B
Doepfer A-138-B Mixer
The A-138b is essentially a 4 into 1 mixer optimised for audio signals rather than control voltages. the 'b' in the name means the the mixer uses logarithmic rather than linear potentiometers.
For me the A-138b is an essential piece of equipment because it enables me to sum the outputs of up to 4 sound sources (for instance VCO's or noise sources) before sending the combined output to my A-108 Low pass filter module.
With one input employed, and with the channel and master levels set to 10, the volume of the output is the same level as the input signal. in other words, this module will not increase the gain of an input, it will only attenuate it.
When using multiple inputs I find I have to reduce the levels of the individual channels quite a lot, otherwise the output from the mixer becomes to much for next module in the chain. So if I am using 3 inputs, I will use a maximum of about 33% of each channel's volume.
The mixer appears to operate very quietly. It does not introduce much 'hiss' into the sound. Some reviewers have found otherwise , so it may be that my ears are not as sensitive as theirs.
I have rated the A-138b as 5 stars except for features, which I have given a 4 for. The reason for this is that the Doepfer website indicates that with no input into channel 1, the channel 1 level will act as a +5 volt DC offset. In other words, the unit *can* increase the level beyond that of an input signal. However, my unit doesn't work like this. As delivered, all 4 inputs on my A-138b work in the same way. The manual says there is a jumper I need to re-position on the rear of the circuit board to achieve the +5 volt DD offset with input level 1. I think this option should have been made available as a toggle switch on the front panel. It would be useful on occasions when I am only using 3 inputs, but I do not want to have to remove the unit from its case and re-position a jumper each time to achieve this!
Overall, another useful and great value unit from Doepfer, in my opinion.
For me the A-138b is an essential piece of equipment because it enables me to sum the outputs of up to 4 sound sources (for instance VCO's or noise sources) before sending the combined output to my A-108 Low pass filter module.
With one input employed, and with the channel and master levels set to 10, the volume of the output is the same level as the input signal. in other words, this module will not increase the gain of an input, it will only attenuate it.
When using multiple inputs I find I have to reduce the levels of the individual channels quite a lot, otherwise the output from the mixer becomes to much for next module in the chain. So if I am using 3 inputs, I will use a maximum of about 33% of each channel's volume.
The mixer appears to operate very quietly. It does not introduce much 'hiss' into the sound. Some reviewers have found otherwise , so it may be that my ears are not as sensitive as theirs.
I have rated the A-138b as 5 stars except for features, which I have given a 4 for. The reason for this is that the Doepfer website indicates that with no input into channel 1, the channel 1 level will act as a +5 volt DC offset. In other words, the unit *can* increase the level beyond that of an input signal. However, my unit doesn't work like this. As delivered, all 4 inputs on my A-138b work in the same way. The manual says there is a jumper I need to re-position on the rear of the circuit board to achieve the +5 volt DD offset with input level 1. I think this option should have been made available as a toggle switch on the front panel. It would be useful on occasions when I am only using 3 inputs, but I do not want to have to remove the unit from its case and re-position a jumper each time to achieve this!
Overall, another useful and great value unit from Doepfer, in my opinion.
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M
I bought this item to use as a mixer for my Doepfer modules, I own 3 more modules and in order to be able to send only one output from my 3 modules I found out this mixer. I was not able to find any disadvantage for this item, the knobs have a good sensitivity, both inputs and outputs work just fine, and it is possible to connect this mixer to the main power suply.
For a low number of outputs, as the ones I have this is a great choice for these systems, for biger systems maybe other options should be considered.
So, all in all, I definitely recomend this item to incorporate in a Doepfer based system
For a low number of outputs, as the ones I have this is a great choice for these systems, for biger systems maybe other options should be considered.
So, all in all, I definitely recomend this item to incorporate in a Doepfer based system
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A
Does its job!
Very useful 4 into 1 mixer. I've used it to mix VCO waves into the Wasp filter and the A-116 wave processor.
Will be used a LOT.
Will be used a LOT.
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L
Mixer for all seasons
If your modular system is growing and you don't have a mixer, buy one. If you have more than 1 Oscillator in your setup, a white noise module or separate drum modules, you'll want this to to mix your sounds nicely, super simple but super effective and does the job it was set out to do.
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d
people say it is not clean
...they obviously have not used phonic am220 mixer then ;)
A fine mixer, I use 2 of these for audio singals. No problems. If it only had 5th input...
A fine mixer, I use 2 of these for audio singals. No problems. If it only had 5th input...
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e
Very nice simple mixer
Good sounding i got 2 of them it cool for soften signals even works good with cv for pitch very precise module.
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Y
cheap mixer
I sold low quality of final sounmd
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A
Doepfer A-138b
Simple and affordable mixer. Linear for CV and logarithmic for audio. Those two always get mixed up and confuses everybody but there you have it! Linear for CV and logarithmic for audio!
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Doefper = quality
Yet another solid Doeper addition to my 30 year old setup !
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A
Doepfer A-138b
A great little 4 channel mixer that serves it's purpose well. Perfect for summing different elements together. I often use it for mixing dry and effected versions of the same source signal before outputting somewhere else. For the price it is great value and has a fairly smooth sound.
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