Jun 7, 2009

Getting a handle on finishing this project

Today I added the side handles.
This is a view pointing the camera upwards about 45 degrees.
Here's a link to these handles.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=262-832&FTR=ph122&CFID=10708174&CFTOKEN=32054622

Here's the back of the Celestion Alnico Gold speaker cabinet.


Jun 6, 2009

Almost Done.

Here are the latest pics of the Amp formerly known as Amp #2.
My friend has named it, so from now on it will now be known as
"Hot Tamale!"

Here's the back.
Two Input Jacks (8 ohm and 16 ohm) and a parallel output jack to daisy chain the speakers together.
Close-up of the back of the head.



And the Top Vent with grill in-place.


May 31, 2009

Grill Cloth The 2nd. attempt.

I was able to get the Grill Cloth on with satisfactory results this 2nd. attempt. I had in mind an elaborate arrangement of small clamps that would tension the grill cloth in about 30 areas on each side. Each clamp would grip the grill cloth then a wire would connect the clamp to a board with screw adjusters to tension each clamp separately. Luckily just using some 3M super 77 spray adhesive on the front of the frame was all I needed. It was tacky enough to allow me to get the fabric lines somewhat straight but still allowed some movement If I needed to pull in a certain area. Whew!
The feet for the head and the bottom cabinet are on order so this pic is just using some other amp feet I had laying around. The Middle cabinet is pretty much all done except for wiring the speaker to the jack plates.

This is a real optical illusion because the two speaker cabs are exactly the same size. The grill cloth and piping really makes the top one seem taller.

Here's the Celestion Green Back (Heritage G12H)

May 30, 2009

Changed the Piping Color and redid the faceplate.

I received a request from my friend to change the piping color back to the original spec of white along with making the piping not follow the face plate all the way down on the side of the amp.
Today I went to the fabric store to pickup some white vinyl for the piping. Since the speakers are also going to have piping I decided to get all three pieces cut and sewed up. Here's the white piping, I think my white balance was a tad off in this pic.

In order to redo the front piping. I needed a different faceplate. This new face plate has a relief cut in the back side in order for the amp to fit snug against the sides of the amp head cabinet. The previous face plate had the amp sitting rearward a little in order to take into account the thickness of the piping running down the side. This new face plate without the piping running down the side needs to be flush. This morning I made the new faceplate and at this point had applied the contact cement a few hours prior.


Attaching the Tolex to the new faceplate.


Some of these corners are tricky. I'm just learning to just wing it and hope for the best. It's kind-of like wrapping a present in some ways, but you can't have an overlap of two thicknesses of Tolex because there's no contact cement on the top of the Tolex for a overlapping layer to stick to. Here's the white piping. I trimmed the piping to the desired width, and now I'm tacking it into place using small tacks. This is the top right hand corner.

Now the fun part. Since the face plate protrudes, there is no place for the piping to basically go after it hits the face plate. Scratching my head I came up with a solution. By cutting a trench in each side of the cabinet. I can get the piping to "disappear" while at the same time the amp will still fit flush. Now I could have just continued the piping up and tacked it to the back side of the face plate board, but then the amp would hit the piping and there would be a gap on each side of the amp, so the the amp wouldn't then be able to fit flush with the sides of the cabinet.

Point of no return now!

Ouch, that was hard to do.
And the right side.

Here you can see how the piping is able to fit in the trench that I dug out. I then used a few tacks to keep the piping in place. You can't tell from this pic, but the faceplate will fit flush against the backside here.

Here's the Tolex faceplate installed. There's a subtle difference in the way the piping disappears between the left and right hand side. At some point I'll redo this, but the clock is ticking on this project.

Here's the final product. I think my friend was right. The two changes were worth it in the end.
The white piping makes it POP visually.


May 19, 2009

Not happy with this result. Back to the drawing board.

My first attempt at adding the Grill cloth was a complete failure. Hopefully the 2nd attempt will
come out looking better. The method I tried was to staple one edge using 1/4" staples on the frame I made. The frame is about 1.5 inch wide poplar boards about 3/16" thick. I routed a lap joint at each corner so they are pretty strong and thick enough to staple the cloth and later the grey piping to. I first stapled one edge. I then stretched the fabric on the opposite side. Stapling from the center outward. Then repeated that on the other two sides. I think my problem was too much tension on the cloth.

(Not pictured) I was able to also Tolex 2 of 4 the back boards for the speaker cabs. The Other two I need to drill some holes for the speaker jack plates prior to adding the Tolex to those two.
I was going to wait to add the speakers after I had the plates done so I can hook them all up at the same time.


May 16, 2009

Finished the front of the head.

Last night I was trying to visualize the head with this white piping that was requested. First the piping is made of plastic and is very stiff, so I knew that I'd run into problems in turning the corners and especially down where the front plate transitions into the amp faceplate. I then decided to go with a color that is as close of a match to the faceplate as possible. I was able to find some vinyl at a local fabrics store that was a close match. The next step is to use a piece of thick string to form the round pipe part of the piping. I made tons of this stuff for my Sailboat cushions so this was easy to do. Here's a good view of the piping being created. My sail sewing machine has a special foot to allow the needle to get real close to the pipe.

I then used some tacks to add the piping to the front head cover plate. I had added the Tolex to the cover plate last night.

Here's the head with the cover plate in place. From here I need to transition the piping making a 90 degree vertical rotation so that instead of it being nailed to the side of the front plate it is nailed to the back of the side trim pieces.

Here is the almost completed head. I still need to add the screens in the back and top and add the feet and handle.


May 15, 2009

Working on the back of the head

Last night I had cutout the front cover and the back cover for the head. Both were pretty involved. Tonight I was able to add the Tolex to the back cover plate. I still need to dress it up a bit by adding a grill, screws and a few Tolex touch-ups.


May 11, 2009

1st. Custom Handle made. 2 more to go.

I had bought some Black handles for the amp, but it just doesn't look right. The handles would be the only only black on the amp and stack besides the feet. So I tore the handle apart to see how they constructed it. I was surprised to find a Steel strap that goes between the two ends. This is a really bullet proof strap, literally it might actually stop a bullet :)
The filler in the strap itself was basically a paper/cardboard, this was used to bulk up the strap to make it thicker.

From my sailboat I have an Industrial Sewing machine and just happened to have some really thick leather laying around. The leather is used in canvas work and on sails for chafe protection. It will be even better than cardboard as it will add a ton of strength to the strap. I'm thinking that the strap could be used to tow a car if the need ever arose.
This was my first attempt at the strap. The white thread just didn't look good IMHO.
My sewing machine is a brute, but isn't up to the job of making really pretty and consistent stitches.

Here is attempt number two. This time using matching Red #69 (really thick) thread.
This turned out ok.

Here's the finished product sitting on the head cabinet. I'll be attaching them last after I get the head completely done so I can get the strap located at the center of gravity.

May 10, 2009

Starting to detail the head.

Tonight I was able to get the corner protectors installed on the head cabinet. I also did a trial fit of the amp installed in the head cabinet. The opening will be covered by a panel and faced with grill-cloth.


May 9, 2009

Cabinet #2 is covered.

Cabinet #2 is all covered. I waited a little longer for the contact cement (Dap green can) to setup and that did the trick. I found that about 2-3 hours after two coats was ideal. At that point it had some grab but you could still reposition if you had to.
Some next steps are to create some back panels, install the speakers which are en route, wire everything up to some jacks in the back. Other steps involve adding the corner protectors, feet and the grill cloth. The most daunting is the grill cloth. I'm going to have to read up on how to do that successfully.

May 6, 2009

Cabinet #2 is progressing

I haven't taken a day off work in a while, so I spent it woodworking :)
The Lower Cabinet (#2) is progressing. I was able to get it built-up yesterday. I still need to sand it and fill in the nail holes. Then it will be ready for Tolex.


May 5, 2009

Speaker Cabinet #1

I've been busy around here, there was a couple estate auctions this past weekend that I attended. I was able to add some tubes to my growing tube collection.

This week I was able to get the 1st speaker cabinet ready for covering. This involved filling and sanding all the little imperfections so that there is a smooth base for the Red Tolex covering.

Tonight I was able to get the Tolex on the cabinet. This cabinet was a lot harder than the smaller head. I think I'm not waiting long enough for the contact cement to setup. I've found both times that it is hard to get the Tolex to stick initially, but by the end of the covering process it is very easy to get it to stick. I think the directions on the can are misleading. Next time I will wait about 2 hours more than I would have normally waited.

Tolex coated with 2 coats of contact cement



I hung the speaker Cab from my garage ceiling in order to get at all of the surfaces.


Here's the somewhat finished product. I still need to get my mini iron and pretty up the corners.
This is the front, the Speaker grill and white piping will cover the inside corners.

This is the back view. This was the hardest part as there were some really tricky angles.
Most of this part (the 45's where you can see a gap) will be covered by the back pieces anyway.


Apr 25, 2009

Finishing up Amp #2

The rear faceplate came this week. Special Thanks goes to BNP Lasers. They look awesome and I can't say enough about their customer service. I would recommend them to anyone building an amp. This is the front faceplate. It took me about 2 weeks to create. If you notice they do go to eleven.








Here is the rear faceplate.
You plug the Tremolo Foot switch which is a stomp switch into this jack. It turns the tremolo on and off.
The line-out circuitry is post Output Transformer. So it contains all of the great sound of this amp. The line-out is controlled by the line-out switch. With the switch in the middle or off position the line out circuity is completely removed from the output signal path. With the line-out switch up the line out circuitry is activated. In this position you must have a speaker connected. In this mode you can be playing through this amp and take the line out into the input on a PA system or a bigger power amp.
Finally with the switch down, it adds a 25 watt 8 ohm resistor to the output so that you can use the line-out to feed into the PA or power amp without a speaker connected to this amp. The resistor prevents damage to the output transformer since it provides the same load as a speaker would.
Below is a line-out level control that will vary the level of the line-out circuit.

Here is the Tube Based (12au7) Active Effects Loop. On the left is the Send level control. The circuit basically is two preamp(s). The 12au7 tube has two channels so one half of the tube controls the SEND and the other half of the tube controls the RETURN. The send level and return level controls allow you to use any pedals. You can adjust the SEND level so that the Input of the pedal is just right. You can also vary the level coming out of the pedal train so that the amp sees the correct level. I used a patch cord from SEND to RETURN and the circuit actually adds more amplification to the 18 watt that the normal gain stage. Thus you get even more distortion at Eleven!
The downside with so much functionality on the back panel is the lack of real-estate. I had to sacrifice a speaker output. To compensate I'll add additional jacks to the speaker cabs to allow them to be daisy chained together. The Attenuate switch in the middle position eliminated the attenuation circuitry from the output signal path. There are three positions, Quiet, Off, and Medium. The Quiet and Medium positions use the attenuation modules on the top of the amp to reduce the power level of the amp (loudness). I'm still creating all of the modules (8 in all).
See the previous posts for more info on the power levels.


The Tube based effects circuitry can be completely removed from the signal path using a Push/Pull switch on the RETURN level knob. Pushed in the effects loop is removed/disabled.
Pulled out the loop is activated.
Pulled out (ON)

Pushed in (Off)


Full rear view