Restoring the Kustom K250-4 amp

This project was a real labor of love.
I've always be partial to Kustom equipment.
My first "real" keyboard was a Kustom roll & pleated organ.
No longer did I have to crank every knob and pedal to be heard over the drummer.

Van in 1972. Band-Krystal.

Dad felt pity on me and my Magnus combo organ from Woolworth's and broke down and bought this for me used from Harris Music in W. Palm Beach for $600.

I think mainly it was because we had to practice in our living room where I used his Wurlitzer organ. Not a very rock 'n roll organ.

That and mom was getting pissed about the cigarette burns on the coffee table.

But I digress.........

Finding the K250-4 was by chance on Craig's List.

The guy kept lowering the price and it wasn't selling.

It was a 40 mile one way trip to his house on the other side of the valley, so I made the journey.

Climbing the stairs to the second floor I finally see the Kustom for the first time. My heart sort of sank.

It was dirty, torn and looked abused.

As I looked it over, he lowered the price again.

Testing it out with his guitar, it crackled a bit, but all the functions operated well.

I shined a light into the back to see it didn't have the original speakers, and he lowered the price again.

I handed him the cash and we carried it out to my truck and off I sped.

Here's what it looked like before the restoration.

Here's the full size "before" shot: http://i986.photobucket.com/albums/ae341/vandenmike/kustom250.jpg

The vinyl and grille cloth was torn, the polarity switch didn't function and it still had a crackling sound while played.
No foot switch or pedal for the tremolo/vibrato, reverb, boost (wah-wah), fuzz came with it, so I knew I'd have to find or reproduce those to get where I wanted.
I was fortunate enough to have the nameplate and handles complete and nice shiny casters. The chrome was 7/10. Very little rust.
The knobs were all original. A big plus.

I had to completely disassemble the head and cabinet to see what was going to be necessary to get this amp as close to original and pretty as possible.

First, the amp head.
Pulling the amp out of it's shell was easy. 4 screws on the bottom and the chassis slid right out. This made repairing the torn vinyl a lot easier.
For the vinyl repair I used the Permatex vinyl repair kit available at most auto parts stores.
I also had to find some vinyl material to use for backing. Found an old black vinyl briefcase at a Saver's store for $2.50. I was able to cut out patches to size out of it and slide them in the holes and splits.
Having a vinyl backing made the vinyl repairs a lot easier. Otherwise I'd be applying vinyl repair to the foam.
I started on the bottom of the head just to get a feel for how the repairs were going to turn out. Didn't want my first try to be somewhere it could be seen in case I muffed it up.
I slid in the backing vinyl (cut a little larger than the hole/split) and secured it with VLP vinyl repair glue. After that dried, on to the Permatex repair kit.
I just filled in the space with a little over-lap, placed the texture material over the liquid vinyl and used the supplied heat iron in the kit.
Turns out that it was easy!. The kit came with a texture material that came close to the original Kustom texture and was barely noticeable. From 2 feet away you couldn't tell it was ever torn.
I spent about a week, 3 hours a day, to get the head to where I was happy with the job.

On to the electronics....

While the vinyl was curing, I went ahead and opened up the amp chassis to check the switch and general condition.
A little dusty, but in overall good condition.
One of the Licon switches was broken.
Of course they haven't made them in 35 years.
Fortunately I found one for sale, used, on eBay.
He was plenty proud of that sucker for $25, but in order to get it to look right, that was the way I had to go.

I also found a loose molex connector for the second channel.

Maybe this is why he kept coming down in price? It was barely connected and might have been cutting in and out.

I found the reverb tank hanging on by one rubber mount.

I fashioned the other mounts by using rubber hose and some threaded rod.

I replaced the electrc cord.

Now, how the heck was I going to get a 4 button foot switch for the on-board effects?

A search of the Internet for an original foot switch was fruitless. Not to be found anywhere.

Fortunately, the guys over at the Vintage Kustom site (http://www.vintagekustom.com/) were a huge help. They gave me a schematic of the original foot switch.

I was able to build a foot switch from generic parts and modify it with LEDs.

The connection on the back of the amp for the 6 pin XLR was also broken. It was plastic.
I installed a metal one.

The scary part was connecting the foot switch and turning the amp on.
What if I had done it wrong?
I got up the courage and turned it on...it worked!
Every thing functioned correctly. Quite a relief.
Fuzz, tremolo/vibrato, reverb and boost available at a touch of the foot switch. Red LEDs lighting to show they're on.

Now, the boost (wah-wah) pedal.
Searched eBay and the Internet. for a couple weeks.
Finally one showed up on eBay.
It looked like a barn find, or something pulled out of a well.
I saw the bidding going crazy and was out bid. It went for over $100! Screwy!
So once again, the guys over at Vintage Kustom came to my rescue.
All this pedal has in it is a 10k ohm pot.
So, off to the used music shops to find an old volume pedal to convert. That sounds easier than it was. After about a week of searching online and in stores, I came across a used stereo DeArmond pedal sitting in a dusty corner of a used instrument shop.
It was in a box with a lot of "junk".
I pulled it out and showed it to the guy at the counter and he said "$15". SCORE!!
A simple operation. A 10k ohm pot at Radio shack and a stereo cable to connect it to the jack in the back of the amp.

Wiring the wah-wah pedal.

A custom printed label and it looks authentic!

On to the speaker cabinet....

Like I said earlier, this doesn't have the original speakers.
Loaded in the cab are 4 12" Celestion Rocket 50's.
Here's where I found trouble.
The holes in the speakers didn't line up correctly so they had them in cockeyed.
They had also just twisted the wires around the terminals.
It had to be completely disassembled anyway to replace the deformed grille cloth, so everything came out.

After pulling the speakers out, I had to remove the grille cloth.
There was about 100 staples holding it on to the wood. That took a while.
The deformation on the grille cloth appeared to be from heat. I tried to reheat and stretch the nylon material but got nowhere.
I went online and found Acoustical Solutions. There I found what I thought to be a nice cloth.

The bare wood was filled, sanded and painted.
Then, I correctly measured and drilled the speaker basket outer rim so the screws fit in properly.
Stretching the new grille cloth and re-stapling it was the hard part.
After the cloth was in place, a new weather-proof gasket was applied to the outer edge.

The cabinet vinyl was patched and the innards reinstalled.

Someone had installed a Marshall stereo input on the back of the cabinet.

This allowed a stereo or mono connection.
A DC reading of 3 ohms was read in the mono selection.
The head was capable of a 3-4 ohm connection.
Playing this for 1/2 an hour at moderate volume showed no sign of trouble.
The head had a built-in thermostat in case of overheating, so no worries there.

I liked what I had done and had a 100% working unit, but wasn't extremely happy with the 4 button homemade foot switch.
It looked homemade, and that wasn't going to cut it.
I went to The Guitar Center and happened upon a box of used items.
There I found a used 4 button foot switch. $40.
I was able to resto-mod it like the one I built from scratch.

A custom label, and it looked much more professional.

I ended up putting the first foot switch up on eBay and sold it for what it cost to make.
Sort of disheartening considering the time and effort it took, along with the rarity, but whatcha' gonna' do?

The final product

I ended up selling it on Craig's List. The buyer came in, saw it, plugged in his Les Paul and tried it, then handed me the envelope with the cash. No quibbling or bargaining.
He knew he was getting the rare of the rare. A Kustom K250-4 from 1973/1974 in perfect working order.

Original schematic of foot switch from Kustom.
Ignore my written notes at top.