View Full Version : What equipment do I need to test & repair my tube amps?


imready
09-20-2009, 01:36 PM
Eventually, I will teach myself how to repair my own equipment. I've got a lot of test equipment here and need to thin it out but don't want to make something go away that I will need later. Right now I'm lucky if I can find the "on" switch. :scratch2: What am I going to need enable to test and repair my tube audio gear? Thanks for your help. John

ferninando
09-20-2009, 01:52 PM
Eventually, I will teach myself how to repair my own equipment. I've got a lot of test equipment here and need to thin it out but don't want to make something go away that I will need later. Right now I'm lucky if I can find the "on" switch. :scratch2: What am I going to need enable to test and repair my tube audio gear? Thanks for your help. John

2ch 100khz scope, audio osc/function gen(sine.. square.), vtvm or dmm with tru rms capability, or RMS audio voltmeter but scope is good enough. solder iron, solder, solder sucker, wire cutters, needle nose pliers, phillips/strait slot screwqdrivers,.
All I use is 2ch scope, function generator, autoranging dmm for AC/DC volts and ohms. and the tools. power scrw drvr, AC power strip/ext cords, connection cables for the funct gen, clip leads red/blk about a dozen or half.

BrandXRC
09-20-2009, 02:00 PM
VTVM is that Vacuum tube volt meter?

jaymanaa
09-20-2009, 02:26 PM
First thing you need is a good bench in a quiet place. I built my own, and would recommend using something that you won't mind if it gets drilled into. Another must have is good lighting, I use fluorescent "kitchen" tubes, and lots of them. A good tube tester is essential as well. Some of those little drawer type organizers are good for all the resistors and caps you will accumulate. Don't scrimp on the soldering iron either, get a good one with adjustable temperature (I use a Hako). I also have a cheapy rat shack desoldering iron, which is very handy when working on older stuff with big blobs of solder and point to point wiring.

Endspec
09-20-2009, 02:36 PM
A good Variac and an ampmeter to go with it. something to put out fires, (every house should have two or more)some cheap speakers for testing (ones you don't care if you smoke them) I also have one of these http://media.digikey.com/photos/Luxo%20Photos/17115BK.jpg

marty59
09-20-2009, 03:02 PM
Depending on how involved you're going to get, a resistive load can take the place of your speakers for primary testing.
Then you can measure for full power/wattage at different frequencies while observing with an oscilliscope and you won't be bleeding your ears as well as looking/testing for distortion.

imready
09-20-2009, 03:22 PM
First thing you need is a good bench in a quiet place. I built my own, and would recommend using something that you won't mind if it gets drilled into. Another must have is good lighting, I use fluorescent "kitchen" tubes, and lots of them. A good tube tester is essential as well. Some of those little drawer type organizers are good for all the resistors and caps you will accumulate. Don't scrimp on the soldering iron either, get a good one with adjustable temperature (I use a Hako). I also have a cheapy rat shack desoldering iron, which is very handy when working on older stuff with big blobs of solder and point to point wiring.

I've always had a need for a soldering iron on the job and at home. A good one is definately on my list of upgrades I need because I sure get frustrated in a hurry when an iron doesn't hold temperature! :yes:

ellconi
09-20-2009, 03:23 PM
Isolation transformer! Mine is also a variac. I also have a cork floor mat that covers the floor of the HV area; No need to stop your heart for your hobby.
Curt

imready
09-20-2009, 03:45 PM
I have lots of little stuff around to help get the job done, and a lot of big stuff too. I think I have 6-8 O-scopes, want to make sure I keep the right one. I believe my Tenma is the newest. I have a lot of stuff that I know nothing about. Audio generators, signal generators, wow and flutter meter, automatic distortion meter, frequency meter and counter, Hickok 156 indicating tracermeter, oscellator and more. Will I ever use any of this great stuff fixing my tube amps???

Endspec
09-20-2009, 03:54 PM
Audio generators, signal generators, wow and flutter meter, automatic distortion meter, all these you can use, the wow and flutter is good for tape decks and turn tables. The tenima scope would the best scope for the job too.

Post a list of equipment you have with model numbers and pic's if possible and that will help us figure out what to keep'

Jcricket
09-20-2009, 04:07 PM
You guys shure made quite a list. Good list too. I started with nothing more than a homemade(poormans light bulb) variac, soldering iron, multi meter, and some hand tools. I am building my tools as I go and learn.

An assortment of caps and resistors really comes in handy too. AS you get more invlolved(at least this is where I am heading) an Oscope and signal generator would be useful. I just got my first oscope - about to figure out how to use it.

Don't get daunted by this list - I think this list is the "ideal" list.

Oh, I REALLY, REALLY second Jays suggestion of a clean, quite, well lit place. You will be working with voltages that can kill you - so no distractions.

becketma
09-20-2009, 05:04 PM
I was in Harbour Freight last nite. I picked up some cheap small files to elongate the bolt holes for 7pin sockets so that 9pin sockets can be installed.

I also picked up a cheap "spring-loaded" center punch.

Best
Bob

rollei35guy
09-20-2009, 05:18 PM
I'll second the lighting suggestion. I have 2 articulating arm lights on my workbench. One has a large magnifier which is very useful.

One of those little 3rd hand things work nice two. The ones with a base, a bar and a couple alligator clips.

Some hemostats are good for heat sinking or just holding stuff. Different types of tweezers.

rollei35guy
09-20-2009, 05:25 PM
While generally they are no-nos, I like a soldering gun or two.

From time to time you will find the need to solder/unsolder something connected (like a can capacitor) to the chassis. It would take forever to heat up with my iron, so I found the biggest, baddest Weller soldering gun I could find (it has two head lamps). I can also repair gutters too.

A lot of items (like lights, storage, tools) can be found at thrift stores.

ronaldw441
09-20-2009, 05:39 PM
Don't forget a couple of insulated jumpers with alligator clips & a high value resistor to drain off the voltage from the power supply capacitors.

KGBMAN
09-20-2009, 05:53 PM
I'm surprised no one has mentioned an LCR meter (or bridge) yet.

You don't need to go expensive with it. Just a decent handheld will do.

imready
09-20-2009, 09:09 PM
Audio generators, signal generators, wow and flutter meter, automatic distortion meter, all these you can use, the wow and flutter is good for tape decks and turn tables. The tenima scope would the best scope for the job too.

Post a list of equipment you have with model numbers and pic's if possible and that will help us figure out what to keep'

Here's a list of some of the stuff I have. I do have a home made lightbulb variac, plenty of tube testers, vom's, capacitor checkers (including my Blue ESR meter which I love) and even older stuff not included in the list. Some of this stuff is still pretty old and very cool. If you really want to see something in living color, I will take a picture for you. Hopefully I got the model numbers, these cataracts make it difficult to see small print. I really don't have a clue about some of this stuff , what is is used for and working condition. Most of it I've never plugged in.

HP wide range oscillator 2000d
HP square wave generator 211a
HP VTVM 4000
HP VTVM 410b
HP ocilliscope 1206a
HP oscillator 204b
Tenma oscilliscope 6025
Tenma auto distortion meter 72-900
Tenma audio generator 72-455
Tenma wow & flutter meter 72-895
Tenma dummy load 72-4060
Heathkit osilliscope (tube) 10 14
Heathkit FM stereo generator 5237
BK precision oscilliscope 1471
Eico oscilliscope 460
Eico audio generator 377
McGrawiEdision signal generator 560fm series 3106
Simpson VTVM 303
Supreme signal generator 571
Supreme cr bridge & signal tracer
Supreme signal generator 661
Knight rf generator ???
Westport Electric frequency meter and counter we-110
Philco rf signal generator 7070
Philco dynamic tester 7030

Endspec
09-20-2009, 09:17 PM
If you lived closer I would say lets open a shop lol
That simpson 303 is a very nice unit too.
were did you find this stuff? at yard sales or a closed shop?
Keep all tenma stuff and the Heathkit FM stereo generator 5237

BrandXRC
09-20-2009, 09:35 PM
I hope this isnt to dumb of a question, but is a VTVM different than just an old school meter with tubes? Does it do anything that a late model dvom will do?

imready
09-20-2009, 09:36 PM
If you lived closer I would say lets open a shop lol
That simpson 303 is a very nice unit too.
were did you find this stuff? at yard sales or a closed shop?
Keep all tenma stuff and the Heathkit FM stereo generator 5237

I bought a lot of this stuff from just two places. I ran and ad for a while in the local paper that I was buying old audio equipment and old test equipment. A guy called me from about 100 miles away, his brother who had worked for the FCC had passed and he had his collection of stuff . like 150 pieces ! It was reasonably price so I bought it, he even delivered. Some very cool bakelit stuff and stuff in nice wood cases. Early tube testers only testing 4 pin tubes,lots of eye tube pieces, you name it ,I love that stuff! Like my own little museum or Frankenstein lab . The second batch of stuff came from a storage unit sale that had already been picked over by some electronics guys I know. They got all the tubes! I got 3 Simpson meters from the bottom of the box, 3 tube oscilliscopes(2 tektronics I didn't mention in the list) and a bunch of other fun little trinkets.

Endspec
09-20-2009, 10:20 PM
I got a [ile of old meters and scope and stuff too from an estate I was helping clean out. even got a rca sp 20 mono amp in good shape that I restored and it plays great.

roberts67
09-20-2009, 11:00 PM
An ESR meter is really handy for testing old caps. They are easy to build and have saved me some money and time.

http://www.anatekcorp.com/blueesr.htm

Peace. Robert

DanO55
09-21-2009, 08:16 AM
An understanding wife helps if you are married. Two in the morning and you are either just getting to bed, or even worse, getting up to work on one of your projects.