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Old 30th September 2009, 06:53 PM   #1041
Tea-Bag is offline Tea-Bag  United States
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Quote:
Originally Posted by Salas View Post
How much did it cost you BTW? You use a very good assortment of parts and a an SMD Vishay resistor switcher pot. Its a good indication for those looking to build fully functional a preamp and use it. You miss the box for now I guess, but it is not rational to include the box in the cost estimation anyway. There someone can go from tin can to exotic. Its looks.
I think I go decent parts inside, and tin can looks on outside. I am not trying to impress anyone. Just want it to sound good. I use whatever recycled metal I find at work or yard sales. Some sheet aluminum for fit and finish.

I never try to cheat myself on resistors or caps. Too many cheap caps in the computer industry. They blow up people. Resistors are an inexpensive upgrade typically, and I only go above dale in the signal path.
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Old 30th September 2009, 06:59 PM   #1042
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Originally Posted by Tea-Bag View Post
Well, the proto builders get to weigh in and we can make a decision. I think gold has a different point of overheating. A lot of builders dont like gold. We could go thicker as well, but for a pre I think it's overkill. It's a sensitive area on the LEDs.

With my iron at 900F on a gold pad, I can burn it off

So this is a good construction note concern anyways. This area is likely a place to be careful.
My opinion is low-melting point lead solder is a way to go here. I have used so many crap solders. I love cardas. Worth the money.
Th board price increase by a $ is not going to hurt the current GB lot as I see lot more price on power supply PCB alone while this one is much more than PSU board. But this issue is not very critical and can be managed by direct soldering leads. I use nice temp controled pencil iron which does not heat the pad that much . But still found one or two pads coming off in the first time soldering. I ignored it thinking that I might have done something wrong but I remember now as Alan reported. Is it related to tinning or base copper adhesion to board ?
Kannan
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Old 30th September 2009, 07:02 PM   #1043
iko is offline iko  Canada
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The problem might be the traces and pads are too thin. I haven't seen the layout or the boards, so I don't know. I know this, that most pcb layout software has very thin traces and pads by default, which are suitable for board machine stuffing but not for regular diy. I usually set the traces much wider than the default, and use bigger pads. It's an easy solution which should not bring the cost of boards up.
Just my 2c.
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Old 30th September 2009, 07:04 PM   #1044
Salas is offline Salas  Greece
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Tea-Bag:

Watch the 4X220R mainly, the 2X220k, the pot and the electrolytics. All other stuff do not have to do match with transparency and tone.

Grufti's is a decent one, with a good pot but not expensive. So its a good indication of some logical but good grade Mezmerize cost. Then he was very thorough in to telling us his subjective evaluation, seems not verging to some custom tonal preference if I got it right. That is why I ask. Indicative cost for an indicative build.
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Old 30th September 2009, 07:07 PM   #1045
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Quote:
Originally Posted by Tea-Bag View Post
I think I go decent parts inside, and tin can looks on outside. I am not trying to impress anyone. Just want it to sound good. I use whatever recycled metal I find at work or yard sales. Some sheet aluminum for fit and finish.

I never try to cheat myself on resistors or caps. Too many cheap caps in the computer industry. They blow up people. Resistors are an inexpensive upgrade typically, and I only go above dale in the signal path.
I only mentioned cases to indicate that the pcb is peanuts compared to the rest - I also spend more on the components and stick the pcb's on a nice block of wood!

I am using silver solder - I will try Cardas if it makes a difference.

Alan
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Old 30th September 2009, 07:11 PM   #1046
grufti is offline grufti  United States
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You are right Tea-Bag, there are advantages and disadvantages to each of those choices. I actually don't have a really strong opinion on this matter at all from personal preference.

"Robust" and "reasonably easy to work with" seem like two good ideas for any diy project. I don't claim to know where these two best meet for these two pcb's.

Unchanged [cheaper, good enough] - gold [more expensive, sometimes no fun to work with] - thicker [more expensive, more robust, better heat dispersion, electrically overkill] ... we can probably live with all of them.


Quote:
Originally Posted by Tea-Bag View Post
Well, the proto builders get to weigh in and we can make a decision. I think gold has a different point of overheating. A lot of builders dont like gold. We could go thicker as well, but for a pre I think it's overkill. It's a sensitive area on the LEDs.

With my iron at 900F on a gold pad, I can burn it off

So this is a good construction note concern anyways. This area is likely a place to be careful.
My opinion is low-melting point lead solder is a way to go here. I have used so many crap solders. I love cardas. Worth the money.
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Old 30th September 2009, 07:11 PM   #1047
Salas is offline Salas  Greece
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Quote:
Originally Posted by ikoflexer View Post
The problem might be the traces and pads are too thin. I haven't seen the layout or the boards, so I don't know. I know this, that most pcb layout software has very thin traces and pads by default, which are suitable for board machine stuffing but not for regular diy. I usually set the traces much wider than the default, and use bigger pads. It's an easy solution which should not bring the cost of boards up.
Just my 2c.
As I hold and I am checking out the two PCBs right now, I see that the Hypno has less exposed pad in the 3 Led position than the the Mez as well as the later being gold. My guess it is its down to the area. Hypno's like rings, when Mez's have a little more.

But those are small boards to keep it neat for signal path and noise. Use a pencil 15-20W and low melting point good solder for all soldering. If you know it, you will avoid it. That is why proto testing rules.
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Old 30th September 2009, 07:18 PM   #1048
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Quote:
Originally Posted by Salas View Post
As I hold and I am checking out the two PCBs right now, I see that the Hypno has less exposed pad in the 3 Led position than the the Mez as well as the later being gold. My guess it is its down to the area. Hypno's like rings, when Mez's have a little more.

But those are small boards to keep it neat for signal path and noise. Use a pencil 15-20W and low melting point good solder for all soldering. If you know it, you will avoid it. That is why proto testing rules.
You are right - i also feel it is not the gold or tin but the pad area causing this. If less area is exposed like the Hypno board - probably we can avoid this
kannan
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Old 30th September 2009, 07:22 PM   #1049
grufti is offline grufti  United States
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I'll gladly add up my parts cost sometime this week. My build cost very little considering how good it is, I can tell you that without going through any mouser invoices. No expensive caps, that's for sure, but connectors add up of course with seven pairs for the Mezmerize. On the other hand, if you only need 4 inputs, you don't really have to install all 6.

Oh, and another vote for Cardas eutectic solder.
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Old 30th September 2009, 07:22 PM   #1050
schro20 is offline schro20  United States
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Default Suggestion for final package: instructions...

I would like to suggest that the final package for the boards come with a sheet (maybe we can collectively put that together here) with some of the gotchas and recommended practices. The thread is long enough now that it's a real pain finding (and not overlooking!) important information.

Here are some suggestions:
- issues with potential shuttering problems: list of suggested solutions
- how to measure IDSS for the sk170 to put "the right one" in the "right spot"
- how to measure the LEDs (and mixing is allowed, for example) to get the right total

What others along these lines do we have?

My experience with the revC GB was that lots of questions like this came later because we didn't put together a sheet like that.

Thoughts?

peter
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