AKSA Power GK-1R+ Linkwitz ORION project

Builder Brad · « **on:** 12 May 2005, 06:11 pm »

Hello Everybody!

I have been enjoying my pair of Linkwitz Orions and Thors subs for the last eighteen months and really thought that I had got the "build it" bug out of my system, having built what is considered to be "the last speaker you will ever need to build".

For anyone not in the know the Orion is a three/four way with the Thor, active speaker designed by Siegfried Linkwitz the same as in Linkwitz Riley more details can be found on:

http://www.linkwitzlab.com/

I had seen a few reviews over the last six months for the AKSA power amplifiers and initially did not investigate any further. i was happy with the Orions and had only considered just one final "tweak" in the form of possible valve mono blocks for the tweeters.

I am currently using 2 Mission stereo power amps to drive the tweeters and mids and have used six BK power 300 watt monoblock modules to drive the woofers and the subs. This system sounds great and I really dont know why I am even considering a;lternative amps its just that.........this is probably sounding quite familiar, I am curious just how good it can get, and I have never really built a complete amp kit before.

I started wondering about initially, possibly, maybe ordering one 55 watt AKSA for starters and I cant quite remember making a final decision but I am now waiting for 1 AKSA25 with the Nivarna+ upgrade, 1 AKSA55 with the Nivarna upgrade and something called the GK -1R. I vaguely remember talking to my wife about how annoying our Denon pre-amp will be with all those buttons when our 6 month old daughter starts to crawl and that I might have a solution….

I do know that I will need to sell the two Mission "powers" and my current pre-amp/processor, a Denon AVCA1SE, which cost £2500 about three years ago. I should get about £275 for each of the missions and around £750 for the Denon, so all in all things should balance and with my curiosity sated that should be the end of matters. Actually it’s not that simple, I am already toying with the Idea of ordering another 2 x AKSA100`s for the woofers and I love the concept DASKA.

This is a great forum and a real confidence boost to anyone considering any of Hughs projects. I am looking forward to receiving the kits in the post any time soon.

In the mean time I have a couple of questions regarding parts supply to the UK. I really want to use conventional frame type transformers on the amps driving the mid and tweeters, having heard so many positive reports, I am prepared for slightly more noise, given the other benefits, and expect to need to play around with the layout in the case to reduce any hum ect. Where can I obtain EI, C Double C or even R core transformers in the UK or Europe? I have really searched and have got a couple of leads but nothing worthwhile to date. Any ideas?
Next up the case for the GK-1R I have looked at the “sticky” thread and like the look of a couple proposed but would ideally like to buy in the UK ???

I will keep the forum updated with my progress

Seano · « **Reply #1 on:** 12 May 2005, 11:46 pm »

Brad
I would suggest that you wait till the GK-1R kit arrives and have a goodly squiz through the instructions before lashing out on a case. There are lots of hints in there about what you need for a case.

In my experience, an off the shelf case for the GK-1 is a bit of a hassle. To work really well you need to make sure that all the various holes in the case are spot on. And this can only really be acheived in a metalshop or by someone with the appropriate skills and tools.

If it were me I'd get a pre-drilled folded metal plate to act as the base and rear panel. With another plate as the front panel. And a folded metal baffle box as an internal sheild for the transformers. And I'd make the case tall enough to be able to lay the main PCB over and accomodate the valves within the chassis rather than poking up through the lid - even in a childless household I've found the tubes to be 'vulnerable'.

I cheated and got a prototype Swift chassis from Hugh which I built up to suit. Except that build is something I'm not totally keen on so it will be revisited in the future to see if I can make it better....

aurelius · « **Reply #2 on:** 13 May 2005, 03:39 am »

Welcome Brad!

I am now in the final stages of my Orion build. I am hoping to get the drivers in the frame this weekend and get them running on 8 x AKSA55 N+ the weekend after... have you found the Orions meet your expectations?

In a short amount of time I will be looking to garner interest for a PCB I have designed that incorporates:
1) +/- 20.6V power supply with FRED diodes and 10,000uF Nichicon Muse per rail
2) + & - 15V volt Jung Super Regulators to run the Orion's crossover and additional circuitry
3) The linkwitz specified acoustic LR4 40Hz subwoofer-orion crossover
4) A linkwitz transform (biquad) for subwoofer equalisation (I may need to change this to provide the option to use a pair of shelving low pass filters instead... the biquads are somewhat limmited).
5) The ability to chose (via switch and relay) to drive the orion woofers from the GK-1R's sub out(taken prior to its unity gain tube stage), such that the mid and tweeter get the tube treatment, but the sub and woofers don't. (Subwoofer is always driven from GK1-R sub out).

I plan to use a pair of 2 x Adire Tempest Infinite baffle subs in my roof.

The board is about 2/3 the size of the Linkwitz active cross over and is quite complex. Due to the switching options (sub [in/out]; bass input [GK1-norm/GK1-subout]) the entire orion active crossover woofer path is duplicated, as is the Highpass section of the subwoofer crossover. If I can get 3 other people interested, it will bring the price down to less than US$75 a pair and make it worth my while...

Unfortunately, it is designed for the small group of people who have both a GK-1R and Orions... let me know if you might be interested in the future.

I'm sure you will enjoy your AKSA gear.

Regards

Mark

Gordy · « **Reply #3 on:** 13 May 2005, 01:10 pm »

Hi All,

I just received an all aluminum chassis from Ken http://www.digitalanaloguediy.com/ and am very impressed with the quality, has very nice wt. to it and all fittings are included in the price! He has three sizes available, one sized for pre's...

Builder Brad · « **Reply #4 on:** 13 May 2005, 05:05 pm »

That was quick!!

Seano,

Good advice I think I will wait until I get all the parts for the GK-1R, I also want to hide the valves and this would probably be the only way to ensure that I get the space necessary in the case. The main power amps will installed in a loft space and will be ok in standard rack mount enclosures, I think I will use Maplin 2U for the 55s and 3U for the 100s.

Aurelius,

You will be pleased with your Orions. When I completed my build I just could not wait to hear both speakers together and ended up listening to the finished one while I drank beer and fitted the drivers ect. to its partner. The single Orion playing on its own was very distracting and it sounded more involving that any speaker that I had heard before. It was quite late and the solitary Orion was playing quite loud, I ended up a little drunk and got to bed even later once I set the other speaker up and finally got to spend a few hours listening to both.

Your plans are very interesting. I originally used two diy power supply kits from the esp. web site for left and right Orion PCB x overs, Rod Elliot designed these to provide very low ripple DC for pre amps ect. I had previously used these supplies on my own active x overs without a problem, however I just could not get rid of the hum and finally ordered the power supply recommended by Siegfried Linkwitz and the hum the mysteriously disappeared. I am certain that further improvements could be made to the power supply given that the one recommended is just a standard medical grade piece of kit. There are some power supply filtering components on the Orion/Phoenix board, is it worth looking at improvements in this area before investing time in board development ect. in that area.

I am interested in your proposal and have a couple of questions.

Do you expect the “valve treatment” to be detrimental to the lower frequency performance of the Orions. If there is an advantage tin bypassing the GK1s valve pre-out you will definitely negate this using a biquad circuit to emulate the shelving low pass filters in the SL design. The biquad circuit produces too much noise, even with reduced gain/boost. I tried to use my Thors with the Orions for HT and initially employed a biquad circuit, being lazy, and not having purchased the Orion/Thor integration plans and boards. I tried various resistor/ capacitor values and chanel gain and could not loose the noise.

Do you have a block diagram of the signal path/ filters ect?

What are you using the AKSAs for at the moment?

How are you planning to power the Subs?

Gordy,

I like the look of the cases offered by Ken, although the shipping costs to the UK is a bit of a pain. Are you putting a GK1 in the case?

http://sound.westhost.com/project05.htm

fajimr · « **Reply #5 on:** 13 May 2005, 06:33 pm »

Quote from: Gordy

Hi All,

I just received an all aluminum chassis from Ken http://www.digitalanaloguediy.com/ and am very impressed with the quality, has very nice wt. to it and all fittings are included in the price! He has three sizes available, one sized for pre's...

Gordy

I'd be VERY interested in your comments on these enclosures as you are building as I just ordered my AKSA 55 ++ and GK-1 kits and will be considering enclosures. BTW- which one did you get for which project?

Gordy · « **Reply #6 on:** 13 May 2005, 08:41 pm »

Hi All,

I have the 130 amp chassis, vastly superior to the Numetal boxes if you're familiar with them and nicer finish, IMO, than the case the 100N+ I had on tour. I don't know if it'll house all the heat sinks with the 100 though... The included fittings are nice mid-range pieces, only the um, fanatical will need think about replacing them! I really appreciated the 3-way power connectors as the IEC holes are aways a pita. A 55N, soon to be + is going in probably.

I'm happy enough with it to seriously consider getting the 60 case with the upgrade dials to use for an int. 3886 amp I've put together for a friend, instead of the IAG chassis I was going to use. A lot less work

HTH, Gordy

Felipe · « **Reply #7 on:** 31 May 2005, 05:12 pm »

Hi all,

To Brad and aurelius :

I've recently been drawned to the Orion project, i found it to be a very exciting one. The active XO aproach always seemed to be the best one.

But i do have a question, and maybe Brad would be the one to answer when he can . In the website, Mr Siegfried Linkwitz is the 1st one to say that "one can spend more money on the amplifiers but it would be no good since any amp can drive that easy cleaned load with limited freq".

I found that to be a doubtfull statement, but after all...its the speaker designer himself that is saying this !!

So....is it worth it to build 8 AKSA amps for those speakers ???
Brad, do you think your system will sound BETTER after replacing those amps you use ? Did you begin your project yet ?
Aurelius, are your Orions playing yet ?

Best regards
Filipe

aurelius · « **Reply #8 on:** 1 Jun 2005, 12:53 pm »

Hi Felipe,

My speaker wire took a little longer to get to me than expected, but I received it this week. Should complete the Orions this weekend. It will take me 2 weeks after that to complete the boxes for the amps. I will post as soon as I get things running.

RE: your general question, all I can say is that there are a few people on this board who have made frequency-range specific modifications (i.e. one mod to the mid-range amps; a different mod to the tweeter amps) to their Orion-driving AKSAs and have noted incremental improvement. It stands to reason that if mods can make an audible difference, so to can the selection of the amp in the first place.

At some future time, I will try to run the Orions off chip amps (gainclones) to subjectively assess the difference, but it is not likely to happen soon.

Regards,

Mark

Felipe · « **Reply #9 on:** 1 Jun 2005, 02:28 pm »

Hi

That is excelent Mark, i hope you complete Orions and they sound like you wished they would. Do you have a reference to compared them to ? Like some branded well known retail stuff ?

There is another thing that i find intriguing, and that is the quality/coloration aspects of the active ANALOG XO in the Orions.
If it works between the poweramps and the preamp, in our case the Fantastic GK-1 wich we all admire, wont it ruin the GK-1 work ?

Should the XO be placed BEFORE the GK-1, after the DAC, but therefore require 6 channels of preamp instead of the normal 2 ??

Lots of doubts....just wondering if 8 channels of amps plus 8 drivers are worth the effort and money....

Builder Brad · « **Reply #10 on:** 1 Jun 2005, 07:24 pm »

Filipe,

I really do hope to hear an improvement, at least when I complete the first stage which is to replace my Denon AV amp with a GK-1R. I will then replace the two Mission "power" amps which currently drive the tweeter and mid range chanels with an AKSA 25n+ and a 55+. If I experience a significant improvement in proportion to the time and money spent I will then continue to upgrade the woofer power amps with AKSA 100s.

I will probably then try some of the "tweaks" sugested on this site to optimise each of the amps for their required frequency band.

The amps that I am currently using exceed the specs of the multi chanel amp as recomended by SL and I could build the full set of AKSAs for less than it would cost to aquire the recomended amp.

Brad

econ · « **Reply #11 on:** 2 Jun 2005, 08:49 am »

Felipe,
I may be wrong but only 6 channels are required . At least thats what I'm planning on running the orions with in the first instance .

andyr · « **Reply #12 on:** 2 Jun 2005, 11:58 am »

Quote from: Felipe

... There is another thing that i find intriguing, and that is the quality/coloration aspects of the active ANALOG XO in the Orions.
If it works between the poweramps and the preamp, in our case the Fantastic GK-1 wich we all admire, wont it ruin the GK-1 work ?

Should the XO be placed BEFORE the GK-1, after the DAC, but therefore require 6 channels of preamp instead of the normal 2 ??

Lots of doubts....just wondering if 8 channels of amps plus 8 drivers are worth the effort and money.... ...

Felipe,

Very reasonable Qs but you need to understand a few things:

1. As you have pointed out, the "fantastic GK-1" feeds the AKSA power amps and imparts, shall we say, "a benign, euphonious colouration" to the sound coming from your source ... which the AKSAs faithfully deliver to your passive speakers.

If you have an active Orion setup then:
* yes, you have another piece of electronics which the signal has to pass through.
* yes, the active crossover may well add its own colourations to the sound ... but then so does the passive crossover that any "normal" speaker has!!

I suggest SL's active circuit is a good one and will not "undo all the good work that the GK-1 has wrought"!! It will merely add its own colourations, not take away the GK-1's ... but then, so does any passive crossover!!

2. An active crossover splits 20-20KHz into 3 frequency bands (in the case of the Orions). Yes, I suppose theoretically you could have 3 stereo GK-1s after your 3-way stereo active crossovers but it makes switching between different sources extremely difficult! After all, source selection is an essential function of the GK-1.

Once again, the active crossover does not take away any of the GK-1's magic ... though if it's a bad active crossover, it might well mask the beauty with all sorts of crap. SL's is NOT a "bad" one!!

3. Is 8 channels of amps plus 8 drivers worth the effort and money? Most people in the world, my wife included, would say "no f'ing way, you wanker"!! However, us underground band of audiophiles who live to get closer to the music ... who wish to feel Marianne Faithfull's lips caress our earlobes as she whispers "Hello Stranger" would say 8 drivers, 8 AKSA channels and a whole lotta money and work IS worth it!!

Go for it, mate! It will be a superb-sounding system. Maybe even better than my 3-way active Maggie IIIAs driven by 6 AKSA monoblocks and a GK-1!

Regards,

Andy

aurelius · « **Reply #13 on:** 2 Jun 2005, 12:34 pm »

Hi again Felipe,

I agree with Andy...

I had exactly the same questions as you... will the downstream active crossover undo the work of the GK-1?

As it turns out, the GK-1 is special, not because it is transparent... but because it adds something... call it emotion, call it magic; its pretty bloody marvelous. So long as the Orion active crossovers are sufficiently transparent (and by all reports they are), you should get the full benefit using 1 GK-1 upstream from the crossovers.

I can confidently suggest this because I have a shyte amp and mediocre speakers and the GK-1's presence is still very noticable in a blind test (takes a few weeks break in, BTW).

Felipe · « **Reply #14 on:** 2 Jun 2005, 02:16 pm »

Hi all,

This is becoming a very interesting thread and maybe an ambitious project.

Brad,

I too hope you notice the improvement that the AKSA's will bring to your system. That would mean that they are worth the money and time spent on this type of project speakers (we all know what an AKSA can do with a passive XO speaker).
Do you think the 100w version is needed for the woofers ? SL says that the woofers connected in parallell become a 2 ohm load, and that may be too low for the 100w, but what about 2 x 55W with a 4 ohm load each ?
It would become cheaper.....

Econ,

6 channels are enough if you connect the woofers to the same AKSA.
But that would create the 2 ohm load as said above....safe or not safe ???
Maybe Hugh can have a say here.....

Andy,

I agree that if the SL XO is "transparent" enough, it would be much logical , pratical, cheaper to have it AFTER the GK-1.
1 thing i didnt get though..... the $300 price asked for the plans, include the instructions, the XO PCB WITH OR WITHOUT the XO parts ???
I too have girlfriend/(soon to be wife) that thinks 100$ is enough for a stereo system.....

aurelius,

let me hear the results later on....

When somebody has a Orion/AKSA system, do not forget to report !!!

Cheers all

andyr · « **Reply #15 on:** 2 Jun 2005, 09:19 pm »

Quote from: Felipe

... Andy,

I agree that if the SL XO is "transparent" enough, it would be much logical , practical, cheaper to have it AFTER the GK-1.
1 thing I didnt get though..... the $300 price asked for the plans, include the instructions, the XO PCB WITH OR WITHOUT the XO parts ??? ...

Sorry, Felipe, I'm not absolutely sure but I believe Siegfried only supplies the PCBs - he's not into making a "kit" like Hugh does.

My own actives use Rod Elliott's active crossover (he also supplies just the PCBs) but this is only the 3-way crossover itself ... Siegfried's boards include other circuits (like the mid-range dipole EQ) which the Orions need.

Regards,

Andy

econ · « **Reply #16 on:** 3 Jun 2005, 09:51 am »

This is a forum for aksa stuff so spending too much time talking about linkwitz speakers might not sit perfectly with some but seeing the intention is to match them with aksas we might be allowed some leeway.

For $ 300 you receive two well crafted pcbs One for each speaker,a set of instructions and a test cd. The pcbs are unpopulated . You have to source the parts. Linkwitz will sell you a ready built xover but for extra money.
S. linkwitz is happy to take questions if you email him.

Thank you for pointing out the impedance drops to 2 ohms!
If memory serves me, from previous posts unconnected to orions, Hugh has advised against tempting fate with this low value.

econ · « **Reply #17 on:** 3 Jun 2005, 10:04 am »

I stand corrected . The orions require 8 channels of amplification .. It says so on the website. pays to read carefully , thanks felipe !

AKSA · « **Reply #18 on:** 3 Jun 2005, 10:58 am »

Hi Paul,

No problem to discuss the Linkwitz projects here; I greatly admire Siegfried - he is a creative and extraordinarily detailed designer, and I'm very pleased to have his digital ghost flitting around the AKSA forum......

If impedances drop to below 2R, then yes, I'd say the 55W AKSA is not suitable, however, Ben Williams runs the Phoenix which is very similar to the Orion as I understand and there seems no issue with his 55W AKSAs..... Ain't life simple???

Cheers,

Hugh

bilbobaggins · « **Reply #19 on:** 3 Jun 2005, 11:45 am »

Quote

I stand corrected . The orions require 8 channels of amplification

Actually, the dipole woofers for Orions and these can be run either separately for a total of 8 channels or the woofers can be run in parallel for a total of 6 channels. However, if run in parallel, the bass amp needs to be a pretty good one. In 8 channels, the load on the woofers is easy so a very modest powered amplier is permitted.

Let me chime in on the Orion/Aksa combination. I have not heard it but I have bought my Orions from a builder who used that very combination along with Audience IC's and loved it. His leanings are toward a tubelike sound in the midrange and for the emotion in the music. Unfortunately, I never got to hear his setup before purchase, but he did tell me that one person did drive to his place to hear both the Don Barringer setup (the demo person in Virginia), who uses the recommended ATI amplifiers, and his AKSA/Audience cable setup and really preferred the AKSA setup with the Orion's. The caveat is that the Don Barringer setup may not be optimally placed in the room due to SAF and other factors -- This is according to some other listeners who've listened at Don's. Furthermore, my seller also has had a lot of hi end gear, such as the Audio Research VT 100.2 and his other supporting electronics were probably of much higher quality than Don's. Lastly, he said that the Audience cables made a big difference and the Orion/Aksa combination really bloomed with that combo. Also, note that the Orion/Aksa combination have been demoed before at DIY gatherings, one of which it was considered the best sound of the day, and you may be able to get some feedback from attendees.

Edit:
One last thing, My seller used the AKSA's for the treble and mids and I believe used a different amp for the bass -- the model I can't remember.

My preferences are for a more neutral sound and it is my belief that the Orions, while not particulaly demanding in 8 channel mode, will still be quite revealing of the differences in the amplifiers used. I''ve used a couple of different multi channels amps and they each have their own signature. One Orion owner on AA used 4 Electrocompaniet amps with excellent results.
http://db.audioasylum.com/cgi/m.mpl?forum=speakers&n=137966&highlight=orions&r=&session=

I'm using two Thule 5 channel amps, one for each speaker, so there are a lot of ways you can approach the amplifier business so it's good you are trying to make an informed choice.