I don't disagree. Here's some food for thought anyway:
Crimp *and* solder a crimp connector? Good? Bad? Why? - Page 1
Looking for loose Mega-fit crimp terminals, gold plated, look what I found.Ok, ok.... I hear you both.I'll get the gold plated terminals.
WARNING: this is purely a curiosity, it has no bearing on all of you serious builders building your Modulus-686 seriously.
I found two products, both gold-plated 12AWG crimp terminals:
Both parts are active, and the price difference is significant: ratio 3:5, so I compared their PDF datasheets, and guess what I found? There is a difference only in one attribute: the "Plating min - Mating". In the more expensive one, it is 0.762uM, and the less expensive one is 0.381uM.
These guys actually build two different parts with two different SKUs just to offer a difference in this one parameter. It must be bloody significant. Is this the thickness of the gold plating in the mating surfaces?
If it's gold on the contact surfaces, I'm guessing it'll be useful for those applications where there are many more connects and disconnects of the plugs, to compensate for the wear.
Wonderful, wonderful, Mouser.
I order the parts for my Mod-686, plus Guardian-686, plus 3 other Neurochrome boards I intend to build real soon, all parts are in stock, and Mouser sends me email saying my order is about to ship, with a tracking number. I am exhibiting signs of elation and euphoria.
Then I get another mail from Mouser, attached below. I am exhibiting very different, jerky, violent, noisy signs now.
I quickly look up their site and identify parts with identical spec which are in stock. I write to them, asking them to replace the back-ordered part with any of these two parts. They cost twice as much as the missing part; they are Murata instead of TDK; $0.22 goes to $0.46, in case you want to know. I tell them I am not willing to wait till 24 Feb 2020 to finish my projects.
Let's see what they say in reply.
Why do these idiots do this? Why don't they tell me "Hey, it seems we're missing one item. Would you like us to hold for a day while you replace that with something else, or shall we refund you the (tiny, tiny) price of the two missing capacitors?" before shipping out my packet? Who the FLOK wants to wait till Feb 2020 for two capacitors? 
I order the parts for my Mod-686, plus Guardian-686, plus 3 other Neurochrome boards I intend to build real soon, all parts are in stock, and Mouser sends me email saying my order is about to ship, with a tracking number. I am exhibiting signs of elation and euphoria.
Then I get another mail from Mouser, attached below. I am exhibiting very different, jerky, violent, noisy signs now.
I quickly look up their site and identify parts with identical spec which are in stock. I write to them, asking them to replace the back-ordered part with any of these two parts. They cost twice as much as the missing part; they are Murata instead of TDK; $0.22 goes to $0.46, in case you want to know. I tell them I am not willing to wait till 24 Feb 2020 to finish my projects.
Let's see what they say in reply.
Why do these idiots do this? Why don't they tell me "Hey, it seems we're missing one item. Would you like us to hold for a day while you replace that with something else, or shall we refund you the (tiny, tiny) price of the two missing capacitors?" before shipping out my packet? Who the FLOK wants to wait till Feb 2020 for two capacitors?
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In the Mouser order process, I believe you have the option to tell them to ship what's in stock and back-order the non-stock items. Then you can always cancel the back-order. Sad that apparently someone else grabbed them before you. $0.46 vs $0.22 is insignificant in the overall cost of your project.
At the moment there is a world-wide shortage of passive components, especially ceramic capacitors; has been for a couple years. FORTY week lead time is the norm these days. For my projects at work where the requirements are very stringent and thus already severely limit my choices, I have consolidated on a very short list of part numbers and have had our distributor preemptively purchase enough to last me at least a year. I put that request in over six months before I needed them. Still, a week ago when I saw just over 500ea of one of my most needed values at both Digi-Key and Mouser, I snapped them up immediately.
At the moment there is a world-wide shortage of passive components, especially ceramic capacitors; has been for a couple years. FORTY week lead time is the norm these days. For my projects at work where the requirements are very stringent and thus already severely limit my choices, I have consolidated on a very short list of part numbers and have had our distributor preemptively purchase enough to last me at least a year. I put that request in over six months before I needed them. Still, a week ago when I saw just over 500ea of one of my most needed values at both Digi-Key and Mouser, I snapped them up immediately.
Thanks for a helpful response.
When I placed my order, there were no items on back-order. If you pick up the projects Tom has created on Mouser, I can almost rattle off each item which you'll find not in stock right now. I've been through the shopping-cart-loading process at least 4 times before I finally placed my order, and I manually replaced all missing items with equivalents each time. So, yes, if something is marked as not in stock when I place my order, I am responsible for accepting the delays for the missing parts. But here, I placed my order with an all-clear cart, I pay for all components, and 48 hours later they tell me one item will take six months.
I am willing to accept this situation, but I'm really pissed off about the lack of options they give me. They don't ask me to choose any alternatives. They don't say they'll let me drop the late item and refund me the amount. They just blandly inform me that my BoM will be incomplete for 6 months without giving me the option of opting out of that part and refunding me the money. The actual amount is tiny, we all agree, but simply taking for granted that I will be willing to pay for a part which they will deliver 6 months from now is downright unethical. I'm choosing my words accurately here: I think this is unethical behaviour.
Rather than accusing Mouser of unethical behavior, perhaps you should contact them, explain the situation and ask them to cancel the back order and adjust the billing accordingly.
I am most happy that very large distributors like Mouser, Digi-Key, etc., continue to sell to small buyers like you and me. Otherwise we'd be at the mercy of sellers of electronic components from questionable sellers on places like eBay.
I am most happy that very large distributors like Mouser, Digi-Key, etc., continue to sell to small buyers like you and me. Otherwise we'd be at the mercy of sellers of electronic components from questionable sellers on places like eBay.
I think I have explained in post 1167 above that I wrote to them immediately. They did not reply.
A few days have passed, and they have taken actions which have straightened out the situation and completely neutralised their earlier behaviour which made me allege unethical behaviour. I managed to piece this picture together by seeing the SMS alerts on my credit card (which was charged, then charged again, then refunded, etc for tiny amounts by Mouser) and an auto-generated email which gave part of the picture but wasn't clear. This morning, I checked my order history and I am beginning to feel that I now understand what they have done.
Net net: they have sorted things out. They have cancelled from my order the back-ordered items. Their first shipment contained everything other than the back-ordered items. They then charged my card for a second small amount and shipped out the replacement parts which I had told them could be used as substitutes. (I haven't seen the packages; I'm only able to see the fact that they have shipped out a second package 4 days after the first.) And there was an auto-generated mail which mentioned that the back-ordered part was "cancelled" and one of the substitutes I had identified has been added as a change to my order.
So, net net, they have completely closed the order correctly, and I've incurred some tiny two-dollar markup for the second shipment. I wish they had communicated more clearly, but I guess they only communicate through auto-generated emails which can be hard to understand sometimes.
No more grounds for my saying their behaviour was unethical. I place this on record.
I'm guessing that since this post was quoted in its entirety that you have similar questions...
Thank you.
If you buy the fully assembled modules, the Modulus-686 comes together pretty easily, especially if you have ModuShop (or some other chassis vendor) cut and thread the holes in the chassis for you.
The SMD pre-populated boards are harder to work with. The soldering is relatively easy. It's mostly the mechanical work that people run into trouble with. Basically the challenge is that you need to get all the LM3886es to lie flat on the heat sink and line up with their respective mounting holes after you're done soldering. The best way to do that is to attach the PCB to the heat sink with the mounting brackets, attach the LM3886es to the heat sink, and then solder. Alternatively, build a jig of some sort.
If you just solder the LM3886es to the board without aligning them with the heat sink, they will not make good thermal contact and performance will suffer. Also, as one builder found out, it is really hard to de-solder the LM3886es, and doing so without some sort of localized hot air reflow runs the risk of wrecking the board. That was an expensive lesson there.
The rest of the build generally comes together pretty easily.
I actually now offer a 4U ModuShop Dissipante CAD file as well. It has all the necessary holes for a stereo Modulus-686 with Guardian-686 speaker protection, ISS for the soft start, 2x Power-686, and toroidal power transformer mounting bolt. I seem to recall that it has speakON and binding post holes as well (it's been a while since I designed this). I'm happy to share the file with those who buy the MOD686 as long as you only take it to ModuShop for manufacturing.
Tom
Thank you.
If you buy the fully assembled modules, the Modulus-686 comes together pretty easily, especially if you have ModuShop (or some other chassis vendor) cut and thread the holes in the chassis for you.
The SMD pre-populated boards are harder to work with. The soldering is relatively easy. It's mostly the mechanical work that people run into trouble with. Basically the challenge is that you need to get all the LM3886es to lie flat on the heat sink and line up with their respective mounting holes after you're done soldering. The best way to do that is to attach the PCB to the heat sink with the mounting brackets, attach the LM3886es to the heat sink, and then solder. Alternatively, build a jig of some sort.
If you just solder the LM3886es to the board without aligning them with the heat sink, they will not make good thermal contact and performance will suffer. Also, as one builder found out, it is really hard to de-solder the LM3886es, and doing so without some sort of localized hot air reflow runs the risk of wrecking the board. That was an expensive lesson there.
The rest of the build generally comes together pretty easily.
I actually now offer a 4U ModuShop Dissipante CAD file as well. It has all the necessary holes for a stereo Modulus-686 with Guardian-686 speaker protection, ISS for the soft start, 2x Power-686, and toroidal power transformer mounting bolt. I seem to recall that it has speakON and binding post holes as well (it's been a while since I designed this). I'm happy to share the file with those who buy the MOD686 as long as you only take it to ModuShop for manufacturing.
Tom
Tom,
Would a Power 86 work fine for a monoblock Mod686 build since I already have them? I am going to start with a +/- 28V build since I already have two 2x22V 200VA. If I find I need more power I can swap out the transformers to go to +/- 36V. Will build it with 4U 400mm heat sinks from modushop so I can accommodate the future sinking capacity if I need the additional power.
Would a Power 86 work fine for a monoblock Mod686 build since I already have them? I am going to start with a +/- 28V build since I already have two 2x22V 200VA. If I find I need more power I can swap out the transformers to go to +/- 36V. Will build it with 4U 400mm heat sinks from modushop so I can accommodate the future sinking capacity if I need the additional power.
I already have 2 of the SMD-only ones, the transformers, fully populated Power 86's, and the brackets. Just need the through hole parts for the Mod686 boards and heat sinks. Will add the guardian686 and ISS eventually. Building my own chassis using a few parts from Modushop and other parts I make myself.
Subs and speakers have been the current priority, but future funds should be able to go towards building amps.
Subs and speakers have been the current priority, but future funds should be able to go towards building amps.
Thanks for the suggestion. I appreciate it.
I doubt I would be able to beat Hypex/Purifi on performance, in particular as long as Bruno's patent on post-inductor feedback is still enforceable. If I can't meet or beat the performance, I don't really see the point of pursuing Class D.
Many are skeptical of Class D ("digital amps"), so pushing on Class A/AB makes some sense too, even though it does prevent me from entering some markets.
That said, Class D is getting better and better, so perhaps it's time for me to take another look at where the market is at.
Tom
I doubt I would be able to beat Hypex/Purifi on performance, in particular as long as Bruno's patent on post-inductor feedback is still enforceable. If I can't meet or beat the performance, I don't really see the point of pursuing Class D.
Many are skeptical of Class D ("digital amps"), so pushing on Class A/AB makes some sense too, even though it does prevent me from entering some markets.
That said, Class D is getting better and better, so perhaps it's time for me to take another look at where the market is at.
Tom