Roll Your Own Ampmix & Vertmix SDIY

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stabilt
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Post by stabilt » Thu May 21, 2015 4:49 pm

sines wrote:
stabilt wrote:A 3.3V zener will give an offset voltage of 6.6V, 2.7V will give an offset voltage of 5.4V. Plus the +-10% tolerance, doubled.
If you change R3 to 4.7k they should work.
If I changed LM4040 to a IN4733A 5.1 Zener Diode, would I change R3 to 2.2k?
Yes that should work well.

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stabilt
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Post by stabilt » Thu May 21, 2015 5:32 pm

lintfresh wrote:I haven't been able to find any damn Ampmix PCB/Panels anywhere for a while. Is there going to be a restock soon??

:help: :help: :help: :help: :help: :waah: :waah: :waah: :waah:
I'm afraid none of the reseller orders we are working on atm have this included, so I don't have a good answer.

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colossus
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Post by colossus » Fri Dec 11, 2015 12:46 pm

I just built up the Ampmix and I'm having a weird issue. The final Mix out pot is working backwards, i.e., when fully clockwise it's at its quietist (but not totally attentuated!!) and it gets louder as it's turned counter-clockwise. Any ideas? I mean, the pot can't be in backwards per the PCB, so I' confused...

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stabilt
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Post by stabilt » Thu Dec 17, 2015 2:18 am

colossus wrote:I just built up the Ampmix and I'm having a weird issue. The final Mix out pot is working backwards, i.e., when fully clockwise it's at its quietist (but not totally attentuated!!) and it gets louder as it's turned counter-clockwise. Any ideas? I mean, the pot can't be in backwards per the PCB, so I' confused...
That sounds very strange.
Have you tried having all channels turned fully off/CCW and only used the 4th channel?

What you describe is like an inverted signal getting mixed into the same signal but non inverted.

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boramx
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Post by boramx » Sat Feb 06, 2016 3:34 pm

Hellu forum and RYO person(s?)-

i just cooked my Ampmix on first power-up. :eurosmoke:

Smoky!

I've done a LOT of soldering and kits in my life, also i've never cooked a module by reversing polarity in 15 years or so of modules.

SO......

yes, smoke, then i check it out. R1 and R2 are DEFINITELY black and stinky.

everything else looks good.

the case for the ribbon cable was installed correctly. the cable was plugged into the bus board correctly.

now for the RUB-
the TL072 was plugged in backwards. yes i know better! i was in a hurry.

so...did the reverse chip cause the smoke?

can i fix by replacing R1&2?

any of the chips?

how can i fix this?

thanks!!!!

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PhineasFreak
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Post by PhineasFreak » Sun Feb 07, 2016 2:16 pm

hi boramx, i would say its pretty much certain that the reversed ic was the issue, and replacing the two 10r's (r1 and r2) should have it working again :)

cheers, :tu:
boramx wrote:Hellu forum and RYO person(s?)-

i just cooked my Ampmix on first power-up. :eurosmoke:

Smoky!

I've done a LOT of soldering and kits in my life, also i've never cooked a module by reversing polarity in 15 years or so of modules.

SO......

yes, smoke, then i check it out. R1 and R2 are DEFINITELY black and stinky.

everything else looks good.

the case for the ribbon cable was installed correctly. the cable was plugged into the bus board correctly.

now for the RUB-
the TL072 was plugged in backwards. yes i know better! i was in a hurry.

so...did the reverse chip cause the smoke?

can i fix by replacing R1&2?

any of the chips?

how can i fix this?

thanks!!!!

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boramx
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Post by boramx » Fri Feb 12, 2016 2:00 pm

Replacing the resistors worked. Cheers!

Just curious-
Why did R1 & R2 get cooked w/the tl072 reversed?

Those resistors seem to be power protection, no? How does the tl072 function in the circuit?

My :deadbanana: seemed like a classic reverse polarity goof, except my power was correctly connected....

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PhineasFreak
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Post by PhineasFreak » Fri Feb 12, 2016 8:08 pm

boramx wrote:Replacing the resistors worked. Cheers!
yay!
boramx wrote:Just curious-
Why did R1 & R2 get cooked w/the tl072 reversed?

Those resistors seem to be power protection, no?
r1 and r2 are indeed protection - if there's a huge current surge cos +12v or -12v are connected to eachother or ground then they burn out rather than something more expensive like the psu...
boramx wrote:How does the tl072 function in the circuit?

My :deadbanana: seemed like a classic reverse polarity goof, except my power was correctly connected....
the tl072 isnt part of the protection circuit - reversing the tl072 connected things to rails that shouldnt have been...

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stabilt
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Post by stabilt » Thu Feb 18, 2016 5:14 am

For a more detailed description of the innards of opamps. There is diodes in opamps that connects each input pin to the power rails to protect from over voltage, if the opamp is upside down those diodes will cause a direct short between the +V and -V power rails as they would be the wrong way around.

With the 10R resistors there is less risk that those internal diodes will burn out and damage the IC. There is both advantages and disadvantages using the 10R resistors.

sihiL
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Post by sihiL » Mon May 09, 2016 1:23 pm

Hey there,

When would there be a new batch of Ampmixes and/or Vertmixes? I'd like to get either one of them, and it would be cool to know when I might have to pay up.

ghostly606
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Post by ghostly606 » Fri Nov 25, 2016 9:18 am

Just finished my AmpMix build (1.3). Channels 1 to 3 work perfectly, but the signal from the Channel 4 / mix output is very weak. Checked all solder points and everything looks ok. This was my first DIY build and have already had to replace PCB and desolder / resolder a lot of the components so I have now got no idea what / where the problem is. Anyone have any suggestions? A schematic would help but I can't find one anywhere online. This has been a real trial and I just want to get the bloody thing finished and racked up! :bang: :despair:

:tu:

ghostly606
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Post by ghostly606 » Fri Nov 25, 2016 9:23 am

ghostly606 wrote:Just finished my AmpMix build (1.3). Channels 1 to 3 work perfectly, but the signal from the Channel 4 / mix output is very weak. Checked all solder points and everything looks ok. This was my first DIY build and have already had to replace PCB and desolder / resolder a lot of the components so I have now got no idea what / where the problem is. Anyone have any suggestions? A schematic would help but I can't find one anywhere online. This has been a real trial and I just want to get the bloody thing finished and racked up! :bang: :despair:

:tu:
Oops, was hiding on the RYO website all along, schematic here.

If anyone can help though I'd be forever obliged!

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lohacker
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Post by lohacker » Tue Apr 10, 2018 3:21 am

I have AmpMix since a long time and using it without issues, however recently I moved it in another case with mainly R*S Serge modules and I've noticed it often clips expecially with VCFQ. With other mixers in my system this don't happen so easily (Mixmode, Linix, Shades, Cascade). Could be possible to mod it for better performances? Thanks

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PhineasFreak
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Post by PhineasFreak » Tue Apr 10, 2018 9:58 am

remember max on any channel is 2x gain so would clip most modules - leave knobs at mid for normal (i.e. 1x gain) mixing

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lohacker
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Post by lohacker » Tue Apr 10, 2018 10:14 am

PhineasFreak wrote:remember max on any channel is 2x gain so would clip most modules - leave knobs at mid for normal (i.e. 1x gain) mixing
Yeah I know this, forgot to mention this happens also at very low levels and using only one channel.

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Mikro93
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Post by Mikro93 » Mon Jul 16, 2018 1:17 am

I built the Ampmix yesterday, full kit from Thonk.

It was a breeze to assemble and worked first try. Very very happy with the module, well designed and fits many useful features in a small footprint.

The detailed instructional pdf was clear and thourough. I'm not a beginner, having built maybe 10 stompboxes, and the kit was so well-labeled I could have built the module without looking at the instructions.

Congrats to Ryo for this lovely piece of machinery :)

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woelfl
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Got 330K instead of 330R for R13,R14,R15,R16 in my kit!

Post by woelfl » Wed Jun 19, 2019 9:15 pm

Hi RYO folks,

Just built Ampmix 1.3 cca. a month ago from a kit I bought at RawVoltage in Vienna. Now, since this was my first bigger soldering undertaking in quite awhile, I thought I horribly messed up something, because the module didn't behave properly. I have Mordax DATA and Joranalogue TEST-3, and though TEST-3 shows correctly that Ampmix draws ~20mA on both +12V and -12V rails, as it should, the voltages I measure with DATA from the Ampmix's outputs are VERY WRONG. Outs 1, 2 and 3 are giving only cca. -1.2V to 1.2V when given -5V to +5V respectively, and out 4 is reversed and giving +7.35V to -7.35V when given -5V to +5V respectively.

After banging my head against the wall for the last two weeks and trying in vain to somehow determine what did I do wrong, consulting with several friends electrical engineers, I accidentally went today thru the leftovers of the kit, as there were some extra resistors, because I needed a resistor in the range of 100-200 ohms just as a first hand solution to drive an LED on a breadboard... and since there was one left over in the bag marked "R13,R14,R15,R16 - 330R", I went for it.

Just to be safe, I checked it with the multimeter, and to my utmost surprise, I discovered that the resistor is NOT 330 Ohms, but 330 KiloOhms! :picard:

Now, my question is this - is it possible that wrong resistors are causing this strange behavior, or might there be something else here wrong as well? And also, where can I get these 330R of the same size and specs as needed for the kit?

Thanks a lot and cheers!

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PhineasFreak
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Post by PhineasFreak » Wed Jun 19, 2019 9:29 pm

see pm reply

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woelfl
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Post by woelfl » Thu Jun 20, 2019 3:56 am

Thanks a lot Thomas for such a quick response... You rule! :nana:

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