Need help with beginner test/breadboard environment - Page 1
Forum section: electronics / beginners

author: Crush
author_rank: Contributor
timestamp: July 19, 2012, 05:31:01 am
content: Hi!I wanted to setup a test environment and no matter what I do, I cannot get recommendations. I thought I'd join this forum and people would be more helpful.My main interest right now is guitar amplifiers, guitar pedals, etc. Using vacuum tubes. I might want to play around with step motors and other things in the future, however, i would only like to buy what I need once. I don't want to have to buy something now, that I'll regret and get stuck with it, and have to upgrade because it wasn't sufficient for my needs.Basically, I'm asking what I need to help my work efficiently. I have a software development background. so am used to logic and compiling. I want a good 'debugging' test environment so I can setup a workbench.Could someone give me recommendations on power supply, oscilloscope, etc. Whatever you would recommend to do some of the things above. I'm not a pro at all. I would just like to do some hobby designs for guitar stuff and maybe step motors in the future.Ideally I'd like to spend less than $300 for these items.Oh and yes i've read for 3 days now and asked around. I'm still back at square 1 not knowing what I need for my setup.

author: vk6zgo
author_rank: Super Contributor
timestamp: July 19, 2012, 06:25:57 am
content: Quote from: Crush on July 19, 2012, 05:31:01 amIf you are going to be playing with vacuum tubes,most of the stuff will have built in (high voltage) supplies,This is good,because new high voltage bench supplies are pretty thin on the ground these days,& if you buy an old one from eBay,you may be buying a headache,You will need a reasonable digital multimeter--Dave has done several videos on these,best have a look!You will obviously need a Soldering Iron/Station.I would recommend an older Weller WTCP for this kind of work,as tube circuit wiring is a bit more "heavy duty" than soldering SMDs!The Hakko products are highly recommended by many others on this forum.Therearesome very cheap & nasty irons around,which just use a lamp dimmer circuit to adjust the tip temp,all running straight off the mains----I strongly advise against them!!Oscilloscope---much good work can be done with the most basic of 'scopes.but I would recommend a dual channelanalog'scope,with at least 50MHz bandwidth.OK,I know you are only working with audio,but the wider bandwidth may be useful later,& the instruments with better bandwidths usually also have more useful "bells & whistles".AnydigitalOscilloscope within your budget would be very disappointing.An audio signal generator would also be nice--not necessarily a "function generator",as these don't always have goodenough distortion figures for Audio work.Your $300 budget is looking pretty sick already,isn't it?AND you haven't bought any consumables,like solder,components,wire,etc.Have a look at Dave's videos in the main body of the EEV Blog site,as he has covered a lot of this material.Also,for stuff on Oscilloscopes.look up w2aew.His videos are extremely informative,unlike some on Youtube.

author: ampdoctor
author_rank: Frequent Contributor
timestamp: July 19, 2012, 08:17:16 pm
content: I would pretty much second what everybody else has said so far. I would like to add a few things to it though. I would suggest you start with simple guitar pedal projects that you can breadboard up with some discrete transistors and ic's. Build a cheap ass LM317 adjustable power supply that you can get a relatively clean 9v or so out of. You really don't need anything high performance here. Just something down and dirty that will get the job done. Not only will this cut your costs down to a decent meter, and soldering station, but it'll let you get your feet wet with electronics without much risk of personal injury or letting the magic smoke out of some very expensive parts.Once you get a sense of what you're doing, then you can pick up a good analog scope. Old Tek 465/466 dual channel scopes are pretty damn cheap on fleabay. Also I don't really see the point in even bothering with an audio generator. Go straight to a mid grade function generator. They'll cost about the same as an audio generator and are far more useful in the long run.I would also add that if you want to dabble with tube amps, I would strongly recommend having somebody with some experience babysit you till you really get a grip on what you're looking at under the hood of those things, as well as teaching you solid safety principles. I've been working on tube gear for close to 20 years and you learn quick to have a healthy respect for those circuits! It's not uncommon to see those things running on 500+ volts.A serious screw up inside a tube amp can knock the living shit out of you or if you're particularly unlucky put you in a 6 foot deep hole in the ground. On a related topic, as I've said, tube gear runs on some pretty high voltages so if you probe the wrong point, or if your hand slips, you risk saying goodbye to a few hundred dollars worth of test gear. So yea, diving head first into tube gear is not advised for somebody just starting out in electronics.

author: vk6zgo
author_rank: Super Contributor
timestamp: July 20, 2012, 09:15:12 am
content: Although I agree that you should start off with some solid state projects,I believe the danger with tube equipment is very overstated.Back in the day,everyone,including myself, started out with tubes--there wasn't anything else!The possibility of sustaining a serious injury working with tube guitar amps & such, is there,but it is extremely rare for anyone to do so.Modern solid state equipment is not without its hazards,too,as the switchmode power supplies which are common these days probably offer more chances to get across really dangerous voltages.It's easy to be safe--don't put your fingers on high voltage points,keep the other hand in your pocket,so you don't complete a circuit across your body!After all,you don't use a rotary lawnmower with bare feet,or start the barbecue with petrol/gasoline.so you know how to take precautions.On the choice between an Audio generator,& a function generator,I repeat that the latter don't always have very good distortion figures,due to the methods used for generation of the sine waves.

author: ampdoctor
author_rank: Frequent Contributor
timestamp: July 21, 2012, 04:57:35 pm
content: Quote from: vk6zgo on July 20, 2012, 09:15:12 amTrue enough, but most of us learned at the knee of somebody experienced and I doubt few of us went poking around inside tube gear completely ignorant to electronics. And while there haven't been many serious injuries no reason to go looking for trouble because as you said the potential is there.With regard to power supplies, I don't think I ever mentioned anything about switchmode supplies. I was thinking he'd be well served to build up some chickenshit supply with maybe a 500ma fuse in it to provide power to a few logic chips, some transistors, and a couple of dual or quad opamps. This would be enough to stay safe and get his hands dirty without breaking the bank.QuoteThat was pretty much my point. the OP clearly didn't know much about what was going on anywhere in those circuits or probably anything about good safety precautions. If he doesn't know what's what how is he supposed to know what to stay away from and where he can safely poke around.QuoteI'm still not completely sold on this point. We are talking about guitar amps and signal shaping components here so anything with less than 1-2% distortion figures is more than adequate. To start out he would pretty much want to use basic sine waves to see where he's got continuity, what levels are going to cause stages to clip or when saturation is occurring, power tube biasing, etc, and low distortion figures here are really not that critical. Once he gets going, having access to other wave shapes, rise and fall times and such will come in quite handy for evaluating tone controls, power supply ringing and lots of other things.

author: vk6zgo
author_rank: Super Contributor
timestamp: July 22, 2012, 04:45:12 am
content: Quote from: ampdoctor on July 21, 2012, 04:57:35 pmYes,I overestimated his level of knowledge,& my advice,while appropriate for someone who knew at least the smallest amount about the subject,was inappropriate for the OP.I guess I assumed he would have used a tube type guitar amplifier,or at least,seen one, so would have an idea of what we were discussing,but I was wrong.You have probably noticed that he started another thread,where he revealed his complete lack of basic knowledge!AnywayCrunchgot all bitter & twisted because we didn't give him the type of answer he wanted , & went off in a huff!