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Swordfishy/ASPEN FETZILLA power amp

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#406
payment etc

Hi Hugh,
Overseas for a few weeks until mid -Oct.
My earlier email to update order my from "2" to "2+P" seems to have failed.
Please advise amount to be paid for 2+P (assumed to be possible) and preferred method -Paypal , cheque, bank transfer etc
best regards, Chris Power (shown as "Powell") Mosman
 
#411
Just found this thread and have not had a chance to read it all, I will do so when I get home tonight.

I am a 35+ years experience EE. I design and manufacture pcbs, however its not audio stuff. Part of my job is to do the board layouts, and I generate all the documentation which is sent to vendors who produce and assemble the boards.

So I am just going to list a few things here about these Fetzilla pcbs. These are observations, not complaints. I understand this is a hobbyist pcb, but if there is going to be a revision then perhaps it would help if I just point out some things we would do differently, or not allow.

Silkscreen is erratic, e.g. placement, orientation, font size changes with component size.

Overlapping placement outlines. (Not a big deal for hand insertion.)

Placement outlines and silkscreen on wrong side of board: R22,23,24,25.

Identical components with different outlines: D1,D2 different from D7,D8, and C8 different from C7.

Components missing from BOM: P1, P2,P3.

Surface mount components R22-25 not called out on BOM.

Product name spelled differently on opposite sides of pcb. Fetzilla/Fetzila.

Nonstandard component footprints.

OK, that's all from my scribbles in the margins. I probably missed some or got some wrong.

To the last point, Mr. Dean suggested to order parts from Mouser or DigiKey. But searches for mica caps having 5mm spacing, as on the board, are not finding parts from them. Same with the fuse holders, typical Littelfuse or Keystone parts have posts too big to fit through the pcb holes. Same with what he calls "RB" capacitors, this designation is not found with their search engines, may be an Aussie designation. I am now digging through the catalogs for anything with 2.5mm and 5mm spacing to see what would fit, it is time consuming.

I have every expectation that when its all built it will sound fantastic, I look forward to building it and hearing it. But right now all I want is a parts list, from which I can call a supplier and order parts.

Tonight I hope to find that a complete parts list with manufacturer's part numbers has been posted during this thread. If not I will struggle on, but probably will be back here begging for help.
 
#413
Geez scoop, you've almost convinced me that Hugh didn't do us all a big favour by going out on a limb and investing the time and effort to provide PCBs.

Seriously though, get the thing built, plug away, you will get there. We are happy to advise on parts and once you do finally get it built and have a listen I will be surprised if your woes don't fade away.

The non standard parts bug me too. However, having come to understand Hugh a little over the last six months I can assure you that any non standard parts are in there because at some point over the last 20 years Hugh has painstakingly tried all the alternatives and decided that the parts in question sound better.
 
#414
scooperman said:
Just found this thread and have not had a chance to read it all, I will do so when I get home tonight.

I am a 35+ years experience EE. I design and manufacture pcbs, however its not audio stuff. Part of my job is to do the board layouts, and I generate all the documentation which is sent to vendors who produce and assemble the boards.

So I am just going to list a few things here about these Fetzilla pcbs. These are observations, not complaints. I understand this is a hobbyist pcb, but if there is going to be a revision then perhaps it would help if I just point out some things we would do differently, or not allow.

Silkscreen is erratic, e.g. placement, orientation, font size changes with component size.

Overlapping placement outlines. (Not a big deal for hand insertion.)

Placement outlines and silkscreen on wrong side of board: R22,23,24,25.

Identical components with different outlines: D1,D2 different from D7,D8, and C8 different from C7.

Components missing from BOM: P1, P2,P3.

Surface mount components R22-25 not called out on BOM.

Product name spelled differently on opposite sides of pcb. Fetzilla/Fetzila.

Nonstandard component footprints.

OK, that's all from my scribbles in the margins. I probably missed some or got some wrong.

To the last point, Mr. Dean suggested to order parts from Mouser or DigiKey. But searches for mica caps having 5mm spacing, as on the board, are not finding parts from them. Same with the fuse holders, typical Littelfuse or Keystone parts have posts too big to fit through the pcb holes. Same with what he calls "RB" capacitors, this designation is not found with their search engines, may be an Aussie designation. I am now digging through the catalogs for anything with 2.5mm and 5mm spacing to see what would fit, it is time consuming.

I have every expectation that when its all built it will sound fantastic, I look forward to building it and hearing it. But right now all I want is a parts list, from which I can call a supplier and order parts.

Tonight I hope to find that a complete parts list with manufacturer's part numbers has been posted during this thread. If not I will struggle on, but probably will be back here begging for help.
Click to expand...

Ha, ha, ha, had to laugh. Finally a man after my own heart. scooperman, I suffer from the same problem. Although not perfect myself, I notice all these minute details and it annoys me. I have learnt to bite my tongue because I have learnt you don't win friends by pointing these things out, especially in public.

For example:

While reading your post I paused at:

"R22,23,24,25" wondering where the 3 R's are

and

"P1, P2,P3" why is there a extra space there. Personally I prefer a space after my commas.

and

"D7,D8, and C8" I pondered over the second comma.

No wonder I am a slow reader.

Hopefully everyone reads this with a smile on their face.

regards
 
#416
Hi Gannaji,

Thanks for your post; the boards were posted to you on 31st August by air mail, and may take longer than expected. I would expect them to be delivered this week, but have not much experience getting parcels/envelopes to the sub-continent.

Let me know end of the week if it has not arrived, but let us stay optimistic!

Cheers,

Hugh
 
#417
As far as I know silvered mica capacitors have pin pitches all of their own.
I don't know why.

Easy fix:
Bend the leads to the required PCB pitch.

Even easier fix:
Don't buy any silvered mica capacitors. They may never be required. Read the thread.
 
#418
AKSA said:
I'm sorry you don't like the pcb, Scoop, I thought it was rather good......!

Cheers,

Hugh
Click to expand...


I promised to go back and read the whole thread. In the first post of the thread, it says


AKSA said:
Folks,
If you see something glaring, please let me know in this forum.

Cheers,

Hugh
Click to expand...


Not sure where I suggested that I "don't like the pcb", if so I am sorry for that impression. I am sure I will like them when I finish building them.

Greg, good to know that it made somebody laugh. Yes I am one of those annoying nitpickers. Every company has different rules for internal documents, and sometimes we have to modify the parts list for certain vendors and subs. Where the BOM is the controlling document, typically the parts list will show numbering such as R1-7 if all eight of them have the same value. If they had non-consecutive numbering but the same component value, the first one gets the R , then comma-separated numbering without the Rs. Saving space on the document gets to be important in densely-populated designs, thus spaces and redundant characters are eliminated. If there is a group of consecutive numbered same-valued components, then the consecutive ones appear hyphen-separated in the comma-separated list.
So you made me laugh with your comments about my typing. I can assure you that when it goes to manufacturing review they fix all the commas and spacing, that's when I get yelled at because at signoff it really is important. Correcting a mistake gets expensive, especially if boards get assembled before the error is found.

Swordfishy, I think I get it now. I did read all the posts, and when I got to my post I can see that (by comparison with most of the others) it could seem negative in tone, if that is how you choose to read it.

But it may have been important (i.e. a design requirement) for C8 to have a different footprint from C7, or for D1 and D2 to be shaped/mounted differently from D7 and D8; if that is the case then my list would bring it to your attention and you would explain it to me.

I emphasize silkscreen issues for two reasons. First, because this product requires hand assembly, it is not designed for machine insertion. So efforts to optimize the silkscreen benefit the assembler. Where space permits, put the reference designator next to (not under) the part. Second, I expect this to have a long product life, I do not see this as a throwaway if it should ever fail. In such case, the technician performing the future rework benefits from consistent silkscreen.

Is any of this important here, for Fetzilla? Oh, probably not. But design excellence is what Mr. Dean is striving to achieve. I believe he has done it (so do you, which is why we all voted with our wallets) and the end result is a wonderful amplifier. I am eager to start assembly, I just need to order parts. Because I was having difficulty translating the parts list into a parts order, I reviewed the board layout part by part, comparing what I found on the pcb with the provided parts list. I found some differences, made a list. Audio experts already know this stuff, what is important and what is not. I don't know so I posted my list here.

Thank you to KLewis for posting a parts list pdf. I note that I saw a few more posts with individual parts and supplier recommendations in the last few pages, I will now go back through them and make notes. I hope to have my ordering BOM completed today.

Apologies to all for my writing style and long-winded post, he said as he continued typing incessantly.

My earlier comments were not helpful, let me try again.
I was going to write this next bit in email to Mr. Dean but perhaps it would be useful to others.

I believe you had some difficulties with the offshore pcb manufacturer. My products are all smt, completely machine assembled except for perhaps a connector or two per board. They are niche products, I rarely build in batches of more than a couple hundred. I tried offshoring but found that the problems were not outweighed by the cost savings when doing such small batches. I now work exclusively with vendors that are within a day's drive. When you are considering a new vendor, it is really helpful to be able to visit their facility, see their operation, talk to their staff. Usually you get the tour of the plant, see the machinery, talk to the techs. On new designs, you can work out most problems over the phone (no language barrier). I can drive to the pcb sub for design review before committing to final layout, I can send the Gerbers to the assemblers and their manufacturing engineers will review them and help me make the boards better for assembly, for example this is too close to the edge of the board, that should be oriented a different rotation, there will be a cold zone here if these two tall components are placed next to each other, and so on. This is how I learn and make a higher-yield, lower manufactured-cost product. Also, I think that when the vendor knows that the customer (me) is not far away, and might show up on his doorstep at any time, that they are a bit more diligent. So if its possible, I recommend working local for small runs.

I think this is where I say "Cheers."
 
#419
scooperman said:
Where the BOM is the controlling document, typically the parts list will show numbering such as R1-7 if all eight of them have the same value.
Click to expand...

😀 ___________ 😕 ___________ 😀

Edit: I realised that this could be construed as taking the P***, so I just thought I'd add that it's a relief to see I'm in good company when people say I can't count!

Hi Hugh,

In a post in the "Other" Fetzilla thread, you suggested it might be a good idea to mount the 3 x diode string on the rear of the board to give some thermal compensation. Is this still an option or is there another mechanism which makes this unnecessary now?

Cheers,

Ron.
 
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#420
RonR said:
😀 ___________ 😕 ___________ 😀

Edit: I realised that this could be construed as taking the P***, so I just thought I'd add that it's a relief to see I'm in good company when people say I can't count!

Hi Hugh,

In a post in the "Other" Fetzilla thread, you suggested it might be a good idea to mount the 3 x diode string on the rear of the board to give some thermal compensation. Is this still an option or is there another mechanism which makes this unnecessary now?

Cheers,

Ron.
Click to expand...



Attaboy, Ron. Maybe I would have noticed that if I had bothered to read it before hitting Submit. Hmm, I wonder if I could sell T-shirts with the logo "Submit"? Anyway, I could edit it, but I like the idea of a post lecturing everybody about not making mistakes which itself has such a dumbass error in it. Should keep me humble for a while.

p.s. I had to look up "taking the P***", we don't say that on this side of the pond. I guess we are separated by a common language.

Saw that about the diodes on the solder side, it was also mentioned earlier in this thread, which is a lot easier to search than the design thread. Edit: post 213 http://www.diyaudio.com/forums/aksa/191053-swordfishy-aspen-fetzilla-power-amp-22.html#post2646319 mentions solder side mounting of D1 and D2.
 
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