[alane]

Hi all,
sorry if i am going over old ground here but i had a look around and couldnt find much on this topic.
I cannot find anywhere that has something similar to the protoboard that tangent uses in his cmoy layouts(i am in ireland and nothing is ever in stock

) .. has anybody done a cmoy amp on regular stirp board (1 side copper plated single parallel strips with no connections between strips) i found the board that pat did and i am trying to figure that out and while i am gratfull to pat the pic he did is hard to make out. I am not experienced enough at this stage to redo the board so that it works on stripboard .. size is not a problem as this is my first real diy audio project and i am not trying to fit this into any small enclosure or anything.
Any help is appreciated.

Alan
Dublin/Ireland

 

[nkd]

If you give me a few minutes i'll take some pics of mine for you. It's not perfect, as i made a few mistakes, but it should help i think.

 

[nkd]

Ack, turns out the flash card in my camera is dead... hopefully someone else will be able to help you!

 

[Rexel]

Hi.

It took me ages to find out I could not get the same protoboard as Tangent used anywhere in the UK, so I used stripboard from Maplin.

I did not take pictures of my completed CMOY on stripboard, but I did take some pics as I worked. Pic 1 and Pic 2

They are not complete, but I think you get the idea. The copper strips run on the other side of the board left to right. I have marked the virtual ground with a green line, and breaks in the copper strip I had to make with a purple line. I have also shown the location of two hidden resistors (one power supply resistor and the other is R4 in the feedback loop) with yellow arrows.

Finally I have shown the location for the power supply jumpers for the OPA2134 with red lines. The power supply lines are the two lines running above the green one.

Please excuse the enormous 0.1uF input caps. I had no idea you could get them smaller

I now have nice WIMA caps that are tiny in comparison.

Layout of this board (it was my first ever, let alone my first CMOY) is not, shall we say, optimal, but it does the job. My first CMOY worked first time

Cheers,

Rexel

 

[alane]

Thanks Rexel and NKD,
I managed to decode pats layout

.. ( located here http://www5.head-fi.org/forums/showt...ht=cmoy+layout ) down the bottom of the post there somewhere .. its distorting like mad and when i bridge the opamp pins 3 and 4 it goes away .. so i have to go checking...
maplin do a DIP board part number FL19V that looks like it will do the job but it is not in stock in any of the stores over here.. but you may be able to get it over there ..

Thanks again for all your assistance .. i hate that yours worked off the bat

if you have any tips on the distortion I would appreciate it.

Alan
Dublin/Ireland

 

[nkd]

Mine distorted when i first turned it on, and i found two of the chips were connected where they wern't supposed to be, due to a bad cut. I know you're using the single chip version, but you could still have the same problem. Are you sure that you've cut the tracks fully under the chip itself?

 

[alane]

cheers nkd,
yeah i checked the breaks under the chip with the multimeter.. they are all cool .. i am not sure if i got the leg/pin numbering right in the last post .. when i bridge pins 3 and 4 i get a strong undistorted signal .. it is not in one ear or the other the effect is across both channels .. connecting pins 3 on the chip to the negative side of the circuit somewhere gives me the same affect so i am reckoning that something is not connected where it should be but this being my first proper project other than some velleman boards i just dont know .. thanks for your help and any other suggestions are welcome.

Alan
Dublin/Irealand

 

[alane]

although now that i mess around a bit i hear that i am not getting stereo when the pins are bridged/connected to power.. i am getting the left channel only but in both ears .. when i move the balance to the right i get a nice little mid frequncy hum when the pins are bridged .. and on further inspection the right channel drops to the hum and the left signal cleans up and sums across the two channels.. wow .. now i am well confused !!

Alan
Dublin/ireland

 

[alane]

Ok .. my thanks to you guys .. but i am such a knob .. i overlooked the jumpers from the negative side of the power supply capacitors to the earth .. i have no idea what they do !! but they were obviously important as i now have un distorted stereo goodness ..

i suppose following the directions is always a good start .. and looking at the layout till your forehead is blue !!

Great forum .. thanks for the help .. i am sure i will be back as i get more ambitious .. tube amp here i come .. ( what happens if i stick my finger ...

)

I will try and tidy up the drawings that pat made and post them back here in case any body else comes across the problem getting the protoboard. ( with pats permission of course )

Alan
Dublin/Ireland

 

[nkd]

Glad to hear you got it working... it's such a great feeling when you turn the thing on and it actually sounds good

 

[Rexel]

I'm glad you got it working!

This is a fun hobby - I just hope you have a deep wallet or a friendly bank manager

Cheers,

Rexel

 

[alane]

Hi,
I said a while ago that i would put this up here .. its not great but it will get people started. Thanks to Pat for the original diagram.

Alan
Ireland/Dublin

 

[damitamit]

nice work.

just to let you know, u can get the proto boards Tangent uses, in the UK.

2/3 of the Radioshack catalogue is available here, its just not advertised anywhere.

I rang up the UK distributor of Radioshack ( i think I got the number by emailing Radioshack US). I've lost the number thou. I spoke to a very nice lady who let me order a couple of things and did some cheap postage by sending it in a envelope.

just so that you know...

Amit