AudioCircle
Other Stuff => Archived Manufacturer Circles => Aspen Amplifiers => Topic started by: AKSA on 16 Nov 2010, 09:43 am
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It's here, folks, have a gander!!
Sounds sensational, I'm very, very pleased. A NAKSA 70 on steroids, no less.
One channel to one heatsink, with integrated power supply:
(http://www.audiocircle.com/image.php?id=38657)
Cheers,
Hugh
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Congratulations Hugh.
Big compliments for the design and buildquality. Great picture too. It looks really marvellous.
This might be a serious sonic competitor for your highly praised Lifeforce amp?
I would love to hear the Naksa100! Who knows...
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Thanks Hans - the picture is taken in bright sunlight from the right angle with my old Sony T200, and reworked with PhotoShop to look like something you'd want to own!! :wink:
Perhaps I should send you one, and if you like it, you buy it...... and if not, you pass it on to someone else?? :lol:
Bey,
Hugh
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Thanks Hans - the picture is taken in bright sunlight from the right angle with my old Sony T200, and reworked with PhotoShop to look like something you'd want to own!! :wink:
Perhaps I should send you one, and if you like it, you buy it...... and if not, you pass it on to someone else?? :lol:
Bey,
Hugh
Well, you can send me two right away :green: :drool:
Cheers,
Jens
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Jens,
You are on, will get cracking. I have a pair ordered from Slovenia, too, and one locally here in Melbourne, so I'm going to be a busy boy. After taking my daughter Soraya to the airport this morning, and spending some time on the Maya this afternoon, I am commencing construction of six of these NAKSA 100s.
The one photographed has now been playing for six hours, and idling overnight. All measurements are immaculate, I'm delighted with the robustness, too, and the sound quality is astonishing.
Thank you for your interest, your confidence, and your order!
Hugh
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Hi Hugh and All
Great to hear everything is going full boar ahead with the 100W version. Just a quick query, the answer I am pretty sure of anyway, can they be built as mono-blocks and paced right next to the loudspeakers? As I said I pretty sure they can but just wanted to check.
Thanks
Bill
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Hi Hugh and All
Great to hear everything is going full boar ahead with the 100W version. Just a quick query, the answer I am pretty sure of anyway, can they be built as mono-blocks and paced right next to the loudspeakers? As I said I pretty sure they can but just wanted to check.
Thanks
Bill
Hi Bill,
Yes, absolutely! These are mono modules right from the start.
What you are describing is the way I'm doing it. I will be using one 300-350 VA tranny per (mono) module, which Hugh assures me will be just fine :wink:
Cheers,
Jens
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Hey Bill,
Just what Jens said, OK? :lol:
Thanks for the post......
Cheers,
Hugh
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So what Jens and Hugh are saying suggests that if one happens to have two AKSA 100N+ already fitted into a bespoke Aspen case then one could continue to use the cases and transformers and simply substitute two appropriately milled & drilled heatsinks wearing new NAKSA 100 modules....
Yes? No? What?
Another query......if one ever gets his GK-1 going again.....would that help or hinder? Or should I discuss a trade/swap/cash exchange with the NAKSA dealer to exchange a set of GK-1M boards with Platinum upgrade & phono input parts, a pair of 'slightly used' AKSA 100N+ modules and a PS to suit for a pair of NAKSA 100 modules and passive attenuator...
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Hi Sean,
Always a pleasure!!
So what Jens and Hugh are saying suggests that if one happens to have two AKSA 100N+ already fitted into a bespoke Aspen case then one could continue to use the cases and transformers and simply substitute two appropriately milled & drilled heatsinks wearing new NAKSA 100 modules....
Yes? No? What?
Yes, although you would have to remove not just the AKSA modules but also the power supply pcb, since the NAKSA power supplies are integrated with the amp itself. If you have a hacksaw and access to a milling machine (or even an angle grinder and finish off with wet/dry sandpaper on a pane of glass!) then yes, you could use your existing heatsinks, so it's surely doable, Sean.
Another query......if one ever gets his GK-1 going again.....would that help or hinder? Or should I discuss a trade/swap/cash exchange with the NAKSA dealer to exchange a set of GK-1M boards with Platinum upgrade & phono input parts, a pair of 'slightly used' AKSA 100N+ modules and a PS to suit for a pair of NAKSA 100 modules and passive attenuator..
A GK1 works well with the NAKSA 100, and still offers sonic advantage. Not as much advantage as with the AKSA and the LF, but definitely worthwhile.
As for exchange, I cannot make any promises, as I must work very hard to sell my present stock in troubled times, let alone obsolete, used models. Sorry, but a commercial reality.....
Cheers,
Hugh
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Hi Hugh,
What's the price for new monoblocs?
Jim
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Hi Jim,
$AUD1420 for two single channels, around the same in USD.
Add 10% GST for Oz; shipping is extra.
These are fully assembled, tested, and g'teed.
Thanks for the inquiry,
Hugh
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Hi All,
I have been fortunate enough to have heard Hugh's new Naksa 100 when connected to the VSonic speakers MK11. The Naksa 100 has raised the bar even higher and the music is absouletly stunning now that Seas woofers are being used. Well done Hugh.
Cheers,
Laurie
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Hey Bill,
Just what Jens said, OK? :lol:
Thanks for the post......
Cheers,
Hugh
Hi Hugh,
So just wondering, could I use say a 500VA or say a 600VA transformer and build both of these as one amp? Do you think I'd be losing much?
Ray
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Hi Ray,
Yes, a single 425VA, or 500VA, or even 600VA would be fine for the NAKSA 100; dual trafos seem not required for this amp, it makes no difference to the imaging performance, which came as a surprise.
The amp was designed as an austerity model for tough times, and is fully $260 cheaper than the LF100 which it will eventually replace. The fact it performs with such verve has been a very pleasant outcome, and just goes to show that despite decades of engineering experience in our history and modern simulation tools there is no substitute for taking a gamble and building it. Despite what is bandied about there is no way you can tell how an amp will sound from the schematic; it will give you an idea, perhaps, if you are very experienced, but the acuity of human hearing is such that no instrumentation can rival it and this makes all amp assessment not just a process of measurement, but a careful session of listening.
Laurie, you must have email up again?
Laurie has mentioned the VSonics Mark II. As many here know, since the Peerless 830884 dropped off the horizon with the demise of Tymphany, we have been obliged to redevelop the speaker. Laurie chose the SEAS Prestige series CA22RNY, another 8" paper cone driver, for it's high force factor, low Qts, 92dB sensitivity, and very light cone (17.9g!!). This has proven most successful. The good news is that for existing owners of the VSonics, the conversion to an even better speaker is a walk in the park, and I will contact them separately.
Last night I played the new amp and speakers to a good friend, a chemical engineer of long experience in audio who has owned both the AKSA and the GK1 for some years.
Rick was stunned. We played a variety of test tracks, from Oremi, Dali Stereo CD, NY Rave 2006, and a female vocalist he knows very well, and he felt that the realism, the immediacy, the musicality, the slam, and the silence between notes was the best he has ever heard in his life. This from a guy who always closes his eyes whilst listening, for whom musicality, imaging and realism are the most important aspects. For myself, I think I agree with Rick, but I'm particularly proud of the layout, it really looks the ducks guts!!
Cheers,
Hugh
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Hello Hugh
Again, with the Naksa 100, you proved that the best amps in the market are not alway from the "big" names of the audio industry.
Congratulation.
Bye
Gaetan
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Merci, Gaetan,
Praise from you is very nice, appreciated.
Hugh
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Hi Ray,
Yes, a single 425VA, or 500VA, or even 600VA would be fine for the NAKSA 100; dual trafos seem not required for this amp, it makes no difference to the imaging performance, which came as a surprise.
Hi Hugh,
ok, so somewheres between a 425 to 600VA transformer is fine. Would I be gaining anything by using a bigger one, the 425VA versus the 600VA? Sure, there are theoretical gains by using a bigger transformer, but in reality there is a substantial cost between the two.
How big is each unit? Inches please? i presume soldering is in order here. So it's the AC, the RCA and Speakers to wire up, and of course some way to turn the amp on or off. Or are you providing connectors you just solder to them and go? Since I can't see your pics, then is the heatsinks included too?
What voltage or range of voltages and current rating for the Trafo for the two secondaries should I be looking at?
i'd figure another couple hundred bucks US for Trafo case and various wire and connectors would finish this out.
Speaking of wiring, are you suggesting two or three prongs for the AC mains?Are you using a captive cord, or IEC type?
I think that rounds it out for questions.
Ray Bronk
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Hi Ray,
You keep me on my toes, but I love the careful thought behind your curiosity, thanks for the questions..... forces me to order my thinking for my website copy, too, a very good thing! You might appreciate that as the designer, and dominated by the design issues, I'm not so focussed on the issues of installing the completed module into a suitable enclosure, and the minutia of the connections.
ok, so somewheres between a 425 to 600VA transformer is fine. Would I be gaining anything by using a bigger one, the 425VA versus the 600VA? Sure, there are theoretical gains by using a bigger transformer, but in reality there is a substantial cost between the two.
As a general rule, I like to use a transformer of at least twice the rating of the max rms power of the amp into 8R. This is only sensible from a headroom POV. This places the minimum rating at 400VA, so 425VA would be optimal. I suggested the higher ratings of 500VA and 600VA because toroidal trafos are made in common values of 500VA and 625VA and DIYers are well known for overbuilding. I will confess to early auditions using a single 300VA, and with my 8R VSonics I can say that this was entirely adequate. However, I really would prefer a minimum trafo size of 400VA, with 425VA the nearest preferred rating that is commonly available.
How big is each unit? Inches please? i presume soldering is in order here. So it's the AC, the RCA and Speakers to wire up, and of course some way to turn the amp on or off. Or are you providing connectors you just solder to them and go? Since I can't see your pics, then is the heatsinks included too?
Each unit is 300mm (11.95") long (heatsink length), 75mm (2.95") tall (fin height), and 105mm deep (4 1/8") deep (top of filter caps to tip of fin).
The only soldering necessary is input hot/cold (pcb pins) and the flying lead connections to the binding posts for the speaker. Speaker connections to the board are high quality pcb spade connectors, all supplied with the module. Connectors are also supplied for the transformer secondary connections to the module (four, two for each secondary). All connectors are crimped, not soldered. It really couldn't be simpler. The mains connection from transformer to IEC socket, including switch, are NOT supplied. These too are simple but will require soldering for maximum safety and reliability.
Two heatsinks are supplied with two single channel modules, one for each amp channel. Each high quality, cast alloy sink weighs 1.105Kgs, or just under 2.5 lbs each, 5 lbs plus the weight of the modules.
What voltage or range of voltages and current rating for the Trafo for the two secondaries should I be looking at? I'd figure another couple hundred bucks US for Trafo case and various wire and connectors would finish this out.
Speaking of wiring, are you suggesting two or three prongs for the AC mains? Are you using a captive cord, or IEC type?
I think that rounds it out for questions.
For a 425VA toroid, at the 35Vac secondaries specified, this corresponds to a 6A rating for each secondary. For 500VA, this increases to 7.15A rating. Your estimate of around $200 is about right!
I suggest a three prong IEC, so that the case can be power earthed. The modules both have provision for a chassis earth as well, recommend ultra-safe practice. The chassis earth is also a press, pcb spade connection, with no soldering.
Thanks for the questions, Ray, very appropriate and carefully thought through!
Cheers,
Hugh
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So - will an evening with the NAKSA 100 be arranged at the Melbourne Audio Club?
This seems to be a very discerning forum, and it is always good to hear comments from these guys ... :wink:
Cheers,
Jens
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Hi Ray,
You keep me on my toes, but I love the careful thought behind your curiosity, thanks for the questions..... forces me to order my thinking for my website copy, too, a very good thing! You might appreciate that as the designer, and dominated by the design issues, I'm not so focussed on the issues of installing the completed module into a suitable enclosure, and the minutia of the connections.
Hi Hugh,
Thanks for the compliments. I had built from a preassembled kit from one of your mates there in Australia and I went through hell getting it finally to work the way it was to be set up. It wasn't his fault though. If I knew what I know now, I would have done things a lot differently.
So from what I read, then probably having each heatsink on the left and right side of the case respectively per channel, and then the transformer in the middle? There's no separate PS board? Just trying to imagine how this would all fit together.
Will the heatsinks be already mounted on the board? Are the terminals clearly labeled on the board?
I presume you are at the input having the amp cap coupled? Ooh that's right, your keeping voltage on the caps minimizes any effects that caps can give. On the output side, what sort of protection is built in there? So if there is a short or current spike at the outputs, I presume like the SkA amp you're using fuses?
on the 8 or 4 ohm or lower issue, is 35 V enough for the transformer? What about handling speakers with difficult loads, say Maggies, or if someone still happens to have a pair, Dolquists speakers. Well, probably not, but just trying to think of some speakers with difficult loads.
Ok, so on the mounting of the board or heatsinks to the case, I presume there's probably holes in the corresponding sides of the heatsink to mount them on there sides to the bottom plate of the case? The fins would stick out the sides of the case. The fins themselves are probably a couple of inches from tip to base, so just trying to get a handle on the case size. Maybe instead there are holes on the ends of the heatsink to mount the sinks that way.
What about fuse sizes at the input say 7A or so for a 500VA trafo?
Probably should have PM you about all this, but maybe someone who is buying and building your amp kit for the first time might learn something from my questions here.
Thanks for answering my questions. As soon as I can get some cash together, will probably get this amp. I figure I could do a lot worse for the money spent, and it would be a standard for me and others for years.
Ray Bronk
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Hi Ray,
Nice questions - you clearly have been down this path, and know all the bumps in the road! :lol:
So from what I read, then probably having each heatsink on the left and right side of the case respectively per channel, and then the transformer in the middle? There's no separate PS board? Just trying to imagine how this would all fit together.
Yes, left channel mounted left side, right channel mounted right side, trafo in the center. Ideal setup. No, there's no separate PS board, you are correct, by mounting power supplies on board it great simplifies wiring and makes it difficult, VERY difficult, to create sparks!
Will the heatsinks be already mounted on the board? Are the terminals clearly labeled on the board?
Yes, the boards are mounted flat against the heatsink with four M3 screws which also secure the output devices. It's a very compact arrangement, and with the amp boards vertical, it gives more space inside the enclosure for the trafo, which is about 4.8" in diameter for a 425VA. Of course, for best cooling, the heatsinks should have their vertical fins exposed at the sides, which means the heatsinks, which are fine looking beasts, become a feature of the enclosure. All terminations are very clearly marked!
I presume you are at the input having the amp cap coupled? Ooh that's right, your keeping voltage on the caps minimizes any effects that caps can give. On the output side, what sort of protection is built in there? So if there is a short or current spike at the outputs, I presume like the SkA amp you're using fuses?
Yes, input is cap coupled, but carries about 2.5V of bias across this cap, greatly enhancing sonics.
Output has two protection systems, neither of them dynamic. (I find dynamic limiting degrades must be quite complex to avoid degrading the sound quality, and prefer other means). One is fusing; 2 x 7.5A fast flow fuses on the rails supplying the output devices; and the other is a current limited emitter resistor on the output, which is designed to fail open just before the fuses. In this way both the output stage and the speaker is protected. This system works very well for direct shorts too.
on the 8 or 4 ohm or lower issue, is 35 V enough for the transformer? What about handling speakers with difficult loads, say Maggies, or if someone still happens to have a pair, Dolquists speakers. Well, probably not, but just trying to think of some speakers with difficult loads.
35Vac secondaries will deliver 48-52V DC to the rails, depending on your local mains. This is enough for 100W into 8R, around 180W into 4R. For 90dB/watt/metre speakers, a medium sized listening room, and moderate masochism, this is quite sufficient to bring pain to any listening session. If you want even more, a 4R speaker is a good idea...... and the output stage is very robust. But who knows? In the future I might build something with more power than the PA on USS Ronald Reagan!! :wink:
"Thanks for answering my questions. As soon as I can get some cash together, will probably get this amp. I figure I could do a lot worse for the money spent, and it would be a standard for me and others for years."
A pleasure, Ray.
Hugh
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Hi Ray,
Nice questions - you clearly have been down this path, and know all the bumps in the road! :lol:
Hi Hugh,
Just one last question I think? Ok, so to mount the heatsinks on the case, would you have holes on the vertical edges of the heatsinks to mount to the open sides of the case, or are there holes on the bottom and tops of the heatsink to mount to the bottom plate of the case?
Ray Bronk
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Ray,
My tentative answer to this would be that because you can choose to mount the heatsink either on the sides of the case, completely exposed, or internally, hidden, the choice would be up to you.
Therefore I've not supplied holes; I have on the NAKSA 70, because in that case the heatsink is always internal, but for the 100, there is this choice. I feel that drilling holes which may never be used is inappropriate, and since a simple drill and a cordless is all you need, best to not drill any holes.
But it's not a big deal, holes are very easy to drill in Al.
Cheers,
Hugh
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Folks,
I'm furiously assembling NAKSA 100s now. Here's a piccie of four all complete, awaiting mounting on their heatsinks then testing:
(http://www.audiocircle.com/image.php?id=39136)
These NAKSAs are premium, pricier versions with Nichicon Gold Muse caps; regular NAKSAs have the Nichicon KZ.
This batch is ten; all are accounted for, all overseas. (Mind you, from Oz, just about everywhere is overseas!! :lol:)
I cannot begin to describe how happy I am with the sonics of this amp, might even call it La Stupenda! :roll:
Cheers,
Hugh
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Folks,
I'm furiously assembling NAKSA 100s now. Here's a piccie of four all complete, awaiting mounting on their heatsinks then testing:
(http://www.audiocircle.com/image.php?id=39136)
These NAKSAs are premium, pricier versions with Nichicon Gold Muse caps; regular NAKSAs have the Nichicon KZ.
This batch is ten; all are accounted for, all overseas. (Mind you, from Oz, just about everywhere is overseas!! :lol:)
I cannot begin to describe how happy I am with the sonics of this amp, might even call it La Stupenda! :roll:
Cheers,
Hugh
Hi hugh,
How much for the premium version?
Ray Bronk
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Hi Ray,
Another $AUD90, making it $AUD1510 all up with the premium supply!
Cheers,
Hugh
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Hi Hugh,
How are the modules coming along? - can hardly wait to get mine :drool:
Very much looking forward to giving them a listen :green:
Cheers,
Jens
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Hi Jens,
I'm mounting them up now; have done four today, another couple tomorrow, Sunday, and Monday. I believe yours will go out on Tuesday, in time for Santa Claus, Jens - I am sorry for delays, but believe me I'm pedalling as fast as I can!!
They look damned nice too..... :bounce:
Cheers,
Hugh
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Hi Hugh,
No worries about speed - just wanted to know so I can start getting the trannies :wink:
Would you say that 300VA, 35 volts would be fine for monoblocks?
Cheers,
Jens
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Hi Hugh,
No worries about speed - just wanted to know so I can start getting the trannies :wink:
Would you say that 300VA, 35 volts would be fine for monoblocks?
Cheers,
Jens
Hi Jens,
Well, I'm not Hugh, but he kinda answered your question by answering mine. I had asked if a 425 VA versus 600 VA what would be the difference? I suggest you look up the page a bit, and you'll see the answer. To sum it up, I don't think if memory serves me right, that making these monoblocks would be of any advantage sonically. He said he had used 300VA but he would have preferred at least 425VA. So if you aren't gonna have them each behind your speakers, then make one unit with a 500VA 35 V and save yourself the cost of fabbing a case for two. If you want to put your money in to the sonics, then get the upgraded one for $1510 which has better caps and such. just a suggestion. That will be one sweet killer amp, no matter what version you get.
Ray Bronk
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Hi Jens (and Ray!!),
The two channels of the NAKSA 100 are normally served by one transformer, with rating from 425VA to 500VA (standard ratings, commonly available).
If you go for monobloc construction, a choice made quite deliberately so you can place the amps right up close to the speakers, then half these ratings would be fine, and more would be no bad thing.
So, you could go as low as 225VA PER CHANNEL, or as high as 300VA PER CHANNEL. Again, these are commonly available ratings. The choice would be entirely arbitrary. Both would give very good results, and in fact would be a bit simpler to wire up because you would not have to splice two additional wires onto each secondary winding of a single transformer to accommodate two modules.
Yes, Jens, the 35Vac rating for each secondary is correct!
Ray, Jens has thoughtfully specified the more expensive caps... a good choice, they are superb caps, I hope my supply holds out!!
Cheers,
Hugh
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Hi Jens (and Ray!!),
The two channels of the NAKSA 100 are normally served by one transformer, with rating from 425VA to 500VA (standard ratings, commonly available).
If you go for monobloc construction, a choice made quite deliberately so you can place the amps right up close to the speakers, then half these ratings would be fine, and more would be no bad thing.
So, you could go as low as 225VA PER CHANNEL, or as high as 300VA PER CHANNEL. Again, these are commonly available ratings. The choice would be entirely arbitrary. Both would give very good results, and in fact would be a bit simpler to wire up because you would not have to splice two additional wires onto each secondary winding of a single transformer to accommodate two modules.
Yes, Jens, the 35Vac rating for each secondary is correct!
Ray, Jens has thoughtfully specified the more expensive caps... a good choice, they are superb caps, I hope my supply holds out!!
Cheers,
Hugh
Hi Hugh,
Well, I'm almost envious. I had suggested just one Trafo, so he wouldn't have to fab two cases. i figured if I read you correctly, no real advantage of having monoblocks unless you are putting them behind each speaker. The other way around this splicing stuff is to get a Trafo with two secondaries of the same voltage. This way you aren't doing to much sacrificing any current needs by pulling off of one secondary. Hey just some food for thought.
Ray
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Hi Jens (and Ray!!),
The two channels of the NAKSA 100 are normally served by one transformer, with rating from 425VA to 500VA (standard ratings, commonly available).
If you go for monobloc construction, a choice made quite deliberately so you can place the amps right up close to the speakers, then half these ratings would be fine, and more would be no bad thing.
So, you could go as low as 225VA PER CHANNEL, or as high as 300VA PER CHANNEL. Again, these are commonly available ratings. The choice would be entirely arbitrary. Both would give very good results, and in fact would be a bit simpler to wire up because you would not have to splice two additional wires onto each secondary winding of a single transformer to accommodate two modules.
Yes, Jens, the 35Vac rating for each secondary is correct!
Ray, Jens has thoughtfully specified the more expensive caps... a good choice, they are superb caps, I hope my supply holds out!!
Cheers,
Hugh
Hi Hugh,
Not to complicate stuff I hope, but this has to be center tapped? Also, can you use a higher voltage on the Trafo. I think I might have a 40V which would bring the supply voltage up to I think about 55 or 56 V. Would that be a problem?
Ray
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Ray,
CAUTION: THERE IS NO CENTER TAP REQUIRED FOR THIS AMP.
BOTH SECONDARIES ARE USED INDEPENDENTLY AND ARE NOT INTERCONNECTED TO FORM A CENTER TAP.
I do not recommend 40Vac trafos, unfortunately. This is taking the output stage a bridge too far, particularly risky for 4R loads. Only two output pairs are used for this amp; for 56V rails, corresponding to 40Vac trafos, you need THREE output pairs, not TWO.
Hope this helps,
Hugh
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Ray,
CAUTION: THERE IS NO CENTER TAP REQUIRED FOR THIS AMP.
BOTH SECONDARIES ARE USED INDEPENDENTLY AND ARE NOT INTERCONNECTED TO FORM A CENTER TAP.
I do not recommend 40Vac trafos, unfortunately. This is taking the output stage a bridge too far, particularly risky for 4R loads. Only two output pairs are used for this amp; for 56V rails, corresponding to 40Vac trafos, you need THREE output pairs, not TWO.
Hope this helps,
Hugh
Hi Hugh,
Ok, thanks for the info. I'm not wishing to bridge your amps. I was just wondering if that trafo needs to be center tapped. Ok, good deal.
So there you go Jens. Unless you are putting them each behind each speaker, or you just happen to have two trafos at 300VA, then just get one 500VA 35V, and one case, and be most blissfully happy, and know that you probably have something that sounds three times its value in sound.
meanwhile, I'll just sit here lol, and wonder where I can get approximately $1510 and a couple hundred more to buy and put this all together.
Back to you Hugh, Are you suggesting any types of wiring schemes for the input and speaker wires?
Ray Bronk
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Ray,
Thanks for your input! I am indeed going to have the modules mounted on the back of my speakers :wink:
Here's a photo of one of my speakers:
(http://www.audiocircle.com/image.php?id=39562)
As you can see, the speaker consists of three modules: bass, treble/mid, and bass. A NAKSA 100 will be mounted on the back of each bass module, and a NAKSA 70 (which is a 2-channel module) will be mounted on the back of the treble/mid module. Each NAKSA module will have its own toroid transformer.
The entire array will be 'governed' by DSP-controlled electronic x-over/equalizer units that will be housed in the treble/mid enclosure.
Bass drivers are 8 ohms, and since each NAKSA 100 module will be powering two drivers, this will be a 4 ohm load. In 4 ohms, the NAKSA 100s deliver close to 200 watts per module, so I'll have around 800 watts of bass power! And that is 'direct-drive', as amplifiers are connected directly to the drivers with no energy-consuming passive x-over inbetween 8)
With this setup, speaker cables will be non-existent (apart from the very short lengths running from the amps into the enclosures) and speaker cable influence on sound will be eliminated. Also, with amplifiers mounted on the rear of speakers, it will be easy to hide the rest of the system (GK-1R, heavily modified Oppo BDP-83SE, and an old Denon tuner) and have a very 'clean' looking system :green:
Cheers,
Jens
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Ray,
Thanks for your input! I am indeed going to have the modules mounted on the back of my speakers :wink:
Here's a photo of one of my speakers:
(http://www.audiocircle.com/image.php?id=39562)
As you can see, the speaker consists of three modules: bass, treble/mid, and bass. A NAKSA 100 will be mounted on the back of each bass module, and a NAKSA 70 (which is a 2-channel module) will be mounted on the back of the treble/mid module. Each NAKSA module will have its own toroid transformer.
The entire array will be 'governed' by DSP-controlled electronic x-over/equalizer units that will be housed in the treble/mid enclosure.
Bass drivers are 8 ohms, and since each NAKSA 100 module will be powering two drivers, this will be a 4 ohm load. In 4 ohms, the NAKSA 100s deliver close to 200 watts per module, so I'll have around 800 watts of bass power! And that is 'direct-drive', as amplifiers are connected directly to the drivers with no energy-consuming passive x-over inbetween 8)
With this setup, speaker cables will be non-existent (apart from the very short lengths running from the amps into the enclosures) and speaker cable influence on sound will be eliminated. Also, with amplifiers mounted on the rear of speakers, it will be easy to hide the rest of the system (GK-1R, heavily modified Oppo BDP-83SE, and an old Denon tuner) and have a very 'clean' looking system :green:
Cheers,
Jens
Hi Jens,
Well, you have me at a slight disadvantage. I am a person who is totally blind, so sorry ol' man, can see your pics. But the setup sure is gonna sound good when it's all through being assembled. Looks like you won't need much case work. That would be worth listening to when it is all done. If I may be nosy, how much do you think it's gonna cost you total when it's all done?
Ray Bronk
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Jens, Ray,
I'm always amused when people slowly begin to see just how serious Jens is with his system. He has NAKSA 70s already, so knows that the 100 is very similar, and to be selected in this company with some of the finest drivers and baffles on the planet is a great privilege....
Jens, one point; you might consider a Zobel correction for all drivers to correct phase shift due to the inductance in each voice coil. I have found this improves depth of image slightly..... but I suggest this only because global feedback amps, even the NAKSA (which has 31dB of global nfb), always benefits with this slight amendment.
Thanks for sharing your system, truly impressive!!
Hugh
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Jens, Ray,
I'm always amused when people slowly begin to see just how serious Jens is with his system. He has NAKSA 70s already, so knows that the 100 is very similar, and to be selected in this company with some of the finest drivers and baffles on the planet is a great privilege....
Jens, one point; you might consider a Zobel correction for all drivers to correct phase shift due to the inductance in each voice coil. I have found this improves depth of image slightly..... but I suggest this only because global feedback amps, even the NAKSA (which has 31dB of global nfb), always benefits with this slight amendment.
Thanks for sharing your system, truly impressive!!
Hugh
Hi Hugh,
Well, lol, I didn't have any idea that was what he was doing.
Hugh, so what do you suggest for the leads for speakers and input? i'd probably use 18 gauge wire for the power side. The Trafos I've seen use 18 gauge, so anything bigger than that would seem ridiculous to use. Anyhow, just thought I'd ask your opinion.
Ray
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Ray,
I fully understand that you cannot see what is going on, however, I hope my descriptions make it fairlly clear what what I am doing :D
Please feel free to ask away, if anything isn't clear!
Hugh,
I know about the Zobel corrections, and I will try with and without. For the tweeter, which will be replaced with the newest Scan-Speak beryllium dome tweeter that has a neodymium magnet system, there will probably not be much to gain. The current micdrange driver will be replaced with an Accuton ceramic driver (weighing around 3.5 kilos!). For this driver, there might be something to be had. However, this driver will be operating in an enclosure with an 'acoustic valve' (a dampened opening in the enclosure, which evens out the impedance peak), so the effect may be cancelled out by the passive components that are introduced. However, I will try it out!
For the bass drivers - I don't know if there is anything to be had there ... :green:
Cheers,
Jens
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Ray,
I fully understand that you cannot see what is going on, however, I hope my descriptions make it fairlly clear what what I am doing :D
Please feel free to ask away, if anything isn't clear!
Hugh,
I know about the Zobel corrections, and I will try with and without. For the tweeter, which will be replaced with the newest Scan-Speak beryllium dome tweeter that has a neodymium magnet system, there will probably not be much to gain. The current micdrange driver will be replaced with an Accuton ceramic driver (weighing around 3.5 kilos!). For this driver, there might be something to be had. However, this driver will be operating in an enclosure with an 'acoustic valve' (a dampened opening in the enclosure, which evens out the impedance peak), so the effect may be cancelled out by the passive components that are introduced. However, I will try it out!
For the bass drivers - I don't know if there is anything to be had there ... :green:
Cheers,
Jens
Hi Jens,
The only possible issue I see now is your IC length between your power amps and preamp. Depending on the cable being used, you could have capacitance issues, but that a different topic for a different circle. you probably already have that all figured out.
Happy listening when you get it all together.
Ray Bronk
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Hi Ray,
I make my own interconnects. These are twisted to minimize capacitance issues. Also, the x-over inputs are designed with long interconnects in mind.
I will need to shield the interconnects, but that is not an issue :wink:
Cheers,
Jens
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Hi Ray,
I make my own interconnects. These are twisted to minimize capacitance issues. Also, the x-over inputs are designed with long interconnects in mind.
I will need to shield the interconnects, but that is not an issue :wink:
Cheers,
Jens
With respect, Jens, if you are twisting 'hot' & 'ground' wires of your IC together, you are generating almost maximum 'C'. (The only configuration with higher 'C' would be foil ICs where the '+' & '-' foils are separated only by, say, 1 layer of plumber's teflon tape.)
You need to space the wires apart to reduce 'C'. (BTW, this naturally increases 'L' but this is irrelevant in an IC, due to the extremely low current flowing.)
Regards,
Andy
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With respect, Jens, if you are twisting 'hot' & 'ground' wires of your IC together, you are generating almost maximum 'C'. (The only configuration with higher 'C' would be foil ICs where the '+' & '-' foils are separated only by, say, 1 layer of plumber's teflon tape.)
You need to space the wires apart to reduce 'C'. (BTW, this naturally increases 'L' but this is irrelevant in an IC, due to the extremely low current flowing.)
Regards,
Andy
Really?
I've always been told that twisting reduces capacitance, but increases inductance ...
However, it may turn out not to be a problem, since the long interconnect run will be between my GK-1R preamp and the x-overs, as this is what the x-over manufacturer recommends. I know of a few people that use these x-overs with long interconnects with no problems at all, i.e. no loss of high frequency (which could be the danger if capacitance goes too high). They all use interconnects that are either twisted or just standard parallel runs (supposedly worse than twisted).
I'll try it out - haven't had any problems with long interconnects in the past. I even used to have a 10 metre shielded, standard, parallel-run interconnect from my hifi video recorder to my stereo system. This worked beautifully :wink:
Cheers,
Jens
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Really?
I've always been told that twisting reduces capacitance, but increases inductance ...
However, it may turn out not to be a problem, since the long interconnect run will be between my GK-1R preamp and the x-overs, as this is what the x-over manufacturer recommends. I know of a few people that use these x-overs with long interconnects with no problems at all, i.e. no loss of high frequency (which could be the danger if capacitance goes too high). They all use interconnects that are either twisted or just standard parallel runs (supposedly worse than twisted).
I'll try it out - haven't had any problems with long interconnects in the past. I even used to have a 10 metre shielded, standard, parallel-run interconnect from my hifi video recorder to my stereo system. This worked beautifully :wink:
Cheers,
Jens
I have a similar situation to you, Jens, in that I have 11m ICs between my GK-1 and the active XOs.
I have no sonic problems (ie. HF roll-off) because:
a) I use low-C cable (although, yes, the fact that the ICs are 11m long makes them have a higher 'C' than many other people have), and
b) My Zin/Zout ratio is very high. Zout of the GK-1 is 120ohms, I believe; Zin of the active XOs is 100K. Hence my ratio is >800 ... and this high a ratio can cope with the relatively high total 'C' with no problems. :D
And re. twisting and 'C' and 'L':
* high 'C' and low 'L' results from having the two conductors very close together. (Foil cables are the best example of this.)
* low 'C' and high 'L' result from spacing the two conductors apart. (Naim NAC-5 is a good example of this, for speaker cable.)
Regards,
Andy
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I have a similar situation to you, Jens, in that I have 11m ICs between my GK-1 and the active XOs.
I have no sonic problems (ie. HF roll-off) because:
a) I use low-C cable (although, yes, the fact that the ICs are 11m long makes them have a higher 'C' than many other people have), and
b) My Zin/Zout ratio is very high. Zout of the GK-1 is 120ohms, I believe; Zin of the active XOs is 100K. Hence my ratio is >800 ... and this high a ratio can cope with the relatively high total 'C' with no problems. :D
And re. twisting and 'C' and 'L':
* high 'C' and low 'L' results from having the two conductors very close together. (Foil cables are the best example of this.)
* low 'C' and high 'L' result from spacing the two conductors apart. (Naim NAC-5 is a good example of this, for speaker cable.)
Regards,
Andy
Well, my interconnects will only be approx. 3 metres long each, perhaps even only 2.5 metres. X-over input impedance is around 10 k, which according to the manufacturer is more than enough to counter any slight increase in capacitance due to the extra length compared to a standard length (e.g. 1 metre) interconnect.
Also, I will have measuring equipment available, so any roll-of will quickly be revealed.
It is not a worry!
Cheers,
Jens
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Just got word from Hugh yesterday that my modules are on their way to Denmark :D
I am very much looking forward to putting these little darlings to work in my system :drool:
Even though they are "only" going to power the bottom end of my system, it should be borne in mind that with an x-over frequency of 250 Hz, they will have a profound effect on both lower midrange as well as the actual bass range.
More later :wink:
Cheers,
Jens
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Jens,
Let us hope the transit is swift and secure, and that they arrive without damage. It's a long way from Oz to Denmark!! :lol:
I received word yesterday from Miro in Ljubliana that his NAKSA 100s made it through safely just yesterday! I'm very happy; he is hooking them up this weekend, so very soon we shall have his assessment!
These really are stunning performers, with a level of bass output, midrange liquidity and top end clarity that is a revelation. It's Saturday night and I've just started on the next ten modules, with more orders swiftly coming on.....
:bounce:
Cheers,
Hugh
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Jens,
Let us hope the transit is swift and secure, and that they arrive without damage. It's a long way from Oz to Denmark!! :lol:
I received word yesterday from Miro in Ljubliana that his NAKSA 100s made it through safely just yesterday! I'm very happy; he is hooking them up this weekend, so very soon we shall have his assessment!
These really are stunning performers, with a level of bass output, midrange liquidity and top end clarity that is a revelation. It's Saturday night and I've just started on the next ten modules, with more orders swiftly coming on.....
:bounce:
Cheers,
Hugh
Hi Hugh,
A question about wiring. I know you don't really put much in to that, but I was wondering what you would use for both the input and speaker/output wiring? Also, how long a length between the board and case terminals for both in and outs would I need? Thank you.
Ray Bronk
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Hi Ray,
I use color coded multistrand high current wire I source locally, six nines copper, rated to 25A continuous. I have not noticed differences with the short runs used inside amps with the one exception of milspec aeronautical wire (Whitmore and Tygadure) which is silver coated copper, with teflon insulation. That seems to sound quite tizzy.
YMMV, of course, but wire and cable choices become more significant with longer distances - like speaker cables.
Cheers,
Hugh
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Hi Ray,
I use color coded multistrand high current wire I source locally, six nines copper, rated to 25A continuous. I have not noticed differences with the short runs used inside amps with the one exception of milspec aeronautical wire (Whitmore and Tygadure) which is silver coated copper, with teflon insulation. That seems to sound quite tizzy.
YMMV, of course, but wire and cable choices become more significant with longer distances - like speaker cables.
Cheers,
Hugh
Hi Hugh,
ok, so how much for input and output wiring approximate in inches respectively are you using, say 6 inches for input and same for outputs. This is assuming case config with amps on either side of case with Trafo in center.
Ray
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Hi Ray,
I use about 6" of coax for inputs, and around 8" for outputs, left and right channels. Power supply leads are around the same length.
Not a lot, in truth, most important qualities are EMI resistance for signal wire, and low DCR for all other leads. The output inductor and 10R resistor are inserted into the hot output wire.
Cheers,
Hugh
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Hi Ray,
I use about 6" of coax for inputs, and around 8" for outputs, left and right channels. Power supply leads are around the same length.
Not a lot, in truth, most important qualities are EMI resistance for signal wire, and low DCR for all other leads. The output inductor and 10R resistor are inserted into the hot output wire.
Cheers,
Hugh
Hi Hugh,
That output inductor, is that to stop possible oscillations at high freqs? i had an amp once that had an inductor in series with one of the leads of the outputs going to the speakers. He told me this was just a safety precaution, to prevent the amp from going in to oscillations at high frequencies if it was overdriven. Well, I then bypassed the choke, and the amp sounded even better without it.
Ray Bronk
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The inductor is a useful tool. It prevents EMI entering the amplifier from the oft unshielded speaker cables; they act as an aerial. Secondly, at very high frequencies, supersonic, should there be any transient instability in the amp, the inductor prevents the amp 'seeing' the highly reactive load of the speaker, with its voice coil inductance and high capacitance values in the crossover. This tends to stomp on oscillations before they do any damage.
Any feedback amp should carry an inductor on its output, typically 1uF to abour 7uH, depending on the design. I use 1.4uH. The jury is out whether you can 'hear' any bad effects from this inductor, but I find that designing for worst case is only prudent.
Cheers,
Hugh
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The inductor is a useful tool. It prevents EMI entering the amplifier from the oft unshielded speaker cables; they act as an aerial. Secondly, at very high frequencies, supersonic, should there be any transient instability in the amp, the inductor prevents the amp 'seeing' the highly reactive load of the speaker, with its voice coil inductance and high capacitance values in the crossover. This tends to stomp on oscillations before they do any damage.
Any feedback amp should carry an inductor on its output, typically 1uF to abour 7uH, depending on the design. I use 1.4uH. The jury is out whether you can 'hear' any bad effects from this inductor, but I find that designing for worst case is only prudent.
Cheers,
Hugh
Hi Hugh,
For an application with virtually no speaker cables (only approx. 20 cms) and no x-over (i.e. no capacitance) between amp and driver - do you think it would be safe to remove the inductor?
Cheers,
Jens
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Hi Hugh,
For an application with virtually no speaker cables (only approx. 20 cms) and no x-over (i.e. no capacitance) between amp and driver - do you think it would be safe to remove the inductor?
Cheers,
Jens
I would be interested in this, too, Hugh - given I have an identical situation (directly coupled amps with 20cm spkr cables).
If you remember, we put in parallel caps across the output BPs of each monoblock to "get rid of" the RFI which we heard in the Maggie drivers - so mebbe the output inductor is no longer needed? :?
Regards,
Andy
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Andy, Jens,
In the case of Maggies, absolutely, IF there is a 3.3nF cap across the speaker terminals to short out any RF which might be picked up and otherwise radiated into the amp.
For conventional drivers, yes, you could try it with and without, but the NAKSA inductors are just 1.5uH, not big, and I rather doubt you'd hear a difference, but it's surely worth a try.
The NAKSA has reduced global feedback, just 31dB, and a VERY low impedance feedback network, making it very difficult for EMI to get into the amplifier. These features make it possible to delete the output inductor, BUT, you need to verify first if there is an audible difference with it and without it.
As you note, my conservatism and extreme caution is showing. After 15 years in this game, I've seen some might interesting things happen, so I'm very aware that problems lurk at every turn!!
Hugh
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Andy, Jens,
In the case of Maggies, absolutely, IF there is a 3.3nF cap across the speaker terminals to short out any RF which might be picked up and otherwise radiated into the amp.
For conventional drivers, yes, you could try it with and without, but the NAKSA inductors are just 1.5uH, not big, and I rather doubt you'd hear a difference, but it's surely worth a try.
The NAKSA has reduced global feedback, just 31dB, and a VERY low impedance feedback network, making it very difficult for EMI to get into the amplifier. These features make it possible to delete the output inductor, BUT, you need to verify first if there is an audible difference with it and without it.
As you note, my conservatism and extreme caution is showing. After 15 years in this game, I've seen some might interesting things happen, so I'm very aware that problems lurk at every turn!!
Hugh
Hi Hugh,
Thank you for this input. I will try it once I have the NAKSA modules mounted on the rear of the speakers, which should make it very easy to bypass the inductor. Theoretically, I believe an inductor affects dampening factor, but I'm not sure how much. Anyway, an inductor is a passive component I would prefer to be without in an all-out active setup :wink:
Andy, if you get to try it out before me, kindly post results here :)
Cheers,
Jens
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Hi Hugh,
Thank you for this input. I will try it once I have the NAKSA modules mounted on the rear of the speakers, which should make it very easy to bypass the inductor. Theoretically, I believe an inductor affects dampening factor, but I'm not sure how much. Anyway, an inductor is a passive component I would prefer to be without in an all-out active setup :wink:
Andy, if you get to try it out before me, kindly post results here :)
Cheers,
Jens
Hi Hugh and Jens,
From what I remember on this one amp I had, it had an inductor in series with one of the speaker leads. There was a difference without it, but suttle at best. If anything the only difference I remember is without the inductor there was a slight volume increase. That was mainly it. Let's put it this way, if the unit in question sounds pretty darn good with it in, just tacking a wire across the inductor will tell you if there is a difference or not. And you can do this in real time, while it is playing tunes. The amplifier I had was manufactured out of Canada. Don't remember the brand. This was in the early .80's. Since then, amplifier designs and parts have improved immensely.
Ray