This is just the most awesome thread. You guys are very generous with your time and knowledge. Learning a lot here.
Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
Amp techs, what's on your bench?
- Thread starter two fingers
- Start date
Agreed, way cool stuff. Following along here, picking up advice/info.
I really don't have anything to add, not a real tech. Just take shots at fixing my own stuff, sometimes it works, sometimes it doesn't.
Yes, I made a bleeder rig and know how to use it. (one hand in pocket).It sucks when "pads" (didn't know that term either) get lifted. Happens sometimes when a resistor burns. I've tried different ways of fixing it, but usually have better luck backing up to a good spot, connecting things point-to-point until I get to a good spot on the other side while cutting the board traces wide enough so they don't arc, sort of making sure the juice goes through the components instead of around them. Looks sort of hacked up but hey, it's my amp. Doesn't have to look pretty in there, just hopefully work.
The vice/clamp thing is great for seeing and working on both sides of the board is great.
Even the best of us have had pads lift, some boards just fail. If it happens carefully scrape the solder mask to expose the trace, a pencil eraser can be used to prepare the trace. Tin the trace and use the component lead (tinned) to the trace.
Several of us mentioned dental tools.
A good assortment of dental picks is a welcome addition to your tool box. They get used in cleaning holes, as mini crow bars and all sorts of ways to bend things into alignment.
A small collection of Hemostats is also priceless. Great tools for use as heat sinks and all sorts of grabbing and clamping tasks. My secret weapon is a long set of hemostats that have saved my bacon countless times digging out small parts that got dropped deep into tape machines. They are easy to find on Amazon or ebay these days.
A good assortment of dental picks is a welcome addition to your tool box. They get used in cleaning holes, as mini crow bars and all sorts of ways to bend things into alignment.
A small collection of Hemostats is also priceless. Great tools for use as heat sinks and all sorts of grabbing and clamping tasks. My secret weapon is a long set of hemostats that have saved my bacon countless times digging out small parts that got dropped deep into tape machines. They are easy to find on Amazon or ebay these days.
Surplus medical/dental tools that may be useful for the toolbox: [Invalid or Expired Link Removed]
An old HP54510A. Not the best for audio work, but I got it for free so can't complain.
I also got a surplus DSO of roughly the same vintage. I'd agree with the above assessments that it's not great for audio work. It's got 8 bit resolution, whereas the dynamic range of audio signals can reach 16 bits or beyond. My DSO can't measure noise at a level that I care about in my designs.
On the other hand, I love the all-digital controls. My scope will never develop flakey knobs and switches, which are the bane of old scopes. And it has some automatic measurement features such as frequency, time, and rms voltage, that are convenient though not vital.
I'd use the scope for looking around at what's going on in a circuit, checking voltages and waveforms, doing diagnosis. If I want to carefully measure something like frequency response, signal-to-noise, or distortion, then I use free tools on my PC, with the proviso that you can smoke your audio hardware as I've already done once.
I use analogue scopes. I have checked out the Agilent digital storage oscilloscope products and have been really impressed. Their newer high resolution screens are amazing. I suppose that the tablet and phone technology is driving the development of the screen technology. The instrument manufacturers will be able to do wonderful things with these products.
I have tried a couple of PC based products. Their performance wasn't close to a Tektronix or Agilent scope. That doesn't mean that they can't be used for audio repair work. Unfortunately, these products come with a very high price tag.
I mostly use an HP8903B audio analyzer. It's a real workhorse. I also like using the HP334A distortion analyzer. Old technology that works well.
Analog scope here - Tektronix 465 - picked up at a surplus store for less than $50. I chose an analog scope to get the big bandwidth together with low noise floor. Plus, I used a 465 in my day job for many years.
My shop is pretty ugly right now. It'll stay that way until either the snow flies or I need to fix something.
My shop is pretty ugly right now. It'll stay that way until either the snow flies or I need to fix something.
One item I have which I have not seen mentioned: I use a Philco 7030 signal tracer, from the 1940's. Basically it's a small audio amp with a selectable pickup probe on the end; you inject an audio signal into your amp and then use the probe to hear the signal as it goes through the various gain stages. Very useful to find out when the signal stops (or gets massively distorted).
I know, right? This is like a new tech dork's dream thread!
(I mean that in a good myself-included way)
Yes, they are very useful tools. I have a couple of Eico 147A's that I use. They are also easy to build. Check out the listening amp Invalid Link Removed.
I should add that good test equipment can be bought at ham radio swap meets. My signal tracers were both under $20. Go to Invalid Link Removed to find a hamfest in your area.
If you find an HP200CD oscillator cheap, they make a great platform for a low wattage tube amp.
One last thing a good shop has to have - a good radio.
Nothing to add to the joy of escaping to the shop like a football, basketball or even baseball game on a big fat tube AM radio. Or a 80 meter net in the winter months.
I gotta get a 80 meter antenna up while it is nice out.
Nothing to add to the joy of escaping to the shop like a football, basketball or even baseball game on a big fat tube AM radio. Or a 80 meter net in the winter months.
I gotta get a 80 meter antenna up while it is nice out.
