Lesmania? Lesmanniasis?

I brought the Lesmann home today after a trip up to Minneapolis and back with a side trip to Mickey's Diner in St. Paul. That's worth the 265 mile one way trip. So the total today was 530 miles and the Mazda averaged 27.9 mpg-not bad for a rolling barn of an SUV and word that the engine is finally getting broken in.

It is a peach, in very nice condition and I got a demonstration of how the Accordio-organ works. I did not purchase the accordion mostly because I can't play one but I was interested in seeing how the entire shebang operated.

The amplifier has an interconnect cable that goes between the accordion and the amplifier. I would guess that the accordion has some sort of organ like tone generator hardware, and I think that means it must be supplied with power through the interconnect cable.

I would think that the accordion itself was not made in the US but imported and modified by Lesmann. I saw one post that says it's a Giulietti but I've no way of verifying that. The owner says it's quite heavy.

It was very pleasant sounding and I expect that the amplifier was built for the kind of service that electric organs demand.

The person I got this from said that he'd had the setup for fifteen years or so and the previous owner was a person who played Persian folk music exclusively with this rig. It's got a tag on the back that says Terlinde Music, St. Paul, Minnesota, so it never strayed too far from home.

I do not know whether Terlinde Music still exists but I did find that Bob Dylan played a concert there on December 24, 1956. They sure knew talent for what that's worth.

I'll be cross posting stuff in the future from my FB page (Elderly Amplification). Visit it if you've got the time.

It's in very good cosmetic condition and had evidently been well cared for. It looks like it still has all the original RCA tubes in it so I'll check them out tomorrow and post some detailed pictures and notes thereafter.

Ohm On The Range: Wiring an Ampeg V4 Impedance Switch.

I've had a V4 here for quite a while because the owner was going through some changes, had a hiatus in Maryland for a year or so and is now back in town.

So I dragged it out of storage and got it up and running but it still had one of the original issues from the first time I saw it and that was, no 8 ohm output. 2 and 4 are fine but nix on the 8.

So the issue was either the switch was defective, incorrectly wired, or the output transformer was bad. It looked as if the output transformer was recent. I changed the switch with no improvement.
I spent way too much time researching this without success and in the end, made a trip to Polk City where a friend of mine has a similar amp so I could do an inspection and narrow the issue down.

When I pulled the chassis of Barry's amp out, two things were obvious. First, Ampeg had cut a corner of the chassis out so that the switch could be accessed and inspected without complete disassembly.
Second of all, the link between the second and third row of switch terminals had never been installed-I suspect, by the person who installed the output transformer.

This morning, it was the work of a few minutes to take a bit of wire, make a link, and solder it in place.

The moral of the story is never expect that work previously done was done right. As Reagan said "Trust-but verify. Play-but cut the cards. And never be afraid to see what you see."

I promise, I'll cross post stuff from my FB page in the future so the entire world can see some of the stuff I'm cookin up.

Stuff That Lasts Forever.

What's pictured above is a Westinghouse fan that was built in 1914 and does service as a ventilation fan in the bedroom of our house.  It does not oscillate which is good because the oscillating mechanisms on these sorts of fans does not survive as well.

It was acquired at an auction in Newton, Iowa about ten years ago and thereby hangs a tale. It looked as if it had never been used due to the way the power cord had been coiled up, but we got it home in a series of misadventures that included a rainstorm and passing the ultimate Iowa citizenship test-hitting a deer.

I still have the National Sportsman accordion amp I bought later that day but that is a relative youngster, having been made in 1953..

The fan runs more or less continuously here in the warm months and I put my hand on the motor frame to see how it's doing. When it runs a little slowly and the motor housing gets a little hot I know it's time to give it some maintenance. This usually consists of some high quality compressed air to blow the lint out of the housing and a cleaning and inspection of the oilers.

There are two knurled cylinders, one beneath each bushing that unscrew. Inside the cylinders are two felt wicks and springs which keep the wick in contact with the bushing.

When maintenance is needed the wicks can be cleaned with some gasoline, dried and re-oiled with some 3 In 1 machine oil. The oilers should not be overfilled because that can cause some splattering on your walls and such. Once you've oiled the wicks and replaced them the fan can be run upside down to allow the oil to penetrate and lubricate the bushings, and it's good for another couple of years.

It's a homily on how well things were made in the past and how they soldier on and shrug off the ravages of time. At 104 years and counting this one has paid its way. It's also a homily on the abysmal quality levels of the junk that passes for consumer goods these days.

The Wen Chainsaw Has To Choose: Get Going Or Go To The Curb

Here's another diversion from the subject of guitar amps.

I've been busy fixing things around the house lately. I have a Wen Lumberjack chainsaw I acquired a few years ago to assist in removal of some of the bushes in front of the house.

They were a species of dwarf cedar and it was necessary to buy a low priced chainsaw to help cut the roots and stumps out of the ground. The Wen Lumberjack is about the cheapest one you can buy at about ninety dollars if I recall correctly. That task was accomplished and some general cleanup around the property done, the chainsaw was put away.

That was about four or five years ago.

When I went to revive it I found that the fuel lines were rotted away. They were some sort of inferior grade of vinyl or latex rubber and they'd crumbled into mush. I ordered a parts kit which contained a set of carburetor gaskets, three or four squeeze bulbs about which more anon, a couple of strainers and the all important fuel hoses of the correct size.

And there it sat for a couple of years until today. I'd removed the remains of the fuel hoses and tried some vinyl from the hardware store but that was a flop. While doing some general cleaning and vacuuming in the garage I figured that today had to be the day.

The squeeze bulbs are a sort of primitive primer and nearly everything with a 2 cycle motor has them. The kit contained a complete assembly and a few extra plastic bulbs as well-good things to have around.

So today I pulled it all apart again and proceeded to replace the lines from the tank to the squeeze bulb and from the squeeze bulb to the Walbro carburetor.

There's a trick to this. The fuel hose from the tank to the squeeze bulb won't push through easily but you can cut the end on an angle and put a little bit of grease on them and it will pull right through. Then you can cut the end square, install the filter and put it all back together.

It still wouldn't start. Pulling the plug and heating it with a torch was no better. Then, I mixed up some fresh fuel and spooned a bit down the carburetor's tiny throat after blowing out the jets and gave it one more try.

I said to it, Listen. It's either run, right now, or you'll get lugged out to the curb and some fellow who's probably not half as nice as I am will play hob with you. Now. What's it going to be, friend?

It gave a few half hearted coughs and the rancid smell of decaying petroleum convinced me that what was needed was to dump out all the old premix and fill the tank up with fresh fuel. After a few fits and starts it purged itself of all the old fuel and now runs satisfactorily.

I'm not sure yet what I am going to do with it, but maybe I'll use it to harvest some firewood for the winter. As it happens, this is maybe why my string trimmer runs like crap and why I should flush out the fuel system.

So far the Toro mower and the elderly Snapper are up and running, but the Snapper is going into reserve status for national emergencies as the Toro does a better job of bagging. The pressure washer is up to par, the snowblower had its wheels and tires replaced, and the two leaf blower/vacuums are running nicely all by themselves. A new base was made for the drill press, I acquired a new circular saw and made enough parts for two or three amp stands, and all that's left is to cut up some steel and make a couple of bacon presses with the Miller welder. Plus, I cleaned up and organized a good part of the garage.

I think that a couple more workbenches are in my future as I do need a disassembly area and storage area for the amps. The garage floor is not adequate.

Not a bad two weeks for a guy who turned seventy yesterday.

Mowin' Down The Enemy: A Diversion

It is high summer here on the prairie and a young man's thoughts turn to yard work and how hateful a thing it is...not to mention it is mid July and that means mid October is only four months away.

A couple of things happened this week that were of interest and may prove useful in a technical sort of way.

Coming back from the grocery store last week I spotted a rather nice looking Toro walk behind mower parked at the curb. After we unloaded the groceries and put them away I got in the pickup and headed back and the mower was still there.

I knocked on the door and asked if the mower was unattached and the nice couple said "Take it, please." So I swung the tailgate down and off we went with a 2009 vintage self propelled walk behind mower. It appeared as if the recent heavy rains we had had briefly flooded the mower

I got it home and it did have compression which was good. After taking off the air filter so that I could dry it out I waited until after dark to see whether there was spark, and to my surprise there was.

Pull the spark plug out, then connect the plug to the wire and turn the engine over a few times by hand. If there's spark you'll see it. If not, you're going to have to get a magneto coil, but they're cheap enough on fleabay for the imported ones.

But it wouldn't start, so the next day I drained the fuel or what was left of it, pulled off the carburetor, blew out the jets and needle and seat, and put it back together.  It started on the first pull but  there was plenty enough emulsified oil and water in the crankcase to drain out and flush with a bit of gasoline. Then I put the air nozzle in and let it have a good proper blow job to air things out.

This is a pretty typical Briggs carburetor. It's got only three passage ways. Carefully detach it from the governor and choke linkage. Remove the bowl and clean it. Take some carburetor spray cleaner and blow out the main jet and idle jets and the fuel inlet passage where the needle and seat goes. check the operation of each passage with a bit of compressed air. Make sure the float is not sunk and the needle shuts off fuel when the float's up. Clean out the sediment well in the fuel bowl drain plug.

That's all there is to it.


Fresh oil-about a pint of detergent 30W- and fuel, and all seems well. I've got a good solid mower for nothing except an hour's worth of work. The drain plug is a 3/8 square pipe plug that sits in the bottom of the crankcase, or you can tip the mower on its side and drain the oil through the filler neck.

While all this was happening the other mower, the Snapper Ninja self propelled number that has been my workhorse for the last five or six years-it came out of an auction for twenty five bucks and it is at least 25 years old- started having problems with the transmission drive.

So I got out the parts manual and ordered some transmission bearings, a drive belt, an idler pulley and a drive disk from Snapper-which happens to be the cheapest source of parts I found.

After cleaning off the rust and dead grass and treating the deck with some rust stopping compound, I reassembled it yesterday and today with some new hardware, and while I was doing that I cooked up a good workaround that had never occurred to me before.

Clean off the corrosion and dead grease that coats everything. Buy your replacement carriage bolts at the hard ware store for a quarter instead of paying $2.35 for one plus shipping.

This mower has two springs that tension the drive mechanism components. Once the drive is assembled you gotta get the springs on but it proved difficult-until I wrapped some safety wire around one end of the spring and grabbed it with my safety wire twisters and pulled it through the hole. Nice.

Take a good look at the springs number 39 and 54. While you're at it look carefully at 73, which is a twisted piece of coat hanger wire that some people want twelve dollars for.

That went swimmingly, and the drive mechanism is functional and working smoothly.

Tomorrow I've got to see about changing both inner tubes on the snow blower's tires, change the oil and drain out the old gas and get it ready for winter. Then it's time for the pressure washer, the string trimmer, the chainsaw and likely the leaf blower too.

Converting a 50 watt Marshall Plexi From 6550s to EL34s The Right Way

A vintage Marshall "Plexi" arrived here that was in bad need of some refreshment. These are pretty much the ultimate rock and roll amps-loud, brash, edgy and in your face. So they are well worth the effort to bring them back to life.

In no particular order it needed a fresh suite of electrolytics and some general freshening up before retubing and troubleshooting.

It was an ebay find I think.

As part of my standard procedure I noted that someone had "converted" it in a prior time to use EL34s but it didn't have any bias voltage, which makes me think that's why whoever had it gave up on it a long time ago. They didn't "convert" it either-just some half assed hack job.

Amps that were destined for the USA were equipped with 6550 power tubes by the distributor in the US which was, I think, Unicord. They changed the sonic signature of the amp, and it didn't sound very British any more.

There are four steps that must be taken to effect the conversion.

First, the bias splitter resistors should be changed from 150k to 220k metal film resistors. For some unknown reason the board was marked 82k.

This is relatively easy to desolder as all these things are by lifting up the board and putting a small light inside, like one of those LED lamps you strap on your forehead. Then you can see what you're doing.

 The 47k resistor should be changed to 22k. Don't bother with mickey mouse scabbing resistors on top of one another as some folks suggest.

It looks crappy. Do it right.

The two 10uf or 8uf 160v electrolytic capacitors need to be replaced. They do not last forever.

Now here comes the tricky stuff.

Install a 220k bias level resistor as shown on the schematic coming from the high voltage tap on one side of the power transformer to the  bias supply diode. Set the bias pot to the lowest setting. You can set up your bias checker with a set of power tubes, make everything ready and briefly throw the standby switch on, take a quick reading and then put it back on standby because you're probably drawing too much current.

Now, take two test leads and parallel the 220k resistor to reduce the bias level down to about half. Then you can see whether you're close enough to do a fine adjustment with the bias pot. If you are, measure the paralleled resistance and find something relatively close.  I ended up with a 100 k resistor. Or you could start with a 100k resistor, or you could fine tune it with a pot and then measure the total paralleled resistance.

The last step is to relocate the negative feedback wire from the 16 ohm speaker out[ut tap to the 8 ohm speaker output tap-which hadn't been done in this amp.

Once you've done all this check and check your voltages again before you button it up, and do a sound check.

You might find, as I did, that this amp has an oscillation problem which is likely how it got shelved to begin with.

If you're ready to button it up, clean off all the flux and schmutz with some anhydrous isopropyl alcohol and an acid brush cut off to about 3/8 inch. It makes a dandy cleaner.

Rock on.

What you should know about buying a tube amp

I am often asked for some opinions about what people should buy in the tube amp world.

Here are my thoughts.

First, the basic platform must be roadable-that is, rugged and durable, able to survive temperature extremes, odd voltages in dodgy ginmills, and one that can withstand being bounced around in the trunk of a car for hours.

Second, the amp must-MUST!-be free of unnecessarily complicated circuitry and gimmicks, because those doodads exponentially increase the likelihood of maintenance issues, breakdowns, and, for the technician, countless hours spent in chasing down intermittent faults. Some of the design features overwork the key components, which are the tubes.

For the most part this rules out Mesa Boogie amps and similar analogues such as Bugera, B52 and many others. They are complicated to work on, service information is closely held and not available to the trade, and that limits the number of people who can or will work on them. I have always thought that vertical information silos depend on key people to be available when you need them. On the other side, broad based systems of general knowledge do not depend on key people and are thus more likely to be available when you need them. I recently had a Dual Rectifier Road King II in the shop with failing muting jfets of which there are 15 or so. By my count it had 33 knobs and 22 relays.

This increases potential failure points in a geometric fashion. If the failure point is A, you have one potential failure point, but if you have five potential failure points you have AxBxCxDxE potential for failure of a critical component. The quality of the components used can only compensate to a certain degree.

This is directly connected to Bayes' Theorem, which applies to probabilities. You can read more about it here.

My math may be a little bit lacking but I think you can see that complication leads to failure at inopportune times.

This is not to say that Boogies are bad, or evil. They are fine in the studio if that's what you like to do.

This in general rules out all amps that have more than two channels and use channel switching via relays, optical couplers like Vactrols, and the like. They're troublesome.

What you can do here, when considering an amp for acquisition, is go to the best most respected amp tech you know and buy them a coffee. Ask them if whatever you're considering is a good buy from the standpoint of serviceability and roadability. You may be surprised at what you learn in a face to face encounter with a real person.

Third-printed circuits. Are they inherently evil? The answer is no, if they're properly built with good components and proper engineering. They're a fact of life in this day and age, but they do require that the technician who works on them have a deft touch. They're less user serviceable than amps of an earlier era. They're also less damage and shock tolerant than traditional methods of hand wiring. Also, when troubleshooting down to board level faults, you may find the amplifier becomes uneconomic to repair.

Printed circuits have been around for a while now. The earliest one I have actually seen was in a Motorola table radio and it had a copyright date of 1956. At that time my father was working on a wave soldering project for Weston, so we've had them for at least sixty years. I'm informed that the first printed circuit boards with plated through holes was made in 1947.

Now, having said that, it is worth asking whether power tube and rectifier tube sockets are mounted directly to the circuit board. They generate heat-lots of heat, and the boards cannot withstand that forever. What happens is that the substrate gets carbonized to some extent, and as we all know carbon is what resistors are made from. That means that you start getting stray voltages and current leakage here and there. Ask the Marshall folks about conductive circuit boards in their DSL amps.

Also, circuit boards for guitar and bass amps are not generally available in the aftermarket, with very few exceptions. That means if the worst happens and a board needs replacement you may be out of luck. Occasionally some boards may be available in the secondary market or from friends in the trade but it is not something that can be relied on.

What this means is that you should spend all the money you are capable of getting your hands on and buying a hand wired amp built the old, artisan way.

Educate yourself on the methods by which your chosen piece of gear is built. Not all hand wired amplifiers are created equal. Learn about maintainability if you intend to take it on the road. Learn about after sale service and what you can expect from the builder.

Does that mean you should buy from a homebuilder who will assemble a kit for you? Probably not, unless you have seen examples of their work in the wild, and if the critics are satisfied.

All of this takes you back to the beginning. By far the best values for the money in the amp world are silverface Fender amps, some of the older Traynors, and some boutique-y amps such as Tungsten, Victoria, and Kendrick.

They're hand wired on eyelet boards and not overly complicated. With ordinary care they will last a lifetime of playing.

And last, do you like the way they sound? Do they speak to your style of music? Ultimately that should be the deciding factor.