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Just now, deepthought said:

Oh, OK. So it's a bit higher! But the 7V might still be a tad lower in gain than a 6V??

I'll leave that for someone who knows about tubes. I don't recall noticing, but I wasn't looking for a gain difference

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Many Many moons ago....    

I had the system absolutely cranking last night for the first time in forever and was blown away at how effortlessly it was driving those big old Sov's. Sound wise it was excellent too with the overal

I believe the vast majority of buyers simply aren't aware of how hard they are to drive, and they can just get away with it because they always have. It makes for really good measurements and numbers

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9 minutes ago, deepthought said:

Bingo 

 

 

2.9ohms. Ouch.

Yeah minimum impedance is known but does it have a nasty phase angle at 50hz further complicating things? There is an impedance graph in that publication but phase is not on the graph. That's what is unknown. I should ask Nigel if I can use his DATs and do a quick measurement.

 

Edit: Looking at that graph the lowest impedance is in the 50-100hz range.

Edited by kelossus
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Just now, sakabatou said:

I'll leave that for someone who knows about tubes. I don't recall noticing, but I wasn't looking for a gain difference

I admit I wasn't listening for gain either. I was just floored by how good the Telefunken diamond 7DJ8's sounded when I put them in.......

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Just now, kelossus said:

Yeah minimum impedance is known but does it have a nasty phase angle at 50hz further complicating things? That's what is unknown.

I must be half asleep. Of course you've seen that data, you contributed to the thread. ?

DATs also gives you a phase angle sweep. If I wasn't working from home, and we weren't on lockdown I'd give you the loan of mine.

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Piss the cover off and insert some tall bottle E80CC's in there with a mu of 27. You'll never go back to the 12AU7 with a mu of 19. ?

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2 minutes ago, deepthought said:

Are you here to help Chris or just prove me wrong? 

Certainly here to help , the thread is asking about "How can I run out of gain"  To understand gain one needs to know about consumer line level, as that is what is output from a CD player in every day use. It is a nominal figure of  0.310mv RMS ... which plainly is not 2V . 

 

 

Power amplifiers are always servants to their input signal. They are tested and measured with a set usually RMS input level - to deliver a wattage into a resistive load, and have ability during that test to drive a speaker cable - but rarely is a actual speaker used.  

 

So discussing gain with audio systems, knowing what our consumer equipment has on its output, with every day media playing -  is really  important.  

 

Bandied around in many forums is a gross misunderstanding that what CD players or DAC's are tested with, exampled by the Stereophile  Audio Precision audio analyzer,  has relationship to what consumers then  experience with commercial CD's ... this is  Quite wrong ... but  there is an entire forum dedicated to convincing you that what is measured by analyzers,  is output from every day devices, and those measurements correlate to music reproduction ... it is just not true.

 

Certainly you can obtain a test CD  using sine waves or the like that might have those levels, but that is a test CD ... not what you use 99.9999% of the rest of the time ( depending on how big your CD collection is ) 

 

The scenario of running out of gain cannot occur at all .... full stop where your power amps sensitivity,  matches well to consumer line level,  and is if that is not good enough, is by far IMO the best scenario for proper music.  reproduction.

 

 

 

 

 

 

 

 

 

 

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2.9Ohm is “ouch” but not outside the range of a 20A output.

 

it might just be worth putting the balanced cables between pre and power amps and trying the turntable again.

 

I hadn’t considered the possibility that a tube change may have reduced gain.
 

I still suspect the power amp but the evidence for another cause is mounting...

Edited by Eggcup the Dafter
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11 hours ago, kelossus said:

Outside of anecdotal accounts of the speakers being hard to drive there is no measurements to substantiate any claim

 

Nominal Impedance
Variance
4 ohms
3.0-4.5

 

and 87dB per w/m

 

ie. Very easy load.   You need an amplifier which won't misbehave at a low impedance.....  but large well-engineered solid state amplifiers like your should show no problems there.

 

Edited by davewantsmoore
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10 hours ago, kelossus said:

Yeah minimum impedance is known but does it have a nasty phase angle at 50hz further complicating things? There is an impedance graph in that publication but phase is not on the graph.

 

The phase can be inferred from the magnitude (the change of the magnitude)

 

10 hours ago, kelossus said:

that publication

 

OK, I hadn't seen that before posting above.

 

That is a remakably flat imedance curve.... they have obviously left out the lowest resonance in their 3.5-4.5 (or whaetever) range.... which is fair enough.

 

This speaker is about as "easy" load as it gets for such a speaker (ie. there's very little out of phase current and voltage, and "wasted" power)

 

 

48 minutes ago, Eggcup the Dafter said:

2.9Ohm is “ouch” but not outside the range of a 20A output.

 

It's hard to say.... it depends totally on how loud he's listening as to whether the current is "clipping".

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10 hours ago, deepthought said:

DATs also gives you a phase angle sweep.

The electrical impedance is a minimum phase system..... so the phase of the imedpance can be inferred from the magnitude.

 

Where the impedance changes, the phase angle deviates from zero.

 

The impedance doesn't change a lot.... so the phase angle is quite flat  (relatively, to most other speakers, that is)

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10 hours ago, stereo coffee said:

output from a CD player in every day use. It is a nominal figure of  0.310mv RMS ... which plainly is not 2V

????

 

All of my CD players over the years have been said to output 2v or thereabouts single-ended.  With no amount of mathematics can I turn 310mv into 2v.  Isn't the relationship between peak v and RMS v about 0.7 (or 1/0.7 = 1.4)?   What am I missing?

 

[~300mv was the number used for tape-in, tape-out, tuner and aux amp inputs on amps in the olden days]

[Sorry, a bit OT but has been raised already]

 

 

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53 minutes ago, Jack Goff said:

Paper values on ohms and watts do not apply.

?

Yes.... they do (assuming what is written on paper, is actually correct).

 

That doesn't mean people for some reason don't like to drive them with a powerful amplifier ..... but this doesn't mean that the laws of physics don't apply.

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14 minutes ago, aechmea said:

????

 

It's confusing  :) 

 

Hint:  In this calculator:  http://www.sengpielaudio.com/calculator-db-volt.htm

 

 

To find "consumer level"  

Enter -10 in "Level Lv" click calcuate, Answer = 0.316V RMS

 

To find unloaded peak level.   Enter 0 in "Level Lu" click calculate.

Answer=  -2.218487499 dBV

 

Enter -2.218487499 in "Level Lv" click calculate

Answer = 2.2V P-P

 

 

... at the end of the day, it is not so important..... as long as we have appropriate gain structure in the system  (which is what Stereo Coffee is essentially going on about).

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5 minutes ago, Jack Goff said:


The part you left out. 
You have to have lived with the speakers. What seems like good matches on paper (the written specs of the Sovereigns) don’t seem to translate when amp matching. 

 

Cool... so there's a different reason for that, in addition to the electrical load (which is easy).

 

5 minutes ago, Jack Goff said:

It’s a shame people like @kab and others with actual experience of these speakers left the forum because of know it all’s with no actual experience with the said equipment. 

 

I'm not saying he, or you, or anyone else is "wrong" about what you expereinced ......  except in where you say "the ohms and watts don't apply".....  They do apply.... there's just a different reason for what you have expereinced.

 

 

Here's an analogy:

 

I had 3 cups of coffee and went for a run this morning.   I got my best time, and I felt like my feet were hardly touching the ground.   It's becasue the laws of gravity don't apply to me like it does to everyone else.

 

Nonesense, right?!

 

As far as electrical impedance goes, and electrical-accoustic efficiency goes..... these speakers are a relatively benign load.

 

 

That being said..... these speaker have high power handling, and can play loud levels with low distortion (won't sound "loud") .... so people are probably choosing to put a substantial amount of power through them.....  but again, that doesn't mean that the electical specs don't tell you what you need to know.

 

You would need a solidly engineered 100w or more (coindidentally exactly what is says on the spec sheet).   It's easy to find 100w which is not well engineered.... so sometimes (often) than can be sidestepped by moving to an amp which is much larger  (as if it makes it to ~500w, then the first couple hundred watts are quite well behaved - or similar).

 

 

Back to the topic at hand.  The PassLabs amp in question is well engineered.   I'd be looking elsewhere than at it in general.

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Is it not  amazing in the year 2021 where we know so much, that we are now on 3 pages of comments where nobody has really provided an answer - warning - sarcastic comment.

 

I think we have here a case of what a lot of us have been saying: that is everything in a system matters. There are just so many variables that nothingon paper / in theory could be believed untill put in practice.

 

I unfortunately do not have the answer, but maybe the answer is:

  • listening to @Jack Goff
  • contacting Simon at VAF as he worked for Duntech and may just be able to sell/source you the right amp and or advise re pre or both
  • contact Kiat that also worked at Duntech and are now selling a new Duntech range
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12 minutes ago, Jventer said:

nobody has really provided an answer

 

Actually they have,  but as usual, it has been lost in the noise.

 

How did a question about gain turn into recommendations for arc welders (warning sarcasm)?

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In the previous thread from 2014 about Duntechs (which I have just read) it turns out that according to comments--by those who know--that an ME 1500 amp's driving ability was very satisfactory where an ME850 amp 'struggled' to drive these speakers adequately!

 

I cannot get my head around this--I have a high opinion of the driving ability of ME amps. If only a notional 100W is required according to the specs and written parameters of the speakers, and it seems that it is not too hard to drive (in theory),  then in the real world both amps 'should' be OK. As should the Pass amp and a host of other high-current contenders. 

 

Obviously that is not correct. Why, I remain uncertain. Considering my lack of technical knowledge anything could be responsible; I can see from all the comments here that something is preventing correct system synergy. And that certain high-current amps can drive the speakers adequately and others can't.

 

Here must be where theory gives way to practice--and reality?

 

 

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42 minutes ago, doogie44 said:

Obviously that is not correct. Why, I remain uncertain. Considering my lack of technical knowledge anything could be responsible; I can see from all the comments here that something is preventing correct system synergy. And that certain high-current amps can drive the speakers adequately and others can't.

 

Here must be where theory gives way to practice--and reality?

The combination of low impedance AND large phase angles means you're effectively driving insanely low impedances. The only way to get an idea of how low is to calculate the EDPR (equivalent peak dissipation resistance). Stereophile is the only review site that has begun doing so and to get an idea of how bad the situation really is, here is a review of the latest Wilson offering (which are notorious for being hard to drive).

https://www.stereophile.com/content/wilson-audio-specialties-sabrinax-loudspeaker-measurements

A good summary here is the following comment: "The SabrinaX has an EPDR of less than 2 ohms between 65Hz and 275Hz, with a minimum value of 1.1 ohms at 90Hz, where music can have high energy. "

These are meant to be 4 ohm speakers, but now you're talking about an amplifier that actually needs to be able to meaningfully drive and scale proportionately for 1 ohm. That's an insane load.

If you want a deep dive into understanding EDPR, here is the original article: https://www.stereophile.com/reference/707heavy/index.html

Edited by Ittaku
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51 minutes ago, aussievintage said:

 

Actually they have,  but as usual, it has been lost in the noise.

 

How did a question about gain turn into recommendations for arc welders (warning sarcasm)?

 

Hi @aussievintage 

Sorry I missed it. As in I have missed the answer.

(And this is not a sarcastic post, but an effort to understand)

Could you please  quote or post the answer.

Please and much appreciated.

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2 minutes ago, Ittaku said:

The combination of low impedance AND large phase angles means you're effectively driving insanely low impedances. The only way to get an idea of how low is to calculate the EDPR (equivalent peak dissipation resistance). Stereophile is the only review site that has begun doing so and to get an idea of how bad the situation really is, here is a review of the latest Wilson offering (which are notorious for being hard to drive).

https://www.stereophile.com/content/wilson-audio-specialties-sabrinax-loudspeaker-measurements

A good summary here is the following comment: "The SabrinaX has an EPDR of less than 2 ohms between 65Hz and 275Hz, with a minimum value of 1.1 ohms at 90Hz, where music can have high energy. "

These are meant to be 4 ohm speakers, but now you're talking about an amplifier that actually needs to be able to meaningfully drive and scale proportionately for 1 ohm. That's an insane load.

If you want a deep dive into understanding EDPR, here is the original article: https://www.stereophile.com/reference/707heavy/index.html

@davewantsmoore has already pointed out that we don't have any large phase angles here, assuming the given measurements are correct for this sample. Those specs surprised me given what I've heard about the Sovereigns.

The supersymmetry design in the Pass Lab amp is referred to elsewhere as a "special subset of bridging". I can't really tell if that is true or relevant but it's worth mentioning for those who can, I guess.

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9 minutes ago, Ittaku said:

A good summary here is the following comment: "The SabrinaX has an EPDR of less than 2 ohms between 65Hz and 275Hz, with a minimum value of 1.1 ohms at 90Hz, where music can have high energy. "

These are meant to be 4 ohm speakers, but now you're talking about an amplifier that actually needs to be able to meaningfully drive and scale proportionately for 1 ohm. That's an insane load.

 

I wonder what the upside is.  I mean, why make a speaker, heck, why BUY a speaker, that is so hard to drive.  

 

1 minute ago, Jventer said:

 

Hi @aussievintage 

Sorry I missed it. As in I have missed the answer.

(And this is not a sarcastic post, but an effort to understand)

Could you please  quote or post the answer.

Please and much appreciated.

 

I believe @stereo coffee and @davewantsmoore have provided the correct approach to understanding the question posed by this thread.

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On 28/03/2021 at 4:40 PM, kelossus said:

In terms of impedance? Nominal Impedance Variance, 4 ohms 3.0-4.5.

 

Haven't seen a graph showing phase angles or anything to determine how hungry they are but those old Dynaudio woofers need a heap of current to get them going. The magnet is so undersized so I think they really on current to make anything happen. Seriously I am drinking a cup of coffee and it's substantially heavier than the magnetic assembly on the 12" Dyn.

Don't let those aluminium voice coils fool you.  They weight much less than copper but can handle more power/heat.

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15 minutes ago, Eggcup the Dafter said:

The supersymmetry design in the Pass Lab amp is referred to elsewhere as a "special subset of bridging". I can't really tell if that is true or relevant but it's worth mentioning for those who can, I guess.

This is very interesting, as regular bridging of an amplifier makes it less able to cope with impedances as it effectively doubles the minimum impedance.

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16 minutes ago, aussievintage said:

I wonder what the upside is.  I mean, why make a speaker, heck, why BUY a speaker, that is so hard to drive. 

I believe the vast majority of buyers simply aren't aware of how hard they are to drive, and they can just get away with it because they always have. It makes for really good measurements and numbers but has done so at huge compromise in other ways that till now haven't shown up in numbers anywhere. There's also a kind of arse-backwards appeal to something that needs expensive and ballsy amplifiers.

Edited by Ittaku
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2 hours ago, Jventer said:

Is it not  amazing

 

Sure....  but there's not really enough known about the problem to say for sure what is going on.

 

The system has lower than typical gain, yes.... but it's not clear enough if simply lack of max level is the issue...or bad sound when it is reached.... or what that max level is.

 

2 hours ago, Jventer said:

 

As much as he protests otherwise.... I don't see that anybody isn't listening to him.     Yes, it could very well be that the amplifier isn't big enough.....   but there isn't enough information to tell.

 

He and others report that they like driving the speakers with big amplifiers.... great - I don't doubt them......  but the reason isn't that this is a challenging electrical load.

 

... but again, that doesn't mean he's not wrong about the amp (size).  The speaker will take a lot of power without sounding bad..... and the poster might be asking too much.......  (that being said, based on the description I suspect it is something else.... but it's hard to be sure because not enough info is provided).

 

 

2 hours ago, Jventer said:
  • contacting Simon at VAF as he worked for Duntech and may just be able to sell/source you the right amp and or advise re pre or both
  • contact Kiat that also worked at Duntech and are now selling a new Duntech range

 

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1 hour ago, Ittaku said:

This is very interesting, as regular bridging of an amplifier makes it less able to cope with impedances as it effectively doubles the minimum impedance.

True, but would the minimum impedance in this case come up as high as 2.9 Ohms? I suppose it's possible, it doesn't seem likely.

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2 hours ago, aussievintage said:

How did a question about gain turn into recommendations for arc welders (warning sarcasm)?

 

People recommend large amps and/or that the Pass might not be up to it..... and while they might not be wrong ..... the (technical) reasons behind their recommendations were misguided.

 

.... and so it digressed into how would you actually figure out if it were the power amplifier clipping.... or what logic would you use to recommended a "massive amp", etc.

 

When peoples experience contradicts basic physics which has been settled for ages longer than anybody here has been alive .....  it isn't because the "physics doesn't apply".    It just means that there's another/different reason (which doesn't contradict basic physics).   :) 

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2 hours ago, doogie44 said:

In the previous thread from 2014 about Duntechs (which I have just read) it turns out that according to comments--by those who know--that an ME 1500 amp's driving ability was very satisfactory where an ME850 amp 'struggled' to drive these speakers adequately!

 

To what level.  That absolutely could be true if you were pushing these speaker to beyond ~115dB@1m ... where the approximately the ME850 would clip.  700w@4ohm

 

2 hours ago, doogie44 said:

If only a notional 100W is required according to the specs and written parameters of the speakers, and it seems that it is not too hard to drive (in theory),  then in the real world both amps 'should' be OK

 

100w would take them to about ~ 105dB@1m.... it just depends on what level you want.

 

2 hours ago, doogie44 said:

 

. As should the Pass amp and a host of other high-current contenders. 

I mean it doesn't even need anything particularly high current, 4ohms quite flat isn't difficult.....  just an amp genuinely engineered to handle 4ohm, with enough power for the SPL is all that's needed.

 

2 hours ago, doogie44 said:

Obviously that is not correct. Why

 

Perhaps people play these speakers to high watts/1m ....  because a) they have low distortion (so don't sound "loud"), and b) because they sit far away from them.

 

 

2 hours ago, doogie44 said:

preventing correct system synergy

 

Probably the preamp being crud, and/or not driving the power amp to full power ..... or the power amp isn't big enough, if he's trying to drive the speakers quite loud.

 

2 hours ago, doogie44 said:

And that certain high-current amps can drive the speakers adequately and others can't.

Given the previous amp only offered ~3dB more power ..... then I'd guess it the gain structure.

 

The DAC puts out a small signal.... and the preamp doesn't amplify it much.... as so the power amp isn't being driven to full power.    But more information would help rule things in/out.

 

2 hours ago, doogie44 said:

Here must be where theory gives way to practice--and reality?

 

No it just mean there isn't enough info.    When whatever is going on is figured out, you will see that no theory is contradicted ;)

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1 hour ago, Eggcup the Dafter said:

Those specs surprised me given what I've heard about the Sovereigns.

 

I was the opposite.   I would have been shocked and disappointed from what I know about the heritage if this speaker had of been particularly inefficient and/or reactive load.

 

That doesn't mean people don't like driving them with large amps.....  cos they turn it up loud and sit back.   Low distortion speakers don't sound "loud" ;) 

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2 hours ago, Ittaku said:

This is very interesting, as regular bridging of an amplifier makes it less able to cope with impedances as it effectively doubles the minimum impedance.

 

It's their patent name for a kind of "balanced amplifier", not really "bridged".

 

That being said, I had a quick read of the manual.... and it does make special mention of wanting to be driven by a symmetrical balanced signal (ie. pin 2 and 3 containing equal signals of opposite phase).

 

From what I remember about the PS audio stuff their designer does interesting things with their balanced signal.....  perhaps it is "unbalanced balanced" if you know what I mean    <shrug>.

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1 minute ago, davewantsmoore said:

 

It's their patent name for a kind of "balanced amplifier", not really "bridged".

Reading further, that looks right.

 

10 minutes ago, davewantsmoore said:

From what I remember about the PS audio stuff their designer does interesting things with their balanced signal.....  perhaps it is "unbalanced balanced" if you know what I mean    <shrug>.

Without reading back, I believe Kelossus is using an unbalanced connection between pre and power though., and from the TT as well.

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3 minutes ago, Eggcup the Dafter said:

Reading further, that looks right.

 

Without reading back, I believe Kelossus is using an unbalanced connection between pre and power though., and from the TT as well.

Correct at the moment I am. I do usually run balanced between the pre and power but I am waiting delivery of the cables.

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2 hours ago, Eggcup the Dafter said:

@davewantsmoore has already pointed out that we don't have any large phase angles here, assuming the given measurements are correct for this sample. Those specs surprised me given what I've heard about the Sovereigns.

The supersymmetry design in the Pass Lab amp is referred to elsewhere as a "special subset of bridging". I can't really tell if that is true or relevant but it's worth mentioning for those who can, I guess.

No, sorry but that's misquote:https://www.passlabs.com/wp-content/uploads/2020/05/x3_om.pdf

"The supersymmetric amplifier is a special subset of balanced amplifiers, unique and covered by U.S. patent."

The Pass Labs stuff can run quite well on 2ohms -https://www.stereophile.com/content/pass-labs-xa305-power-amplifier-measurements

I was actually was running my XA25 on 1.5ohms for a while. Not knowing that one of the bypassed capacitors had shorted in my midrange driver on one side. I worked it out as it was cutting the one channel when I was driving at about 95dB+. Otherwise, it worked just fine at less anti-social volumes.

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I was/am one of the arc welder advocates in this thread. 

 

To clarify, my comments were in relation to suggestion that the base was soft and not tight. This is different to an overall loudness issue assuming the levels were similar between the amps and is different from gain issues.

 

I've had higher wattage amps with soft base and lower wattage amps with tight base but with high current capability. My thoughts are that my higher wattage amp 'clipped' base from lack of instantaneous current capability.

 

Back to the OP and discussion, I'm not clear on whether overall loudness is the issue (gain) or lack of tight base (potential amp limiting in current or slew) . Or whether the lack of tight base is making the level feel lower than it is so the levels are actually higher and then causing further 'clipping' of base. 

 

 

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