Hehe I know 🙂 but still... that kind if things makes me sleep bad 😀
Every component was a perfect fit though.
But now I know to the next time so that's good 😎
Every component was a perfect fit though.
But now I know to the next time so that's good 😎
Gcollier said:
I'm with you. I've taken my conversation with carlos off-line, where he and I can trade barbs without derailing the thread.
In the spirit of this thread, I'll throw in my ideas on what could be done to improve the amp based on the carlos-style of doing this.
1) Why not move the opamp, buffer and bypass caps to SMD? You could dramatically shorten the feedback path, get the caps even closer to the pins, and generally have a much smaller design.
2) Why not use independent regulators for each chip? Put panasonic AN77L12 and AN79L12 100ma regulators on the opamp and another pair on the buf634.. You could then place the regulator VERY close to the chip and reduce the size of the bypass caps (putting it before the regulator). Yes, this could possibly limit the output current of the buf634, but in a preamp, do you really need 200ma on the output? If you desire more, go with a 250/500ma regulator in a SOIC-8 package.
motherone i'm with you on that to, i'm gonna try something like this design but with SMD. but on the otherhand there are some other chips that are interesting too so.... we will see 🙂
But for now i would be happy to get this thing going as it was my "first" own board to make. I have to do some basics and learn by my mistakes first 😀
But for now i would be happy to get this thing going as it was my "first" own board to make. I have to do some basics and learn by my mistakes first 😀
Congrats on the boards, Tobias. I'm sure it's a thrill to have your layout work on the first mfg. run!
Gcollier said:
Unfortunately it does.🙄
Sometimes it gets this way, and it doesn't make sense.
Look at my thread about the snubberized PSU...
But you are right, move on.
Sorry about that.
motherone said:
What's the point?
Don't bother with me, let's move on.
You don't believe on a good layout, I do.
No problem.
motherone said:
Am I allowed to disagree on this, or not?
Yes, you can shorten the feedback loop by placing the buffer to the right of the op-amp (as I do).
But you don't need SMD for that, and the best way to use the BUF634 is in TO220 package, heatsinked, wide BW, +/-18V PSU.
I also give importance to a very short feedback loop (you can find my posts on my thread), that's another reason to use the TO220 package, and not to parallel buffers.
motherone said:
Independent regs yes (I have suggested that), smaller caps on the chip's pins, no.
No, no, no.
Sorry, don't be mad with me, but no.😀
It's not a question of output current.
I'm too tired to discuss this all over again, it's posted somewhere.
While there is a lot of great factual and intelectual material in this thread, for me I have the following two desires:
1) A simple small preamp board that the average DIYer can build and learn from.
2) A preamp that despite desire #1 sounds absolutely fabulous.
While his may not be "optimum", (but hey even Carlos says this is unachievable) It will be excellent.
Having built N00bers design with seperate grounds, I can say it meets those criteria. I think The other designs from George, Tobias, and others also would fit the bill.
I wonder if at some point we can have a vote on what we collectively like best. Based on that I propose to handle a group buy.
Because I know N00ber's design works, and I really like how small it is, I am leaning toward it right now. It really is an awesome little board, you could easily fit a dozen channels(why I have no idea) in a small box.
Seriously, if you took his design even without the latest improvements it is a very solid DIY board. With bigger pads in some places and the inproved PS inputs and such it will be a real winner.
Maybe it would be helpful to standardize on that design as a basis for moving forward.
We can create new threads for other ideas, and propose group buys for them as well. 🙂
My 2C.
Cheers,
Russ
P.S. This has been a very fun and inspirational/educational thread.
1) A simple small preamp board that the average DIYer can build and learn from.
2) A preamp that despite desire #1 sounds absolutely fabulous.
While his may not be "optimum", (but hey even Carlos says this is unachievable) It will be excellent.
Having built N00bers design with seperate grounds, I can say it meets those criteria. I think The other designs from George, Tobias, and others also would fit the bill.
I wonder if at some point we can have a vote on what we collectively like best. Based on that I propose to handle a group buy.
Because I know N00ber's design works, and I really like how small it is, I am leaning toward it right now. It really is an awesome little board, you could easily fit a dozen channels(why I have no idea) in a small box.
Seriously, if you took his design even without the latest improvements it is a very solid DIY board. With bigger pads in some places and the inproved PS inputs and such it will be a real winner.
Maybe it would be helpful to standardize on that design as a basis for moving forward.
We can create new threads for other ideas, and propose group buys for them as well. 🙂
My 2C.
Cheers,
Russ
P.S. This has been a very fun and inspirational/educational thread.
If one were to design with individual regs. would it be a waste if they shared the same supply? like if i have two big caps one for pos. and one for neg. and then two traces from each one to its own reg.?
Or should it be four "connectors"? two V+ and two V-
Or should it be four "connectors"? two V+ and two V-
http://www.ettnet.se/~tobias/diy/zzz.png
Some lousy attemt for a starground (under the small caps) 🙂
Maybee it's time to leave this opa/buf combination 😀
Some lousy attemt for a starground (under the small caps) 🙂
Maybee it's time to leave this opa/buf combination 😀
I looked back through the thread and haven't seen this board, except for the (apparently) flawed version here:Russ White said:
http://www.diyaudio.com/forums/showthread.php?postid=664863#post664863
N00ber, would it be possible to post the schematic and layout you have now? That way we know what Russ is referring to.
Russ White said:
Russ,
If you have enough parts to put together another couple of boards I can send you two different designs that I have. You can then draw your own comparisons between them and noobers and let us know. We could base the group buy that.
Let me know. 😀
G.
G, that would make me very happy. 🙂 I have plenty of parts. And even if I didn't I would get them. 🙂
I've been thinking about a full purpose best bang for the buck integrated amp based on the gainclone for a long time and would like to present some guidelines and a feature set:
Inverted "T" configuration with SuperSymmetry on amplifier section
JFET buffered to achieve maximum current/minimum phase error
unregulated power supply
1 digital input to a five channel DAC
2 general purpose inputs
2 tape (analog) inputs and outputs
1 tuner (analog) input
1 phono input with MM/MC circuits
1 headphone jack and amplifier
Does anyone here see why this project couldn't be completed for less than $250? I think this can all fit in standard 430mm form factor with plenty of room. Please feel free to critique the idea and point out some of the difficulties we are likely to encounter.
Inverted "T" configuration with SuperSymmetry on amplifier section
JFET buffered to achieve maximum current/minimum phase error
unregulated power supply
1 digital input to a five channel DAC
2 general purpose inputs
2 tape (analog) inputs and outputs
1 tuner (analog) input
1 phono input with MM/MC circuits
1 headphone jack and amplifier
Does anyone here see why this project couldn't be completed for less than $250? I think this can all fit in standard 430mm form factor with plenty of room. Please feel free to critique the idea and point out some of the difficulties we are likely to encounter.
I think that's a great idea. The difficulty will lie in getting everyone to agree on the best designs for each component.
Perhaps, if modular enough (reg on board each module, etc), there could be a small library of parts (a few different pre's, two different phono stages, etc) that could be selected and plugged together.
Can you say "can-of-worms?" Let's hear some ideas folks...
Perhaps, if modular enough (reg on board each module, etc), there could be a small library of parts (a few different pre's, two different phono stages, etc) that could be selected and plugged together.
Can you say "can-of-worms?" Let's hear some ideas folks...
BrianDonegan
Yeah, these can be built with different part selections but let's shoot the elephants before chasing the mice. My personal design choice would be using the 3875 in the amp section and switching in an Analog video amp chip for the phono stage but I'm no authority so I have no solid opinion which buffer to use. I presented the guidelines as a general spec, we can hammer out the part details once we get enough agreement on the concept. Am I to understand that you are for this concept without reservation?
Yeah, these can be built with different part selections but let's shoot the elephants before chasing the mice. My personal design choice would be using the 3875 in the amp section and switching in an Analog video amp chip for the phono stage but I'm no authority so I have no solid opinion which buffer to use. I presented the guidelines as a general spec, we can hammer out the part details once we get enough agreement on the concept. Am I to understand that you are for this concept without reservation?
Wow, this is great conversation, but it really sounds like a new thread topic since we are not talking about an integrated amp on this one. Why don't we take this to a new thread. I am certainly interested.
Russ White
I think if the moderators see the next five posts or so referencing my proposed project, I think they'll split this off and make it a new thread. I think the gainclone is better suited to integration than to a separate box but in essence, my proposed project could fall easily under the topic of this thread. Am I to understand that you have nothing to add or remove from my guideline and accept it as is?
I think if the moderators see the next five posts or so referencing my proposed project, I think they'll split this off and make it a new thread. I think the gainclone is better suited to integration than to a separate box but in essence, my proposed project could fall easily under the topic of this thread. Am I to understand that you have nothing to add or remove from my guideline and accept it as is?
I rather like your integrated amp ideas, yes, I may have somethings to add later, but this thread is specific to "preamp" suggestions which is why I spoke up.
Just want to check something, i have 2k & 4k7 resistors at home that i was gonna use in this thing that will give me a gain of 3,35 right?
And 10k pot, 1k IN and 100k to ground, 50 out. Does it seem resonable? I don't want to desolder this thing as its a 2 layer board.
And 10k pot, 1k IN and 100k to ground, 50 out. Does it seem resonable? I don't want to desolder this thing as its a 2 layer board.
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