ack's system - end of round 1

[Folsom]

There may be awful consequences to mounting capacitors off-board.

Can I get a pick near where the wires from the transformer run in? I bet there are some easy mods that'll make it really sing. Frankly most of the recommendations so far are closer to squeezing whisky from rocks... if the electrolyics are old they do need replaced but not necessarily with different caps. I'm sure better drivers help.

You're welcome to PM me. I actually do modify things for people, I've got a pair of subwoofer servo amps on my table right now.

 

[opus112]

Adding more capacitance might help, though it may equally well have negative side-effects due to the charging current pulses from the transformer becoming shorter and greater in magnitude (meaning increased HF). In upgrading amp PSUs I'll always include some series inductance, creating a CLC filter. Most of the capacitance should come after the inductor, a rough guide is 20% upfront.

 

[Folsom]

You have to be pretty careful adding inductors, there's some things to know. Long wires and inductors can potentially hurt current response. But that's certainly a good thing to look at. I've had good results with them but it wasn't always plug and play.

It's not easy to add inductors on some of these boards because they're all on one PCB.

 

[ayreman]

So the Mundorfs don't fit in the enclosure, and obviously neither the board - they are 9cm D x 10.5cm H, really huge.

I used these custom-made ones and they have exactly the same dimentions as the stock ones:
http://hificollective.co.uk/catalog/10000uf-100vdc-mlytic-electrolytic-caps.html
Check out the pics of my modded Stentors (The pics are large so will have to upload in several posts.)

 

[ayreman]

Next batch of photos

 

[ayreman]

Last batch: ultra-clean power & AQ Fire "distruction" to extract PSS solid-core conductors

P.S. I would add a second REL Stadium III, modify both and forget about Magico (or anything else for that matter).

 

[ack]

I have a lot of respect for people who second-guess manufacturers and modify their equipment, because just about every one of them designs and builds to a certain price point. I see you have done a number of modifications, which is really GREAT! These subwoofer mods certainly look impressive as well. Thanks for the pointer to the custom Mundorfs - never seen these particular ones before. It looks like your engineer has the schematic??? Regarding the second set of external capacitors, what exactly is he supplementing, with the rainbow and white wires? The same Mundorfs??? If so, why not use Mundorfs again?

I have a space problem, so one sub is all I can use. Sonically, what are your results? Are the mods really worth it, for what's basically a Class B amplifier???

 

[ayreman]

I have a lot of respect for people who second-guess manufacturers and modify their equipment, because just about every one of them designs and builds to a certain price point. I see you have done a number of modifications, which is really GREAT! These subwoofer mods certainly look impressive as well. Thanks for the pointer to the custom Mundorfs - never seen these particular ones before. It looks like your engineer has the schematic??? Regarding the second set of external capacitors, what exactly is he supplementing, with the rainbow and white wires? The same Mundorfs??? If so, why not use Mundorfs again?

I have a space problem, so one sub is all I can use. Sonically, what are your results? Are the mods really worth it, for what's basically a Class B amplifier???

The custom Mundorfs was not easy to find. I miraculously succeeded in talking Mundorf's distrubutor into ordering them especially for me and what you see in stock now are leftovers from my order. Had to wait for 3 months!

Yes, my enginees does have the schematic and knows exactly what he's doing. The Audyn caps there are doing 2 things: the four 22mF caps are connected to bypass amp power while the smaller ones (6.8mF) are soldered to PCB PSs to ensure maximum filtration. BTW it would be wrong to call them "external" because they are installed inside the subs (just neatly tucked out of the way and screwed inside to the left side of the cabinet). So you would never guess they are there to begin with.

I am VERY happy with the results. I can not imagine a better pair of subs for a stereo rig on this planet! The level of lower bass articulation is unheard of. The depth, speed, punch and slam are indescribable (even in my mother tongue). And, of course, they affect not only the bass per se. The entire frequency range is so lush and rich I can not believe music can sound so real and alive at home. I stopped going to live concerts a few years ago. Music at home sounds so much better!

 

[microstrip]

(...) I have a space problem, so one sub is all I can use. Sonically, what are your results? Are the mods really worth it, for what's basically a Class B amplifier???

Good question. Considering the excellent results I have listened to when integrating Descent i's with Martin Logan ESL's I would consider getting a ML subwoofer. I have very little experience with the new BalancedForce subs, can not emit an opinion on them.

 

[ack]

The custom Mundorfs was not easy to find. I miraculously succeeded in talking Mundorf's distrubutor into ordering them especially for me and what you see in stock now are leftovers from my order. Had to wait for 3 months!

It's (was?) not unusual for them to build custom anything - most of my crossover caps are custom and all of the inductors; and yes, it does take a long time to get them; I would also bet some of Magico and others' units are also custom. My source is usually https://www.audiyo.com for custom and https://partsconnexion.com for stock. One of the great things about Mundorf, as of a few years ago at least, is that they have not charged a fee for building custom stuff. But in the datasheet of their Mlytics I now see "4-6 weeks shipping and at least 144 units for custom orders"????

Yes, my enginees does have the schematic and knows exactly what he's doing. The Audyn caps there are doing 2 things: the four 22mF caps are connected to bypass amp power while the smaller ones (6.8mF) are soldered to PCB PSs to ensure maximum filtration. BTW it would be wrong to call them "external" because they are installed inside the subs (just neatly tucked out of the way and screwed inside to the left side of the cabinet). So you would never guess they are there to begin with.

I am VERY happy with the results. I can not imagine a better pair of subs for a stereo rig on this planet! The level of lower bass articulation is unheard of. The depth, speed, punch and slam are indescribable (even in my mother tongue). And, of course, they affect not only the bass per se. The entire frequency range is so lush and rich I can not believe music can sound so real and alive at home. I stopped going to live concerts a few years ago. Music at home sounds so much better!

Bass articulation - exactly what I wanted to hear. Too bad your engineer is so far away from me, else I would be all over him! I guess I could always send over my board, if he also has my schematic. It seems to me I should try at least the 10KuF Mundorfs myself, but we are splitting hairs in terms of ESR by looking at the spec sheets: 28mOhms in the stock vs something unknown but roughly around 10mOhms for the Mundorfs (based on the 14mOhms for their 10Kuf/63V rating). Is this really worth it?

The other issue is that I am fixated against any ported woofers, and the Magicos fit that bill - plus the fact I have heard them and they are remarkable, and you can literally cut off their response through computer software.

 

[PeterA]

The entire frequency range is so lush and rich I can not believe music can sound so real and alive at home. I stopped going to live concerts a few years ago. Music at home sounds so much better!

Congratulations on your successful modifications and resulting sonics. Are you actually saying that you prefer the sound of your system to live, unamplified music, or were you just going to loud amplified electronic music in typical rock concert venues? I think many of us get better sound at home than some of the terrible amplified concerts that we have all attended.

 

[YashN]

I have a lot of respect for people who second-guess manufacturers and modify their equipment, because just about every one of them designs and builds to a certain price point.

Absolutely: Laws of business dictate the demand/supply curve as well as the pursuit of profit margins, with the inevitable accountants and managers ordering the cutting of engineering corners.

A Pure Engineering perspective can bring a commercial product several levels above what it is when sold in its normal incarnation.

 

[YashN]

I can not believe music can sound so real and alive at home. I stopped going to live concerts a few years ago. Music at home sounds so much better!

Same results here. I still go to shows, but the sound cannot match what I have at home for quality. Theirs can be painfully louder and distorted.

I also have an increasingly hard time enjoying music on other people's systems.

 

[ack]

Absolutely: Laws of business dictate the demand/supply curve as well as the pursuit of profit margins, with the inevitable accountants and managers ordering the cutting of engineering corners.

More than that, I cringe every time I point out a potential design/execution flaw and have others tell me that So-and-So designer knows what he's doing and would have done the right thing, therefore, my assumptions are wrong. I call BS on those types of responses... Show-me is my approach, because it is likely that manufacturers bring premature products to market, especially if their market share is falling, or are up to here in debt, and so many other reasons.

 

[microstrip]

More than that, I cringe every time I point out a potential design/execution flaw and have others tell me that So-and-So designer knows what he's doing and would have done the right thing, therefore, my assumptions are wrong. I call BS on those types of responses... Show-me is my approach, because it is likely that manufacturers bring premature products to market, especially if their market share is falling, or are up to here in debt, and so many other reasons.

Perhaps not in your case, but most of the time the design/execution flaws people point are simply design options. Just because a change makes an improvement in our case does not mean that it will result in improvements in other systems. But surely we have a lot of premature faults, even in quality brands. I also never buy a car during the first years of production, I wait until they clear the initial problems.

BTW, I am guilty of suggesting adding better and larger capacitance capacitors without suggesting that the rectifier diodes should be checked for maximum peak current.

 

[ayreman]

Are you actually saying that you prefer the sound of your system to live, unamplified music, or were you just going to loud amplified electronic music in typical rock concert venues? I think many of us get better sound at home than some of the terrible amplified concerts that we have all attended.

Yes, I was referring to amplified concerts only. Problem is finding decent concerts without any amplification is very hard these days...

The last three concerts I attended were George Michael, Sting and Robert Plant. The latter was the straw that broke the camel's back. It was insanely loud to begin with and toward the end of the show they cranked it up even more. I had to put earplugs into my ears and it was still loud! Consider absurdity of the situation: you buy en expensive ticket to go and see a hard rock legend and, instead of enjoying it, you are siting there in agony with earplugs in your ears. This was 3 years ago. After that I said to myself: "This was the last live concert in my life". I'd rather invest more money in perfecting my home system instead of spending it on tickets. And that's exactly what I did feeling happier that ever

 

[YashN]

More than that, I cringe every time I point out a potential design/execution flaw and have others tell me that So-and-So designer knows what he's doing and would have done the right thing,.

Designer/Engineering department flaws happen too for sure.

 

[ack]

BTW, I am guilty of suggesting adding better and larger capacitance capacitors without suggesting that the rectifier diodes should be checked for maximum peak current.

Yeah, no worries, I am aware of that, and also the higher current draw is part of the reason I installed the fan inside the Alpha DAC (not shown in prior pictures). I also let it run in the oven for a couple of days, to see what sort of heat it might build up in a contained environment... it was fine.

 

[leyenda]

Hi Ack, just saw that the SDR3000 is listed as modded. What kind of mods were performed on the xport? Thks.

 

[ack]

It's not modified. If you are talking about my signature, it refers to the Alpha DAC, like the XP-25 as well.