Double Bass Brad Sarno’s V8 Octal preamp

[Ric Vice]

"And the big secret I've discovered with piezo's and tubes is that by the sheer nature of a tube's inherently very-high impedance, a tube can very smoothly and naturally track the wildly fluctuating output impedances from a piezo. When a piezo sees a solid state device, they seem hard, harsh, barky, and crispy-distorted. Then so many people try to EQ those problems away. Midrange parametric surgery, high end darkening, etc. But when a piezo sees a tube grid, there's an amazing dance there, they just get along so well. The response from the pickujp becomes MUCH more smooth and normal, natural sounding, more like a good microphone than a pickup"

The Sarno Black Box does indeed do this, but that's what it's designed to do, as a Input Impedance Buffer/Preamp with a Variable load you can adjust. Tube Preamps do sound very good, as an example I have a Ampeg B-15N(C) that sounds very nice, but
it doesn't do, what the Sarno does, as all of it's inputs are set at different fixed impedances. Channel 1 Input 1, at 5.6 Megohms, Channel 1 Input 2, at 1 Meg Ohm, and Channel 2 at

.

 

[Ric Vice]

Here's a riddle related to this statement: When playing with the Noble pre, it seems to work its magic whether or not it is the first thing in the chain; while I was fooling around with my travel bass, I put a Keeley Bassist in front of it just to see what would happen. It sounded great. Then I put the Keeley after. Still sounded great. I wonder what's going on there?

That is indeed interesting. Now, mind you, I don't own either of these devices (intentional pun) however, it appears that, as a compressor, the Keeley will modify the ADSR profile. Minor adjustments in Attack, Decay, Sustain, and Release of individual notes, makes a huge difference

playing fast passages on a Double Bass. Tubes on the other hand are said to distort the even order harmonics (the pretty ones) vs odd order (nasty ones) so I don't think it makes a difference where you insert the Noble in the signal chain, as long as it's

somewhere before the power amplifier, it's going to make the sound warmer. You will loose the 10 Meg Ohms input impedance provided by the Noble, but the Phil Jones Superflignt Case, is 4 Meg Ohms. I don't think it matters what the impedance is, as long as it's above

4-5 Meg Ohms. When I move the Headway EDB-2 up to 20 Meg Ohms from 5 Meg Ohms, there is a difference, but it's not as pronounced as moving it from 1 Meg Ohm to 5 Meg Ohms. Just my take.

 

[Chris Fitzgerald]

@Ric Vice Sorry, I forgot to mention that I had the Keeley set to where it wasn't compressing anything 95% of the time. I used it as a limiter only for the odd slammed low note, and to bring the pickup signal of the travel bass up a bit before it got to the Noble. Honestly, I couldn't hear any difference WRT input impedance. But the bit you posted about it not making a difference where int he chain the tubes are is what I find interesting. That could potentially be useful when I travel.

 

[Kristian]

"And the big secret I've discovered with piezo's and tubes is that by the sheer nature of a tube's inherently very-high impedance, a tube can very smoothly and naturally track the wildly fluctuating output impedances from a piezo. When a piezo sees a solid state device, they seem hard, harsh, barky, and crispy-distorted. Then so many people try to EQ those problems away. Midrange parametric surgery, high end darkening, etc. But when a piezo sees a tube grid, there's an amazing dance there, they just get along so well. The response from the pickujp becomes MUCH more smooth and normal, natural sounding, more like a good microphone than a pickup"

The Sarno Black Box does indeed do this, but that's what it's designed to do, as a Input Impedance Buffer/Preamp with a Variable load you can adjust. Tube Preamps do sound very good, as an example I have a Ampeg B-15N(C) that sounds very nice, but
it doesn't do, what the Sarno does, as all of it's inputs are set at different fixed impedances. Channel 1 Input 1, at 5.6 Megohms, Channel 1 Input 2, at 1 Meg Ohm, and Channel 2 at

.

I can choose between 1 or 10 meg ohm on my Paradox and the higher meg ohm makes the lower notes sound more organic and "mic like" but the the highs are still very rough and metallic (I'm using the wilson k1). I would love to try a tube preamp and see what that does to my sound, especially the higher frequencies and also with the bow.

 

[Ric Vice]

Well,
You realize I'm just making this up as I go along, from bits and pieces I've learned from you and others, along the way here on Talkbass. I have a kind of rolodex of info I can draw on in my head.
So far it's still working. I just remembered that Piro (Flatback) made the comment in the Sarno BB thread, that it didn't seem to matter, if he plugged that device into the front end of the Grace Felix or
inserted it into the effects chain, as he still got the improvment in tone, regardless of where he plugged it in. Years ago, Robgrow, explained to me that effects loops are generally placed, after the EQ section of the
Pre Amp, but still in one of it's stages, not between the Pre Amp and Power Amp sections. Just my take. My favorite tube device is the Pultec EQ that was used by the Beatles and others. It's simple but it works magic.

 

[Ric Vice]

I can choose between 1 or 10 meg ohm on my Paradox and the higher meg ohm makes the lower notes sound more organic and "mic like" but the the highs are still very rough and metallic (I'm using the wilson k1). I would love to try a tube preamp and see what that does to my sound, especially the higher frequencies and also with the bow.

From using the it on a few gigs, it's gets more sound out of a piezo pickup then I've ever experienced, it improves low end, midrange and treble. Notes sound more natural, and the timbre of each note improves.

 

[DoubleMIDI]

Two things coming to my mind:
1. Electronic distortion of a periodic wave (we can discuss how much deviation a signal from an instrument has from a periodic wave) has exactly harmonic partials, the partials of an instrument vibration are not exactly periodic. So they may beat and higher partials may even sound harsh ecause of that.
2. The speaker is the worst part of sound wave reproduction. Some kind of small signal distortion (maybe like with tubes) might let it sound better (but that does not come closer to the original signal, just sound better to our ears).

But since any instrument sounds unnatural when amplified above natural listeners sound pressure levels, any amplification above the natural volume level sounds unnatural. That is a problem without FOH support because the listeners reach a lower sound pressure level than the player (other musicians in between).

I just thought we should keep that also in mind when discussing amplification.

 

[flatback]

At first I really liked having the BB>V8 then I realized that it didn't make so much difference by just going straight into the V8, but with this new very bright MAS18 my ears tellme that it does make some kind of difference and I have put it back. The last few gigs have been really nice. I can accidentally tweak it wrong and get it sounding very zingy and 70's DI, or have the exact opposite so that it sounds pretty much like a large diaphragm mic in an isolation booth.
It is a little weird with this new cab, I have to really find new eq points on the V8, the cab is voiced with so much mid forward. But man the tubes are just so nice

 

[Ric Vice]

Piro,
Are you using the Vari Z on both the V8 and The Sarno Black Box? Sorry, I'm confused.

 

[Ric Vice]

Two things coming to my mind:
1. Electronic distortion of a periodic wave (we can discuss how much deviation a signal from an instrument has from a periodic wave) has exactly harmonic partials, the partials of an instrument vibration are not exactly periodic. So they may beat and higher partials may even sound harsh ecause of that.
2. The speaker is the worst part of sound wave reproduction. Some kind of small signal distortion (maybe like with tubes) might let it sound better (but that does not come closer to the original signal, just sound better to our ears).

But since any instrument sounds unnatural when amplified above natural listeners sound pressure levels, any amplification above the natural volume level sounds unnatural. That is a problem without FOH support because the listeners reach a lower sound pressure level than the player (other musicians in between).

I just thought we should keep that also in mind when discussing amplification.

While I respect the technical information you've provided and realize how important it is. We all deal with the daily reality, that no piezo pickup, can reproduce the acoustical properties of a fine Double Bass, or even a average Double Bass, for that matter. It's been the contention (whether true or not) that tubes tend to emphasize even order harmonics, and I assume that's why tube based condenser microphones, (high end tube stereo systems as well) are valued in high end recording studios. I've had the Sarno BB long enough now to hear it in action and it improves timbre especially midrange timbre, that's what I'm looking for in a buffer preamp. Other buffer preamps do a great job of improving bass response, but they don't as a rule, IME, improve the midrange. Just my take.

 

[Keithunem]

At first I really liked having the BB>V8 then I realized that it didn't make so much difference by just going straight into the V8, but with this new very bright MAS18 my ears tellme that it does make some kind of difference and I have put it back. The last few gigs have been really nice. I can accidentally tweak it wrong and get it sounding very zingy and 70's DI, or have the exact opposite so that it sounds pretty much like a large diaphragm mic in an isolation booth.
It is a little weird with this new cab, I have to really find new eq points on the V8, the cab is voiced with so much mid forward. But man the tubes are just so nice

Piro, Does your MAS 18 have the Eminence driver that Mike has used for a couple years or is it the newest version which may be a little more mid-forward? Either way, sometimes I get so used to setting up and eq'ing my different signal chains that when I try a different cab for example it throws me off a bit. I've got so many different combinations now at my disposal that it's driving me crazy! Time for me to simplify... on the other hand, past experience tells me that you will get this 18 dialed in soon enough. When I get a certain combo dialed in, I snap a photo for that combo. When I use it in another room I just make minor adjustments as I go along with HPF, etc...

 

[Ric Vice]

Piro, Does your MAS 18 have the Eminence driver that Mike has used for a couple years or is it the newest version which may be a little more mid forward...............When I get a certain combo dialed in, I snap a photo for that combo. When I use it in another room I just make minor adjustments as I go along with HPF, etc...

Keith,
Mike has not changed the Eminence 8" drivers out, what he changed was the tweeter which was originally, I believe a super tweeter. The new cabinet has a different tweeter. The low end is more focused and clear, while the midrange is forward by comparison. When the Eminence speakers are no longer affordable Mike will likely switch over to Ciare, but that's something only he can decide when the time comes. Pictures to come.

 

[DoubleMIDI]

. It's been the contention (whether true or not) that tubes tend to emphasize even order harmonics, and I assume that's why tube based condenser microphones, (high end tube stereo systems as well) are valued in high end recording studios.

As far as I know the even order harmonics are generated mainly outside of the linear range (overdrive/distorted signal). But I'm sure that neither tubes nor solid state parts are exactly linear in the "linear" range and may differ in their non-linearity. That may explain why one sounds better to our ears than the other. But recordings of acoustic music (classical) can sound better than real ode experience. So they might be more pleasant to our ear but are not very close to a real world live experience.

Nothing wrong with a more pleasant sound than acoustic reality, but it is a kind of distortion of the original signal (which by itself is not the sound listeners of acoustic performances because listeners typically do not listen close to the bass top).

So the key is keeping the character of the instrument and make it as pleasant and functional as possible. Almost every part in the amplifying chain (including relative position of sound source and transducer) changes the signal in some way, some less, some more.

BTW, enhancing even order partials is mostly equivalent to adding a bit of the higher octave to the existing sound. So higher order (above 5) prime partials are enhanced an octave higher than with even and odd partial distortion which makes the sound clearer and mighty.

 

[Keithunem]

Keith,
Mike has not changed the Eminence 8" drivers out, what he changed was the tweeter which was originally, I believe a super tweeter. The new cabinet has a different tweeter. The low end is more focused and clear, while the midrange is forward by comparison. When the Eminence speakers are no longer affordable Mike will likely switch over to Ciare, but that's something only he can decide when the time comes. Pictures to come.

View attachment 3649149
View attachment 3649150
View attachment 3649152

With the top picture and the two side by side, why is the bottom port so much bigger on the right speaker?

 

[flatback]

Rick when using both the V8 and BB only the first VariZ is the tube buffer. When I asked Brad if I should run them together (I was trying to determine if there was any advantage) he said the BB>V8 was essentially the guts of the Revelation preamp which has the BB front end going into the Octal preamp. I still haven't gotten used to the honky mids on the MAS18. I found I had the eq on the V8 with the treble all the way up and the bass knob at 12 the other day after the first set. I think I read that the higher you have the treble the lower the mid boost is in the eq. By turning up the treble and boosting the lower mids (or lower mids then having the treble turned down) it mitigates a lot of that ugly mid tone. With my MAS46 flat sounds that way.

 

[Keithunem]

Rick when using both the V8 and BB only the first VariZ is the tube buffer. When I asked Brad if I should run them together (I was trying to determine if there was any advantage) he said the BB>V8 was essentially the guts of the Revelation preamp which has the BB front end going into the Octal preamp. I still haven't gotten used to the honky mids on the MAS18. I found I had the eq on the V8 with the treble all the way up and the bass knob at 12 the other day after the first set. I think I read that the higher you have the treble the lower the mid boost is in the eq. By turning up the treble and boosting the lower mids (or lower mids then having the treble turned down) it mitigates a lot of that ugly mid tone. With my MAS46 flat sounds that way.

I could very well be wrong but I think the description you just gave on how the treble up or down affects the midrange scoop or boost relates to the tone stack on the Noble, not the V8.... once again, I could be way off...?!

 

[Povl Carstensen]

As far as I know the even order harmonics are generated mainly outside of the linear range (overdrive/distorted signal). But I'm sure that neither tubes nor solid state parts are exactly linear in the "linear" range and may differ in their non-linearity. That may explain why one sounds better to our ears than the other. But recordings of acoustic music (classical) can sound better than real ode experience. So they might be more pleasant to our ear but are not very close to a real world live experience.

Nothing wrong with a more pleasant sound than acoustic reality, but it is a kind of distortion of the original signal (which by itself is not the sound listeners of acoustic performances because listeners typically do not listen close to the bass top).

So the key is keeping the character of the instrument and make it as pleasant and functional as possible. Almost every part in the amplifying chain (including relative position of sound source and transducer) changes the signal in some way, some less, some more.

BTW, enhancing even order partials is mostly equivalent to adding a bit of the higher octave to the existing sound. So higher order (above 5) prime partials are enhanced an octave higher than with even and odd partial distortion which makes the sound clearer and mighty.

Also, with tubes there might be a slight compression at play, that brings the sound forward, in a pleasant way.

 

[Ric Vice]

With the top picture and the two side by side, why is the bottom port so much bigger on the right speaker?

It is somewhat bigger, Mike added a vented 1" high compartment to the bottom of the box to accommodate all the power amp and high pass filter circuitry. So it changed the look of cabinet.

 

[flatback]

Yeah I think it is the same kind of eq circuit as on the Noble with a variable mid boost that travels up and down depending on where the treble is set. It seems to me that when the treble is set all the way up there is a mid boost below the ugly frequencies (700-800) that kind of balances them out. My experience so far is that when I listen back to recordings of my gigs what sounds like whiny upper mids in my ear playing becomes a clear woodiness in the recording but it is more forward then I like and feels hard to tame. First world bass problems. Just ordered a set of perpetuals so I am wondering if the strings will tame the whine a little.

 

[Ric Vice]

I still haven't gotten used to the honky mids on the MAS18. I found I had the eq on the V8 with the treble all the way up and the bass knob at 12 the other day after the first set. I think I read that the higher you have the treble the lower the mid boost is in the eq. By turning up the treble and boosting the lower mids (or lower mids then having the treble turned down) it mitigates a lot of that ugly mid tone. With my MAS46 flat sounds that way.

Piro,
Well, I'm just not having that issue so far, since we use different pickups that's probably the biggest difference between our setups. I'm think taking my MAS 4x5.5 out tonight because it's a EB rock gig for the olde New Year's Eve
but I might change over my thinking and go with the new 1/8. Probably not thought, as I don't have a cover for the cabinet yet and since I'm playing EB it wouldn't tell me much about the midrange anyway.