Aerius tweeks

[Gothover]

Although my upgrades are not yet complete, because I need to replace the 15uf caps, I did what I could and reassembled the speakers.

The test, To be honest, I would not have noticed a difference just listeneing, but the fact that the ultra low level hum I had was incredibly coherant after the upgrade is definatly a sign that a difference has been made. I was now able to trace the ground loop hum down to a bad ground on my preamp.

I am now truly convinced that the cap replacement is a legitimate upgrade, and would reccomend it without hesitation.

Thanks, DH

 

[RoboRob]

Today I also did the capacitor upgrade mod on both my front Aeriuses. I bough some ClarityCaps (2x 10 and 2x 33uF SA's and 2x 22uF ESA because the SA version was not available for 22uF).

I still determining if and how much the difference is. I think there is some but not really significant...

regards,
Rob.

 

[HiFiFuchs]

Hi out there,

I am new here on the ML Forum and I am the happy owner of a set of 1993 ML Aerius LS.
I can see that it is along time ago that someone wrote comments to Aerius tweeks on the forum and I would be very happy if some of you experiences ML owners would give me some advise on possible X-over tweeks (cap change).

In the low pass there is two serial caps 470uF + 100uF both ELCOs. I reallz do wonder if it makes a major change to change especially the big 470uF ELCO to a MKP.
First of all large MKPs are quite expensive and secondly they are quite large. I am thinking of swapping the low pass "suction filter" with one bipolar 560 uF Audio grade Elco and add a high quality 10uF MKP to get the 570uF and by-pass them with a MKP silver cap with 0,1uF.

There is also a 80uF parallel bi-polar cap which I will change to a MKP with the same value.

Does that make sence?

In the high pass filter where now are one 22uF bi-polar Elco and a 10uF MKP I am thinking of changing them with one 22uF audio MKP and a 10uF audio MKP plus by-passing them with one 0,1uF MKP silver cap.


There is also a 15uF parallel bi-polar cap which I will change to a MKP with the same value.

What is your experience?

I would be very happy to get as many comments and opinions as possible.
Thank you in advance.

Kind regards

Rino

 

[HiFiFuchs]

Hi and wish you All a marry Christmas,

Despite not having received any comments to my tweet above I did the re-capping around 4 years ago as described. I am very happy with the result.
I also have re-foiled panels since app 3 years.

Now I would like to ask you for another possible tweak to the x-over.
Some CDs are quite heavy on Bass others are absolutely perfect balanced when it comes to High, mid and low frequencies. Playing these CDs with increased Bass the Bass gets quite muddy and I am looking for a solution which will solve the heavy Bass.

My question to All of you is, if it is possible to implement something like the "3dB Bass Control" similar to the one implemented in the ML SL3 in my Aerius (not i), to be able to decrease the Bass when required?

I do not have the required knowledge to estimate if this is possible or not and if yes how to do it. I do have both the schematic from the SL3 and my Aerius (attached) meaning if someone would be kind enough to tell my what is possible, I feel quite okay installing the needed components and switches.

Kind regards
Rino

 

[Tosh]

While it is possible, I don't recommend adding resistance to drop the level, as it further reduces the amplifier's control over the woofer (ruins the damping factor) and makes it even more muddy (and the passive xo makes it too muddy already).

But if you didn't want to go to an active xo on the bass, you could still try passive bi-amping, and then use an attenuator in front of the bass amp to adjust the bass level.

 

[HiFiFuchs]

While it is possible, I don't recommend adding resistance to drop the level, as it further reduces the amplifier's control over the woofer (ruins the damping factor) and makes it even more muddy (and the passive xo makes it too muddy already).

But if you didn't want to go to an active xo on the bass, you could still try passive bi-amping, and then use an attenuator in front of the bass amp to adjust the bass level.

Hi Tosh,

Thank you very much for your advise, much appreciated. I will follow your recommendation and live with the slightly fat/muddy bass as it only concerns some recordings (CDs).

I am already driving the Aerius in vertical passive bi-amping and my special confected speaker cables (Kimber 12TC) does not allow doing horizontal bi-amping but I might consider trying this with some other cables one day.

 

[Tosh]

Good on you for already bi-amping!
Could you not squeeze in a stereo pot before the inputs to the amps to control the bass level?

 

[Brandon Hartwick]

Stick an active X-over on the woofer and just bypass the existing passive crossover totally. You get full control over the level of bass you desire and it just sound much, much better. Unfortunately the passive bass crossovers on older Martin Logan speakers were terrible.

 

[HiFiFuchs]

As I do not want to go active I decided to do some recapping on my Aerius today.

With reference to above tweed #23 did the following referencing the attached schematic:

Swapped the original C1 PP 10UF with a Audyn Q4 10UF
also swapped the C3 - 15UF ELECTRO to a Audyn Q4 15UF
at the same time I removed the bypass Audyn Q4 installed earlier and installed a Audyn Plus 0,1UF in the same place bypassing C1 and C2

I left the Bass XO part as described above in tweed #23. I will attend to the Bass XO later.

WOW was that an improvement, I´m absolutely flabbergasted!
The soundstage turned deeper and wider and the high frequencies is far more detailed. I did not expect such a vast improvement. - Well worth it!

 

[Russr]

As I do not want to go active I decided to do some recapping on my Aerius today.

With reference to above tweed #23 did the following referencing the attached schematic:

Swapped the original C1 PP 10UF with a Audyn Q4 10UF
also swapped the C3 - 15UF ELECTRO to a Audyn Q4 15UF
at the same time I removed the bypass Audyn Q4 installed earlier and installed a Audyn Plus 0,1UF in the same place bypassing C1 and C2

I left the Bass XO part as described above in tweed #23. I will attend to the Bass XO later.

WOW was that an improvement, I´m absolutely flabbergasted!
The soundstage turned deeper and wider and the high frequencies is far more detailed. I did not expect such a vast improvement. - Well worth it!

Matter of interest, what was the cost associated with the Crossover work described above?

 

[HiFiFuchs]

To be honest, I am not sure as I purchased and implemented the first step (see tweed #23).
As per todays price list the complete upgrade would cost 109 € per speaker and it is well worth it!
The most cost intensive cap is the Audyn Q4 - 100UF which cost 48,75 € and to be honest I am not convinced that the swap to MKPs are worth it.
Today I would rather implement two good high audio grade ELCOs, i.e. Audyn 100UF/Audyn 470UF and possibly bridge the 100UF and the parallel 470UF with either a 5,6UF Audyn Q4 (5,95 €/piece ) or a Audyn Plus (25,30 €/piece) which would drastically reduce the total cost.

 

[HiFiFuchs]

Here in Germany there is a company named HiFi Zenit who offers an upgrade to the bass XO section:
They're just reworking the passive bass crossover to target a lower frequency cut-off, which is said to be an improvement over stock Bass XO Section. The new implemented components reduces the overall resistance by 50% which should course a firmer/stiffer low frequency.

I have attached a picture of the mod and the link to the German web page is: https://www.hifi-zenit.de/elektrostaten/hybrid-bassproblem

In case you are interested you will have to run the text through Google Translator or similar.
I will report back here as soon as the mod is implemented and tested.

 

[HiFiFuchs]

I would be very happy if someone of you have done the above mentioned or a similar mod, lowering the Bass cut-off frequency.

 

[Brandon Hartwick]

I

I would be very happy if someone of you have done the above mentioned or a similar mod, lowering the Bass cut-off frequency.

I don't believe anyone here has done that crossover modification. Everyone here is going to suggest the same thing that was mentioned on DIYaudio and will tell you to go active on the woofers.

This way you can run tubes on the panels and have proper control over the woofers, it also presents an easier load on the amplifier since you're not dealing with the different impedance curves of the panel and woofer.