Friday, July 29, 2016

Bastard Bassman







This started out life as a Bassman 50 that I acquired with a little horse trading. I may have mentioned it before, but I acquired a Teisco guitar at an auction for a cool fifty bucks-that's the benefit of superior knowledge-and, having no love for it I offered it for trade on Craigslist, the "why pay more?" store.

A friend of mine came up with a Sound City 120 in need of repair and we swapped.

I promptly offered the Sound City for trade for a Bassman and I acquired a Bassman 50 head in short order. After the usual tidying up inside, all was good. I then turned it into a tube rectified job with a socket and a Super Reverb power transformer-you need the 5v winding which the original PT does not have. Ultimately it will become a 6G6 Bassman but for now it is what it is.

About six weeks ago I ordered a combo cabinet for the Bassman head from J.D. Newell, the only place to shop for amp cabinets. It arrived yesterday, and I stuffed the hole with an Eminence from a defunct Tech 21 Power Engine that I acquired. It occurs to me that I also have a nice 12" Peavey Black Widow that I may try out and see if it fits.

The result is what you see here.  The total cost of the entire project amounts to $412.50-$52.50 for the guitar, $50 for shipping the Sound City to Texas, $220 for the cabinet, $50 for the blackface faceplate, and $40 for shipping the cabinet here. The power transformer, tube socket, and high class Mullard rectifier were all things I had here.

I don't know why more people don't do this with orphan amp heads.

Wednesday, July 27, 2016

Stemming the Flood: Repairing A Leaky Pinion Seal In A Ford Ranger.

I realize this is way distant from my usual material but it did happen on the way back from snagging the Traynor amp I described.

The following applies only to a Ford 8.8 open rear end, although I am keeping my eyes open for a Traction Lok unit. I'd lile to have limited slip this winter. If you don't know what rear you have check the driver's side door for a build code label or check the tag on the rear end itself. They look different from the seven inch rear anyway.

It was hot, sweaty, and I was sort of flogging the truck, and when I arrived in Louisville the Ranger burped out about a cupful of gear oil from the rear end pinion seal and dirtied up my sister's driveway. A trip to an auto parts emporium got me gear oil and a tool to remove the fill plug, and I put in 12 ounces of gear oil.

I should also mention that I'd changed the oil and filter and used Castrol 5W30 and when good and hot the oil pressure gauge would flicker when taking off from a stop. Some STP cured that but I'm going back to Valvoline for good.

On the trip home, at my next stop I put in 8 ounces of gear oil, then four ounces, and then the level maintained itself. However, it did make a mess in my driveway as well when I got home.

The critical point here is that the torque on the pinion nut crushes a sleeve which sets the preload for the differential gearset, and that is why care must be taken with disassembly and reassembly unless your idea of a fine day is removing and setting up a rear end.

These notes apply only to a 2wd 2002 Ford Ranger with the 8.8 rear end, 4.10 rear gears and an open rear end.

You've got to know what rear you're working on, and there are plenty of resources after you have gotten the code off the builder's data plate in the door jamb and/or the tag affixed to the rear end.

The first job is to mark with a punch and a hammer the driveshaft flange and the pinion flange and unbolt the driveshaft and get it out of the way. I used a hammer and a punch. The driveshaft is held in with bolts that take a twelve point 12mm box wrench. Then push the driveshaft out of your way.

The next task is to clean everything off with Brakleen or other suitable degreasers. Then, index mark the shaft, the nut, and the flange with something like paper white, lacquer, or anything. This is critical, because if you don't have these references you're screwed. Really. .

My impact wrench didn't do the job so I used a 1-1/16 socket, a breaker bar and a cheater pipe to remove the pinion nut which was the  handle from my engine hoist. When the nut loosens, then take a ratchet and turn the nut off while counting the turns. In my case it was 16-1/2 turns.

Then, using a gear puller pull the flange and check the sealing surface for wear and grooves. Clean with scotchbrite if it is needed.

With a small hammer and a chisel or a screwdriver remove the old seal. Clean the area with solvent and remove the sealer if the seal was installed with it. Dress any scratches or dings with a small half round file.

One can then carefully install your new seal, first packing it with grease and wiping a little rtv on the outside.

Start it with a small hammer and then finish with a block of wood, making sure you don't damage the sealing surface or distort the seal itself.  Make sure it's bottomed out on its mating surface.

Buy the best seal you can, either National, from the Ford dealer or CR if they sell in your area. Don't go cheap.

Reassemble in reverse order, counting the turns of the pinion nut until it bottoms out. Then, you can reef the nut down with your breaker bar and cheater pipe. All your index marks should now line up perfectly. Then you can reinstall your driveshaft.

If you've done this correctly you will have preserved your preload inside the differential.

You can now remove the cover to drain what's left in the differential and reinstall the cover, torquing the bolts to about 20 foot pounds in a star pattern.

The NAPA folks sell a gasket for this task which is more trustworthy than a mere bead of RTV. Reinstall the cover, gasket and a thin coat of sealer, bolt it up, and then let it sit for a good 24 hours cure time.

Refill the differential with about 2.7 quarts of  a good grade of 80W-90W hypoid gear oil. A limited slip rear requires anti friction additive to the gear oil.

Take a road test to make sure you didn't damage the seal on installation and have to do it all over again
.




Monday, July 25, 2016

And Now For Something Completely Different









Here's something that I acquired a few years ago and hadn't pulled it out until recently.

I have no idea who made it at all and it could be a homebuilt.

The speaker's a Magnavox field coil job made for Crosley, and the tube lineup is 6J5-6J5-6J5-6V6-6V6-80. The 80 rectifier and the field coil dates this to likely prewar or possibly just post war.

It probably pushes 6 or 8 watts at full tilt and it's got an interesting neon bulb that flickers when it goes into clipping. If I had to take a guess it is probably a converted record player amp.

Wednesday, July 20, 2016

Mystery Traynor



Here's a very interesting Traynor combo I acquired in a trade recently. It''s a YRM-1 but with a difference-it's a combo with 4-10 inch speakers, reverb, tremelo and master volume. You can see about how large it is by comparison to the Twin Twelve in the background.


It passed the strange stuff test with flying colors so I had to have it, even if it necessitated a detour to Carbondale Illinois on a pretty hot day when I was supposed to be in Louisville. The pinion seal on the Ranger took a dump on this trip, made a mess and caused no end of grief, and that'll have to be fixed but it'll keep until the weather cools off a little.

One thing I noticed when I got back home was that the output transformer seemed a little on the smallish side and I was right. Someone in this amp's past replaced the original Hammond with a Schumacher Bandmaster output-a little light for the task, methinks. But there's some good iron in the laboratory and on fleabay so all I gotta do is measure up the original mounting holes and see what can be acquired. I'm thinking a Twin Reverb output would be swell, you figure double the impedance for only a single pair of tubes, and if memory serves me right I may have one. I don't like EL34s much.

As well the vibrato needs tuning because the volume goes down a bit too much for my taste although it does oscillate fine. The reverb is swampy and lush, it's got lots of volume and overall it is in pretty fair shape.

This is the first one of these I've ever seen. Most of the YRM-1s were heads intended to create the Bassmaster tone with reverb and vibrato and a master volume. It'll need a look around inside when I get some spare time.

Wednesday, July 13, 2016

When Mud Daubers Look For A Home

Here's the inside of a Harmony H303 amp I did up for a friend.

It's a very simple three tube series string widowmaker that could deliver a jolt, but someone had their head screwed on straight at Harmony and it came equipped with a factory installed isolation transformer that is a necessary item if you have one of these creations and it doesn't have one.

The filaments are connected in series which gives you 35v, 50v and 12v for the 35W4, 50C5 and 12AU6 tubes. The total output's about 3.5w into a smallish speaker. Take the 97 volts and add enough resistance to make up 120 more or less, and use the chassis as a return path.

Very effective, cheap and dangerous if you are connected to the chassis by a guitar cord or a microphone. It was a variation on the All American Five radio which, if it sat on a shelf and came in a plastic case was perfectly fine. But not a guitar amp.

An isolation transformer does just that-it isolates the chassis from line voltage.

It was a gut job because the output transformer was wasted as were the paper capacitors and the electrolytics.

What was interesting was the collection of mud dauber nests that were inside it.