[PaulB]

This project started as a speaker project (Linkwitz Orions) but transformed into something a bit larger.

Decided on the Orions having almost started the Phoenix project prior to Orion availability. However the problem was amplification... spent a lot of time researching HT amps (6 or 8 channel) and almost bought a Rotel. Just knew my logic was flawed all along: build a set of speakers with some of the most transparent drivers available and then drive them with a cheap amp?

As I didn't wish to spend $20K+ on amps the DIY idea entered my head. By the way the Orion active cross-over was my first attempt at DIY - got to buy a lot of tools much to my wife's amusement

To cut a long story short I built three stereo amps: 100/55/25 watters for the bass/mid/tweeters. All three basically worked from switch-on although I was measuring the amps wrongly and took a bit of Hugh's time to work out all was ok. Hugh does understand customer service!

I will not go into a detailed post of sonics here but suffice to say these are special amps - I had the opportunity to hear a 100w courtesy of Shayne in Sydney before I bought (thanks mate), so knew pretty much what to expect.

My (ever patient) wife has a good ear and the other night said '...are those the new amps playing, they sound so real'?

At present playing through Mission 753's using my Marantz SR8000 as a pre and Pioneer 717 cd/dvd player.

The amps all sound similar but the 100w has substantially better bass, 55 watter a bit more refined and 25w a little bit more again (with bass/impact droping as power decreases).

Actually thinking about another 100w so I don't need to run the Orions bass units in parallel, and then a GK-1...

I have posted a few pics on site also.

[Larry]

I have posted a few pics on site also.

Where are the pics?

[SamL]

Wau! That's a lot af amp you've build. Good on you.
BTW, according to SL, the 2x 10" XLS will go down to 2ohm at 150hz and I am not sure if AKSA 100 is happy with this.

Sam

[PaulB]

pictures here: http://www.audiocircle.com/index.php?action=gallery;area=browse;album=33

can someone tell me how I can add this link more neatly?

[Larry]

pictures here: http://www.audiocircle.com/index.php?action=gallery;area=browse;album=33

can someone tell me how I can add this link more neatly?

Do you have pics for your Linkwitz Orions?

You can use URL tags. So your pics are here.

[PaulB]

No pics of Orions let. Knocked them up last Saturday with carpenter friend. Still bare frames - have not installed sides or drivers. Not following SL's side panel design as my wife point blank refused to have them in the house! Shouuld be quite neat when finished tough may sound a little different to originals.

[Larry]

... spent a lot of time researching HT amps (6 or 8 channel) and almost bought a Rotel.

Which Rotel amp did you refer to? 60W or 200W? (A 6 channel 60W Rotel amp can be had for about AU$1000 on sale at present. )

Why I ask you this because the other days I almost heard the Rotel A/V processor with a Rotel amp however the boy in the shop had some difficulties to make the system work and he promised me to call me after he sorts it out. I am interested in Rotel A/V processor however to audition it an amp has to be in. I like to hear people who have compared the Rotel amp with AKSA so that when I hear the combination of Rotel A/V processor and Rotel amp I could factor the amp in the equation, hopefully. This is not reliable but seems the way to go as no one from Sydney hifi shops is willing to lend any gears out for people to bring home to try. Not their practice I guess.

[PaulB]

1066 (I think?) 6x60w's

I can tell you how the SR8000 compares with AKSA...

The 8000 retailed for $2900 when new and is a very (sonically) rate piece of kit - at least in the HT community. and it does sound rather good although not in the same class as my valve amps (Transcendent Sounds SC150's). The AKSA is very significantly better. Howver the Marantz is dead silent. I am still trying to remove the last bit of hum from the AKSA's. I think half a day playing with leads should do it.

[Oz_Audio]

I have a Rotel R980BX 120 w channel steroe amp.

My AKSA 55 kills it in all areas.  I use it for the Linkwitz Phoenix sub at the moment, but will be upgrading to an AKSA 100.

The Orion is crossed at 100 hZ @ 24dB, so 2 ohms at 150 Hz should not be a problem - too high.

Paul

I would love to hear the Orions when they are finished.  I hope to build them later this year with 4 x 55 AKSA and a 100 for a pair of Thor subs.

Mark

[JohnR]

Paul may have wanted to embed the pictures directly. If you look at an individual picture you will see a URL that you can copy. Then use the Img button on the post screen, paste the URL, and then use the Img* button.

eg



PS Nice work!

[Larry]

1066 (I think?) 6x60w's

Rotel 1066 is not an amp, but a A/V processor.

Rotel 6 channel 60w amp is about AU$1000 but 6 channel 200w amp is about AU$5000. These two amps would sound very different.

By the way, Rotel is not considered as a good amp producer.

Any company has only one or two line of products that are their killing products and all other products using the same brand may just be killing their brands.

And also, in a company of a medium size or larger, the products of different lines are very possibly designed by very different engineers.

[tg3]

To cut a long story short I built three stereo amps: 100/55/25 watters for the bass/mid/tweeters.

Could you elaborate on your AKSA 25W amp?

[PaulB]

The 25w is the same as the 55w expect for a couple of capacitor values and smaller value transformers.

[Larry]

I can tell you how the SR8000 compares with AKSA...

The 8000 retailed for $2900 when new and is a very (sonically) rate piece of kit - at least in the HT community. and it does sound rather good although not in the same class as my valve amps (Transcendent Sounds SC150's). The AKSA is very significantly better. Howver the Marantz is dead silent. I am still trying to remove the last bit of hum from the AKSA's. I think half a day playing with leads should do it.

SR8000 is A/V receiver, which consists of two sections, A/V preamp/processor and multicahnnel amp.

When you compare a A/V receiver with an amp, you must be careful.

Let's do a simple calculation. Allocate 1/3 of the price to A/V processor section and 2/3 for the amp section. Then the amp section in SR8000 is about AU$2000 for 6 channels. AKSA is about AU$1000 per 2 channels DIY so it is about AU$3000 stock. (This is how I calculate the DIY saving. If you spend $1 for DIY, you should get $3 worth from stock. At least 2/3 of the price in business is not linked to cost of manufacture. This is a pretty conservative estimation.) In this case, you are comparing a 6 channel amp of AU$2000 (Marantz receiver's amp section) to a 6 channel amp of AU$9000 (3 two channel 100W AKSAs. Of cause, the AU$6000 out of AU$9000 is what you save by DIY.) So there is no doubt that a $9000 amp must beat a $2000 amp. Even you don't factor the stock cost into AKSA, you still use a AU$3000 amp (3 two channel AKSAs) to compare with a $2000 amp (Marantz receiver's amp section).

So, when I am thinking of Rotel 1066 A/V processor  (AU$2000 stock) plus AKSAs (3xAU$1000 DIY and 3xAU$3000 stock), I am thinking of the performance of an A/V receiver costing above AU$10,000 stock.

[SamL]

Sorry my mistake. It is 2 ohm at 120hz.

* Opt 02 - Alternatively to Opt 01, the AT1506 150 W/channel, 6-channel power amplifier unit can be used. The two 10" woofer drivers of each speaker must be connected in parallel, which presents to the amplifier an impedance minimum of 2 ohm around 120 Hz. Below 100 Hz up to 4 dB higher sound output can be obtained compared to the AT6012, but the drivers can be bottomed out severely below 35 Hz.  *

Maybe time for a AKSA 150?

Sam

[PaulB]

Also heard the Halcro 58m's (with B&W 800's) 2 hours before auditioning Shayne's AKSA 100w Nirvana. I thought the AKSA sounded just as impressive via 10+ old stand mounted REF's.

I was not seriously comparing the amps to a mid range HT receiver. The AKSA product is without doubt high-end kit.

By the way the SC150's cost me US$1000 each a few years ago and have be re-valved (tubed) with super dupper NOS stuff (Telsa ECC83 gold pin & Mullard 4003's). The AKSA sounded MUCH better.

[John H]

Hi Paul:

I also have a 25W AKSA - believe me, it's  too long a story to explain how this came about.  It's exactly the same as a 55W (but not the latest version) except for a lower value of R3 to take account of the lower supply voltage (+/- 23V).  Sounds  great.  But I would be interested to know the details and reasons for the capacitor changes you made.

Thanks for info.  John H

[PaulB]

Hi John,

looking back over Hugh's build instructions it is only C5 (22pf rather than 36 pf). Mine are all Nirvana - I think stock is higher value.  Also Hugh advises moving from 22 to 27 if any oscillation.

[Larry]

I also have a 25W AKSA - believe me, it's  too long a story to explain how this came about.  It's exactly the same as a 55W (but not the latest version) except for a lower value of R3 to take account of the lower supply voltage (+/- 23V).  Sounds  great.  But I would be interested to know the details and reasons for the capacitor changes you made.

Why did you reduce the power to biamp the system? If you use the same amps, say two 55W AKSAs, what would happen to the sound?

[Larry]

the problem was amplification... spent a lot of time researching HT amps

I can tell you how the SR8000 compares with AKSA...

I was not seriously comparing the amps to a mid range HT receiver.

What do you really want to say?