Krell KSA50 vs Aleph-X

[still4given]

Hi Guys,

I am in the process of finishing my second KSA50 and am planning on building an Aleph-X next.

I'm wondering if any of you have built and/or listened to both and could give me an idea of the sonic differences between the two.

I'm trying to decide on how much effort and money to invest in this Aleph-X. I already have a 1200vA 4X12v transformer and 4 9"X11" heatsinks. It should put out about 50WPC@8ohm and 70WPC@4ohm.

Any comparisons at all will be helpful.

Thanks, Terry

[kilowattski]

Terry,

The Aleph X will be the most difficult amplifier you have built to date. It will take alot of tweaking to get the amp just right. Alot of the values are just guidelines or starting points. If you succeed you will be rewarded to one of the sweetest amps I have ever heard. Go to the Aleph X builders thread and download the AXE-2 spreadsheet so you can calculate the heatsinks (you will probably need both your 9x11 sinks for one channel), the transformer and number of devices you will need. One thing on your side is that there are alot of us who have built them and can give you a hand. A scope is a neccesity for this project.

[still4given]

Originally posted by kilowattski
Terry,

The Aleph X will be the most difficult amplifier you have built to date. It will take alot of tweaking to get the amp just right. Alot of the values are just guidelines or starting points. If you succeed you will be rewarded to one of the sweetest amps I have ever heard. Go to the Aleph X builders thread and download the AXE-2 spreadsheet so you can calculate the heatsinks (you will probably need both your 9x11 sinks for one channel), the transformer and number of devices you will need. One thing on your side is that there are alot of us who have built them and can give you a hand. A scope is a neccesity for this project.

Well I was kind of hoping that I would get some help. It seems that most of the folks who have finished them have stopped visiting the main AX thread. I ask questions there and only a couple of folks ever answer. Fortunately one of them is Mr Nelson Pass, but since he hasn't built one, his answers are usually more of a broad nature.

I can tell that this is not going to be an easy project. I just wanted to hear someone say that it was going to be worth it. I should have all of the parts on the BOM this weekend, but you say they may be wrong?

I don't have a working scope. I bought one but I think the CRT is bad. Never got around to fixing it. Maybe I had better shelve this amp until I get more experience. I would hate to go through all it is going to take and then not have it perform right.

Thanks, Terry

[Netlist]

Terry,
I'm not the one to compare with the KSA50 as I never heard it but you should give the AlephX a go. If it's your first amp, you'll have a though time...or not if you carefully plan every step. Start building with what you have, you'll find help along the line. Print out the WIKI pages. Like kilowattski said, it's a very rewarding project.

/Hugo

[macka]

I have build several X alephs from the original thread and they all worked fine first time ..without a scope being hauled up on the bench.

The most important thing is to take care match the diff pair fets and the power fets on the lower side of the amp to ensure low relative and absolute offset...that is where most people seem to come unstuck.

You can you this with a regulated 15 volt dc supply and a reasonable multimeter.

macka

[lgreen]

Terry, take care of my A-X boards! As a fellow Krell diyer, I'm trying to build and A-X with you in parallel, as soon as I redo my BOSOZ (2 months time). However, in the meantime i'm making some boards and doing some testing. If you need a scope i'll figure out a way to get mine to you but I am with you. Reading the A-X "build" wiki only gets one so far, its not like the Krell wiki that is constantly updated and the "krell" thread which has everyone returning every other day or so.....though you have been suspiciously absent for awhile.....ooops...correction you are back! only about 2 posts or more......but I digress......

To me, the impediment to an Aleph X is the matched MOSFETS, do you have those or are you working on those by now? If so, I would consider the progress significant.

Otherwise I guess my point is that any additional help will be appreciated by at least two people.

Hey, put this in the "pass labs" forum?

Thanks.

[Mark A. Gulbrandsen]

I built two stock X's and was somewhat disappointed. I ended up with a somewhat soft top end... much more soft than my Aleph 2's. I sold my completed X boards to a person in Milwaukee but never heard back as to how he felt they sounded.

All visitors that come over agree by a wide margin that the KSA-50 is better than my A-2's. In a few weeks we will have another amp shootout at my house.... I have a much larger listening room now......

On another note its also just possible that he 50 is just better suited to my Dynaudios than the X was or the 2's are..... The 50 seems to exert an authority over the entire audible spectrum that other amps just don't have.

Just my 2 cents worth.....

Mark
P.S. The X would be a very good learning experience for you and possibly would be better suited for your system.

[still4given]

Originally posted by lgreen
Terry, take care of my A-X boards! As a fellow Krell diyer, I'm trying to build and A-X with you in parallel, as soon as I redo my BOSOZ (2 months time). However, in the meantime i'm making some boards and doing some testing. If you need a scope i'll figure out a way to get mine to you but I am with you. Reading the A-X "build" wiki only gets one so far, its not like the Krell wiki that is constantly updated and the "krell" thread which has everyone returning every other day or so.....though you have been suspiciously absent for awhile.....ooops...correction you are back! only about 2 posts or more......but I digress......

To me, the impediment to an Aleph X is the matched MOSFETS, do you have those or are you working on those by now? If so, I would consider the progress significant.

Otherwise I guess my point is that any additional help will be appreciated by at least two people.

Hey, put this in the "pass labs" forum?

Thanks.

Fear not my friend,

Your boards are safe with me. I will have all of the parts this weekend. Bob Ellis sent me a drawing for a circuit to use to match the MOSFETs. As soon as I figure out how to use it I will begin. I have 40 devices. I ought to be able to get at least two sets of 4 matches I think.

I still need to get some aluminum to build the chassis for both amps. That is why my second Krell is not done.

I purposefully placed this thread here because I figured I would get a less biased group looking at it. If I placed it in the Pass Labs forum The A X would win hands down. I wanted to get unbiased opinions.

Thanks for all of the responses so far.

Blessings, Terry

[MikeW]

The Aleph-x has better midrange. The Krell has better bass. I liked the Krell better than I thought I would. I should have my Aleph-x back this week so I can play them side by side.

[still4given]

Originally posted by MikeW
The Aleph-x has better midrange. The Krell has better bass. I liked the Krell better than I thought I would. I should have my Aleph-x back this week so I can play them side by side.

Hi Mike,

I'll look forward to your impressions of how they compare.

Blessings, Terry