Getting there....
Still missing some improtant parts, but managed to get one buffer tested.
Bit early to pass commnent on the sound quality of the buffer, but it is running well with a Sure T amp.
I could swear it improves the sound, but through one mission 760i speaker and an unmodded Sure amp, I think that I would be jumping the gun
Still missing some improtant parts, but managed to get one buffer tested.
Bit early to pass commnent on the sound quality of the buffer, but it is running well with a Sure T amp.
I could swear it improves the sound, but through one mission 760i speaker and an unmodded Sure amp, I think that I would be jumping the gun
justblair said:
I plan to use a pair of these buffers with my dual mono chipamp. I have just read this post and realised I may need to purchase some additional components for it to work.
I intend to locate the buffers close to the amplifier boards and house the transformers in a separate enclosure. I believe I will need an additional capacitor and resistor per buffer (Thanks Puffin
Can someone suggest a suitable part, and where I will locate it on the buffer pcb?
How would I go about connecting my 50K alps volume pot to this?
justblair said:Boards arrived from fab today...
Thanks to all the suggestions and help so far. This is my first circuit I have had fabbed for me. I have to say, that I am converted. No bad smells, no yellow stains from the chemicals, and the solder mask makes putting the thing together an absolute breeze.
Some more pics
Hi Blair
Fabulous work.
This is just what I need to replace my Meridian 101 preamp.
Can you provide me with some boards ?
Regards
Ricardo
Pedja Rogic Buffer as a Headphone Amplifier
Hi, I would like to know whether this buffer can be used to drive a pair of hedphones.
I have come across a lot of headphone amplifiers which employs op-amps like opa2134 or other similar ICs. as a matter of fact i made a cmoy headphone amplifier, but not very satisfied by its performance.
So, someone who has made PR buffer can please connect a pair of headphones and share his experiances.
Hi, I would like to know whether this buffer can be used to drive a pair of hedphones.
I have come across a lot of headphone amplifiers which employs op-amps like opa2134 or other similar ICs. as a matter of fact i made a cmoy headphone amplifier, but not very satisfied by its performance.
So, someone who has made PR buffer can please connect a pair of headphones and share his experiances.
A year has past since I received the parts to build these buffers!
I've just built a couple of power supplies and I am almost ready to start using them.
But before I do...
Blair's recommends setting the trimmers between 240-340R. I have set mine to 300R and I now need to adjust the trimmer so the J309 is emitting 6mA
http://www.justblair.co.uk/buildpedbuff.html
Am I right in thinking I need to attach one of the DMM probes to the emitter leg of the J309 and the other to ground, then turn the trimmer until I get a reading of 6mA?
Any help will be greatly appreciated!
Thanks
Richard
I've just built a couple of power supplies and I am almost ready to start using them.
But before I do...
Blair's recommends setting the trimmers between 240-340R. I have set mine to 300R and I now need to adjust the trimmer so the J309 is emitting 6mA
http://www.justblair.co.uk/buildpedbuff.html
Am I right in thinking I need to attach one of the DMM probes to the emitter leg of the J309 and the other to ground, then turn the trimmer until I get a reading of 6mA?
Any help will be greatly appreciated!
Thanks
Richard
I really should have checked here first, hey Nick!
http://myweb.tiscali.co.uk/nuukspot/decdun/gainclone2.html
'Also note that the 270R resistor is shown as a 'starting point' only! It is a good idea to use a 500R or 1K multiturn trimmer in this position to start off with. Set it to 270R and then apply the power to the circuit. Carefully measure the voltage across the trimmer and then use a calculator to divide the voltage by the resistance (in ohms). This will give you the current drawn and you want to aim for round about 6mA (0.006A). If it needs adjusting, alter the resistance (probably up), measure it, and then measure the voltage again. Do this until it is close to 6 mA. You will need to do this for both channels! You can leave the trimmers in place or replace them with suitable value resistors.'
http://myweb.tiscali.co.uk/nuukspot/decdun/gainclone2.html
'Also note that the 270R resistor is shown as a 'starting point' only! It is a good idea to use a 500R or 1K multiturn trimmer in this position to start off with. Set it to 270R and then apply the power to the circuit. Carefully measure the voltage across the trimmer and then use a calculator to divide the voltage by the resistance (in ohms). This will give you the current drawn and you want to aim for round about 6mA (0.006A). If it needs adjusting, alter the resistance (probably up), measure it, and then measure the voltage again. Do this until it is close to 6 mA. You will need to do this for both channels! You can leave the trimmers in place or replace them with suitable value resistors.'
Hi (shades removed)
Its so unlike me to encounter any problems when working on a new project
I have one buffer set to 6ma (2.49v /410R), but the other buffers trim pot turned out to faulty and I only have a 5k pot in my parts bin. I have soldered a 430R resistor in its place and when measure the voltage it drops by almost 1v over a short period. The main power supplies are stable but have checked the on board regulators yet.
Any ideas?
(shades removed)Its so unlike me to encounter any problems when working on a new project
I have one buffer set to 6ma (2.49v /410R), but the other buffers trim pot turned out to faulty and I only have a 5k pot in my parts bin. I have soldered a 430R resistor in its place and when measure the voltage it drops by almost 1v over a short period. The main power supplies are stable but have checked the on board regulators yet.
Any ideas?
Nuuk said:Richard, if I may give you a lesson in life, may I suggest that you have not yet realised that we are ALL pupils and teachers!
If you had a problem, and then found the solution, that solution could well help others so it would be good to tell us how you sorted it.
There are no limits to my incompetence…..I guess I was little bit embarrassed (after a recent episode
) and wanted to respond before wasting anyone’s time!I discovered my error late last night….I kept on thinking it must have something to do with the J310 as both power supplies were stable but the power kept dropping.
I then discovered I needed to rotate the J310 180 degrees….Duh!
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