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A-138b Mixer ( (Logarithmic Response)

2016-11-07 by Diego Ragnini

Greetings to everybody,

I am a newbie on this group.

I need some technical info about this module. I don't own this module yet. 

I foresee to use it in order to mix 1 signal at 10vpp (eurorack level) + 3 signals at 3vpp (line level). 

In order to get them output at approximately the same amplitude, I do believe having to attenuate the higher signal around level 4' and the 3 line level fully clockwise. Do you think it would work?

In other terms:
does the attenuator provide an increment of amplitude when the knob is fully clockwise, or simply outputs the original signal level?

Best regards,

FM

Re: [Doepfer_a100] A-138b Mixer ( (Logarithmic Response)

2016-11-07 by Jacco Ville

Hello and welcome,

Like the purpose of the module says, it's an attenuator so it's not likely that it amplifies. 
However, attenuating the hottest source can possibly match with the others who aren't attenuated. 
This might result in a low total signal which has to be amplified again. 
There are modules that are made for these tasks. 

Cheers
Jacco Ville

Show quoted textHide quoted text

> Op 7 nov. 2016 om 22:26 heeft Diego Ragnini diegora@free.fr [Doepfer_a100] <Doepfer_a100@yahoogroups.com> het volgende geschreven:
> 
> Greetings to everybody,
> 
> I am a newbie on this group.
> 
> I need some technical info about this module. I don't own this module yet. 
> 
> I foresee to use it in order to mix 1 signal at 10vpp (eurorack level) + 3 signals at 3vpp (line level). 
> 
> In order to get them output at approximately the same amplitude, I do believe having to attenuate the higher signal around level 4' and the 3 line level fully clockwise. Do you think it would work?
> 
> In other terms:
> does the attenuator provide an increment of amplitude when the knob is fully clockwise, or simply outputs the original signal level?
> 
> Best regards,
> 
> FM
> 
>

Re: [Doepfer_a100] A-138b Mixer ( (Logarithmic Response)

2016-11-07 by Diego Ragnini

Thanks a lot,

indeed, the idea is that the mixed signal should go through an A-138d CFX to be sent to a stomp box. A eurorack level signal here, usually, needs to be very much attenuated (as far as I know). So, I did believe that in my case things should work enough well.

Best, Diego

Il giorno 07/nov/2016, alle ore 22:34, "Jacco Ville jaccoville@yahoo.com [Doepfer_a100]" <Doepfer_a100@yahoogroups.com> ha scritto:

Hello and welcome,

Like the purpose of the module says, it's an attenuator so it's not likely that it amplifies.
However, attenuating the hottest source can possibly match with the others who aren't attenuated.
This might result in a low total signal which has to be amplified again.
There are modules that are made for these tasks.

Cheers
Jacco Ville

Op 7 nov. 2016 om 22:26 heeft Diego Ragnini diegora@free.fr [Doepfer_a100] <Doepfer_a100@yahoogroups.com> het volgende geschreven:

Greetings to everybody,

I am a newbie on this group.

I need some technical info about this module. I don't own this module yet.

I foresee to use it in order to mix 1 signal at 10vpp (eurorack level) + 3 signals at 3vpp (line level).

In order to get them output at approximately the same amplitude, I do believe having to attenuate the higher signal around level 4' and the 3 line level fully clockwise. Do you think it would work?

In other terms:
does the attenuator provide an increment of amplitude when the knob is fully clockwise, or simply outputs the original signal level?

Best regards,

FM

Re: [Doepfer_a100] A-138b Mixer ( (Logarithmic Response)

2016-11-08 by Analog Monster

This isn't guaranteed to work. There's more to it than just voltage level, there is also impedance. A guitar passive pickup output (which is in general the signal a guitar pedal is designed to operate with) is a high impedance output while modular levels are low impedance. This is why on soundcards you get jacks for guitar inputs labelled as "hi-z" inputs (z is the symbol for impedance). You can consider impedance as "frequency dependent resistance". You can't fix this with a DI box, you need something that does re amping. This will probably be more expensive than your pedals but makes loads of difference. I've used the pigtronix keymaster for this and it's great.

The a-138b would allow you to mix line level and eurorack by ear, it won't be exact but will probably be fine. What would be far better though is if the line level signals are brought up to eurorack levels-that's what the a-119 external input/envelope follower is for. Otherwise all the line level signals you want to process in the modular will be quieter, probably have more noise and may even get unexpected behaviour out of certain modules (a module is expecting -+5v and it only gets -+1.7ish v if you feed it line level).

Show quoted textHide quoted text

> On 7 Nov 2016, at 21:47, Diego Ragnini diegora@free.fr [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> 
> Thanks a lot,
> 
> 
> indeed, the idea is that the mixed signal should go through an A-138d CFX to be sent to a stomp box. A eurorack level signal here, usually, needs to be very much attenuated (as far as I know). So, I did believe that in my case things should work enough well. 
> 
> Best, Diego
> 
>> Il giorno 07/nov/2016, alle ore 22:34, "Jacco Ville jaccoville@yahoo.com [Doepfer_a100]" <Doepfer_a100@yahoogroups.com> ha scritto:
>> 
>>  
>> 
>> Hello and welcome,
>> 
>> Like the purpose of the module says, it's an attenuator so it's not likely that it amplifies. 
>> However, attenuating the hottest source can possibly match with the others who aren't attenuated. 
>> This might result in a low total signal which has to be amplified again. 
>> There are modules that are made for these tasks. 
>> 
>> Cheers
>> Jacco Ville
>> 
>> 
>> 
>> 
>> 
>> 
>>> Op 7 nov. 2016 om 22:26 heeft Diego Ragnini diegora@free.fr [Doepfer_a100] <Doepfer_a100@yahoogroups.com> het volgende geschreven:
>>> 
>>>  
>>> Greetings to everybody,
>>> 
>>> I am a newbie on this group.
>>> 
>>> I need some technical info about this module. I don't own this module yet. 
>>> 
>>> I foresee to use it in order to mix 1 signal at 10vpp (eurorack level) + 3 signals at 3vpp (line level). 
>>> 
>>> In order to get them output at approximately the same amplitude, I do believe having to attenuate the higher signal around level 4' and the 3 line level fully clockwise. Do you think it would work?
>>> 
>>> In other terms:
>>> does the attenuator provide an increment of amplitude when the knob is fully clockwise, or simply outputs the original signal level?
>>> 
>>> Best regards,
>>> 
>>> FM
>>> 
>> 
> 
>

Re: [Doepfer_a100] A-138b Mixer ( (Logarithmic Response)

2016-11-08 by Diego Ragnini

Thanks a lot for participating to the discussion.

I already own the A-119 module, it works fine (though pre-amp quality is always a matter of comparison and that's why engineers dedicate important budgets to it in serious studios). I would need 3 of them whereas the case can host neither 1 ! Indeed it is a small case, just a portable 1 row 84HP, and it is filled of modules...

As for the impedance matter, yes I know the issue, but I do believe that it concerns rather high impedance instruments: line level and eurorack level are not so far in terms of impedance. In any case, if a loss of brightness would occur while mixing the 3 line levels into the A-138b, here it's no so important since the case is intended to produce noisy drones and dark matter distortions… Moreover, the mixed signal will pass through the A-138d whose purpose is just to interface with stomp boxes. Usually at the A-138d the user will widely attenuate the (eurorack) level. Since I use to set the attenuation knob very CCW because the eurorack amplitude is too high for pedals, I really am optimist, believing to have a wide marge to re-gain the whole signal, if necessary, before sending it to the pedals.

I commonly enjoy to re-amp line levels with much fun. Try to re-amp a recorded voice or just a soft are generated track into a tube amp by means of a Radial Engineering Pro-RMP Studio Reamper (Transformer Isolated Passive Reamp): you can rebirth any source and donate a bright touch of analog to digitalized tracks.

Before purchasing the A-138d, I asked Doepfer to make clear if the module could manage efficiently the impedance matter. Mr Doepfer answered me this way:

«Normally you don't have to pay attention to the the impedances as it simply manages the amplitude levels. But for the sake of completeness here are the values: FX return: 1M - FX send : 50k»

Best, FM

Il giorno 08/nov/2016, alle ore 17:19, Analog Monster analogmonster@ymail.com [Doepfer_a100] <Doepfer_a100@yahoogroups.com> ha scritto:

This isn't guaranteed to work. There's more to it than just voltage level, there is also impedance. A guitar passive pickup output (which is in general the signal a guitar pedal is designed to operate with) is a high impedance output while modular levels are low impedance. This is why on soundcards you get jacks for guitar inputs labelled as "hi-z" inputs (z is the symbol for impedance). You can consider impedance as "frequency dependent resistance". You can't fix this with a DI box, you need something that does re amping. This will probably be more expensive than your pedals but makes loads of difference. I've used the pigtronix keymaster for this and it's great.

The a-138b would allow you to mix line level and eurorack by ear, it won't be exact but will probably be fine. What would be far better though is if the line level signals are brought up to eurorack levels-that's what the a-119 ex ternal input/envelope follower is for. Otherwise all the line level signals you want to process in the modular will be quieter, probably have more noise and may even get unexpected behaviour out of certain modules (a module is expecting -+5v and it only gets -+1.7ish v if you feed it line level).

On 7 Nov 2016, at 21:47, Diego Ragnini diegora@free.fr [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:

Thanks a lot,

indeed, the idea is that the mixed signal should go through an A-138d CFX to be sent to a stomp box. A eurorack level signal here, usually, needs to be very much attenuated (as far as I know). So, I did believe that in my case things should work enough well.

Best, Diego

Il giorno 07/nov/2016, alle ore 22:34, "Jacco Ville jaccoville@yahoo.com [Doepfer_a100]" <Doepfer_a100@yahoogroups.com> ha scritto:

Hello and welcome,

Like the purpose of the module says, it's an attenuator so it's not likely that it amplifies.
However, attenuating the hottest source can possibly match with the others who aren't attenuated.
This might result in a low total signal which has to be amplified again.
There are modules that are made for these tasks.

Cheers
Jacco Ville

Op 7 nov. 2016 om 22:26 heeft Diego Ragnini diegora@free.fr [Doepfer_a100] <Doepfer_a100@yahoogroups.com> het volgende geschreven:

Greetings to everybody,

I am a newbie on this group.

I need some technical info about this module. I don't own this module yet.

I foresee to use it in order to mix 1 signal at 10vpp (eurorack level) + 3 signals at 3vpp (line level).

In order to get them output at approximately the same amplitude, I do believe having to attenuate the higher signal around level 4' and the 3 line level fully clockwise. Do you think it would work?

In other terms:
does the attenuator provide an increment of amplitude when the knob is fully clockwise, or simply outputs the original signal level?

Best regards,

FM