I've got a shonky old Xone 32 I use (needs about £80 of parts from A&H to fix it up, but i never seem to get round to buying them!)...but I'm using Traktor Scratch Pro now and really would like 4 channels.
From looking at it, it seems an op-amp based design would be easy enough to work out (slight design niggles like exactly how to do the monitoring - I think I'd like to have a selector switch to let me choose which channel the single pair of VU/LED meters was showing, or master of course)
The modular design of the old Formula Sound mixers makes sense to me too. it would SEEM to be quite easy to build separate boards for each component (channel with level and gain/ EQ / output board with summing amp, record and master, headphone monitor board). You could have little jumper leads at the right points for the send/receive to things like EQ's for example. This would make the project a bit more bite-sized, with (hopefully) some little victories along the way to keep interest.
The other thought I had (seems more DIY audio...) was to have a more simple design with valve input buffers driving a simple passive EQ and Analogue pot per channel, with a valve headphone amp bolted on. Basically because it would be different to anything I might buy.
So...4 x simple 'old school' (ie with tone) hifi preamp circuits, with a summing amp, and a contraption of some form for monitoring selection...
From looking at it, it seems an op-amp based design would be easy enough to work out (slight design niggles like exactly how to do the monitoring - I think I'd like to have a selector switch to let me choose which channel the single pair of VU/LED meters was showing, or master of course)
The modular design of the old Formula Sound mixers makes sense to me too. it would SEEM to be quite easy to build separate boards for each component (channel with level and gain/ EQ / output board with summing amp, record and master, headphone monitor board). You could have little jumper leads at the right points for the send/receive to things like EQ's for example. This would make the project a bit more bite-sized, with (hopefully) some little victories along the way to keep interest.
The other thought I had (seems more DIY audio...) was to have a more simple design with valve input buffers driving a simple passive EQ and Analogue pot per channel, with a valve headphone amp bolted on. Basically because it would be different to anything I might buy.
So...4 x simple 'old school' (ie with tone) hifi preamp circuits, with a summing amp, and a contraption of some form for monitoring selection...
Bypass switch?
The difference between a mixer with EQ's and one without would surly be that one is a tool for blending signals, and the other has an element of being a creative tool (for blending signals
)?I suppose this is where the idea of modular mixer gets real legs, you can have as much or as little as you like.
The Idea of making a mixer from scratch is something that I find interesting.
I would think that it would be quite easy to surpass the audio quality of most commercial mixers.
I don,t DJ mix myself, but spent many years setting up rigs for dance music.
Often DJ's seem to go for mixers that are not the best quality in audio terms, but have the right controls to enable them to get the mix that they want.
For instance the Formula Sound mixers are superb quality but the crossover slope is not ideal for most mixing, as it attenuates both channels when in the centre.
I have a Newmark 4 channel mixer that I used sucessfully for many years. I took it apart and added about 12 Elna RSH series electrolytics, and a handful of 0.47 Wima MKT caps to the voltage rails, and this gave it quite a boost in audio quality.
I would think a separate PSU would be good.
At one point I was using a Citronic 2 channel that I made a oversized external PSU with a T03 packaged LM338 regulator, with good results.
You should be careful to ensure that you design sufficient headroom in to your mixer to ensure that it does not distort. I have a friend who modifies his mixers so that with a standard 2v line input it will not clip with every control on max!
I would think that it would be quite easy to surpass the audio quality of most commercial mixers.
I don,t DJ mix myself, but spent many years setting up rigs for dance music.
Often DJ's seem to go for mixers that are not the best quality in audio terms, but have the right controls to enable them to get the mix that they want.
For instance the Formula Sound mixers are superb quality but the crossover slope is not ideal for most mixing, as it attenuates both channels when in the centre.
I have a Newmark 4 channel mixer that I used sucessfully for many years. I took it apart and added about 12 Elna RSH series electrolytics, and a handful of 0.47 Wima MKT caps to the voltage rails, and this gave it quite a boost in audio quality.
I would think a separate PSU would be good.
At one point I was using a Citronic 2 channel that I made a oversized external PSU with a T03 packaged LM338 regulator, with good results.
You should be careful to ensure that you design sufficient headroom in to your mixer to ensure that it does not distort. I have a friend who modifies his mixers so that with a standard 2v line input it will not clip with every control on max!
I am 100% determined to build a mixer - at some point...
My first point of call is to build a phono stage to allow me to run my decks into a unit that gives 2 outputs - one for the DVS system when I'm using timecode vinyl, and the other for when I'm mixing vinyl (the delay induced by the vinyl going through the Traktor software, and the flattening of the sound by it getting converted to digital and then back again is awful!)
I have pages of note about what I want to build, so I need to finalise a specification for the mixer itself and then get to it.
Bypass switch?
The difference between a mixer with EQ's and one without would surly be that one is a tool for blending signals, and the other has an element of being a creative tool (for blending signals
I suppose this is where the idea of modular mixer gets real legs, you can have as much or as little as you like.
Bypass switch indeed - the mixer design I am working on has true bypassable send-returns before the last two triode stages and I'm hoping to either build (if I get the schematics) or buy a good quality outboard EQ for it!
Bah, you people make me wanna put a few extra holes into that little Velleman Promix 50S that i have. I don't need a full EQ, but a bass cut circuit would be very nice. That way i can keep my hands on the faders and off the keyboard. I already figured out how to keep my hands off the mouse in VirtualDJ, but i still need the keyboard for a lotta things.
Hmm. *thinks*... Wait a sec. Gut an USB keyboard, wire buttons to shortcut keys, and fit 'em inside the mixer. That sounds like a good idea. Wonder why i never thought of this before.
Since we're on topic - anyone know what's the best way to use faders in terms of signal going thru them? My Velleman mixer does passive mixing with pretty high values (47k IIRC, most likely to achieve decent muting of the inactive channel when the crossfader is moved fully to one side) then has a gain stage afterwards. This doesn't seem like the optimal solution to me, am i right?
Hmm. *thinks*... Wait a sec. Gut an USB keyboard, wire buttons to shortcut keys, and fit 'em inside the mixer. That sounds like a good idea. Wonder why i never thought of this before.
Since we're on topic - anyone know what's the best way to use faders in terms of signal going thru them? My Velleman mixer does passive mixing with pretty high values (47k IIRC, most likely to achieve decent muting of the inactive channel when the crossfader is moved fully to one side) then has a gain stage afterwards. This doesn't seem like the optimal solution to me, am i right?
Semi on topic (mixers sort of depend on volume control no matter what you want beyond that)...has anyone any experience of using high performance IC based pots?
I use Linn kit at home, and it is all solid state in the preamp, and it sounds awesome. I've found sites with info on controlling IC volume control chips using normal pots, so the interface would feel like a normal mixer, but with out having to put the signal through the pot itself.
Please note that I am not after digital volume control here (as is AD conversion, digital manipulation, DA conversion).
One thing I have found is that when pricing up the bits for any of the designs I've played with, the Alps pots are the bit that makes me move on to something else!
I use Linn kit at home, and it is all solid state in the preamp, and it sounds awesome. I've found sites with info on controlling IC volume control chips using normal pots, so the interface would feel like a normal mixer, but with out having to put the signal through the pot itself.
Please note that I am not after digital volume control here (as is AD conversion, digital manipulation, DA conversion).
One thing I have found is that when pricing up the bits for any of the designs I've played with, the Alps pots are the bit that makes me move on to something else!
I just figured i won't even need extra holes. My mixer has phono/line switches in the form of push buttons. They're virtually always on "line", i wouldn't use them on phono anyway unless i was running timecodes - those 4558s hiss quite a bit with high gain.
Thus, the switches can be replaced by ordinary push buttons, and wired to the bass cut function. There's also a talkover switch that i will never need either - methinks i'll wire that to the Sync function in VDJ. Now i just need to buy a cheapo USB keyboard.
Thus, the switches can be replaced by ordinary push buttons, and wired to the bass cut function. There's also a talkover switch that i will never need either - methinks i'll wire that to the Sync function in VDJ. Now i just need to buy a cheapo USB keyboard.
I did think of building a mixera 3-4 years ago. I own a Behringer small mixer, which works quite well for home use and have even played on it in a club, but I wanted to build something like the Red Sound Infader. I did try to build it, at the time I had no idea that Infader existed (I found out about it today from this topic) I thought that I had came up with a revolutionary idea. At first I tried to build something that would just separate the bass (under 100-200 Hz) and the rest of the frequency range, then build two of these and see if I can manage to mix the basses.
But my knowledge of electronics is not very good. I built some LC and RC filters but that will never work. I got the bass louder in the bass part, but I could not kill the higher frequencies entirely.
Then I built the thing on transistors. I found a schematic which filtered the bass and then a transistor subtracted it from the main signal or vice versa, again it did not kill the bass entirely. Maybe I just did not have enough knowledge to make it work or is it just impossible to do without going digital?
Then I searched for IC-s that would do this for me, but did not find anything. There are some EQ chips but I am not sure if these will work for this purpose.
If anyone knows how to build a mixer like Infader then I would also like to know how.
But my knowledge of electronics is not very good. I built some LC and RC filters but that will never work. I got the bass louder in the bass part, but I could not kill the higher frequencies entirely.
Then I built the thing on transistors. I found a schematic which filtered the bass and then a transistor subtracted it from the main signal or vice versa, again it did not kill the bass entirely. Maybe I just did not have enough knowledge to make it work or is it just impossible to do without going digital?
Then I searched for IC-s that would do this for me, but did not find anything. There are some EQ chips but I am not sure if these will work for this purpose.
If anyone knows how to build a mixer like Infader then I would also like to know how.
I would like to tune my behringer djx700, thought about, to take out the internal PS, ad an fx button and separate fx channels (internal/external) what would give me the posibility to put 2 fx at each channel.
Power supply ripping should result in a better noise ratio and less heat inside.
Anybody know what to do to improve the EQ sound quality, maybe also ajusting the frequencies?
Also Some extra gain and output level would be very welcome...
On the other hand, maybe digital mixing would make it even more interesting...
Power supply ripping should result in a better noise ratio and less heat inside.
Anybody know what to do to improve the EQ sound quality, maybe also ajusting the frequencies?
Also Some extra gain and output level would be very welcome...
On the other hand, maybe digital mixing would make it even more interesting...
Rawdata1:
Not sure it's worth spending money and time on this. Taking out the PSU could in theory improve things but I cannot imagine it will transform a budget mixer to a wonder machine and it will create other hassles for you (you need to make a housing for the PSU, install a socket onto the mixer to connect it etc). It will also completely obliterate the resale value of the mixer - even though you see it as an improvement, potential buyers are likely to see it as a liability.
As for more substantial improvements, I have not seen schematics and layout for any behringer mixers, but tend to agree with pern that mass market commercial units, particularly those packed with functions and DSPs, will be a pain to reverse engineer. For example, to add simple switch-able sends and returns to each channel you probably have to do some pretty awkward tweaks to the pcb (break connections and add jumper cables to other boards and so on), not to mention find space on the top for the toggle switches and at the back for the send/returns. "Improving the EQ sound quality" sounds difficult to define and even more difficult to implement. You can probably change the cross-over frequencies by tweaking some of the components, on the assumption that the design is analogue and simple enough to get you hear around and you can physically do the soldering work.
The gain may be very easy to tweak: many commercial mixers have small jumper switches inside that let you chose different levels of input sensitivity. Check the manual/online to see if yours does too. You can probably also further beef up the gain by tweaking the pre-amp sections. But if you are thinking about taking the PSU out to "improve on noise", are you sure this is something you want to do?
Having owned cheap and mid-range mixers, my advice to you would be to not bother with any of this, if it is better sound you want to achieve. If you want to improve quality at the expense of functionality, there are a few commercial and DIY options around that are great and well within your mixer's price range. If you need all the fancy on-board FX, EQ-kills, cross-over curves and BPM counters, stick with the stock Behringer until you can afford something better and then upgrade and sell it on to partly fund the new purchase.
If on the other hand you want to do this for fun and education, I suggest you get a simpler mixer as a "barebones" base and start playing with that.
Good luck.
Nikos
Not sure it's worth spending money and time on this. Taking out the PSU could in theory improve things but I cannot imagine it will transform a budget mixer to a wonder machine and it will create other hassles for you (you need to make a housing for the PSU, install a socket onto the mixer to connect it etc). It will also completely obliterate the resale value of the mixer - even though you see it as an improvement, potential buyers are likely to see it as a liability.
As for more substantial improvements, I have not seen schematics and layout for any behringer mixers, but tend to agree with pern that mass market commercial units, particularly those packed with functions and DSPs, will be a pain to reverse engineer. For example, to add simple switch-able sends and returns to each channel you probably have to do some pretty awkward tweaks to the pcb (break connections and add jumper cables to other boards and so on), not to mention find space on the top for the toggle switches and at the back for the send/returns. "Improving the EQ sound quality" sounds difficult to define and even more difficult to implement. You can probably change the cross-over frequencies by tweaking some of the components, on the assumption that the design is analogue and simple enough to get you hear around and you can physically do the soldering work.
The gain may be very easy to tweak: many commercial mixers have small jumper switches inside that let you chose different levels of input sensitivity. Check the manual/online to see if yours does too. You can probably also further beef up the gain by tweaking the pre-amp sections. But if you are thinking about taking the PSU out to "improve on noise", are you sure this is something you want to do?
Having owned cheap and mid-range mixers, my advice to you would be to not bother with any of this, if it is better sound you want to achieve. If you want to improve quality at the expense of functionality, there are a few commercial and DIY options around that are great and well within your mixer's price range. If you need all the fancy on-board FX, EQ-kills, cross-over curves and BPM counters, stick with the stock Behringer until you can afford something better and then upgrade and sell it on to partly fund the new purchase.
If on the other hand you want to do this for fun and education, I suggest you get a simpler mixer as a "barebones" base and start playing with that.
Good luck.
Nikos
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