What about a poll? Including the transformer is out of question, which means we have 3 items to be discussed: heatsink, input caps and PSU filter caps.
I have some spare heatsinks at hand so I would prefer not to pay for them, let alone the extra cost of shipping. But I would yield to the majority.
Of course averyone of us will have some of the parts requested in the kit. If anyone of us asked not to have "this part, and the other one" this would automatically change this from a Group Buy to a Total Mess...
Power trafos are obviously ou of this discussion (and the option about them is already given) but a Group Buy is a Group Buy. Otherwise you can always buy every single part of the kit by yourself, and in this case you have the very comfortable option to get only the boards...
Please let's not make this thing totally unmanageble for the promoter and everyone else...
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+1 - Exactly the same issues that I face as an overseas buyer. Keep those items as optional, and let each buyer choose on including them individually.
I strongly agree with that. Transformers are heavy and bulky. Heatsinks are more of "personal taste" and chassis election dependant. But I would include the PSU smoothing caps, not too heavy and have the same "rights" as other caps from the kit. I would put the expensive input cap as an optional extra.
This is exactly why I suggested a poll. I don't want Uriah to mess around with a hundred options. But it seems there are a few more decisions to be made, including or excluding certain parts is not totally out of question.
If the promoter decides to include a heatsink, I can live with it, too. If he decides not to have the PSU caps in the group buy, I can handle that too, and source those parts locally.
I think 'a Group Buy is a Group Buy' is not an argument.
Havent seen the thread in a day or so. Wow you guys are getting excited.
This is how I run a group buy. I tell you guys what I will supply and you decide if you want to buy it or not. I am not going to cater to any 1 or 10 people at all under any circumstances. It will only cause confusion later and I am not about to try to offer several versions.
I will offer to provide a transformer or not. And that is only for US customers as shipping a transformer overseas is silly.
I will offer the exact same kit to everyone an it will include power supply caps. Everything to populate the board. I will provide a WIMA DC blocking cap, not the Fostex cap. This will provide good sound at a low price and will allow anyone to have a great starting point until they either decide to go DC coupled or find a great input cap that sounds best to them.
This kit will not provide heatsinks. Simply the parts to populate the board. Chassis and all other components external to the board are up to you guys.
Trust me, if you guys had to run a 100 kit group buy making each order or even 10% of the order custom orders would result in pulling out all your hair
I prefer to keep my hair as long as possible.
I think midweek I will have pricing.
Uriah
This is how I run a group buy. I tell you guys what I will supply and you decide if you want to buy it or not. I am not going to cater to any 1 or 10 people at all under any circumstances. It will only cause confusion later and I am not about to try to offer several versions.
I will offer to provide a transformer or not. And that is only for US customers as shipping a transformer overseas is silly.
I will offer the exact same kit to everyone an it will include power supply caps. Everything to populate the board. I will provide a WIMA DC blocking cap, not the Fostex cap. This will provide good sound at a low price and will allow anyone to have a great starting point until they either decide to go DC coupled or find a great input cap that sounds best to them.
This kit will not provide heatsinks. Simply the parts to populate the board. Chassis and all other components external to the board are up to you guys.
Trust me, if you guys had to run a 100 kit group buy making each order or even 10% of the order custom orders would result in pulling out all your hair
I prefer to keep my hair as long as possible.I think midweek I will have pricing.
Uriah
You are right, udailey, there's too much work in this project to make it more complex. We were giving our opinions and you have heard us.
I'm happy with the way this is going ahead.
BTW, could it be possible for you to post the schematic or board layout picture. I am still starting to read the 150 pages original thread, but would be great to have the final ones after so much iterations in the thread.
Thanks for all
I'm happy with the way this is going ahead.
BTW, could it be possible for you to post the schematic or board layout picture. I am still starting to read the 150 pages original thread, but would be great to have the final ones after so much iterations in the thread.
Thanks for all
Here are some questions and answers I put together before I decided whether to run the group buy or not. A huge amount of information.
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html
Original introduction and subsequent design thread.
Can I ask the orginal designer some questions? No. He is a good guy but he no longer participates on this forum.
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-299.html#post1666211
Thats for gerbers, boms, etc.
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-303.html#post1681700
Single sided for etching.
The Dim-bulb Radio Tester
Lets just say that when firing it up for the first time, if you dont use this or a Variac, then dont blame anyone else if something goes 'poof.'
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-305.html#post1685919
24V secondaries are best but 22V would be fine..
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-308.html#post1690023
A discussion about grounding as it can be a bit confusing with this amp.
http://www.diyaudio.com/forums/chip-amps/115698-understanding-star-grounding.html
Grounding - Read this please
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-309.html#post1696302
What pot to use?
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-312.html#post1994728
Many caps on the board are .22uf but spec'd for .1 in Mauro's schematic. Why the change?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-84.html#post1894099
Dont try to improve it with the normal "tweaks". This amp is tweaked already. Leave the opamp alone. Just stop. Resist.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-82.html#post1884786
Fuse and switch installed correctly.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-78.html#post1881513
what it looks like assembled.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-78.html#post1881527
Can I use different diodes instead of the recommended rectification?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-76.html#post1853965
Should I put fuses on the secondaries?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-74.html#post1829568
DC offset at output of amp. Whats okay? How do I measure it?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-73.html#post1828475
I want the technically perfect heatsink. If you just want a guess then us a 2.5"x2.5"2" cpu heatsink.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-72.html#post1828150
Is it worth the build?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-66.html#post1817872
I want to swap my own caps. How should I do that so I dont end up over soldering the board and lifting a trace?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-53.html#post1785029
I have noise after putting in large input caps or just some hiss anyway, here is one explanation.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-48.html#post1783502
Should I do MonoBlocks? Well, I dont know but there is a discussion here.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-45.html#post1775852
I like cap swapping. Anything else I might like ?
Picasa Web Albums - Peter - RevC Measurem...
Some REVC measurements from Peter
From Mauro's webpage:
Passing band (typical-3db): 2Hz-70Khz
* The maximum power (8ohm): 40Wrms
* The maximum power (4ohm): 56Wrms
* Damping factor (8ohm): >200
* Relationship S/N (600ohm): >96 dB not weighed
* Typical THD (20Hz-20Khz, 1-40W 8ohm <0,05%
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-85.html#post1894413
Cap recommendations by Dario
I have a pic of the top of the board.. pdf below
Also an eagle schematic
Uriah
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html
Original introduction and subsequent design thread.
Can I ask the orginal designer some questions? No. He is a good guy but he no longer participates on this forum.
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-299.html#post1666211
Thats for gerbers, boms, etc.
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-303.html#post1681700
Single sided for etching.
The Dim-bulb Radio Tester
Lets just say that when firing it up for the first time, if you dont use this or a Variac, then dont blame anyone else if something goes 'poof.'
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-305.html#post1685919
24V secondaries are best but 22V would be fine..
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-308.html#post1690023
A discussion about grounding as it can be a bit confusing with this amp.
http://www.diyaudio.com/forums/chip-amps/115698-understanding-star-grounding.html
Grounding - Read this please
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-309.html#post1696302
What pot to use?
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach-312.html#post1994728
Many caps on the board are .22uf but spec'd for .1 in Mauro's schematic. Why the change?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-84.html#post1894099
Dont try to improve it with the normal "tweaks". This amp is tweaked already. Leave the opamp alone. Just stop. Resist.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-82.html#post1884786
Fuse and switch installed correctly.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-78.html#post1881513
what it looks like assembled.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-78.html#post1881527
Can I use different diodes instead of the recommended rectification?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-76.html#post1853965
Should I put fuses on the secondaries?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-74.html#post1829568
DC offset at output of amp. Whats okay? How do I measure it?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-73.html#post1828475
I want the technically perfect heatsink. If you just want a guess then us a 2.5"x2.5"2" cpu heatsink.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-72.html#post1828150
Is it worth the build?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-66.html#post1817872
I want to swap my own caps. How should I do that so I dont end up over soldering the board and lifting a trace?
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-53.html#post1785029
I have noise after putting in large input caps or just some hiss anyway, here is one explanation.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-48.html#post1783502
Should I do MonoBlocks? Well, I dont know but there is a discussion here.
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-45.html#post1775852
I like cap swapping. Anything else I might like ?
Picasa Web Albums - Peter - RevC Measurem...
Some REVC measurements from Peter
From Mauro's webpage:
Passing band (typical-3db): 2Hz-70Khz
* The maximum power (8ohm): 40Wrms
* The maximum power (4ohm): 56Wrms
* Damping factor (8ohm): >200
* Relationship S/N (600ohm): >96 dB not weighed
* Typical THD (20Hz-20Khz, 1-40W 8ohm <0,05%
http://www.diyaudio.com/forums/chip-amps/134726-new-my-ref-rev-c-thread-85.html#post1894413
Cap recommendations by Dario
I have a pic of the top of the board.. pdf below
Also an eagle schematic
Uriah
Uriah,
I agree that is the correct strategy for this group buy: supply ALL of the best quality parts sufficient to build a complete amplifier circuit board, but no parts external to that. There is little money to be saved and no agreement to be had on enclosures, heatsinks, etc. and everyone has their favorite cap.
Participants are encouraged to share their construction plans and results in another thread when the time comes. Those who recognize the importance of using high quality parts can make that decision for themselves. Others may believe economy takes precedence, but should understand the performance of the amp may be somewhat compromised.
Peace,
Tom E
I agree that is the correct strategy for this group buy: supply ALL of the best quality parts sufficient to build a complete amplifier circuit board, but no parts external to that. There is little money to be saved and no agreement to be had on enclosures, heatsinks, etc. and everyone has their favorite cap.
Participants are encouraged to share their construction plans and results in another thread when the time comes. Those who recognize the importance of using high quality parts can make that decision for themselves. Others may believe economy takes precedence, but should understand the performance of the amp may be somewhat compromised.
Peace,
Tom E
Havent seen the thread in a day or so. Wow you guys are getting excited.
This is how I run a group buy. I tell you guys what I will supply and you decide if you want to buy it or not. I am not going to cater to any 1 or 10 people at all under any circumstances. It will only cause confusion later and I am not about to try to offer several versions.
I will offer to provide a transformer or not. And that is only for US customers as shipping a transformer overseas is silly.
I will offer the exact same kit to everyone an it will include power supply caps. Everything to populate the board. I will provide a WIMA DC blocking cap, not the Fostex cap. This will provide good sound at a low price and will allow anyone to have a great starting point until they either decide to go DC coupled or find a great input cap that sounds best to them.
This kit will not provide heatsinks. Simply the parts to populate the board. Chassis and all other components external to the board are up to you guys.
Trust me, if you guys had to run a 100 kit group buy making each order or even 10% of the order custom orders would result in pulling out all your hair
I think midweek I will have pricing.
Uriah
Agree.
This is the way it all started, and above all the only way you can manage it without going crazy. Go ahead this way, please.
Udailey, I have noticed that in the BOM:
R5, R8 22K1 PRP 1/4W 0.1% (matched by hand)
R6, R9 47K5 PRP 1/4W 0.1% (matched by hand)
What have you thought about that, match them yourself? Provide us a bunch to try to find matches and then discard the rest? Or maybe using those Welwyns RC55Y 0.1%?
Thanks in advance
R5, R8 22K1 PRP 1/4W 0.1% (matched by hand)
R6, R9 47K5 PRP 1/4W 0.1% (matched by hand)
What have you thought about that, match them yourself? Provide us a bunch to try to find matches and then discard the rest? Or maybe using those Welwyns RC55Y 0.1%?
Thanks in advance
As I can see, we will be supplied with hook-up wire (Ohno UPOCC solid core copper with Teflon insulation), which I suppose is for low-signal level. What is the recommendation for the thicker wires from output to binding posts?
It would be nice to include a lenght of a nice one. Or it doesn't matter so much that we can use anything stranded with a high gauge?
Regards
It would be nice to include a lenght of a nice one. Or it doesn't matter so much that we can use anything stranded with a high gauge?
Regards
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