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Old 12th May 2007, 01:50 PM   #791
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Thanks Shin! I still have to finish turning one of the knobs to complete it, but oh well...

I really like the SKA's! I've built quite a few amplifiers in my lifetime (mostly high powered PA class systems) but I really liked the sound of these. I don't subscribe to the subjectivist babble - so I'm not going to venture into all the perceived subtleties of the sound - but compared to anything else that I own (or commercial kit I auditioned) I always end up putting my SKA's back into my system. Is it the best amp that money can buy? I doubt it, BUT I honestly believe that you won't buy anything out there for 4 times the money and get that performance. Greg is a great designer and looking at the end result I believe he put a lot of time into this design. Again, amplifiers are such a touchy subject that I'd rather just leave it there

How was your experience with them? How extensively have you compared it to other kit? Commercial or DIY?
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Old 12th May 2007, 02:19 PM   #792
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Thanks for that Gert.

I've played around with most of the popular kitsets around here.

My introduction to all this was Rod Elliots P101 lateral MOSFET amp then soon after that I quickly got the bug and moved onto the AKSA 55N+ then the GB150D and ultimately the GB300D. At that point I took stock and compared all those and came to the conclusion that the GB amps were an altogether excellent value and outright performance was the best of the bunch.

Having said that, I was on a bit of a personal mission for the best DIY amp I could find and since I'd only tried a few options at that point I really got the itch to order other kitsets to try out, thinking I'd probably find something better. Unfortunately buying kitsets and DIY amps, whilst much cheaper than buying commercial, is still expensive and I had a serious loudspeaker project ongoing at the same time and not much in the way of disposible cash to indulge my desire to seek out other amps. So I sold the P101's, AKSA's and all the GB amps. It later turned out to be a bad idea to sell the GB amps but the other two I was happy to let go.

After the sale of the amps, I picked up Peter Daniel Audiosector LM3875(Patek SE version) and LM4785 chipamps as well as loaning a LM3886 from Vikash(mod on here). I tried all these with linear and SMPS supplies. Wasn't very impressed with any them TBH but I had moderately tough loads to drive and these really aren't suited to that, I dismissed them anyway.

After that was UcD700 which was pretty nice overall. Especially the imaging and bass. Whilst initially impressive I again kept thinking back to the GB's.

Then NewClass D's NCD400 but I had some grounding/hum issues I could never fully resolve so had a refund.

The finally one I tried was Aussieamps NX150. Similar sound to the UcD700 and P101. Very controlled with powerful and controlled bass but somehow cold sounding and a little less smooth.

After all that I'm thoroughly tired of trying out amps and have gone back to what I consider the best out of that bunch - the GB300's.

EDIT: There are other I'd like to hear though such as the Pass Class A designs, KrellClone KSA50, AKSA Lifeforce 100, Symasym and others. Some of those will be hopefully be at the UK DIY meet later this year so maybe I'll get my chance. For now I'm happy to build up the GB300 knowing they're one of the best for DIY'ers.
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Old 12th May 2007, 04:02 PM   #793
Tenson is offline Tenson  United Kingdom
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Ant,

How do the GB150 and 300 compare? Is it just power or are they different besides that?

Have you tried them in both class A and A/B operation?

From your previous recommendation to me, I plan to get a GB150 to run my mids/tweeters but wonder whether to go for a GB300 (donít need the power though) and whether to run class A or not.

Cheers
Si
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Old 12th May 2007, 04:20 PM   #794
jleaman is offline jleaman  Belgium
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Quote:
Originally posted by Tenson
Ant,

How do the GB150 and 300 compare? Is it just power or are they different besides that?

Have you tried them in both class A and A/B operation?

From your previous recommendation to me, I plan to get a GB150 to run my mids/tweeters but wonder whether to go for a GB300 (donít need the power though) and whether to run class A or not.

Cheers
Si

There is a huge difference in sound from class A to Class A/B. I run 4 15Watt class A amp's and it is PLENTY of power. Unless you have some huge power eating woofer then you need a nice Class A/B or Class D.

Jase
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Old 12th May 2007, 05:31 PM   #795
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Quote:
Originally posted by Tenson
Ant,

How do the GB150 and 300 compare? Is it just power or are they different besides that?

Have you tried them in both class A and A/B operation?

From your previous recommendation to me, I plan to get a GB150 to run my mids/tweeters but wonder whether to go for a GB300 (donít need the power though) and whether to run class A or not.

Cheers
Si
The 300 is more of the same really. Sounds that bit more immediate and direct thats especially noticable in the bass. When I had my first lot of 150's and 300's the 300 had a modification built in as standard that the 150's didn't so that could have been the cause of some differences. As I understand it now, Greg has given details of the mod which can be applied to the 150 using just a few extra components.

I'd go for the 300 if I were you, even if you don't need the power. There's only $40(about £20) difference in price and that extra headroom is a nice thing to have. Of course you do need to factor in larger heatsinks and more robust supplies which will cost slightly more than the 150's.

About class A:

I had four GB150 modules and configured a pair for class A and left the other for class A/B. I heard no difference really, maybe and I mean maybe slightly better bass but it was really difficult to say for certain and this was using a A/B comparison in a very ear strained fashion. I would have really loved to have tried the GB300's in class A but require quite huge heatsinks to do so which I didn't have back then. I expect the chassis I'm using now would be suitable for a stereo GB300 running 100w class A though.
I've also had the NX150 running in both class A and class A/B and again found no real difference. Although I only had two modules so it was impossible to compare directly.

My own thoughts are that excellent class A/B amps are of such a refined state right now and are using quality modern output devices that the old "class A is best" marketing of the 80's and early 90's really needs to be laid to rest. You can get equally great sound from both.
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Old 12th May 2007, 07:03 PM   #796
Tenson is offline Tenson  United Kingdom
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Thanks Ant that answers my question! I was hoping to go a/b because I don't really want all that heat in my room. It already gets hot enough in here with 1.5KW of amps and a water cooling tower for the computer.
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Old 13th May 2007, 04:18 AM   #797
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Now that you played with ordinary amps and probably realize that
good amp designs should be neutral in sound, plus headroom is very
important, get some proamps on the used market and run them in
bridged mode for amazing clipping headroom.

I run the budget line array with four PLX3402 in bridge mode,
abnormal impedance. Not only is the cheap array handling this,
I can probably drive more into it because high clipping headroom
is the real secret, not necessarily the power ratings on amps
that scare people away.

I'd recommend QSC PLX3402's all around because you can score
alot of them for a nice price now. PLX3002 would be fine too.

If you want to drive a monster subwoofer or bass array, I'd look at
scoring some used Crown CE4000's because they are;

Universal SMPS+PFC+BCA

One guy on the AVS forum just scored a couple of CE4000's
for $660 each. That is a steal.

Don't starve your new speakers with lack of headroom,
headroom beyond what normal home amps offer
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Old 13th May 2007, 06:41 AM   #798
AR2 is offline AR2  United States
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In my opinion it is matching a certain amp to the certain speaker more important than going after certain amp. Older B&Ws are just really bad with solid state amps and perfect with tubes particularly in the treble region. Some low sensitivity bass speakers are looking for more amps which only big amps could provide. What I am running is Aleph 30 class A with ribbons, and after many tests and many amps tried that is the best match.
Shin, I would strongly advise you to try Aleph 30 with your ribbons.

Next are Cary Audio 2A3 monoblocks and they are the best right there. For the

Lambda bass I am feeding Pass Lab X600 which are giving me around 1300W at 4 ohm. No other amp could drive these monsters and with Pass Lab I was finally able to have outstanding base. Lambdas are great speakers but they needed to have a lots of Amps to match them with the top. What Thylantyr was pointing out: headroom, headroom, headroom is the really good advice.
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Old 13th May 2007, 12:31 PM   #799
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Quote:
Originally posted by thylantyr
Don't starve your new speakers with lack of headroom,
headroom beyond what normal home amps offer
You don't think 3kw into 8ohms is enough?
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Old 13th May 2007, 12:35 PM   #800
Tenson is offline Tenson  United Kingdom
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Quote:
Originally posted by thylantyr
Now that you played with ordinary amps and probably realize that
good amp designs should be neutral in sound, plus headroom is very
important, get some proamps on the used market and run them in
bridged mode for amazing clipping headroom.

I run the budget line array with four PLX3402 in bridge mode,
abnormal impedance. Not only is the cheap array handling this,
I can probably drive more into it because high clipping headroom
is the real secret, not necessarily the power ratings on amps
that scare people away.

I'd recommend QSC PLX3402's all around because you can score
alot of them for a nice price now. PLX3002 would be fine too.

If you want to drive a monster subwoofer or bass array, I'd look at
scoring some used Crown CE4000's because they are;

Universal SMPS+PFC+BCA

One guy on the AVS forum just scored a couple of CE4000's
for $660 each. That is a steal.

Don't starve your new speakers with lack of headroom,
headroom beyond what normal home amps offer
Power is important, but so if the overall sound quality of the amp. In an ideal world (and Shin seems to live there!) you want both. Bryston have always been a favourite of mine. I am running Alesis RA500 at the moment. I plan to use the RA500s for the bass and a GB150 for the mid and tweeters.
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