Is "BLOOM" a sustainy, harmonicy, type of thing?

[tictac]

I've heard people talk about bloom every now and then but I'm not sure exactly what it is. Seems to apply more toward distorted tones but can you get Bloom from a clean amp too?

Reason I'm asking is I just rewired my stereo non-reverb SSS style amp from cap coupled ala Fender Twin to direct coupled cathode followers.

Things are diffrent now. For one thing I used to have to have the high filter all the way up. Now it's set two notches down. the amp doesn't sound more "brittle" just like more frequencies are getting through to the speakers.

The amp seems to have more sustain; when I strum an E chord it just stays there hanging in the air so to speak; you can hear a high harmonic B note coming thru a second of two after you hit the chord and hold it. Happens on a Cmaj7 too.

One of the posts talking about direct coupling used the phrase "acoustic guitar like". I kinda get that statement now; I haven't played in about two weeks and my out-of-shapeness is painfully revealed with this amp now. Have plugged any pedals in yet but can't wait to hook up the Eventide Timefactor...

I was just wondering if this phenomena is the "bloom" everyone talks about or something else.... Sorry if this is "Floating on a football field of marshmallows" type talk but it was a new experience for me and I thought it was cool...


TT

[LeftyStrat]

Sounds like bloom to me. Another way to describe it is that whatever note or chord you play and sustain seems to 'evolve' over time, either with different harmonics in a single note, or different notes in a chord becoming prominent.

Lack of bloom pretty much means it's downhill after you hit it. Some people might use terms like 'swell', 'swirl', or 'animated,' but I like 'bloom' because:

"Every note you play is like a delicate flower slowly unfolding before you."

[vibratoking]

There have been quite a few discussions regarding bloom and note flipping and feedback. There is no consensus about what these terms mean and it makes for a difficult discussion because of the lack of definition. In my mind, bloom and feedback are not the same thing. I don't know what the heck note flipping is. Here is a link to a rather long discussion that had no resolution AFAIK.

https://tubeamparchive.com/viewtopic.ph ... ight=bloom

[Max]

One of the posts talking about direct coupling used the phrase "acoustic guitar like". I kinda get that statement now.

I don't get that kind of generalizing statement - at least not in regard to the differences between original Dumble amps with a direct coupled driver tube and a cap coupled driver tube:

I often played original Dumble amps with direct coupled driver tubes and I often played original Dumble amps with cap coupled driver tubes. And out of curiosity sometimes I played with the same Dumble preamp in combination with different Dumble power amps with different versions of coupling.

And at least in my personal perception I couldn't notice some general difference in regard to sustain, blooming, or "acoustic guitar like" etc. The individual differences between different direct coupled specimens have IMO often been more obvious than the differences between some cap coupled specimen and some direct coupled specimen - at least in my personal perception.

Some examples:

In regard to "acoustic guitar like" IMO some of the cap coupled Dumble amps I played might even be closer to the "natural" character of a Martin etc. kind of acoustic guitar.

In my personal perception some of the early direct coupled SSSs with 8, 7, or 6 twin triodes did sound more different in comparison to some of the later direct coupled SSSs with 5 twin triodes than some cap coupled Dumble amps in comparison with some direct coupled Dumble amps.

As you'll know some of the Dumble amps with filters have an internal trim pot to adjust the gain and Q of the filter stage. And in my personal perception different adjustments of this trim pot did sometimes result in larger differences in regard to the overall feel, timbre, sustain etc. than the perceivable differences in regard to timbre and feel etc. between some direct coupled specimen and some cap coupled specimen of Dumble amp.

And AFAIR Eric Johnson e.g. at least sometimes - or perhaps even often - preferred the tone of his cap coupled Dumble Odyssey Concert power amp in combination with his Dumble Manzamp and SSS preamps.

So what you write will IMO of course be fact in regard to your personal perception of your individual specimen of a SSS kind of amp - but I've strong doubts that such kind of generalization (direct coupling = acoustic guitar like) is correct.

Cheers,

Max

[tictac]

whatever note or chord you play and sustain seems to 'evolve' over time, either with different harmonics in a single note, or different notes in a chord becoming prominent.

Thats what going on, so I guess I've finally experienced "BLOOM" I like it!

So what you write will IMO of course be fact in regard to your personal perception of your individual specimen of a SSS kind of amp - but I've strong doubts that such kind of generalization (direct coupling = acoustic guitar like) is correct.

Well, I didn't originate the "acoustic guitar" thing anyways... somebody else said it. I think what they were trying to say and what I'm trying to say is.... hey there sure is a bunch of overtones and harmonics and stuff goin on there that I didn't hear before... hmmm... how can I describe it? Like an acoustic guitar? yeah, kinda... sorta... (Sure it's not a pre WWII Martin D-28)

I was plugged into a pair of EVM-12's in De-Tuned Cab's; wonder what it'll sound like plugged into the JBL D-130 cabs freshly reconed from Weber? Gotta break those things in somehows... (Maybe a Taylor Leo Kottke?)

TT

[Max]

what I'm trying to say is.... hey there sure is a bunch of overtones and harmonics and stuff goin on there that I didn't hear before...

This will for sure be the case in regard to your individual perception of your individual amp.

But in my personal perception of original Dumble amps with cap coupled (see e.g. Aaron's Odyssey Concert layout) and direct coupled (see e.g. Aaron's SSS #001 and SSS#002 layouts) driver tubes I never noticed an obvious general correlaton like "direct coupled driver = more overtones and harmonics" vs. "cap coupled driver = less overtones and harmonics".

But please don't take me wrong now: I don't cast doubt on your personal perception of your individal amp. I cast doubt only on such a kind of generalization - at least in regard to all the original Dumble amps with an inverter / driver configuration I am familiar with (around 10 AFAIR right now).

Cheers,

Max

[dobbhill]

Tictac:
Could you divulge a bit more about your circuit changes, please? I'm curious about what tubes you used, and how you biased them to direct couple them. Also, stereo 100wpc? Speakers you are using for this amp arrangement? How loud are you playing?
So many variables....Especially speakers!!

Enjoy the journey,
D

[tictac]

I'm using Svetlana 6550's bias @ 44mA per tube which is about 60% plate dissapation; I have individual bias adjustment for each tube which you can see below. I'm using EVM-12L speakers, not playing terribly loud but enough to get the full effect of the amp + speakers...

TT

[vibratoking]

Thats what going on, so I guess I've finally experienced "BLOOM" I like it!

I am confused. You ask what bloom is in the title of your post. I haven't seen any answers to your specific question and now you have finally experienced it? From what you have described I can't be sure what your definition is. Maybe you can define it? Until the definition problem is resolved, I don't see how you can apply the word bloom to what you have heard from your amp.

[tictac]

vibratoking said...

I haven't seen any answers to your specific question...

LeftyStrat said what I described sounded like bloom to him, and then added to the description...

Sounds like bloom to me. Another way to describe it is that whatever note or chord you play and sustain seems to 'evolve' over time, either with different harmonics in a single note, or different notes in a chord becoming prominent.

I thought that what he said was a specific answer to my question so I'm not sure why you are confused... Maybe you didn't see his reply?

TT

[vibratoking]

With all due respect to you and Lefty, I don't think there is an agreed upon definition that has been put forth by this forum. I did read Lefty's post. Did you read the full thread that I posted? I am guessing no based on your response.

Your description sounds more like feedback to me, but I can't be sure since you haven't told us anything about volume, proximity to the speaker, etc... If you read the thread I posted fully, you will see that some members believe that bloom happens with almost no volume and some even state it happens on some electric guitars that are not even plugged in. So my question remains, what is the defintion of bloom that we should use for the purpose of describing the characteristics of your amp? BTW, I don't think the defintion can be done with words. I feel it has to be done with clips and then a term can be applied to the characteristic of such clips. These clips could be made a sticky for reference purposes. If I remember correctly, there was a clip posted that supposedely contained note flipping - somewhere in the middle of the clip. IMO, it was nearly impossible to tell with any certainty which moment contained the flipping. I think the clips have to contain one note that has the intended characteristic. There should be separate clips that contain succinct examples of uncontrolled feedback, controlled feedback, and blooming, at least. Perhaps another for note flipping or any other characteristic if it is actually different from one of the others. Unfortunately, nothing less will suffice, IMO.

Sorry if I seem overly demanding or strict, but this is a subject that has been discussed many times with no resolution. Further discussion without defining what we are talking about is fruitless, IMO.

[Max]

...I just rewired my stereo non-reverb SSS style amp from cap coupled ala Fender Twin to direct coupled cathode followers.

AFAIU the schematic you posted it shows the cathodes of the driver tube direct coupled to the power tubes. So I assume this being the configuration after the changes you made? Is this correct? If so: What in detail was the driver tube > power tube coupling configuration before these changes?

Cheers,

Max

[tictac]

12BH7 driver, 1k/33k cathode network, .22uF coupling cap, 1k5 grid resistor. 100k bias feed resistors....

[Max]

12BH7 driver, 1k/33k cathode network, .22uF coupling cap, 1k5 grid resistor. 100k bias feed resistors....

So do I understand this right, that your first coupling version was similar in its general structure (but not in detail) to the kind of coupling version shown in the attched schematic?

Cheers,

Max

[LeftyStrat]

I just had an interesting thought about this. As pointed out in Merlin's preamp book, cathode followers can introduce compression to half the waveform, which would introduce even harmonics. In this particular amp, since you don't have the reverb circuit, prior to the change there were no cathode followers in the signal path.

In the SSS with reverb, Dumble uses cathode followers for the reverb mixer. So perhaps this could be the deciding factor in choosing between the post pi driver types?