Hell, at $5-10 a board, I'd be down for at least 3, maybe more! This would be a good group buy!
Member
Joined 2002
I'm willing to go in for a couple boards 🙂 ... so hopefully someone steps up and does this group buy
Naz
Naz
Member
Joined 2002
naz said:
I'm About to get a pcb quote i just need these File's to send them the gerber files is all : O )
Thanks Jleaman.. You should see about getting them gold plated ala Peter Daniels style. Maybe BrianGT or PD could give you some pointers on ordering these if you haven't done it before.
Mike
Mike
Member
Joined 2002
Before we go crazy with a group buy and ordering lots of boards, maybe we should get some listening impressions from a few of these designs. I for one am very happy with my design, the sond is very detailed. I had friends over last night and we did a listening test between OPA134, OPA627, OPA637 and AD743. The OPA627 won hands down in a blind test, it was the most detailed of all the opamps (yes even more than the OPA637). The sound was not overly grainy as I have heard with the OPA637, bass was very nice...punchy and firm. Most people commented..."oh great now I have to go home and listen to my $hitty stereo". We also noted how much more detail that could be discerned such as breathing in the mic, scratching of guitar strings etc...nice! Now I am definately NOT saying this is the best design. There are some other ones here that look really good, but before we go too far we should consider what we really want. For me:
1. Isolate signal and power ground as much as possible.
2. Option for input cap or none.
3. A large groundplane
4. Sufficient space for tweaking (for example at least enough room to get in with chip pullers to remove opamps.)
5. Option for output resistor.
1. Isolate signal and power ground as much as possible.
2. Option for input cap or none.
3. A large groundplane
4. Sufficient space for tweaking (for example at least enough room to get in with chip pullers to remove opamps.)
5. Option for output resistor.
Gcollier said:
ZING!
Any design should be fully tested, I completely agree.
There are some designs here that will perform better than the others, so test'em all and pick the best.
Gcollier said:
Were you testing this as a line preamp?
At what gain?
Would it be beneficial to have 1 or more people audition the all the designs?
Or it has the potential to turn into one of those "mine is better than yours threads"
Im not in the position at the momet to provide someone with a premade amp, nor a board for that matter, as i have another baby on the way 😀 😀, but i am more than willing to provide my eagle files or Gerber files, if i can ever figure out how to do it.
Just a suggestion, doing some more work on the amp once i get home from work.
Im never satisfied 😛
Maybe we should agree on some basic requirements, then pick/tweak the design to match. Here is what I was thinking...
1) Capability of combining boards for multi-chanel setups. This could be mono, or stereo boards, but easily daisy chained to support a HT setup. If grouping stereo boards, an 'extra' channel could always be for a sub or just not used.
2) Volume control. I like the Pot-on-board design. It does limit #1, however. Maybe the DS1802 volume control would be better for that. Seperate volume board???
3) Source selection. I guess this would be a seperate board as well. Or a rotary switch.
4) Power supply. Would need to support mutli chanels (current) and multiple voltages (if the DS volume was used - unless there is regulation added to the ds volume board).
Okay, there's something to start with, now lets simplify (improve) it.
Also, I agree that we should listen to the preamp before making a bunch of them. They sem sufficiently simple that they could be home etched. I might be able to make a few. Prehaps someone else could make a few and we could get a couple of each working so we could do some listening tests.
1) Capability of combining boards for multi-chanel setups. This could be mono, or stereo boards, but easily daisy chained to support a HT setup. If grouping stereo boards, an 'extra' channel could always be for a sub or just not used.
2) Volume control. I like the Pot-on-board design. It does limit #1, however. Maybe the DS1802 volume control would be better for that. Seperate volume board???
3) Source selection. I guess this would be a seperate board as well. Or a rotary switch.
4) Power supply. Would need to support mutli chanels (current) and multiple voltages (if the DS volume was used - unless there is regulation added to the ds volume board).
Okay, there's something to start with, now lets simplify (improve) it.
Also, I agree that we should listen to the preamp before making a bunch of them. They sem sufficiently simple that they could be home etched. I might be able to make a few. Prehaps someone else could make a few and we could get a couple of each working so we could do some listening tests.
Just posted my preamp here for information:🙂
http://www.diyaudio.com/forums/showthread.php?threadid=55558
Steen.
http://www.diyaudio.com/forums/showthread.php?threadid=55558
Steen.
carlosfm said:
ZING!
Any design should be fully tested, I completely agree.
There are some designs here that will perform better than the others, so test'em all and pick the best.
Were you testing this as a line preamp?
At what gain?
Carlos:
I was using this as a line preamp at a gain of 8. The design was the the stereo version with the DS1802 volume control posted earlier in the thread. The amp I used was a stereo BrianGT LM3875 feeding a pair of 89dB efficient DIY 3 ways. I realize that there are MANY variables in testing any of these designs which is why I think that several of us should try them out...then do the group buy.
G.
You could change your CRC- to a RCRC filter.
Regarding protection diodes: I think it is wise to use them when you use the Cadj and a big output cap.
Regarding protection diodes: I think it is wise to use them when you use the Cadj and a big output cap.
Thanks Alcaid!
Suspected that i'd needed them. It was just that they were kinda "angry" and didn't want to fit my layout 😉
The last el.cap should it be smaller than the two at the input?
Saw something like 47uF somewhere else.
Suspected that i'd needed them. It was just that they were kinda "angry" and didn't want to fit my layout 😉
The last el.cap should it be smaller than the two at the input?
Saw something like 47uF somewhere else.
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