tobias_svensk said:
You just have to tame them 😉
tobias_svensk said:
I think your values are fine. A smaller value could be enough, but 47uF seems a little low.
Read good PSU articles here: http://www.tnt-audio.com/clinica/solidstate.html
Has anyone tried the opa627 and buf634 with staight wire(no resistor) bewteen buf634 output to the inverted input of the opa627?
A headphone amp will often have a virtual ground which is provided by a "rail splitter" like the TLE2426 or a simple voltage divider (2 resistors) like a CMOY amp uses. A ground channel is simply a way top divide up the 0V ground reference into two parts. One part services the low current needs of the input and feedback loops of the signal channels, while the "ground channel" which is usually an opamp with a buffer in the feedback loop takes on the high current task of driving the load, which in the case of the headphone amp is always passive. It works beautifully. I am not sure it would work with anything other than a passive load.
But in anycase the opa627 and the buf634 work fine in that situation without any resistor in the feedback loop, so they should work for the signal channels as well.
Cheers.
But in anycase the opa627 and the buf634 work fine in that situation without any resistor in the feedback loop, so they should work for the signal channels as well.
Cheers.
Member
Joined 2002
Was it not you that emailed me like 1-2 weeks ago? I had missed that mail and replied to you like some days ago. 🙂
Member
Joined 2002
tobias_svensk said:
I could give you a count and tell you how many email's a day i get.
let's just say it is well over 120 😀 not including DIY post reply's..What was your email about. ?
J'
Yo Jason, you mailed me about the pcb and i replied but never got an answer so i thought you didn't get the mail 🙂
Member
Joined 2002
tobias_svensk said:
Im lost..😀 let's start all over. Email me so we can talk and do this all over..
Hehe, maybe there is another Jason in this thread?
Some Jason emailed me and wanted my Eagle files for the OPA627+BUF634 PCB.
Here's a timekiller for those who is bored:
3D view with orbit/zoom/pan
You will need this plugin:
plugin
🙂
Some Jason emailed me and wanted my Eagle files for the OPA627+BUF634 PCB.
Here's a timekiller for those who is bored:
3D view with orbit/zoom/pan
You will need this plugin:
plugin
🙂
Ok here is what I have
I still havent built it yet, but there's still time 😉
I have moved some componets around to make more room for other components and added the input capacitor pads.
This will probably be the final revision as this started as a project for myself 😉, and i am more than happy with the layout.
Although I may remove the, the input cap pads, as it adds a lot of real estate to the board which is being used by anything else.
The pins of most large capacitors are long enough to be bent to fit the resistor pads, and there is no harm in having the cap haning off the end of the board, and smaller caps should also fit in the resistor pads.
Still sticking with the dual mono and no onboard pot.
As these boards ended up being tweaked for a groupbuy to fit different tastes, they cant all be satisfied
Someone some where (sorry 🙁 ), metioned using these preamps in a 5.1 ch system. I think leaving just pads for the inputs gives more mounting options, i.e. digital, optical encoder, relay, or pot for volume control, but this is only my opinion
The input has been great and I have learned alot along the way., thx guys
If there is enough interest I will post my eagle files (sorry no schematic, we all know it anyway 😉 )
Good luck all
I still havent built it yet, but there's still time 😉
I have moved some componets around to make more room for other components and added the input capacitor pads.
This will probably be the final revision as this started as a project for myself 😉, and i am more than happy with the layout.
Although I may remove the, the input cap pads, as it adds a lot of real estate to the board which is being used by anything else.
The pins of most large capacitors are long enough to be bent to fit the resistor pads, and there is no harm in having the cap haning off the end of the board, and smaller caps should also fit in the resistor pads.
Still sticking with the dual mono and no onboard pot.
As these boards ended up being tweaked for a groupbuy to fit different tastes, they cant all be satisfied
Someone some where (sorry 🙁 ), metioned using these preamps in a 5.1 ch system. I think leaving just pads for the inputs gives more mounting options, i.e. digital, optical encoder, relay, or pot for volume control, but this is only my opinion
The input has been great and I have learned alot along the way., thx guys
If there is enough interest I will post my eagle files (sorry no schematic, we all know it anyway 😉 )
Good luck all
Attachments
Member
Joined 2002
tobias_svensk said:
Me i emailed a few people : O ) I collect them now im learing difrent ways touse Eagle. Practice Makes Perfect.
Eagle files would be great. I want to at least eych it and hae a listen. Might be exactly the all-purpose pre I am looking for...
WorkingAtHome said:
Sorry WorkingAtHome, I did search a little to find out who had made the multi channel comments, but i could see it for looking at it, i knew your post looked familiar
I dont have the time or money right now to get any boards made up, so if anyone does make up some of my boards, let me know how they sound, and how they compare to any comercial equipment you may have.
Man this thing is super tiny its 1.85*1.4 inches (roughly)
Here is the eagle brd file, I dont know how to convert this into a pdf, sorry.
But if enough people want it, someone please feel free to do it( and send me a mail and tell me how its done 😉 )
Have fun with it
Craig
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