very crude piece of metal to one of the power transformer
screws(mounted on top), this is what the extra screw in the top of the cabinet
holds."

[osing]

Sluckey - that's perfect - thanks for sharing. I like the idea of the extra support and taking some strain off the other chassis screw on that side, so I think I will use a third screw and L bracket on my build.

[osing]

So it took me while, but I finally managed to add the tweed and grille cloth. Everything seems to have gone well except for a couple of minor issues.


For one, I did not realize the the tweed would shrink when the glue was applied, so the bottom ended up being narrower than the distance between the sides, thus there is a small gap with wood exposed on the top of the bottom "narrow panel" on both sides. It's not a big deal, but lesson learned. I was a bit luckier with the top as I managed to stretch it a bit when applying, but as a result some of the diagonal lines warped a little on the top right hand side, resulting in the angle of the 4 diagonal lines "breaking" where the top meets the side piece. Nothing to lose sleep over.


Further, even though I had gone back and opened up the top cutout a bit more to ensure a good fit with the "Normal 2" input, I still struggled getting the chassis to fit properly. In fact, I ended up having to put some spacers behind the top rear panel as I needed to position the chassis farther towards the rear in order to ensure I can actually plug something into the "Normal 2" input.


I have not yet drilled the hole for the third bolt to accommodate the L bracket for the power transformer - I will do so once I have the actual transformer in hand.


The big question for me know is whether I should apply a finish to the cab. I found a good thread on using shellac and lacquer here:


http://www.mylespaul.com/forums/squawk-box/133747-shellac-tweed-step-step-guide-one-guys-system.html


I am going to try it on a scrap piece of tweed first to see how it looks.


Does anyone around here just leave the tweed bare, or do most of you finish it in some way to protect it and/or change the color (e.g. shellac and lacquer or Polyshades polyurethane)? Anyone have any thoughts on whether the sound is affected in a negative way by finishing it? The only thing I can think of is that adding finish could dull the cab a bit, but I am hoping that is not the case.

[sluckey]

I like shellac on tweed. It's fast and easy with a brush. I've used Zinnser's clear and amber. You can control how dark the amber is by the number of coats. If you get it as dark as you want but still need another coat just use clear. Here's a link to the two cabs I've done...

     http://home.comcast.net/~seluckey/amps/5e3/5e3.htm

[osing]

Sluckey, those both look great, and I really like the amber color of the TDR! That's probably the route I will take. Did you put a coat of lacquer over the shellac?

[sluckey]

No lacquer. Just shellac cut 50/50 with denatured alcohol. It's about the consistency of water and brushes on very easy. Each amber coat makes the finish a little darker. I think the TDR has 4 coats of amber only. If I were to do the TDR again I'd probably just do two coats of amber and two coats of clear.

Shellac is not a tough finish like polyurethane. I'd never use it on a table top. But it works well on tweed and if you need to spruce it up 5 years down the road, just brush on another coat. The new coat kinda melts into the old coat.

I never was too happy with the color of the 5E3. This spring I put one amber coat on the 5E3 to give it a light honey tone. I just took this pic 10 minutes ago...
 

[osing]

That's pretty nice looking! Any issues with stains on the tweed with just the shellac? I don't plan on using my amp as a coaster, but I have read that stains can form if you spill things on it (especially alcohol, I guess), which is why some seem to advocate lacquer.


I might try with and without lacquer on my test pieces of tweed. I sure as hell don't want to screw things up now that I am in the final stages of the cabinet (a mere two months later :-) I do like the idea of being able to just add some more shellac when needed at a later time.

[Willabe]

I never was too happy with the color of the 5E3. This spring I put one amber coat on the 5E3 to give it a light honey tone.

That does look better. 

(They both look great.)
 

[osing]

Ok, the cab is finally finished. I ended up applying a clear spray shellac first in order to prevent the amber shellac from going on unevenly and also prevent discoloring at the seams. However, when I added the amber shellac, the seams did get bit discolored. I covered the amber with the clear wax free shellac and finally some coats of lacquer. I am happy with the results!

[sluckey]

Nice color. I think it looks great.

[tubenit]

That does look great!  Very nicely done. 

With respect, Tubenit

[osing]

Thanks guys! My fingers are itching to get started on the amp itself, but it's going to take some time as I don't have much spare time over the coming weeks!