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Amp techs, what's on your bench?

two fingers

two fingers

Opinionated blowhard. But not mad about it.
Inactive
Feb 7, 2005
33,959
116,684
55
Eastern NC USA
#1
So, again, I am in school for electronics these days. Fixing amps will probably never be my day job, but I would like to work on my own stuff and do some repairs on the side at least. You guys have already shared a lot with me and I appreciate it. I was wondering if you could share with me what is typically on your bench. Pick a question or two. (I'll number then so you don't have to copy/paste the ones you choose to answer.) I don't expect anyone to spend all day with this or answer everything. And a pic of your workbench would be amazing (even if we need to set up something private so you don't post it for the world).

1) What kind of counter do you work on?

2) What kind of light and/or magnifier do you use (if any)?

3) What's the biggest thing you have learned about what you do need and/or what you don't need on your bench?

With some kinds of tools/equipment, getting "the best" really matters. Others, not so much. What's an example of either/or?

4) Where do you fall on the great tube tester debate? A lot of reading I have done simply says that the "best tester is a circuit" and that testers aren't worth the boxes they are housed in. Do you find this to be the case?

5) What's the one thing you reach for the most? What's the one thing that has sat there for years and you rarely (if ever) need it even though you thought you would?

6) Any other general advice?

Thank you so much!!!
 
#2
So many questions grasshopper. ;)

1) In a somewhat small house now. Whatever stable surface is available (was supposed to stop doing this stuff in 2004). Have a standard flat door on legs in the garage with a shelf when the weather is cool enough (about 6 months of use).

2) Standard bench mag with circular fluorescent (winter), "helping hands" inside the house.

3) A good quality dual trace scope, two decent high input impedance DVMs, good signal generator, high capacity non-inductive dummy load, ESR meter, variac, isolation transformer. The spectrum analyzer is the least needed. Distortion analyser gets used for final checks but necessary?

4) Tube testers are a starting point, not the last word.

5) DVMs used most. Gave away a Vector scope.

6) Don't take life so seriously, you'll never get out of it alive :D. Okay, when you thought you learned it all, you've learned nothing so enjoy the challenges.
 
#3
These days, it's more of a factory than a repair bench, but I still do all of my own gear repairs plus occasional favors for friends.

1) What kind of counter do you work on?

Homemade workbench, 2 x 4 foot top made from plywood and 2x4's. The bench is varnished with whatever I had left over from some other project. Above the bench is a shelf for test equipment. My test leads are permanently plugged in, and hang from hooks above the bench.

In my opinion, if you're doing this for a business, you want to have your workbench and all of your work tools kept separate from your home bench and tools, so your work and home projects don't interfere with one another.

Next to the workbench I've got a place for this computer, where I keep my work stuff separate from my home stuff. Turn around, and there are plywood shelves on the wall, for tools and parts. There's a bass and amp (not my current gigging gear) that are now effectively part of my test equipment.

Everything is within roughly 6 x 8 feet of space. There's a small space in my garage for cutting metal, to keep any kind of metal chips out of the house.

2) What kind of light and/or magnifier do you use (if any)?

Typical 4 foot fluorescent tubes above the bench. I've also got a 10 - 20 x stereo magnifying scope, which I find to be vital for locating problems such as bad solder joints.

3) What's the biggest thing you have learned about what you do need and/or what you don't need on your bench?

I don't need a lot of fancy test equipment. I greatly prefer a digital scope because of its frequency and voltage measurement capabilities. I use my PC as a signal generator and audio analyzer, which requires extreme caution because you can fry the PC audio hardware. I'll probably get an inexpensive signal generator someday.

With some kinds of tools/equipment, getting "the best" really matters. Others, not so much. What's an example of either/or?

A good temp-controlled soldering iron is very nice to have. If you're working on tube gear, a more powerful iron such as one of the old Weller soldering guns, would be useful for larger parts and wires that are soldered directly to chassis and pot cases. I want a voltmeter that I can trust.

4) Where do you fall on the great tube tester debate? A lot of reading I have done simply says that the "best tester is a circuit" and that testers aren't worth the boxes they are housed in. Do you find this to be the case?

Don't know, since I haven't worked on tube gear in a very long time. My only thought about tubes is that if you have a way to reassure customers that their tubes are good, and that you've saved them money by not replacing them, you'll earn a lot of goodwill and karma.

5) What's the one thing you reach for the most? What's the one thing that has sat there for years and you rarely (if ever) need it even though you thought you would?

The voltmeter and the microscope.

6) Any other general advice?

Safety, safety, safety.

I recall from other threads that you've already got some business experience. But it bears repeating that you shouldn't undersell yourself. You'll have to charge a rate that makes some gear not worth repairing, and that's OK. Also, you'll have to turn down some jobs. I wouldn't take a job where I was asked to do something half-assed to save money, or work on gear that was unsafe.
 
#5
I'm not a tech by trade but rather a private builder. Anyway:

1.I use a standard desk with an acceptable height, I do most of the work sitting with shorter periods of standing work.

2. An office table lamp + a headlamp. A PCB holder with magnifying glass (cheap)

3. Good to have:
- A Variac is really useful for soft starts and testing
- I have a cheap USB handheld scope + an old Velleman PC scope + an IPAD with a signal generator app.
- One or more good DMMs, or at least DVMs
- A good soldering station
- A 600W dummy load, good to have + a couple of speakers for testing.
- A lamp current limiter for troubleshooting
- Good tools and some chopsticks for poking.


4. I will get one at some point, but it's not required for me right now. My amps all have built in voltmeters and individual bias adjustment so I can sort out "odd" tubes in the amps, monitor drift etc. But I think that the new Orange tester may be a future purchase.

5. The DMM, wire cutter and other tools (and the soldering iron of course)

6. Stay focused.
 
#6
1. Varnished solid core door on a home made set of legs. It is high enough to be comfortable either from a short bar stool or standing.

2. Fluorescent ceiling light. Old spun aluminum clip on incandescent if I need more. I use reading glasses.

3. My favorite accessory is a digital camera hooked up to a LCD panel. My bench and the floor around it are kept operating room clean. That gives me a better chance of finding parts I drop. Get the best screw drivers you can afford. Dental tools are very handy. Technitool offers some pretty decent tool kits.

4. I do more tube than SS repair. The circuit is the tester for me.

5. My decades old RCA vacuum tube voltmeter and cap checker are a tie for favorites. I don't need any of my TV test gear these days, can't remember the last TV I fixed

6. Time in the saddle is king - it is what builds intuition. When you get stumped, hand calc what a circuit ought to do. Some crap is crap and the owner will love it. Always give 'em a little more than they'd expect.
 
#7
http://youtu.be/mzXqiHQudlc

Scope, auto-ranging multimeter, clamp-on ammeter if you can get one, variac, nicest soldering station you can get (my Hakko 926 has lasted since 1992 or so), oscillator, dummy load.

I have a tube tester, but rarely use it. It's good to know if a tube has a short in it, but that's about it.

Homemade bench. Decide whether you want it at sitting level, or standing level. I like both.

Chris
 
#8
1) A large, well lit, well ventilated, workspace is nice. Not just in terms of organizing your work but in terms of safety. At home, I have a laminated maple workbench (60" X 30" X 2 3/4") that is also used for woodworking and cabinet recovering. Everything is stored away and I take out what is needed.

2) I use a line of LED lamps that I bought at Home Depot. They look like regular incandescent bulbs and have multiple LED's in them. They light the area up like daylight. When necessary, I use LED lights that are mounted on gooseneck arms. I work with a flip-up head magnifier called an Optivisor when I need to see up close. This is an indispensable tool.

3) A nice setup for working on amps would consist of a scope, a low noise signal generator, various voltage and current meters analog and digital, dummy loads, a variac, a signal tracer, an ESR meter, a capacitor tester, and a computer. An audio analyzer is good to have. A soldering station should include a variable heat iron, clip on heat sinks, picks and scrapers, solder suckers and solder wick, solvents, and a fume extractor.

I have a lot of test equipment that I've accumulated over the years. Different tools are used for specific tasks depending on the type of work that you are doing. Despite the high cost, deals can be found on used high end Agilent (HP), Tektronix, etc., test equipment. There is also surplus and used military test equipment available. For some work they specify the make and model of test gear that is required. Sometimes calibration paperwork is required that is part of a validation process. This can get very expensive. In general, good tools of the trade are expensive. But you don't need to have expensive stuff to get the job done.

Buy the best equipment that you can afford. Upgrades can be made in the future. If I could only have one high end piece of gear, it would be a decent bench volt meter like Link Removed one. It has data logging capabilities as well as an accurate way of measuring resistance.

4) A shop should have a tube tester have but they have their limitations. If you want to grade and match tubes, look for a maximatcher or an [Invalid or Expired Link Removed].

5) The equipment that you use the most varies according to what you are doing. Amp repair requires the type of equipment mentioned above. If you are working on on communication systems, you need a specific set of tools. R&D kicks things up a notch.
 
#9
I have a SS Telequipment dual channel scope, An old tube Heathkit single trace scope that I refurbished, Signal Generator, two AC powered Fluke bench digital multimeters, a bunch of cheap hand held DMMs, two analogue multimeters, one Fet amplified. 20A variac, at one time a theatre lighting dimmer. 15A isolation transformer. A ballast box, using standard household lamps, to limit current to a unit under test. Weller variable heat thermostatically controlled soldering station - don't know how I ever did without this thing. A desoldering iron that I replaced the pump with my shop vac - wrote an article about the conversion for Audio Express magazine. High power dummy loads made out of suitable sections of a dryer heating element.

I also have a dangerous little box that allows AC mains to be connected to a transformer's flying leads. it's fused at a low value with a momentary switch to apply power.

I built a variable constant current source with a digital volt meter to test/match zener diodes and to match MOSFETs for parallel use.

I have a little old Heathkit tube tester and a Hickok tube tester if I really need to know more about a particular tube.

The bench is the frame from my old oil tank with 3/4" ply on top with a carpet covering. AC supply is 120,0,120V into an AC socket bay from an old Data General mini computer I was involved with back in the day. Each leg is GFI protected and a breaker come power switch controls the lot. This breaker is mounted by my knee so that a quick push to the side kills all power.

I guess that pretty much covers it. :)

Edit: All I have to do is get the shop cleaned up and back in use. The place became an easy dumping ground when I had my first stroke. :( You know what it's like: "Whats this? ", "I don't know -put it in dad's room, he'll sort it out!". Then I had a second stroke! :scowl:

<sigh> I hate gettin' old! :bawl:
 
#10
two fingers said:
1) What kind of counter do you work on?
Click to expand...


Used IKEA workstation table:

Link Removed

2) What kind of light and/or magnifier do you use (if any)?

Natural light, progressive eyeglasses. I have a few gooseneck lamps and various small flashlights that get used a lot too, and a little handheld magnifier with LEDs in it. Having a killer view from my shop window sometimes helps morale a lot when I'm fighting it.

3) What's the biggest thing you have learned about what you do need and/or what you don't need on your bench?

Need adapters of every ilk, and the capacity to make new ones on the spot. A good set of high capacity dummy loads is mission-critical in my world. Air filtration is really important and I still need to address that better.

Link Removed


3a) With some kinds of tools/equipment, getting "the best" really matters. Others, not so much. What's an example of either/or?

300 watt iron: cheapest possible. DMM: a 20 year investment, don't cheap out. My ancient 30 Meg Hitachi scope does nearly everything a digital Tek scope would for my purposes.

4) Where do you fall on the great tube tester debate? A lot of reading I have done simply says that the "best tester is a circuit" and that testers aren't worth the boxes they are housed in. Do you find this to be the case?

As far as tube amps I work mainly on Fenders, so my personal guitar amp is my tube tester, and I have a sufficient tube stash to just substitute known-goods as needed. I can borrow a curve tracer any time I want, but have yet to feel the need. I have owned a few testers, always ended up giving them away.

5) What's the one thing you reach for the most? What's the one thing that has sat there for years and you rarely (if ever) need it even though you thought you would?

Vise grips. Almost never turn on the Pace desoldering station or Fluke frequency counter. It'd be nice to have a dedicated computer in my workshop for schematics and running audio analysis software. You may have noticed that I like to test and document things like tone control curves a lot. ;)

6) Any other general advice?

Buy lots of soldering iron tips and learn when to use each one. Build some DIY stuff. Keep one hand in your pocket!
 
#11
the tip on soldering tips reminded me of the first time I tried to use my soldering station after stroke #2. Pull the iron out of it's holder and applied it to the work. NO TIP!!! Did the job with one of my older irons. Went out and bought a few more tips. Put one in the iron and it fell right out again! "Say what??" I thought. Realized the screw on barrel was also missing so I started a search. I eventually found it and the original tip in a cardboard box. How it got there I have no clue. Put it down to the workshop gremlins. You know? Them little blighters who take your pliars or cutters and hide them after you just put them down?? You have to refocus and hunt the darn tool only to find the gremlins have put it back just where you left it!!!

Damn gremlins! :D
 
#18
1) Standard office type desk

2) Ikea flexi desklight so I can point it anywhere, no magnifier as eyes are good for close up (short sighted).

3) Even if you buy a massive selection box of fuses, it won't have the right ones.

I use a cheap DMM because it gets killed often, nice one is nice when something needs to be dead accurate, but I just don't want to worry about it blowing up if have an ht cap discharge into it or something.

4) Best tester is the circuit if the circuit works right. If the circuit works right, it isn't on my bench. Not having to dissemble the amp further than being able to pull the valves out saves a lot of time and makes for while U wait fixes of stuff that just has a dud valve. Plus people that sell valves as 'tested good' because they've put them in an amp and it makes sound need stringing up. They can be pretty wrecked and still make sound.

5) Chopstick when the amp is on, toothbrush and meths/denatured alcohol, mostly in old amps and they are always grotty.

6) Buy broken and sell fixed involves less having to deal with musicians and better money, if you can do selling, the sell is a skill.
 

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