That's better
Did a molding experiment:
Silicone mold, black polyurethane resin. Looks pretty darn good for my first attempt.
I should have 10 new boards (still not enough expressed interest to go for a higher quantity) for the speaker testing jig on Monday or Tuesday - sign up now by PM please.
The mic is coming along. I have successfully made a mold from the original and cast a sample (shown above) - it looks very good. Some hand work is still involved - drilling the hole through the wand for the wire, cleaning up the end where it is poured into the mold.
The mic preamp schematic:
Like the speaker testing jig, it takes inspiration from Eric Wallin's mic preamp but with some changes. It uses the power on indicator LED in a dual purpose as a voltage reference for the regulator. The regulator uses 1/2 of the LM6132 opamp to provide precision voltage to the mic capsule.
The other half of the LM6132 amplifies the signal from the mic capsule and it has 2 gain settings, selectable with SW1. D1 prevents accidental damage from trying to connect the battery incorrectly - I already made that mistake and had to replace the opamp.
The board layout only uses through hole parts:
And is very compact but easy enough to assemble.
The mic is coming along. I have successfully made a mold from the original and cast a sample (shown above) - it looks very good. Some hand work is still involved - drilling the hole through the wand for the wire, cleaning up the end where it is poured into the mold.
The mic preamp schematic:
Like the speaker testing jig, it takes inspiration from Eric Wallin's mic preamp but with some changes. It uses the power on indicator LED in a dual purpose as a voltage reference for the regulator. The regulator uses 1/2 of the LM6132 opamp to provide precision voltage to the mic capsule.
The other half of the LM6132 amplifies the signal from the mic capsule and it has 2 gain settings, selectable with SW1. D1 prevents accidental damage from trying to connect the battery incorrectly - I already made that mistake and had to replace the opamp
.The board layout only uses through hole parts:
And is very compact but easy enough to assemble.
Thanks Katana
Speaker Testing Jig:
Based on round one, the majority want the full kit. Going with this and to simplify things quite a bit on my end, I'm going to restrict the choices to 2 from now on:
1. Board only - $12.00 plus $5.00 shipping worldwide.
A BOM with Digikey part numbers will be supplied with this.
2. Full kit - $62.00 plus $10.00 shipping worldwide:
No changes or substitutions please.
Please PM me for availability and to order.
Speaker Testing Jig:
Based on round one, the majority want the full kit. Going with this and to simplify things quite a bit on my end, I'm going to restrict the choices to 2 from now on:
1. Board only - $12.00 plus $5.00 shipping worldwide.
A BOM with Digikey part numbers will be supplied with this.
2. Full kit - $62.00 plus $10.00 shipping worldwide:
No changes or substitutions please.
Please PM me for availability and to order.
Hi John,
Amazing work sir!! I'll have to get you to show me how to mold parts, I am impressed.
Your handiwork puts my efforts to shame, anyone who knows me will agree. The jig kit is really good too. If you keep going, you'll have an on-line store up and running.
I'm interested in a mic setup, so I'll wait for pricing. I do see you have a low noise power source for the condenser microphone. Folks, this one is well designed from the looks of things.
My own original setup consisted of three condenser mics hanging in the air running off power supplies over shielded cable. It wasn't pretty but it worked just well enough. This setup is way far beyond what I used.
It's cool to see someone build something you did ages ago, but do it far better. Hat's off to you John! BTW, did you want to borrow a book again? No problem as you are working on the (much improved) jigs you need for the work.
-Chris
Amazing work sir!! I'll have to get you to show me how to mold parts, I am impressed.
Your handiwork puts my efforts to shame, anyone who knows me will agree. The jig kit is really good too. If you keep going, you'll have an on-line store up and running.
I'm interested in a mic setup, so I'll wait for pricing. I do see you have a low noise power source for the condenser microphone. Folks, this one is well designed from the looks of things.
My own original setup consisted of three condenser mics hanging in the air running off power supplies over shielded cable. It wasn't pretty but it worked just well enough. This setup is way far beyond what I used.
It's cool to see someone build something you did ages ago, but do it far better. Hat's off to you John! BTW, did you want to borrow a book again? No problem as you are working on the (much improved) jigs you need for the work.
-Chris
Hi Chris,
Thanks, I like to explore new and different ways of wasting my money - casting stuff is the latest
Online store, eh? Not my ultimate goal, I'm just trying to "stay in the game", make it a bit more interesting than just making more stuff for myself.
I see holes that need filling - holes I fell into when I started back into this hobby. One of the first electronic projects I did was to construct the Wallin jig. I think it wound up costing me (all parts in plus shipping and gas to go to Radio Shack) 3 times more than one of these full kits. Oh, and when I got the thing together and tried it, it didn't work! Then I needed an amp to do frequency response...
The mic is another costly item for the beginning DIYer - buying one then finding that you need a preamp with phantom power, cable, adapters, etc and soon you have spent enough to buy a higher end pair of speakers and save yourself some grief.
I figured it was a good idea to let the guys that want to build speakers find the equipments to test them at a reasonable price, something that will work and work well.
I have cast 2 other cases and they are near perfect also so I will call this aspect of the prototype process a success. I need to look the circuit board over a few more times for mistakes and then I have that out to Myro to make a few.
In other news, what is happening at Digikey? Last I checked there were more than 70,000 WM-61A capsules and now there are none - they are on backorder. Also a few of the parts I ordered for the jig are no longer in stock and at least 2 have had their status changed to non-stocked items.
Thanks, I like to explore new and different ways of wasting my money - casting stuff is the latest
Online store, eh? Not my ultimate goal, I'm just trying to "stay in the game", make it a bit more interesting than just making more stuff for myself.
I see holes that need filling - holes I fell into when I started back into this hobby. One of the first electronic projects I did was to construct the Wallin jig. I think it wound up costing me (all parts in plus shipping and gas to go to Radio Shack) 3 times more than one of these full kits. Oh, and when I got the thing together and tried it, it didn't work!
Then I needed an amp to do frequency response...The mic is another costly item for the beginning DIYer - buying one then finding that you need a preamp with phantom power, cable, adapters, etc and soon you have spent enough to buy a higher end pair of speakers and save yourself some grief.
I figured it was a good idea to let the guys that want to build speakers find the equipments to test them at a reasonable price, something that will work and work well.
I have cast 2 other cases and they are near perfect also so I will call this aspect of the prototype process a success. I need to look the circuit board over a few more times for mistakes and then I have that out to Myro to make a few.
In other news, what is happening at Digikey? Last I checked there were more than 70,000 WM-61A capsules and now there are none - they are on backorder. Also a few of the parts I ordered for the jig are no longer in stock and at least 2 have had their status changed to non-stocked items.
Hi John,
I also had some items I have used become non-stocked. A couple Panasonic surface mount diff pairs. It seems like you just can't win these days.
Mouser may have what you need, or Newark. Mouser charges $20 just to ship to Canada, steep but bearable. Then we have Avnet and other distribution houses, more like manufacturer representatives these days.
-Chris
I also had some items I have used become non-stocked. A couple Panasonic surface mount diff pairs. It seems like you just can't win these days.
Mouser may have what you need, or Newark. Mouser charges $20 just to ship to Canada, steep but bearable. Then we have Avnet and other distribution houses, more like manufacturer representatives these days.
-Chris
Hi Chris,
Getting all of the parts at one location keeps the cost (and complexity) down so I'll probably look for reasonable substitutes for these parts from Digikey. The switches and jacks are problematic as I would need to revise the board layout to accommodate them.
Ok, 7 boards left, 3 spoken for. Now is the best time to get this - the next round will be more expensive, by at least $10.00 (for the full kit).
7 left, full kit or board only.
Getting all of the parts at one location keeps the cost (and complexity) down so I'll probably look for reasonable substitutes for these parts from Digikey. The switches and jacks are problematic as I would need to revise the board layout to accommodate them.
Ok, 7 boards left, 3 spoken for. Now is the best time to get this - the next round will be more expensive, by at least $10.00 (for the full kit).
7 left, full kit or board only.
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Hi Andrew, Mark,
Thanks
I'm working on an assembly instruction thread that I'll post in lieu of written instructions. It will have lotsa photos and details.
Still some left and I would ask the members who PMed their order to please pay and send me your mailing address. Being able to make up the mailing list quickly reduces the chance of frak ups.
Thanks
I'm working on an assembly instruction thread that I'll post in lieu of written instructions. It will have lotsa photos and details.
Still some left and I would ask the members who PMed their order to please pay and send me your mailing address. Being able to make up the mailing list quickly reduces the chance of frak ups.
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