SuppersReady, I can certainly echo your findings.
Over the last 3 years I have progressed like this:
Preamp: from a Hafler clone (35 years old) - to a B1 - to the Aksa Lender
Power amp: from a Naim 160 clone (35 years old) - to a $1 TDA7297 - to the ACA
All this using the same set of Tannoy monitor speakers, each upgrade brought a significant improvement.
Except for the Tannoy monitors, I have heard the Aksa Lender + ACA setup with the following speakers also - Mini Karlsonators (0.4x with TC9FD), Mini Karlsonators (0.53x with dual 3fe25) and Frugal Horn XLs with Mark Audio 10.3s.
The Aksa Lender + ACA certainly gives tremendous bass. What I found is that the mids and treble, although it sounds less pronounced initially, are much more natural, balanced and detailed. Especially with the Mark Audio drivers. With the Lender + ACA + Mini Karlsonators (dual Faital 3fe25’s), I have never heard such an amazing soundstage and imaging as with any other system before.
94dB, according to X. The drivers are 91dB each, but they are connected in parallel.
Thanks for the positive feedback. I'm in the process of ordering a chassis and associated parts so that I can leave it switched on and make a proper assessment of how it sounds.
Twocents, your comments were especially helpful regarding how the AKSA/ACA combination sounds. I hadn't looked at Karlsonators before; is there a site that covers the theory or any build plans? They're very out of the ordinary!
Twocents, your comments were especially helpful regarding how the AKSA/ACA combination sounds. I hadn't looked at Karlsonators before; is there a site that covers the theory or any build plans? They're very out of the ordinary!
The thread is here: Mini Karlsonator (0.53X) with Dual TC9FD's
There are various plans scattered throughout the thread. This will get you started: Post #2560
There is a build log with photos starting at post #32.
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If anyone wants to build the new dual rail version of the Aksa Lender Preamp called the Melbourne - there is a GB going on now. Each little board is self contained and has its own CRCRC filter even. Just needs +/-24supply andnconnect input and output - so very versatile. It uses the M2X standoff and bolts format for input and output and voltage rails. It’s a very capable headphone amp as well and thus driving a 600ohm (design load as Edcor transformer on M2 presents a 600ohm load) as a Preamp is no problem. Output is optionally DC coupled if one wishes. Dc offset within 10mV or so depending on components and tweaking.
I’ll keep it open for a few more days still. In the meantime, JPS64 is making a new motherboard for it and it will use dual linear potted 10VA trafos with BJT cap multiplier for an integrated amp that fits in a 1U case.
Melbourne Daughterboard for M2X
The daughterboards are also pin compatible with the Mark Johnson M2X Class A speaker amp.
The idea is that JPS64’s new motherboard will integrate all of this and reduce the clutter.
I’ll keep it open for a few more days still. In the meantime, JPS64 is making a new motherboard for it and it will use dual linear potted 10VA trafos with BJT cap multiplier for an integrated amp that fits in a 1U case.
Melbourne Daughterboard for M2X
The daughterboards are also pin compatible with the Mark Johnson M2X Class A speaker amp.
The idea is that JPS64’s new motherboard will integrate all of this and reduce the clutter.
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I know the forum is not really devoted to the inexperienced and I understand. It might be painful to explain everything in the basic details all the time. But since I’m interested in building an M2x I have to ask:
What does this really add? By your description I understand that this is a preamp to the M2x, making it an integrated amplifier i.e. I can connect a 2V signal directly to it. Is that correct or the Melbourne is in fact one more alternative to the other ones already offered, just a different sound signature?
Will it give you a means of volume control as well?
Different sound signature - classic Aksa harmonic profile (look at FFT spectrum in post 1) of moderately low distortion with predominantly 2nd harmonic and descending higher orders. Plus it has gain so that you don’t need a separate preamp. There will be a new motherboard that holds these DB’s so that you have a stand-alone preamp.
There will be volume control on the new MB. On the M2X as DB, no volume control.
There will be volume control on the new MB. On the M2X as DB, no volume control.
Hi xrk.
The Lender and the Melbourne are both built as pre-amps?
Can you explain the sound difference between the Lender and the Melbourne version for people like me that don't know what you have said, and don't know the difference?
Is the Melbourne more accurate, and how much difference?
If we use the Melbourne for the ACA Class A amp, is the method of running the ACA from it similar by changing resistors?
Still waiting for the Mundorfs here.
I am indeed waiting for this motherboard. I have bought recently two stereo sets of your DB, one for M2x, one to go with motherboard for a separate preamp. What a great idea!
Russellc
Finally, the Mundorfs arrived and installed them.
Sat down to listen to a few CD's and sounds good.
Unfortunately, adding the Mundorf has made no change to the cracking in the speakers if the volume is slightly above normal (no way I'm trying to make it very loud). It's sounds like the tweeters are crackling just above the normal volume.
That's a bit of a problem because the various of CD's have some different income volumes. If I set the volume up for quiet CD's it will make crackling if the next CD is starts.
So, is the problem something with my Lender pre-amp, or does the Pass ACA causes the crackling sounds when the volume is at the PASS AMP's limit?
Sat down to listen to a few CD's and sounds good.
Unfortunately, adding the Mundorf has made no change to the cracking in the speakers if the volume is slightly above normal (no way I'm trying to make it very loud). It's sounds like the tweeters are crackling just above the normal volume.
That's a bit of a problem because the various of CD's have some different income volumes. If I set the volume up for quiet CD's it will make crackling if the next CD is starts.
So, is the problem something with my Lender pre-amp, or does the Pass ACA causes the crackling sounds when the volume is at the PASS AMP's limit?
Attachments
If the sound happens only on high crescendos then it sounds like your ACA is clipping. You can tell if you connect a more powerful amplifier and crackling goes away. ACA is limited to 5w rms for 19v supply. 5w is 18vpp. Tweeters often draw high voltage transients on crescendos. You will hear this with soprano female vocals on opera, or piano played fortissimo or trumpets at full blast. The crackling is not caused by the Aksa Lender - but because Aksa Lender permits the 14dB gain of ACA to be driven to clipping levels.
An oscope will show clipping easily.
An oscope will show clipping easily.
Thanks for your response.
Ok, will drag out our old amp and test it. That sounds to be the problem, always has the tweeter making the crackling if the volume is up.
Next question: It sounds I will need more amp power. Can get another Pass ACA, would it make enough power for a variety of speakers or should I swap to something else with higher power to build? Would want something that sounds as good as the Pass.
Ok, will drag out our old amp and test it. That sounds to be the problem, always has the tweeter making the crackling if the volume is up.
Next question: It sounds I will need more amp power. Can get another Pass ACA, would it make enough power for a variety of speakers or should I swap to something else with higher power to build? Would want something that sounds as good as the Pass.