green bean diodes

[sam_c]

Ive built a green bean using a pair of 1n34A's for the symmetrical clipping and 2x1n914, 1x3mm red led for the asymmetrical clipping.

I have only tested it briefly and plan to debug it later today, but I have found that one set of diodes has a MUCH higher output than the other.  I think my multimeter has a diode test function so i will be checking the fwd voltage for each of those tonight to try and rule out any bad ones.   Im assuming that if one of the diodes was fried completely that it would prevent the selected clipping section from working all together?

is a large difference in output normal between the 'comp' settings depending on which diodes are used?

Im using a TL072 opamp at the moment, but I also have some 4558D Ic's to try too. 

[jkokura]

Yes, different diodes may create a very different volume difference. Running without diodes will give you a much louder signal still.

jacob

[sam_c]

thanks Jacob.

I have another grean bean board populated with different diodes too.  I think I went for a pair of bat41's and 3x1n914's.  I will test that board out to see if they are a closer match in terms of output. 

If I have the same problem with that board, I will put both sets of higher output diodes on one board and the lower output on the 2nd board. 

todays top tip, start socketing diodes from now on

[jkokura]

Part of the issue will be that using Asymmetrical on one side and symmetrical on the other will be a difference in volume period.

I would suggest that you not worry about it so much. The only time you would really have to worry about it is if you were switching between diode types during the middle of a song with your foot. If you're switching a toggle, you can simply adjust the output volume while you do it.

Jacob

[sam_c]

yeah, if its an inherent problem with the 2 types of clipping i will leave it as is.  Thanks for your advice.

My only concern would be some one trying out the pedal, messing with the settings and when they flick the comp switch.... BAM - a huge jump in volume that could cause a brown trouser disaster.  I might label them 'loud' and 'insanity'    just to prepare people for the suprise.

thanks again.

[plesur]

brown trouser disaster

If there's not a band called this already, there should be 

[sam_c]

I had some time last night to try the pedal and I am sure that there is a problem with the symmetrical pair of 1n34a's.

with the symmetrical clipping, I get just under unity signal passing through and the gain control does not work.   

I am going to desolder the 1n34a's and put sockets in there, just to see if I can get the cirucit working as it should with some different diodes.

Other than, it sounds great in the asymmetrical posiiton.  I think i prefer the OCD though.

[sam_c]

brown trouser disaster

If there's not a band called this already, there should be 

  I think it would make a better album name than a band name.