I had a conversation with my friend Aaron Day a week ago and we were
brainstorming how insertion loss can be useful if one wants to add some
more gain to a signal chain. and in that context, some extra saturation
could be a bonus.

so here is my initial idea for a (fully passive) studio device.
I believe it is best suited for mixing (it can be a mono or ganged stereo unit).
it is definitely going to be high-end, with switched controls for everything.

first the gain-staging part; I want to facilitate several scenarios—

1. run a preamp (or any other unit with gain) really hot into this unit and
   bring the signal level back to normal for the rest of the chain.
   even if the preceding unit has an output attenuator, forgoing it helps to
   wring every bit of character out of the unit.
2. load down the output stage of the unit preceding it, so that it shows
   more of its character and maybe even compresses a little on peaks. works
   for any kind of unit, also at normal levels.
3. bring a normal signal level down so that a preamp can be inserted
   after this unit and run with a righteous amount of gain (think: mic gain),
   where more character occurs.
4. any combination of the above (that’s 4 more scenarios).

so far, that is quite utilitarian. but then there is the saturation part.

right at the heart of this unit—between the input attenuation that gets a
hot signal back to normal and the output attenuation to feed a preamp—
there is the saturator with fine control over its character and action.

and then there is one more thing… the exciter.
which is a second complete implementation of the saturator, but instead
of ‘compressing’ the signal in a rough and ready way, it ‘expands’ it.


This thread is the place to discuss every single aspect of this unit and to
find out the wishes and needs of those who can really use something like this.
then I can start designing it and show that process to you.

to kick this off, I got some questions about levels:

normal line level is (roundabout) +4dBu, right?

a hot output signal is in the region of +14–24dBu?

a righteous amount of gain from a preamp is 30–50dB?


I look forward to your replies, —ps

1. there's a difference between 'nominal' and 'normal'
   ('normal' to me equals the max i/o level before clipping at which the huge majority of my outboard operates: however, for easy patching to/from any gear, i'm using tons of line level converters between the outboard and patchbay and settled for +21dBu...)
   
   
2. 'hot' imo is anywhere above +24dBu
   
   
3. depends entirely on type of mics and scenario (if not genre):
   
   - dynamic mics in close position on loud instruments/on loud stages, typically used in rock music, rarely need more than 20dB of gain: a sm-58 on a singer typically 24dB (as i dare to say after mixing literally thousands of concerts in 40+ years).
   
   -sdc's in a more distant position on instruments with a large dynamic range, typically used in classial music, can require 20-40dB of gain.
   
   - any situation needing more than that imo indicates a poor mic selection/position, not adequate for the task...
   
   - pls don't get me started on ribbon mics!

p.s. to use very high gain settings (mostly on transformer balanced and/or tube preamps) but then to attenuate the output indeed is a thing... - of the past though! ;-)

Particularly curious about the passive exciter concept. Something like this could be useful following the Burl BDA4M, allowing you to calibrate the output extra hot and hit the the transformer harder, but it would depend on how much gain is lost.

Like in your EQ thread, I wonder a simplified version of it with limited controls would be like, maybe just a bypass switch, saturator on/off, and exciter on/off. And then if I had 16 channels of it ... across the whole console. I like things that give an overall sound/starting-point/cohesion.

one brush with reality (thanks Didier) and things get a lot clearer.

in general I have gotten more tuned in with the vision that this is a
tool to be used for mixing. i.e. for DAW to DAW processing of
tracks and buses (drumbus!), or DAW–console/summing–DAW mix.

that sets what the ballpark is for my level questions and future ones.

yeah, so this is about the practical working level (range) that people
have settled for when using outboard in mixing/processing.

thinking of specs of DACs, ADCs and analog outboard (I did not look
up consoles) I have pencilled in this ‘working level’ as +14–22dBu.

does that sound right? I’d love too hear from people who got
plenty of experience in this field.

gotcha. I am pencilling in this hot level as +22–34dBu.

I realise now that this question is about the righteous amount of gain…
for the preamp. this is about inserting a preamp on a track for it to
add character. and in a way that is very different than using the regular
line-in solution of that pre (pad or line transformer (Neve) at the input;
~20dB of gain from the amplifier). thus Mic mode for the Neves, no
20dB pad and 40+dB of gain for a livelier sound (less feedback around
the amplifier).

the more gain the merrier, but it has to stop somewhere for noise
reasons, so I am I am pencilling in this righteous preamp gain as 40–60dB.

purely passive EQ is also a thing of the (distant) past, but is blowing
peoples minds in the 2020s

I am immediately thinking of a custom solution for the BDA4M—

one box for a BDA4M card; 4 channels, quad-ganged controls.

with the 6 defined output levels of the BURL and your personal
working level known, the attenuation side can be dialled in.

further features can then be selected. but those still have to be
developed and tuned in with the aid of this thread.

overall this can be a more to-the-point solution that (per channel)
is definitely lower in cost.

Can you explain how this concept is different from something like the Handsome Audio Zulu?

speaking of gain ranges: i mentioned a few examples just to illustrate 'typical' use in different revording/live mixing situations and i'm fully aware of the practice of going beyond these (reasonable) levels became fashionable (again)...

now IF i want to mess with clean signals, i find mismatching of impedance settings often more interesting than overdriving an input or output stage although some (modern) mics seem to be largely immune to various impedance settings.

anyway, maybe you wanna look at hendyamps' nuclear unicorn and of course david hill's hedd converter*, both of which can seriously mess with overtones albeit the latter is more on the conservative side while the former is on the abrasive side... - oh, and spl's tube vitalizer is also pretty cool, sorry: hot!



* sorry, digital obviously but highly effective in what it does (even though more or less a copy of spl's spectralizer from their digital red range)

definitely intriguing. if I am imagining 16 channels and mixing I would be thinking (as an example) "ok these 8 I want to tuck in to the mix slightly with saturation, these other 4 I want to pop out with the exciter, and these last 4 I want to keep clean so I will bypass".

i wouldn't want individual tuning of those functions, if I wanted more or less I would set the operating level accordingly

this is pretty specific to my personal setup of course, but ultimately I am trying to use clean EQ/compression/etc in the box to maximize control/recall-ability, but marry that with a "house sound" of unique hardware that is mostly minimal in control

it starts right there: at the overall concept.

the Handsome Audio Zulu is a tape simulator. I am sure they put a ton
of R&D in it and did all they could to get as close as it gets. cool that
it is fully passive. it is no surprise that all the controls are from the
world of tape.

for this new unit we re researching here, I will never say it has anything
to do with tape; tape will not be on my mind when working on it;
I will certainly not do that ton of R&D into tape.

what this new unit will allow is to to use more gain, make it more tasty
and insert more gainy outboard units in a track/bus processing chain.
and and on top of that saturate and excite the signal, with a lot of
flavours and control.

edit: oh and let me add that when saturation and exciter are not in use
this new unit will have the same ‘transparent analog’ sound as my EQs;
i.e. no box tone. all the extra mojo will come from the other analog
boxes in the chain.

with those different concepts, the outcome can only be different.

this is has potential. is the mismatch as simple as a hi Z mic into a lo Z
preamp input? or are there other ways to mismatch?

yeah thanks for mentioning these units that live in the same
neighbourhood. good to check their concept, functionality and
faceplate complexity.

If you are planning on using 1:1 transformer, then having adjustable source and load impedance can lead to interesting effects and the effect will vary depending on what preamp circuit is used before/after of course. Roger Foote made an active box exploiting this concept Foote Mastering Tool Box

Need one of these to follow my isa one.

check out focusrite isa 428/828 or cloudlifter cl-z(i): switchable or continuously variable impedance (over a relatively wide range).

[maybe off-topic and i'm not sure that an electronic circuit could mimic the slower transient behaviour/compression-like artefacts of dynamic mics (which imo gets enhanced by some type of 'slow' preamp designs) - would be nice though: even me, a die-hard user of digital desks, would (occasionally) use it on the way in!]

up to now there isn’t any transformer in the planning.

but the point of this unit to interact with the unit in front and/or after
it and when there is a transformer on that output/input, then loading/
mismatched drive can be used to make those transformers more colourful.

but then also when there is no transformer on that output/input, there
is a chance of more colour from loading/mismatched drive.

(cool that you point out the Foote Mastering Tool Box. I found the
faceplate of the MTB-2 and that showed what you meant.)

funny, the moment you posted that I had just checked out the ISA one
(always liked them, what a nice form factor).

just want to say that putting this unit in front of your ISA gonna be
just as cool, with a different set of results.

with 16 channels it is a good idea to handle that with 4 x quad-ganged
controls. a clever optimum.

I also realised in the meanwhile that there would be serious economics
from putting 16 channels in one 4RU box, instead of 4 1RU boxes.
(a 4RU chassis cost just a little more than a 1RU one.)

I design standard products and then everything I build is custom, that
is how things are rolling at the moment. same here; once this new unit’s
design has matured, designing and building this 16 channel playback
box is a (cool) custom order.

ps: it occurred to me yesterday that this playback (D/A) box has a
counterpart: the 16 channel recording box, to put in front of the A/D.
a slightly more crazy idea (commitment to a rough sound on the way in),
but I keep thinking of it being used for tracking drums

this, together with j.colt’s input is pointing at the output mismatch
control (to go into a mic preamp).

a quick read-up on it tells me it is the compression of the dynamic
transducer itself. which is not surprising because a dynamic mic capsule
in reverse (a direct radiator speaker) has a lot of compression/distortion
as soon as it is moving.

would a little compression from loading down the output stage of an
active piece of outboard give a similar sound? only one way to find out…

here is a bunch of ideas/goals that I have for the saturator.
I am just gonna throw them out here to see your reaction and
any other ideas you got—

• no matter whether the working level is 14dBu, or 22dBu, saturation
  can be dialled in from mild box flavour, to crushing the waveform.
  
  
• four flavours of saturation (e.g. silicon, germanium, LED, etc.) that
  can be mixed. the flavour mix is set separately for the + and - half of
  the waveform; this tunes the (level-dependent) relationship of even
  and odd harmonics.
  
• a zener option has a nice ring to it, but I got to see if I can make it work
  
  
• just like for a compressor, an hpf on the ‘detector’ sounds like a good
  thing. but then, why not also an lpf? OK, so now the saturation can be set
  to work on a sub-section of the spectrum. hpf 20–2kHz, lpf 250–32kHz.
  I think it is good that both of them are always on, keeping infrasonic mud
  and DC out of the detector and high-freq hash from coming out of the
  saturator (btw: hpf & lpf do not work on the actual audio signal). I am
  also thinking about some simple shelving options for the hpf & lpf.
  
  
• so far the saturator. the exciter? exactly the same: its own front
  panel section with the same controls. the saturator and exciter can be
  individually bypassed.

I think there is a lot of scope there for the saturator and exciter to be
played off against each other, with different flavours and working in
different (overlapping) parts of the spectrum. the two of them are also
infectious: if one gets into action (in a frequency region) the the other
becomes more sensitive (in that frequency region) and pushed into
action too.

another question:

has anyone got experiences to share with mic preamps that are
a bit temperamental (sound / colour-wise) regarding which microphone
one hooks up?

and the other way around: microphones that are fussy about the preamp
(not just regarding gain)?

could be really interesting

As a list of internal function blocks, it certainly seems pretty comprehensive. However I'm getting choice paralysis just reading the idea of independent +/- flavor mix though.

I wonder if you can borrow the big center knob idea from the Gyraf 22 and have essentially a "tilt" control that blends some set of those options rather than making them all independently controllable.

I know I always come from the same place with my comments, but I will die on the hill that a box with a musically useful UI will always give better results. And anyway, I say let ITB be the place where things get tweaky to the extreme.

on a similar note, regarding the hpf/lpf, I have a Korg PE1000 keyboard with two horizontal sliders which physically lock when they meet (so they dont overlap, but can also then move together). Seems like it could be a nice way to tune the filter band.

Regarding the saturator and exciter playing off each other, I'm reminded of Goly's new Crosscompressor. Could be interesting to have the high's excited whenever the lows are being saturating, and have that relationship on a knob somehow, that kind of thing.

I'm still struggling to visualize how this will be very different from the Zulu other than using different words on the knobs. The Zulu doesn't really sound like tape, it's just a passive tone shaper that sucks off 6-15db of gain in the process depending upon the control settings.

They use tapey words like "enhance" but they really just mean wet/dry. Then they use words like "bias" but it's really just translates to being an amount of saturation + HF roll off. The "headroom" and "deck" controls seem to just swap out a couple passives via rotary switches to slightly change the flavor of the bias control.


Not saying your idea is bad or not useful, I'm just trying to understand the novelty in comparison to a piece of existing hardware I'm familiar with. Even if it was just a slightly different zulu with a different choice of labeling on the controls, I'm down for that and would rather give my money to anyone other than Langston.

thanks for the description of how that one works out in practice.
I did not know that one had (quite variable) insertion loss.
actually I realise I got very little info from their website.

it is good that you rattle the cage again concerning this unit on a
product level (i.e. how is this going to be valuable and useful in a studio?).

the heart and soul of this unit is the part that currently has the working
title of gain buddy. this is what allows the unit (or the chain) before it to
be run at a hot level and/or allows to insert a preamp after it and run that
at righteous gain. on top of the input/output gain staging tools the gain
buddy has impedance tools to get more colour out of the preceding
unit and the following preamp.

the unique thing is the focus on the chain, especially the interaction with
the units right before and after, instead of the normal inward view of
what will this box do in isolation.

if later someone comes along and orders a custom unit—2 gain buddies
in a box, no saturator/exciter—then I will think: OK, you gonna get the
puristic version.

also note that this gain buddy part will have no box sound at all, just like
the EQs I make. I suspect that is not the case with the Zulu.

gain buddy?!

frankly, i don't care about the 'sound' as long as it does something valuable/that's 'interesting' (even if it's messing with my carefully adjusted gain structure) but pls find another name - or i won't buy the unit!

capisce?!

OK, I think I caught your drift

it is just a working description; I am open to suggestions…

how about Z-freak?

in the light of recent history, everyone should be veeery careful about wanting to use the z-logo voluntarily...

oof good point, didnt think of that (also Z-freak is a terrible name!)

How about the Passively Engineered Natural Impedance Selector

So a letter in the alphabet now also cancelled? This is dumb even by gs standards... I like gain buddy.

A bit similar to tc pullet, actually I'd like a passive eq like pullet but with low and sub frequencies, please.

remember we are looking for a neutral descriptor of this “gain enabler
and character enhancer” department of this unit, not the model name.

I make exactly those EQs. check my site, get in touch with your wishes.