Tone Sniffer Mark III

Sometimes folks need a signal tracer.and they hunt up an old Eico or Heathkit and retube and recap it but I have found something betterI believe that can be assembled on the cheap.

You should always have a test amp in the shop and preferably something that has a line in/line out function which is helpful if you're trying to isolate a problem to a particular part of your amp. One that filled the bill for me was a cheapish Dean Markley bass amp which ran me fifty bucks and a trip to beautiful downtown metropolitan Lorimor, Iowa.

I happened upon a project on a forum somewhere that consists of assembling a small project box, a 1 meg pot, a .1uf/630v or better capacitor, and a probe with some coax. These can be found in your junk box or hand assembled with the body of a BiC pen, a nail, and a sleeve.

The one I built is pictured above.

The pot is used to attenuate the signal the probe picks up so you don't fry the preamp in your shop mule amp, which is something I did with the two small Radio Shack pocket amps I had at one point. You can start at zero and slowly ramp the volume up.

Now, starting with your signal generator putting a signal in the amp under test with its output into a dummy load, you can take your tone sniffer and following the circuit see where the signal dies. At that point it is pretty easy to substitute or bridge the offending component.

I have used this rig to isolate problems and fix a number of amps with serious volume drops.

It's also of use when you're testing an amp with your scope hooked up and you can see that the volume is way lower than it ought to be.

On the subject of scopes, I'm pretty sure my Hitachi V680 died so I went and bought a Hantek digital scope for about $280, and I'm going to try it out tomorrow and see how it performs.

Stay tuned.

The $105 Bassman Cometh

One of the things that I've wanted for a while is a Bassman head that I could keep and love, but was not so expensive as to compel me to sell it for a profit, or that I might be pilloried by the Vintage Amp Police for having a little fun with it.

Let me back up a bit....there's more to this story.

I was at an auction late last year and I picked up a Teisco Del Rey solid body guitar like this one on the cheap-fifty two dollars to be exact. It was covered in sticky schmutz and looked like a wall hanger in a ginmill or somebody's so called "man cave".

Not that I wanted it, mind you, but I figured it would be a good money maker.  So I cleaned it up a bit and put it on Craigslist with a notation that I would trade it for a dead tube amp.

So a pal of mine calls up and says he's got an amp and let's trade for your guitar. What I ended up with was the Sound City 120 head you see here. It was dead but about fifteen minutes of work got it running well enough. Large and powerful, but not my cup of tea as they say. Then, I posted a pic of it on one of my internet hangouts offering to trade it for a Fender Bassman.

Within ten minutes I had been offered a Bassman 70, which is an ultralinear amp which I did not want, and a Bassman 50, which is pretty much the same as an AB165 Bassman, which I did. An agreement was made.

Shipping the Sound City to San Angelo Texas ran me about fifty three dollars, and the Bassman arrived on the return. So I'd gotten myself a silverface Bassman for a total of $105.

I just started improving it the other day. It needed a good crud cleaning which I am about half finished with, and I ditched all the blue Paktron capacitors for Mojotone Dijons-a great improvement. The power supply capacitors had already been replaced.

Right now it works pretty well and sounds as you would expect a Bassman to sound. I'm thinking a custom cabinet with a single 12 inch speaker or a couple 10s would be.