Hi there,
I was going through this DIY DJ mixer thread on the forum, and I noticed there was some talk about a very basic DJ mixer set up (mancuso inspired) where say for example: you have two turntables, then you connect the turntables to two phono amps, and then you run that to I guess what would be a summing amp (??) and then run the "resulting" signal to your amp and furthermore speakers.
I thought this was really interesting. The possibility of having a very simple mixer with two stereo channels in and one (maybe another for cueing) stereo channel out as a basic unit which you could then add an isolator or filters to in the output stage could be really great. Because, once you take a DJ mixer and remove all the eqing and effects, you're basically left with a summing amp with phono stages right?
my idea was to just get two really nice phono amps (possibly tube, and yes I'm aware tubes are **** in terms of fidelity, but pleasant coloration can be nice sometimes) and then hook them up to a summing amp and then maybe just get an isolator for the master output if I want to eq it...
So, I guess I'm looking for a simple/reliable summing amp schematic someone out there might recommend. And, also, would this be possible to do with a passive summing box type setup? I don't think so right? why?
Any input is greatly appreciated.
Cheers,
ben
I was going through this DIY DJ mixer thread on the forum, and I noticed there was some talk about a very basic DJ mixer set up (mancuso inspired) where say for example: you have two turntables, then you connect the turntables to two phono amps, and then you run that to I guess what would be a summing amp (??) and then run the "resulting" signal to your amp and furthermore speakers.
I thought this was really interesting. The possibility of having a very simple mixer with two stereo channels in and one (maybe another for cueing) stereo channel out as a basic unit which you could then add an isolator or filters to in the output stage could be really great. Because, once you take a DJ mixer and remove all the eqing and effects, you're basically left with a summing amp with phono stages right?
my idea was to just get two really nice phono amps (possibly tube, and yes I'm aware tubes are **** in terms of fidelity, but pleasant coloration can be nice sometimes) and then hook them up to a summing amp and then maybe just get an isolator for the master output if I want to eq it...
So, I guess I'm looking for a simple/reliable summing amp schematic someone out there might recommend. And, also, would this be possible to do with a passive summing box type setup? I don't think so right? why?
Any input is greatly appreciated.
Cheers,
ben
Thanks for the prompt reply! much appreciated. That sounds interesting...
On that note, I'd like to mention one of the main references that got me thinking about this. This is a DIY design by bozure, for what seems to be a very simple mixer, Bozure.com - Custom Made, Standard and DIY Professional Rotary DJ-Mixers However, that schematic is far from simple, when comparing to that JFET setup. What in your opinion would be the main difference between the two? Or do you figure Bozure's design just uses the same concept repeatedly to achieve further functionality with the cueing, master, send receive etc
On that note, I'd like to mention one of the main references that got me thinking about this. This is a DIY design by bozure, for what seems to be a very simple mixer, Bozure.com - Custom Made, Standard and DIY Professional Rotary DJ-Mixers However, that schematic is far from simple, when comparing to that JFET setup. What in your opinion would be the main difference between the two? Or do you figure Bozure's design just uses the same concept repeatedly to achieve further functionality with the cueing, master, send receive etc
I designed and built a valve disco mixer a few years back.
It had 2 stereo channels, a line input and a high gain mic input.
Loved the sound of it, gave the music a bit of color and bite.
However it was mono out.
Recently I revisited the project and designed a proper stereo version with stereo out as well. I must have improved with circuitry and pcb layout as this time it had almost zero noise/hum.
It had 2 stereo channels, a line input and a high gain mic input.
Loved the sound of it, gave the music a bit of color and bite.
However it was mono out.
Recently I revisited the project and designed a proper stereo version with stereo out as well. I must have improved with circuitry and pcb layout as this time it had almost zero noise/hum.
An externally hosted image should be here but it was not working when we last tested it.
Comparing the JFET mixer to the Bozure is apples and oranges. One is a basic building block, and the other a complete working mixer circuit with 2 channels, input gain and master volume, FX send/receive, and even a separate headphone out with cue bending and dedicated volume control.
The equivalent of the JFET mixer would be the very first stage in the Bozure - same principles, only that the opamp makes a far better inverting amplifier.
The equivalent of the JFET mixer would be the very first stage in the Bozure - same principles, only that the opamp makes a far better inverting amplifier.
For 2 channels you can do passive mixing like this one but with -6db and high output impedance.
A preamp with short cables with this mixer is needed.
The only dj mixer that uses fet at the summing amp is the vintage Bozak cma-10-2dl
You can study the schematics here. Very tube like sounding mixer.
A British company have cloned it but I don't know with what part have replaced the fet 2N3822
A preamp with short cables with this mixer is needed.
The only dj mixer that uses fet at the summing amp is the vintage Bozak cma-10-2dl
You can study the schematics here. Very tube like sounding mixer.
A British company have cloned it but I don't know with what part have replaced the fet 2N3822
Thanks for the input guys. Much appreciated. Thanks for the links bozakdla! really helpful...yeah, I guess ideally the best would be 3 channels, just in case you want to add a CDJ (with line level input, no pre amplification required). So you're saying 3 channels wouldn't be possible with a passive setup?
I think you're talking about these mixers ?
pretty nice, not sure about the given valve phono stages, I feel like mixers should give the user the option of not having to have a colored phono stage.
there's also the condesa mixers, which claim to be fully discrete signal path as is the bozak. The Bozak is always praised for its "warmth" yet it doesn't use valves. I've heard that technically speaking, this "warmth" is really the result of THD for 2nd and 3rd harmonics due to its discrete signal path. Is this something that would be easily achieved with a passive mixer in your opinion?
I think you're talking about these mixers ?
pretty nice, not sure about the given valve phono stages, I feel like mixers should give the user the option of not having to have a colored phono stage.
there's also the condesa mixers, which claim to be fully discrete signal path as is the bozak. The Bozak is always praised for its "warmth" yet it doesn't use valves. I've heard that technically speaking, this "warmth" is really the result of THD for 2nd and 3rd harmonics due to its discrete signal path. Is this something that would be easily achieved with a passive mixer in your opinion?
wow, that model one mixer looks interesting, I wonder how much it's going for, because it's literally just a few resistors and potentiometers with a headphone preamp...seems like it would be extremely cheap to make one of those. In that setup the cue channel is toggled from 1 to 2 meaning that you can't listen to both channels at the same time, what would be the best way to integrate a potentiometer in order to select the channels for the headphone cueing? (so, if you were half way through the potentiometer you would hear both channels together)
I'm talking about this Bozak clone. The one that you posted also has very good reviews it's not all tube based only the output stage is tube.
The Condesa's circuit design is very similar to the original Bozak, with some exceptions according to the builder.
It's not only the phono stages of the Bozak that makes it warmth sound it happens with cd also.
You can't achieve the warmth in a passive mixer you need active circuit properly designed for that. Maybe a jfet or a tube buffer or preamp after the passive mixer will do some of the warmth sound trick.
The Bozure schematic that you posted shows how to integrate a potentiometer for the headphone cueing mix both channels.
Yes you're right, at 550Euro you get also an external power supply
The Condesa's circuit design is very similar to the original Bozak, with some exceptions according to the builder.
It's not only the phono stages of the Bozak that makes it warmth sound it happens with cd also.
You can't achieve the warmth in a passive mixer you need active circuit properly designed for that. Maybe a jfet or a tube buffer or preamp after the passive mixer will do some of the warmth sound trick.
The Bozure schematic that you posted shows how to integrate a potentiometer for the headphone cueing mix both channels.
Yes you're right, at 550Euro you get also an external power supply
Thanks again for the Input bozakdla!
adason, I'm def going to build something, I got my 2 decks out from storage and I left the mixer behind on purpose, so I force myself to build a solution hehe So, now I'm stuck with having to build something...
Given my very limited knowledge in electronics I think I will start with the passive mixer set up. similar to the 500Euro model one mixer. I'm currently on the look out for some cheap NAD phono amps. going to get some alps pots and a headphone amp and try to figure it out I'll def post results once I have any. I think this will be the first step, and then maybe once this is established, I can try something with a summing stage...Baby steps here...
adason, I'm def going to build something, I got my 2 decks out from storage and I left the mixer behind on purpose, so I force myself to build a solution hehe So, now I'm stuck with having to build something...
Given my very limited knowledge in electronics I think I will start with the passive mixer set up. similar to the 500Euro model one mixer. I'm currently on the look out for some cheap NAD phono amps. going to get some alps pots and a headphone amp and try to figure it out
I'll def post results once I have any. I think this will be the first step, and then maybe once this is established, I can try something with a summing stage...Baby steps here...
Just got some nice alps pots ordered!
So, It seems like I'm going to have to go with a few more stages. I've noticed a few designs like the Urei1620 and the bozure M2 mixer(which seems to be heavily inspired in the Urei1620) have a summing amp stage, then a buffer amp stage, and then the signal goes straight to tape out on one hand but then at the same time gets sent to another opamp stage before it goes to the master out. I thought tape and master out were at same levels for all practical purposes. What do these output amp stages do? couldn't the signal be sent to an amp from tape out? Or are these stages doing more besides making the signal larger?
So, It seems like I'm going to have to go with a few more stages. I've noticed a few designs like the Urei1620 and the bozure M2 mixer(which seems to be heavily inspired in the Urei1620) have a summing amp stage, then a buffer amp stage, and then the signal goes straight to tape out on one hand but then at the same time gets sent to another opamp stage before it goes to the master out. I thought tape and master out were at same levels for all practical purposes. What do these output amp stages do? couldn't the signal be sent to an amp from tape out? Or are these stages doing more besides making the signal larger?
Hey guys,
So I think I'm going with a very basic virtual ground opamp summing amplifier setup. I have a bunch of NE5543's laying around. I thought I'd start experimenting with those...I figure I could do it with two inverting stages, does anyone have any recommendations regarding power supply for these?
So I think I'm going with a very basic virtual ground opamp summing amplifier setup. I have a bunch of NE5543's laying around. I thought I'd start experimenting with those...I figure I could do it with two inverting stages, does anyone have any recommendations regarding power supply for these?
Just use a 12/0/-12v DC supply.
But be careful with the charging pulses into the smoothing capacitors, separate the audio ground and smoothing ground supplies.
I didn't on a USB mixer I designed and got masses of hum on the output.