Primaluna. Evo 400 - bass issues

This will be long, I really need some help determining why I’m getting poor bass response. I’m pretty sure it’s this amp, the PrimaLuna Evo 400 power amp. I’ve been trying speakers with it with poor results. In the interim I’ve been using cheap Mackie MR5 studio monitors out of my preamp, the Evo 300. I’ve had great results with these and that is the problem. These are tiny 5” near field monitors and the bass response I’ve been getting is excellent. The bass has been so good I decide to try to find a bookshelf speaker that is similar as I like how they disappear and based on the bass I was getting from these I thought I’d be good to go. I listen to predominately jazz so I’m not looking for thunderous bass just enough to fill in the rhythm section and bass walks etc. These Mackie’s do that. With that said, they don’t compare in the mids and highs but the bass is there. Here are the specs on the Mackie:


VPI Prime Signature, Hana ML, Herron VTPH-2a, Evo 300, Evo 400, Audioquest Niagara 1200. Stock tubes in the 400, Evo 300 has upgraded Psvane and 1960 Mullard rectifiers.


16.5 feet long 15 feet wide (room opens to the right another 12 feet) 8 feet ceiling

Mackie’s are 2 feet of the side wall and the back walls. I keep that for all the speakers I’ve tried.

Speakers I’ve tried:

Tannoy Turnberry’s

B&W 805

B&W 606

Ascend Acoustics Sierra 2EX

Probably my favorite were the 805 but there was no bass. With all of these speakers I found very minimaL bass response. I thought the Ascend would be good because of the impedance curve but they sounded the worst.

Personally I think the issue is the room, but then how am I getting good bass with the Mackie’s? So now I think it’s the amp. When I read about other peoples experiences with this amp bass doesn’t seem to be an issue. What gives? Am I just use to the solid state monitors and how they provide bass vs tubes? Is it the room? Poor speaker matching? I recently had the 606’s over again as they are a friends that he uses in a surround setup. They really sounded nice but again poor bass and they are rated to go deeper than the Mackie’s.

Thanks for reading.







@jazzjunkie80923 Are you using the stock EL34 tubes? And are you sure your speaker cables are in phase? Are you using the 8 ohm taps or 4 ohm taps?

Given the size of the room, your amp should be able to power these speakers sufficiently, even if it's not endgame performance.

Square rooms are really tough, though and are more prone to phasing issues, so this could be the problem.

I believe the Primaluna Evo 400 can accept KT150 tubes. If true, try them ... they definitely have much punchier and impactful bass than EL34's. But you might miss the special midrange sauce that EL34's add to the flavor. 

I’ve owned PL gear in various forms and with various speakers over the last few years in addition to SS amplification.  While you may also have room issues, all things being equal I have found that the PL bass has good quantity but lacks attack, or speed, compared to a good SS amp like a Bryston or Luxman.  This has been the case for me in all my trials without exception.  At one point I had two HP amps (the predecessors to your Evo 400) running as monos with KT120s, and in the bass/speed department a Luxman 509 integrated at the same w/ch rating into 8 ohms handily defeated the PL.  But the PL still have other great qualities.  It seems like an amp should have good bass or no bass, but IME it’s not that simple, it’s further nuanced.  As I said earlier, the PL have bass in quantity (a sustained organ note for example will be on par with, or close to, the SS amp) but the attack, or transient response is slower.  

Yes, wires are in phase. 
I tried both taps, something was lost going to 4 ohms overall though maybe a bit more bass. I’d like to think it’s the room but that doesn’t explain the sound with the powered speakers imo. The 400 has the stock tubes. 


Pull the speakers away from the wall. All but the smallest monitors will have more bass

I had a EVO 400 purchased from Upscale Audio.  Same issue I had.  Bass!!!  I tubed rolled to KT150s as well.  Didn't make much of a difference.  Your room may have something to do it with it for sure.  But in my opinion this amp just doesn't cut it for bass.  I switched to Black Ice Audio F35 Integrated, with a Black Ice Audio F360 Pre.  This setup changed the game for me. It was also cheaper than the Primaluna.  Im running Zu Omen Def Supremes on them.  

Primalunas have plenty of bass even with EL34s. That’s probably not your problem unless you have a faulty amp. Which would be rare as Primaluna has some of the best quality control in the business.

Smaller speakers like your Mackies are easier to place in a modestly sized room with a big side opening. Medium to large speakers take a bit of finesse/trial and error if it’s not something you have a lot of experience doing or your room conditions are not helping. And then there is the matching of speakers to amp.

The room is such a strong player in the acoustic signature of a system. A room must be exploited to the fullest to get the best sound out of it. This takes time. A lot of folks fit the system into the furniture layout and tweak from there. That is probably too much of a compromise against the system and you can’t expect much. Throwing money at gear at this point is a serious waste of money.

Unless you have a dedicated listening space, you’ll need to know how to compromise in a way that puts your system first and the furniture layout second. I’m lucky. I have an old home with formal rooms. More importantly I was able to get my wife to agree to a compromise that works for the both of us. It doesn’t look like a compromise as the rules for the living room are sneaky enough to get good bass and imaging while looking like the room favors the fireplace.

I have a Primaluna Evo 400 pushing Tannoy Turnberrys. They sound big in my 22’ x 16’ room with 8’ ceilings. Bass in never a problem. I’ve had them for a year and I’m still tweaking the room.

You said you listened to all the speakers in the same position. But I’m certain each of those speakers has its own perfect place in the room. You need to find that spot.

My speakers are 1/5th the width of the room from the side walls. They are 1/10th the depth of the room from the front wall. This is not optimum but is good enough for living. When I do serious listening they move forward off the back wall to about 1/7th the depth of the room.



Hello jazzjunkie80923. Put both speakers side by side - almost touching. Do you have bass? If No, check those speaker wires again. Are both woofers moving? If Yes, the placement is the problem and the room is causing the problem, As a double check, play a mono source. Is the image dead center? if so, good. IF NOT, something is seriously wrong. Using making tape, cover the wals the speakers are "looking at" with some kind of towels; the thicker the better. Does the bass change? Is the listening room carpeted? If NO, throw some some blankets on the floor. Does the bass improve? No? get a solid state amp!  Good Luck!

If you have used all the speakers in the same positions move the speakers around. Rooms have good and bad bass spots totally due to the room even including spots with literally no bass.

I had an Evo 400 integrated and then Dialogue Premium separates later on. PL in my opinion didn't have enough bass, but I didn't notice until I sold it. I rolled el34, kt88, kt120's and kt150's and none solved lack of bass. My PS Audio BHK 250 smokes the PL in the bass department. Not even close. Detail was also gained and I'm happier with the change. BHK is more laid back, so not my end all be all amp, but a define positive move from the PL. 

Another PL and no bass thread.

PL user, and very long time ear witness of bass performance in many setups. Both PL and non PL tube/SS.

The PL with the stock EL34’s output plenty of bass. I have heard the OP’s combo of PL/Tannoy-no shortage of bass.

Mystery PL no bass problem thread of the week.

Edit- My experience of hearing PL/Tannoy was with an EARLIER PL generation(Dialogue Premium)-not EVO, which is purportedly even "better."


I had a tube integrated with the kt-120's in it and the bass was there but uncontrolled. I haven't heard a good tube amp < $10k that did bass well enough to move away from SS. The PSA BHK amp would blow away the PL, the Rogue, and other tube amps close to the price of the BHK. 

I also used the 4ohm tap to get better controlled bass from the tube amp.

Thanks for the replies.

Yes I’ve tried several positions with the speakers when they were here. Not one produced the response of the Mackie’s. 

In an attempt to further diagnose the issue I lugged the amp to a friends with a bigger room, better acoustics with treatment. Hadn’t been able to hook up in the past as he is a ways away. Amp performed the the same. Put it up against his BHK 250. It’s the amp. Still sounds lovely but the low end is not there for me. I’ll list her for sale. Thanks for the replies. 

Audioquest Niagara is known to limit bass. Plug into the wall and see if you get improvement.

Also you're using speakers that aren't very sensitive.  You will see problems first in the bass area.  



I don’t believe that is true. But nothing wrong with trying the amp plugged into the wall.


Perhaps add a subwoofer(s) one that can be tuned to the room like a JL F-112,113


A friend of mine had a similar issue using PL amps and not getting enough bass from his Von Schweikert speakers. Hi tried several things and ended up using a used ss amp to drive the woofer and keeping the PL for the mid/trebble, was very happy with this solution.

I'd first recommend contacting Kevin Deal at Upscale Audio. He can help you with all things PL.

Have you tried to move the speakers much closer to the rear wall? Have you tried to move them much further into the room? These tests will help you to determine if the room is causing some or all of the bass loss.

I'd also make sure to plug your amp directly into the wall. The AQ1200 could be the problem, or at least contributing to it. Example, my amp plugged into a Shunyata Research Hydra 6 resulted in total loss of bass. Plugging the amp into an IsoTek Aquarius kept most of the bass, but lost the top end and sounded a little like a blanket had been put on the speakers. Tried the IsoTek Sigmas and it was able to deliver the power my amp needs and it actually sounds overall a little better with strong defined bass and great mids and upper frequencies. Using the Sigmas to this day and loving it.

Good luck in figuring this out for your room.

B&W used to be a bit hard to drive. Maybe the new ones aren't. I listened to Fyne speakers at a store and liked them. They are pretty easy to drive and has good bass for their size. F500 or F500SP may be an option for you to try.

Best bass from small speakers I've heard was probably Boenicke W5 but they cost around $7k.

Maybe switching amp is easier. 

Just a quick post that I have an int Evo 300 w/ KT-150s and have plenty of bass. Seems just like the right amount acutally and is more recording dependent than anything else.

I do always find the posts intriguing which say that they went to another amp and it sounds much better. I don't doubt it but I am very happy with mine and hard to imagine much better with an excellent recording. I'll go to my first hifi show in Feb so will find out soon.

Speakers are Spatial Sapphire M3

The tube amplifier like Evo 400 has in general higher output impedance which gives lower damping factor.  For example, in its ultralinear mode the output impedance measured 2.3Ω, giving a damping factor (DF) of 3.4, while in its triode mode the DF is a bit better (but still low on the low side) as 3.8.  These figures are much lower than most of the SS / transistor amplifier from which your studio monitor Mackie is powered (class A/B), resulting in uncontrolled / lose bass performance.  That might give you an impression that speakers like B&W 805 has no bass imo. 

This is going to be fun but I am dead serious by a preamp with tone controls 

I can't help with Speaker Advice. Many good suggestions have been already made. My suggestion will repeat. Phasing correct polarity to the speakers.


The other is  to try KT 77JJ tubes or equivalent. Not only did I get remarkable low end from the stock Primaluna EL34s but also better mids and highs. It was great before but much better with my speakers with the KT 77s with my EVO 100 integrated. Good luck!


This is quite the PrimaLu a discussion, I have the EVO 400 amplifier, even with the stock tubes bass was great with the Forte IVs, now with the EL34 NOS Mullards is really good. 

ALL I do is Stream with airplay so I have a Naim Dac and streamer hooked to the amplifier, everything sounds great, a friend has a PrimaLuna Dialogue Premium Preamp, would I gain anything buying this? I will never hook a phono or anything but the Dac streamer I have now…

@lanx0003 brings up an excellent point…the Mackie MR5 are powered speakers that also have some sort of a LF adjustment. So your comparison is not exactly apples to apples if you compare to passive speakers. The Mackies may be “tuned” or EQd to emphasize the bass from the factory.