Author Topic: Log -- Rissole - COMPLETED  (Read 15446 times)

alanp

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Re: Log -- Rissole - COMPLETED
« Reply #60 on: April 06, 2014, 10:46:27 PM »
D7 you can safely leave out.

Have you got the Decaypedal pad grounded? (Either through a switched 1/4" jack, or a wire link.)

Perhaps a photo of both sides would help...
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JZA

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Re: Log -- Rissole - COMPLETED
« Reply #61 on: April 07, 2014, 07:18:19 AM »
yes Alan got the decay pad grounded, send and return linked and continuity tested , all sockets grounded to PCB ground,  all led's are lit at a constant brightness , get brighter or dimmer if I adjust int pot. Blend gives dry and wet , can just hear a filtered slight difference on wet but obviously doesn't change or envelope.
Has anyone given voltage readings for the chip pins of a working build, think that would help, I will post some photos incase someone can spot an obvious mistake. I will also start stuffing my second PCB as I have some parts of different manufacture to try.
This has really hurt my brain.
Thanks for trying Mr.p !
Jza
The green led's sure look pretty , just wish they would dance for me !

JZA

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Re: Log -- Rissole - COMPLETED
« Reply #62 on: April 07, 2014, 07:26:32 AM »
Is there a layout eagle file to help me test the circuit ? I struggle to correlate the schematic to the minute traces . Might help , but I understand if its in a vault somewhere. :)

LaceSensor

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Re: Log -- Rissole - COMPLETED
« Reply #63 on: April 07, 2014, 10:11:18 AM »
yes Alan got the decay pad grounded, send and return linked and continuity tested , all sockets grounded to PCB ground,  all led's are lit at a constant brightness , get brighter or dimmer if I adjust int pot. Blend gives dry and wet , can just hear a filtered slight difference on wet but obviously doesn't change or envelope.
Has anyone given voltage readings for the chip pins of a working build, think that would help, I will post some photos incase someone can spot an obvious mistake. I will also start stuffing my second PCB as I have some parts of different manufacture to try.
This has really hurt my brain.
Thanks for trying Mr.p !
Jza
The green led's sure look pretty , just wish they would dance for me !

sounds like the envelop detection isnt working

what dual op amp are you using, and where did you buy it from?

1458 and ne5532 are recommended, just dont buy them from Tayda

id bet money on that being your issue
« Last Edit: April 07, 2014, 10:17:42 AM by LaceSensor »

JZA

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Re: Log -- Rissole - COMPLETED
« Reply #64 on: April 07, 2014, 04:16:32 PM »
Thanks lace I will give that a go , I'm using mc1458 I bought a tube off eBay .. worked in other projects , could be a duff one I will try changing that .. I got some ne5532 here somewhere too, also bought some more tl07cn for other builds , could be that. All socketed so should be a quick test.
Thanks Jza

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Re: Log -- Rissole - COMPLETED
« Reply #65 on: April 07, 2014, 06:55:22 PM »
Hmm still no envelope , tried new mc1458, ne5532 , a vintage mc1458, even swapped the tl074cn . 
I checked for fabrication error on my spare PCB. All good tho!

Ok recap on my build, I have all pots and switches installed correctly, all switches continuity test good in position A1. I have decay pedal pad grounded, send and return connected via switched sockets and at times with a patch cable to make sure.  I'm running it from 9v battery that I've even swapped.

Even without any input connected the lights are fully bright as. Would expect in up position and completely dark in down position . The intensity works as a glorified dimmer switch but input signal won't affect the lights at all .
The blend pot works and I can hear wet and dry , the wet sounds filtered , just needs movement.
So any ideas people?
I'm making another audio probe , lost the last one . Will put a constant tone through and see what I learn in the meantime.
JZA

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Re: Log -- Rissole - COMPLETED
« Reply #66 on: April 08, 2014, 07:21:27 PM »
Has anyone got a reliable source for 1458 known to work in this build or perhaps a spare chip ? Preferably in UK ?
Even though I have tried 4 different sources everything is pointing at this being the reason for no envelope.
I have noticed that with th Rissole , Meatsphere, and even the Nautilus that particular chips only seem to work, still not sure why this is , am I right in thinking all 1458 opamps are themselves clones of the 4458 vintage opamps as used in mutron iii and other pedals in the early 70's , I wonder if  there is something in the Rissole circuits to be changed to accomadate all 458 chips.
Any thoughts or facts or chips ???

alanp

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Re: Log -- Rissole - COMPLETED
« Reply #67 on: April 08, 2014, 07:57:40 PM »
I've got the same circuit as the Meatsphere and the McMeat... :?
"Hot water, good dentishtry and shoft lavatory paper."
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JZA

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Re: Log -- Rissole - COMPLETED
« Reply #68 on: April 08, 2014, 09:37:07 PM »
Yes that's why I mentioned them....  Think you may ave missed my point and questions,
What is it about these circuits that they are so fussy about which opamp can be used to generate envelopes?
With an answer to that we could establish what to modify in these circuits so accepting any opamp or at least a wider tolerance .
I suppose the meatball would be just as fussy with which chip to use. Obviously designed with one chip in mind!
I guess nobody here really knows the maths behind the original design.
If I could have working voltages I might get somewhere.
Can someone give pin readings please? Obviously with a constant tone and with no input would be most usefull . Hopefully I could modify my circuit to suit my chips that way. Surely I need more or less volts to the ins of the opamps. ????

alanp

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Re: Log -- Rissole - COMPLETED
« Reply #69 on: April 08, 2014, 09:53:31 PM »
Mine is with someone in another city right now :(

When I did a big mouser order, I made a point of including the IC that this thing needs... seem to have better luck with mouser than tayda for this project, for the dual opamp. I used a LM1458.
"Hot water, good dentishtry and shoft lavatory paper."
- Cohen the Barbarian, on what is greatest in life
My OSHpark shared projects
My website

LaceSensor

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Re: Log -- Rissole - COMPLETED
« Reply #70 on: April 09, 2014, 02:30:58 AM »
Yes that's why I mentioned them....  Think you may ave missed my point and questions,
What is it about these circuits that they are so fussy about which opamp can be used to generate envelopes?
With an answer to that we could establish what to modify in these circuits so accepting any opamp or at least a wider tolerance .
I suppose the meatball would be just as fussy with which chip to use. Obviously designed with one chip in mind!
I guess nobody here really knows the maths behind the original design.
If I could have working voltages I might get somewhere.
Can someone give pin readings please? Obviously with a constant tone and with no input would be most usefull . Hopefully I could modify my circuit to suit my chips that way. Surely I need more or less volts to the ins of the opamps. ????
#

build your other PCB
the project works, its verified. So either you have made a mistake and havent properly debugged, or have chips which arent going to envelope.


JZA

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Re: Log -- Rissole - COMPLETED
« Reply #71 on: April 09, 2014, 11:38:17 AM »
I agree with you both, I have lm1458 on order.
I found this info which explains the reason for inactive envelopes using mc1458 in this circuit.. The NPN inputs certainly can't turn-on until 0.6V above the supply rail; actually over 1.5V to get the second stage active. Likewise the output can't pull-down all the way to the rail.
Seems obvious , but could be modified to suit any opamp.
Just waiting for my parts to arrive now.
Jza

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Re: Log -- Rissole - COMPLETED
« Reply #72 on: April 10, 2014, 08:08:17 AM »
I forgot to mention I built a stripboard version of the meatsphere using my mc1458 chips and that enveloped perfect , the build was mostly the meatsphere but I incorporated the Rissole mods , so that was the reason for my intial persistence with these chips ... I will get to the bottom of this, I guess there is a timeline regarding tolerances, am sure a couple of value changes on the Rissole will allow for any opamp use.
Should have mentioned this earlier !

JZA

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Re: Log -- Rissole - COMPLETED
« Reply #73 on: April 18, 2014, 06:52:53 AM »
Ahhh success on my 3rd board  , works fine with any opamp !, so now I can resolve the problem with the other 2 boards, obviously its not the opamps , I will get back to you all when I find the spanner in the works. The only difference on the 3rd build is the make of electro caps and pots, although they all read the same with the volt meter , could be ampage difference?  We'll I will sort it soon.

JZA

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Re: Log -- Rissole - COMPLETED
« Reply #74 on: April 26, 2014, 10:39:51 PM »
Finally resolved the issue with that first build, the trace between attack 3 and c6 was out, maybe burnt from soldering or a faulty board, either way these traces are just way too thin, I will use a different fabricator next time, especially as I live in UK. Anyone recommend fabricators for PCB in the uk ?
3 builds done.