Choky is of course a little more 
GB: F1 boards
Anyone interested in participating in the GB, please see the group buy thread rather than leaving your request here. Only names added to the GB Wiki are considered participating in the group.
MEGA-Amp, mithomas, Planet10 have already been added to the wiki.
First Watt F1 GB
Also please continue to provide design review and comments on the boards.
-David
Anyone interested in participating in the GB, please see the group buy thread rather than leaving your request here. Only names added to the GB Wiki are considered participating in the group.
MEGA-Amp, mithomas, Planet10 have already been added to the wiki.
First Watt F1 GB
Also please continue to provide design review and comments on the boards.
-David
Re: F1 Boards
Hello Suds,
I'd rather not confuse people with dueling group buys. I don't mind you offering boards, but please start or use your own thread. We have a lot of English second language DIYer's and they my think the cost and specs you stated above apply to the actual boards in this thread.
Also you need Nelson explicit permission for a GB.
Thank you,
-David
suds said:
Hello Suds,
I'd rather not confuse people with dueling group buys. I don't mind you offering boards, but please start or use your own thread. We have a lot of English second language DIYer's and they my think the cost and specs you stated above apply to the actual boards in this thread.
Also you need Nelson explicit permission for a GB.
Thank you,
-David
BOM item for thermal pads.
Just another thought regarding the BOM.
For F1, needs some serious dissapation.
Has anyone found Mica for these to-247 cases? Is the berquest the way to go here. I think a recommendation should be made.
With the F2 I used bergquist BER178-ND. I was wondering if one has a mica source for these, or a better pad device for this application. On another free-association thought does one use grease under these? I tend to use some ceremic thermal grease, to hold them in place. I hope they don't rot out.
Just another thought regarding the BOM.
For F1, needs some serious dissapation.
Has anyone found Mica for these to-247 cases? Is the berquest the way to go here. I think a recommendation should be made.
With the F2 I used bergquist BER178-ND. I was wondering if one has a mica source for these, or a better pad device for this application. On another free-association thought does one use grease under these? I tend to use some ceremic thermal grease, to hold them in place. I hope they don't rot out.
Updated F1 Boards
Below are images of updated F1 boards, version 1.1. The only changes made were to make a larger foot print for the Wima caps, and move the Pot P1, LED1 and R20 to make room for the larger Wima foot print.
The prototype boards are coming by UPS and should be here by Wednesday or Thursday.
All the parts are in and I'm eager to start building. My prized MOTH drivers very generously donated by Nelson will finally have a worthy amp to drive them.
-David
Bottom Layer looking through the top w/silkscreen shown for reference:
Top layer with Silkscreen:
Below are images of updated F1 boards, version 1.1. The only changes made were to make a larger foot print for the Wima caps, and move the Pot P1, LED1 and R20 to make room for the larger Wima foot print.
The prototype boards are coming by UPS and should be here by Wednesday or Thursday.
All the parts are in and I'm eager to start building. My prized MOTH drivers very generously donated by Nelson will finally have a worthy amp to drive them.
-David
Bottom Layer looking through the top w/silkscreen shown for reference:
An externally hosted image should be here but it was not working when we last tested it.
Top layer with Silkscreen:
An externally hosted image should be here but it was not working when we last tested it.
knobs
David.
Looks good!
Looks like room for the big MKP10 WIMAs.
Have you considered using the multiturn 3296W pots?
There may be a offset legged one that goes into this footprint.
I could not find one after looking some.
Also, the resistors mentioned in the BOM are 1/10 watt? I thought we were supposed to use 1/4 watts on these projects.
I have been using CMF55 series. Nelson does mention using that model, but his production looks like CMF55's to me. I've been using them and PRP resistors for most of my projects.
Mike
David.
Looks good!
Looks like room for the big MKP10 WIMAs.
Have you considered using the multiturn 3296W pots?
There may be a offset legged one that goes into this footprint.
I could not find one after looking some.
Also, the resistors mentioned in the BOM are 1/10 watt? I thought we were supposed to use 1/4 watts on these projects.
I have been using CMF55 series. Nelson does mention using that model, but his production looks like CMF55's to me. I've been using them and PRP resistors for most of my projects.
Mike
Re: knobs
Hi Mike,
Nelson specified Vishay/Dale RN55D's in another thread. They come in 1/8w and 1/10w ratings.
Nelson has just confirmed to me that the selected RN55D's 1/8watt are correct.
I use Vishay/Dale RN55D or RN60D's in nearly all my projects. You cannot beat the performance for the price. Especially for DIY or low volume
where ROHS is not an issue. The CMF data sheet does not claim low noise like the RN55D/60D data sheet from Vishay.
Vishay RN55D Data Sheet
Vishay CMF55 Data Sheet
Mike just for you I added a multi-turn Bourns pot option for P1. Mouser part #652-3296W-1-502LF
-David
Version 1.2 F1 Boards, only change is vertical multi-turn pot option for P1:
Top layer with Silkscreen:
Bottom Layer with top layer Silkscreen:
Hi Mike,
Nelson specified Vishay/Dale RN55D's in another thread. They come in 1/8w and 1/10w ratings.
Nelson has just confirmed to me that the selected RN55D's 1/8watt are correct.
Nelson Pass said:
I use Vishay/Dale RN55D or RN60D's in nearly all my projects. You cannot beat the performance for the price. Especially for DIY or low volume
where ROHS is not an issue. The CMF data sheet does not claim low noise like the RN55D/60D data sheet from Vishay.
Vishay RN55D Data Sheet
Vishay CMF55 Data Sheet
Mike just for you I added a multi-turn Bourns pot option for P1. Mouser part #652-3296W-1-502LF
-David
Version 1.2 F1 Boards, only change is vertical multi-turn pot option for P1:
Top layer with Silkscreen:
An externally hosted image should be here but it was not working when we last tested it.
Bottom Layer with top layer Silkscreen:
An externally hosted image should be here but it was not working when we last tested it.
Re: Re: knobs
Done with multiturn
Sorry for the distraction, and thanks!
Actually researching the resistor spec sheets have me more confused. RN55 looks to be similiar mil spec as CMF55, but probably sounds different based on ROHS status, who knows..
But the wattage on mouser says one thing, another on Digikey for CMF. I guess it depends on the temperature.
If papa sayz RD55's are good, you say there good. I will shutup now.
dw8083 said:
Done with multiturn
Sorry for the distraction, and thanks!
Actually researching the resistor spec sheets have me more confused. RN55 looks to be similiar mil spec as CMF55, but probably sounds different based on ROHS status, who knows..
But the wattage on mouser says one thing, another on Digikey for CMF. I guess it depends on the temperature.
If papa sayz RD55's are good, you say there good. I will shutup now.
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