Soldering: Help a chap out.

[WhiskeyJack]

Yup, all of that stuff is good for soldering. I just did some amp sugery today. Had to get under the board on my 73 Plexi and replace some resistors. That's some scary shit on an amp that old, but it worked out fine.

Your confidence is admirable.

[Greg_L]

Your confidence is admirable.

Thanks. I guess it's confidence. Maybe. You'll get it. You're taking the right steps to get there. Get that practice kit and start sticking shit together. Actually, to go even more basic, just stick wires together. Get some scrap wire, tine the ends, j-hook em, and solder em together. You'll see how solder flows. It's pretty simple.

[Lt. Bob]

Yup, all of that stuff is good for soldering. I just did some amp sugery today. Had to get under the board on my 73 Plexi and replace some resistors. That's some scary shit on an amp that old, but it worked out fine.

Of course it did .... you've been doing this a while now and, as you've discovered, it ain't rocket science.
EVERYONE can do this stuff if they take their time and do some practicing first, which is what you did when you first started ..... now you're fairly comfortable with it.
Can't be anywhere near as difficult as swapping out an engine and you wouldn't think twice about doing that.

The actual difficult part of electronic repair can be the diagnosis.
If nothings burnt or broken then it can get harder to know what to fix or repair.

But 90% of the time there is an obvious burnt part or bad connection or broken wire.

How'd you know the resistors needed replacing?

[Greg_L]

Of course it did .... you've been doing this a while now and, as you've discovered, it ain't rocket science.
EVERYONE can do this stuff if they take their time and do some practicing first, which is what you did when you first started ..... now you're fairly comfortable with it.
Can't be anywhere near as difficult as swapping out an engine and you wouldn't think twice about doing that.

The actual difficult part of electronic repair can be the diagnosis.
If nothings burnt or broken then it can get harder to know what to fix or repair.

But 90% of the time there is an obvious burnt part or bad connection or broken wire.

How'd you know the resistors needed replacing?

Absolutely true - all of it. The actual soldering is easy and anyone can do it with a little practice. I know it probably seems daunting to the inexperienced but once you "get it" it's nothing. The hardest part of soldering on an amp or in a guitar cavity is just getting to the little bits you need to get to and not burning anything else. And the diagnosing is indeed where the skill comes in. Like you said, if something is exploded, no problem, just fix it. Hopefully it won't happen again. If nothing is visibly damaged, then you have your work cut out for you. You can't see a resistor or capacitor that has drifted out of spec. You just kind of have to know what each bit does and why and what to expect from it with a scope or multimeter. And reading a schematic obviously helps. Knowing the signal flow is pretty important. I'm still working on the "figuring-out" part. I'm getting there.

For my amp, I was just going over it with a fine tooth comb. It's mostly original. I wanted to make sure nothing has drifted or started leaking. I know that it's been converted to EL34s, which is great, but I'm always suspicious of the work performed. I bought it this way. And I know the tubes in it were shot, so I wanted to see if anything was goofy, and sure enough, I found goofiness. I don't know who did the mod, but it involves changing two bias feed resistors from 150k (6550) to 220k (EL34), and the bias supply resistor needs to be 27k. So I'm looking at mine, and I see the resistors that have been changed. They snipped out the original resistors and soldered the new ones to the legs of the old ones. Not the best way to do it, but acceptable if you don't want to lift the board. So I'm reading the bands on the resistors...one of them is 220k, okay no problem, and the other is 22k? That aint right. Whoever did this grabbed a wrong resistor. And they did a shit job soldering them in. The 27k bias supply was the correct value, but it isn't an "original" resistor so I changed it too since I was under there anyway. These resistors are critical and can't be halfassed, or worse, the wrong fucking values. So I got in touch with a guy that has the original period-correct Piher resistors and got the correct ones from him and just put them in. Now it's got the correct values and type of resistors for it's year. It biased up very easily, the bias pot has tons of wiggle room now, and the break up is a little smoother. All good.

[Lt. Bob]

just out of curiosity, how much did it cost to get period correct Piher resistors?

[WhiskeyJack]

Of course it did .... you've been doing this a while now and, as you've discovered, it ain't rocket science.
EVERYONE can do this stuff if they take their time and do some practicing first, which is what you did when you first started ..... now you're fairly comfortable with it.
Can't be anywhere near as difficult as swapping out an engine and you wouldn't think twice about doing that.

The actual difficult part of electronic repair can be the diagnosis.
If nothings burnt or broken then it can get harder to know what to fix or repair.

But 90% of the time there is an obvious burnt part or bad connection or broken wire.

How'd you know the resistors needed replacing?

Absolutely true - all of it. The actual soldering is easy and anyone can do it with a little practice. I know it probably seems daunting to the inexperienced but once you "get it" it's nothing. The hardest part of soldering on an amp or in a guitar cavity is just getting to the little bits you need to get to and not burning anything else. And the diagnosing is indeed where the skill comes in. Like you said, if something is exploded, no problem, just fix it. Hopefully it won't happen again. If nothing is visibly damaged, then you have your work cut out for you. You can't see a resistor or capacitor that has drifted out of spec. You just kind of have to know what each bit does and why and what to expect from it with a scope or multimeter. And reading a schematic obviously helps. Knowing the signal flow is pretty important. I'm still working on the "figuring-out" part. I'm getting there.

For my amp, I was just going over it with a fine tooth comb. It's mostly original. I wanted to make sure nothing has drifted or started leaking. I know that it's been converted to EL34s, which is great, but I'm always suspicious of the work performed. I bought it this way. And I know the tubes in it were shot, so I wanted to see if anything was goofy, and sure enough, I found goofiness. I don't know who did the mod, but it involves changing two bias feed resistors from 150k (6550) to 220k (EL34), and the bias supply resistor needs to be 27k. So I'm looking at mine, and I see the resistors that have been changed. They snipped out the original resistors and soldered the new ones to the legs of the old ones. Not the best way to do it, but acceptable if you don't want to lift the board. So I'm reading the bands on the resistors...one of them is 220k, okay no problem, and the other is 22k? That aint right. Whoever did this grabbed a wrong resistor. And they did a shit job soldering them in. The 27k bias supply was the correct value, but it isn't an "original" resistor so I changed it too since I was under there anyway. These resistors are critical and can't be halfassed, or worse, the wrong fucking values. So I got in touch with a guy that has the original period-correct Piher resistors and got the correct ones from him and just put them in. Now it's got the correct values and type of resistors for it's year. It biased up very easily, the bias pot has tons of wiggle room now, and the break up is a little smoother. All good.

So you came upon all that just by looking? it wasn't an auditory que that made your ears prick up and say "hmmm, i need to investigate" and afterwards you did notice a difference?

[Greg_L]

just out of curiosity, how much did it cost to get period correct Piher resistors?

I haven't paid for them yet, but the guy said 10 bucks. He sent them to me, I checked them, put them in, and he hasn't sent me his paypal info yet.

10 bucks is ridiculous for three 1/2 watt resistors, but it's only ten bucks and I'm happy to have the correct stuff in there.

So you came upon all that just by looking? it wasn't an auditory que that made your ears prick up and say "hmmm, i need to investigate" and afterwards you did notice a difference?

A little bit of both. I was already familiar with a 6550-to-EL34 conversion, I've done them before, so I knew what to look for. At first I saw that the correct resistors were changed so I didn't think too much about it. Then I put new tubes in it and got it biased, but it took a little more tuning than what I think should be necessary. But it still biased up fine. Then over time I noticed it's starting to sound a little harsher than it should, kind of like the bias is too hot. So I checked the bias and it was way too hot on two tubes. Hmm, that's weird. So then I started probing around those previously swapped out resistors and I discovered that one of them is totally incorrect. At first I measured them in the circuit and got wild readings. You're not really supposed to do that, but you can sometimes. I thought maybe the horrid soldering had them touching each other somewhere. Then I cleaned them up and read the color bands, and sure enough, one of them was a 22k when it should be 220k. And that's what they measured. That's not right, so I got to finding the right ones and put them in. Now all is well. The bias is right, and it sounds right again.

[WhiskeyJack]

That's insane man. good on you.

[Greg_L]

That's insane man. good on you.

Thanks dude but it's really not that big a deal. I've gotten to the point that I will never pay an amp tech ever again. Fuck those guys. They're as bad as soundmen.

My buddies Jube reissue blew up a capacitor and I've got that thing here to fix too. A one dollar part. A tech would charge at least 100 bucks. I'm doing it for Star Pizza and beer.

[WhiskeyJack]

That's insane man. good on you.

Thanks dude but it's really not that big a deal. I've gotten to the point that I will never pay an amp tech ever again. Fuck those guys. They're as bad as soundmen.

My buddies Jube reissue blew up a capacitor and I've got that thing here to fix too. A one dollar part. A tech would charge at least 100 bucks. I'm doing it for Star Pizza and beer.

That's a fair price !! I think it'll the act itself won't be so bad. My dad used to let me do some with him but i was like little. And i don't rememebr any of it. Like riding a bike i guess. Just gotta wait for the shit to show up.

[Greg_L]

That's a fair price !! I think it'll the act itself won't be so bad. My dad used to let me do some with him but i was like little. And i don't rememebr any of it. Like riding a bike i guess. Just gotta wait for the shit to show up.

Yeah dude you can do it. And then you'll be like, what else can I tinker with? You should try your hand at some pedals. Tadpui built a few nice pedal kits on his youtube channel.

[WhiskeyJack]

That's a fair price !! I think it'll the act itself won't be so bad. My dad used to let me do some with him but i was like little. And i don't rememebr any of it. Like riding a bike i guess. Just gotta wait for the shit to show up.

Yeah dude you can do it. And then you'll be like, what else can I tinker with? You should try your hand at some pedals. Tadpui built a few nice pedal kits on his youtube channel.

I originally set out to find a boost pedal or overdrive or something cause i don't really have one. but amazon yielded no results so for the sake of getting things ordered i just got that stupid little robot. I'll send it to my nephew or something when i am done. But you are exactly right dude. Ihave been looking at all kinds of small little kits to get for practice and i founds some good clone diy pedals and trinity amps also has a 1w one knb micro amp so i might get that too. But the Mutt90's and fixing my other guitars is paramount right now.

I have my priority list of what i am going to tackle. I like making stuff myself. this seems like a natural progression for me.

[Greg_L]

I originally set out to find a boost pedal or overdrive or something cause i don't really have one. but amazon yielded no results so for the sake of getting things ordered i just got that stupid little robot. I'll send it to my nephew or something when i am done. But you are exactly right dude. Ihave been looking at all kinds of small little kits to get for practice and i founds some good clone diy pedals and trinity amps also has a 1w one knb micro amp so i might get that too. But the Mutt90's and fixing my other guitars is paramount right now.

I have my priority list of what i am going to tackle. I like making stuff myself. this seems like a natural progression for me.

Yeah fix your guitars. Then build some pedals. That would be a good progression.

[Tadpui]

Oh hey guys, I've actually got a related situation...

My friend's Scarlett 18i20 crapped out on him. He sent it to me just to see if it worked on any of my computers, or if it was something weird about his computer. And if it worked for me, I'd have a really popular interface to review and test on YT.
Well, it's dead on all of my computers as well. The power light comes on, all of the preamps seem to work fine, but it simply won't connect to the computer via USB. Same issue for me as it was for him.

So as far as he's concerned, it's a boat anchor at this point. UPS reamed him on the shipping cost to get it to me, and the cost of shipping it back plus the cost of shipping it to Focusrite (or whomever) to repair it pretty much makes it a lost cause compared to what it would cost to just replace it.

We got this crazy idea since it's in interface purgatory right now: what if I tried to diagnose and repair it? I thought I might just try to replace the USB port on it and see if that works. But I'm not certain that's the problem. It seems fine except for its USB connectivity, but I have no diagnostic skills. I at least stand a chance of replacing a defective component but I really hate to start soldering on a jack with nothing to go on except that it doesn't realize that it's connected to a computer and computers don't realize that it's connected to them. Definitely a USB problem, but no guarantee that its the jack.

I just got a sack of USB jacks in the mail today (apparently you can't buy just 1 online) but I'm reluctant to just tear into it without doing a little investigation first. Any advice on where to start?

[Greg_L]

Yikes. I have no advice. I'd only suggest you crack it open and at least have a look around in there. Maybe you'll get lucky and see an obvious problem.

[SweetDan]

...I thought I might just try to replace the USB port on it and see if that works. But I'm not certain that's the problem. It seems fine except for its USB connectivity, but I have no diagnostic skills. I at least stand a chance of replacing a defective component but I really hate to start soldering on a jack with nothing to go on except that it doesn't realize that it's connected to a computer and computers don't realize that it's connected to them. Definitely a USB problem, but no guarantee that its the jack.

I just got a sack of USB jacks in the mail today (apparently you can't buy just 1 online) but I'm reluctant to just tear into it without doing a little investigation first. Any advice on where to start?

I'd start w/the computer-side of things first. Got linux? If so, see what you can dig up for troubleshooting help: https://www.google.com/search?q=ubuntu+ ... ot+working . This looks good: https://help.ubuntu.com/community/Sound ... gProcedure (PM me if you start to dig into this but get stuck somewhere, since I had to do this kind of troubleshooting once-upon-a-time when I was recording into Audacity on Linux!) Only after investigating all that would I dig out the soldering iron (and even then I'd take out the board & sockets and double-check there wasn't a blown capacitor or loose wire or something).

Of course, I don't know if this helps you or your friend, assuming neither of you is using Linux for audio, but at least it might help you determine if it's truly a hardware issue or if there's a software/configuration gremlin adding to your troubles.

[SweetDan]

I originally set out to find a boost pedal or overdrive or something cause i don't really have one...

...I like making stuff myself. this seems like a natural progression for me.

Yeah fix your guitars. Then build some pedals. That would be a good progression.

A DIY mini-amp can be fun too; challenging, but not impossible:

- http://www.runoffgroove.com/ruby.html
- http://www.runoffgroove.com/littlegem.html

I built myself a "Ruby" several years ago. I ought to put something up in the tone thread...

[Lt. Bob]

here:
https://www.aliexpress.com/item/DIY-Ove ... e0cced8dc6

http://www.musiciansfriend.com/amplifie ... -pedal-kit

https://www.amplifiedparts.com/products ... st-ii-fuzz

http://www.diyguitarpedals.com.au/shop/ ... ucts_id=72

[muttley]

As others have said. fixing old stuff and making kits up is a good and inexpensive way to build up bth you understanding and skills... Get a few single chip pedals or amp boxes and make them up, even just get some pcb boards and make them up from parts bare bones. With guitars get and old beater on ebay and solder away, it doesnt matter what it plays like to start with just that you can get sound out of it and troubleshoot connection issues. Its cheap fun and worth the effort. I'm guessing most of would have started that way. Very few of us went straight in on a valued or expensive piece of kit. Confidence is king, and that comes from having faith in you skill set.. Thats why I always advise with my mantra "test on scrap"

[WhiskeyJack]

My shit should be arriving friday !!!!