Soldering Pots?

mightymike · Post by **mightymike** » Mon Jan 08, 2007 1:58 pm

rockstah wrote:Mike, im not much into looks myself - more about performance for me. but i can understand it for people who are.
i wonder if the have the pots drifted any with all this heat on them?

Well both ways will perform the same as long as you used the samed size bus I guess. I doubt some one with dog hearing could hear the difference.

I can check some to see how much they drifted. If they did, it would only be slightly upwards; probably by the same percentage as the Allen Bradley CC, that according to the spec sheet on page 5 of my Art of electronics book, says +/- 2%. with 300 degrees Celicius at 1/8" inch away.

I say no more than +2%, cause I've never seen a CC drift down with heat, and I drift some CC's intentionaly like my 820s. But I do to doses of 30 seconds, at 850 degrees F, at 1/8" away, to make a 820 that reads 950 Ohm into a 1.1k.

You can only drift them so far.
I can get an 820 into the 900s,
But then again that's 2 doses of 30 seconds a 850.
I'm only applying heat for 4 to 5 seconds on my pots, and it's to the outer casing.

I'll check and get back, but I wish I had wrote down what they were before.

I'll do a before and after on the next one.

But the amp in my signature has those kind of pots, soldered that way, and sounds good (imo) and Chris ****** does them that way, so you know it can't be all bad.

Like I said, it's not for everyone.
I'm not saying my way is better.
But I like it better.

rockstah · Post by **rockstah** » Mon Jan 08, 2007 2:08 pm

haha no my point was it works to ground just the lugs of the pots that need to be grounded.

and again i can understand for looks if someone wants to go through the whole process to get the backs soldered. in my book its just not needed.

mightymike · Post by **mightymike** » Mon Jan 08, 2007 2:18 pm

To me it's easier.
And looks better.

To each his own.

NitroLiq · Post by **NitroLiq** » Mon Jan 08, 2007 2:18 pm

rockstah wrote:
NitroLiq wrote:I think a lot of it is personal preference, Mark. Some solder to the pot backs, others run it through the pot lugs (as you already know), and others solder it to the bottom of the turretboard like this.
oo i like that look! but where and how are the pots grounded? btw what circuit is this? ...the phase inverter circuit is intriguing.

That's trinityamps' take on the 18w TMB circuit, the SIII. This type of bussbar setup works just like putting the bar on the pots. Any ground wires that would be soldered from the pots to the buss on the back of the pots would just be soldered to the bussbar. The difference is that you don't ground the bussbar itself to a groundlug. You solder a ground wire off the end of the bussbar to the groundlug. Here's a pic of the bottom side of the board. You can see the green wire coming off the pwr side of the board (where the yellow cap is). That would go to a ground lug.

mightymike · Post by **mightymike** » Mon Jan 08, 2007 2:18 pm

I think that's a Ceritone Board, with the buss on the side of the board.
He does his ground like that.

I think he solders a wire from it to a chassis lug to ground it.

NitroLiq · Post by **NitroLiq** » Mon Jan 08, 2007 2:21 pm

No, it's trinityamps. They basically took the standard 18w TMB layout and corrected some layout issues and tweaked a little. Most 18 watters are laid out that way, including Nik's.

For my 36 watter, I would've tried soldering to the backs of the pots as that's how I drew it up in the layout but since I'm using PECs and with all the problems ppl were having, I decided to do it this way. It's just another way and looks just as neat providing you can get the bussbar straight. A few things I learned about this method:

1) The heavy radiators you find in NYC apartments are great for bending 16awg copper wire (loop it around, grab each end with pliers, lean back and pull with all your might...kinda like rowing a boat!)

2) Copper stays hot a for a few seconds longer than suspected...I think I modified my thumbprints from grabbing onto it to hold it in place...ouch!

3) It's a very cramped area to work with with the bar in place in relation to the board and the pots...remember the game Operation? Kinda like that, except no startling buzz and no red nose to light up (hopefully)!

mightymike · Post by **mightymike** » Mon Jan 08, 2007 2:32 pm

I wish I had the before readings, and I will get them on my next one and do a real before and after, but measuring the super Trem Project I have:

1.024 M Vol 2
1.030 M Vol 1
269.9K Treble
25.9K Mid
1.056 Bass
5.02 Presense

That 269 Treble was already reading over, so that wasn't caused by my Soldering.

NitroLiq · Post by **NitroLiq** » Mon Jan 08, 2007 2:41 pm

I remember someone over at 18watt, actually, it might've been Stephen from Trinity, got into a discussion about all this. He didn't find a difference soldering to the backs of alphas or doing the hanging buss (off the board) so he stuck with the board method...personal preference.

JimiJames · Post by **JimiJames** » Mon Jan 08, 2007 3:09 pm

mightymike wrote: .......... and I drift some CC's intentionaly like my 820s. But I do to doses of 30 seconds, at 850 degrees F, at 1/8" away, to make a 820 that reads 950 Ohm into a 1.1k.................

You can only drift them so far.
I can get an 820 into the 900s,
But then again that's 2 doses of 30 seconds a 850.
I'm only applying heat for 4 to 5 seconds on my pots, and it's to the outer casing.....

Berry interestink !
... like replacing resistors with different "nearby" values. The ultra tweak.
I am currently putting together another MainBoard and have gone through all the reistors on the board getting each one
as close to the value on the chart. I got the extremely close but none of them were spot on... As a matter of fact all were under...? (I'll be using CF's)

On the pots...
Aren't the Pec's Stainless Steel backs?
I see that your solder is moltened really well like vulcanic heat

to make it look so liquified. It's obvious that you have no issues
and I couldn't see myself applying that intense heat to Pec's I wouldn't think twice doing it to other brands with alloy backs.
So, Mike your using a variable Station right,
what type/brand of solder do you prefer to use ? I tried soldering the back of a PEC with a 60wt iron and with RadioSnatch solder with no "permenant luck.
I tested the weld by wedging a small screwdriver and applying upwards pressure on the buss wire only to have it pop off. I can see in your pic
that no way would that happen from the looks of those welds.

I must say for PECs I'm with rockstah. It's more about performance because I build amps for myself.
I've never worked with a variable iron before but if I did I would practice your techinique
and if I were going on vintage spec I would solder those pots just like yours, pal!

NitroLiq · Post by **NitroLiq** » Mon Jan 08, 2007 3:33 pm

JimiJames wrote:I must say for PECs I'm with rockstah. It's more about performance because I build amps for myself.
I've never worked with a variable iron before but if I did I would practice your techinique and if I were going on vintage spec I would solder those pots just like yours, pal!

That's it in a nutshell. At near $60 for a full set of PECs for my amp, I wouldn't want to chance messing them up, though I guess removing the backs and soldering takes away that reason. Still seems like more work than necessary but if I were going for historic accuracy, it makes sense...I'd probably cop out and use alphas!

mightymike · Post by **mightymike** » Mon Jan 08, 2007 3:37 pm

How is soldering the backs less in the performance dept?

Do my amps sound like they are performing less becasue of it?
I've never removed the back, and they aren't drifting much at all cause I'm quick. Part of that is the great soldering Iron, but it won't stick unless you use the right solder, and prep it right.

Also didn't the orginals drift?
I bet no more than the PEC pots, and Visa versa depending on the person doing the work.

I have a Hakko Soldering station (Future Product), the one with the Brass Brillo thing to clean the tip, and it has 6.5, 7.0, 7.5, and 8.0 settings.

Not 850.
So my highest setting is the 8.0 which I think is 800 degrees.

When you turn the soldering Iron on, it takes about 3 seconds, and it beeps, and you're ready to solder. I've had the same tip since I bought it 8 amps ago, and it has transformed my amp building, to where my solder joints look like this now.

http://mightymike12000.home.comcast.net ... H_spec.jpg

I use really thin solder on my boards. Kester brand, and solder my turrets on the 6.5 setting, and it's quick. On my pots I use something else.
Stainless steel soldering is a whole different ball game. I also use chemicals, before and after. But that's all I can say about that.
Sorry

With a shitty soldering Iron, it took me longer than 5 sec to solder Alpha Pots backs.

Soldering to the terminals doesn't equal better performance,
soldering to the back doesn't equal better performance.
It will sound the same. Those pots are rugged as heck.
My measurements show everythings within spec.

Hakko soldering stations rock.

Even if you don't like the soldered back look, that Hakko is a great tool to have.

rockstah · Post by **rockstah** » Mon Jan 08, 2007 3:59 pm

again my whole thing is performance - (does it get the job done?) is easy.
i dont think there is any difference in how the circuit acts either way.
to me its easier worring about the 4 pots that need grounding and going through each of there ground lugs. its just easier. *shrug* if i wanted the look i would go through the hassle. its just not important to me.

JJ as far mesuring the resistors to exact spec its time to start thinking why you would actually be doing that. as far as we have talked about before on the phone. cf and cc resistors measure differnet, cf are usually just under or right on spec and cc are usually right on or over.
but like i said start looking at those particular resistor positions in the circuit and how they effcet things. if in one position they are higher or lower. for example a plate resistor will make the tube run hotter thus giving more gain. good or bad is subjective- start looking at the other positions to see what they actually do. what if my mix resistor measures low compared to high? etc.
also i think it is kewl to start with spec as far as if u are really trying to learn the circuit and how things effect it.

Mark

JimiJames · Post by **JimiJames** » Mon Jan 08, 2007 4:15 pm

mightymike wrote:How is soldering the backs less in the performance dept?
Do my amps sound like they are performing less becasue of it?
.

No man.. c'mon. you know what I mean. I explained I don't have a Soldering Station as I figured out you did and was saying if I did I would practice to get welds lookin' like yours.

I have no desire with my regular Hakko iron to guess if I did it right. I suck at that ! Atleast you know you did right without a doubt ! shattup !

JimiJames · Post by **JimiJames** » Mon Jan 08, 2007 4:40 pm

rockstah wrote: JJ as far mesuring the resistors to exact spec its time to start thinking why you would actually be doing that. as far as we have talked about before on the phone. cf and cc resistors measure differnet, cf are usually just under or right on spec and cc are usually right on or over.
but like i said start looking at those particular resistor positions in the circuit and how they effcet things. if in one position they are higher or lower. for example a plate resistor will make the tube run hotter thus giving more gain. good or bad is subjective- start looking at the other positions to see what they actually do. what if my mix resistor measures low compared to high? etc.
also i think it is kewl to start with spec as far as if u are really trying to learn the circuit and how things effect it.

Mark

Yes absolutely Mark and the learning process will come of course but the curiosity part of it is as well needed.
I want to eliminate certain areas for self awareness and know for sure. A process of elimination perhaps...
I know the different tollerences with the different resistors respectively thus color codes and the silver & gold markings for the example ... besides the posts that I have read on that.
I will start looking at those particular resistor positions in the circuit and how they effect things because it's imparative to understanding an amp voice.
Your advice is taken to heart and will happen with time. It's a "little-by-little" thing for me right now and looking forward to getting things moving. Locomotively speaking... I can't wait.

I love this shit man !

mightymike · Post by **mightymike** » Tue Jan 09, 2007 7:59 am

Ah Ok Ok
I missunderstood and thought you guys were thinking the pots were getting hurt in some way, and hurting performance. Sorry if I came off a little defensive.