Jozua said:
Seems to show that thick isn't always better and looks aren't everything.
I've been using off-the-rail 1.9mm silverplated teflon coaxial as internal wiring for ages, the reason i don't use it externally is because it looks so whimpy.
Wondered myself many times why pro manufacturers take such a risk by cabletieing inputs and outputs for cosmetic reasons.
Jozua, i take it the MKII refreshing was well worth it ?
Now excuse me, a whale is supposed to have grounded at the beach.
Going to hit it over the head with a non-Pb-free-all-over-thing.
My doc just told me that smoking is bad for my WIKI.
If it wasn't that the original <2mm diameter interconnect wire was also cable tied tight I wouldn't have done it with the new vdH one, but since the vdH is almost 10mm thick and it makes an unappealling curl when left untied I did it.
I do have my doubts about using a balanced cable for unbalanced purposes, and I think that by shorting the braid to ground at both sides or even just the other may change things.
I do have my doubts about using a balanced cable for unbalanced purposes, and I think that by shorting the braid to ground at both sides or even just the other may change things.
Jacco
The amp is beginning to show it's true colours. Very smooth non-aggressive sound.
If this is the effect of the Black Gate caps then I am sold on them. In the KSA Mk1 they made a reasonable difference but in the Mk2 amp they truly sound exceptional.
For the moment the Mk1 still has a tighter bass than the Mk2 but this is only after about 20 hours of playing with the new caps.
Jozua
The amp is beginning to show it's true colours. Very smooth non-aggressive sound.
If this is the effect of the Black Gate caps then I am sold on them. In the KSA Mk1 they made a reasonable difference but in the Mk2 amp they truly sound exceptional.
For the moment the Mk1 still has a tighter bass than the Mk2 but this is only after about 20 hours of playing with the new caps.
Jozua
I tend to agree with you on that. I've used BG's in a couple of past projects with no real audible difference between them and $2.00 caps. I used the same devices in mine but wired it with silver plated 12 ga stranded/ teflon covered. Have always used this wire in past projects and it does make a huge difference. My KRell sounded excellent fomr the minute it was turned on... I cranked the bias up to 575mv from 300mv last night and it just gets sweeter and sweeter sounding. Absolutely amazing!
Jozua... You need to can the SS line stage and build the 12B4 to really hear what your KSA-100 is capable of, I would say the SS line stage is more your limiting factor at this point. I had a similar Krell KBL line stage and the 12B4 is miles and miles ahead of it.
Mark
Mark
Please send me info on the 12b4.
The output devices were also rewired with Van Den Hul CS16 wire which I believe is silver coated high grade copper with a teflon covering. The orginal wire was real cheapo.
Please contact me privately at hugot@icon.co.za. There are other issues I would like to discuss off-line.
Thanks.
Jozua
Please send me info on the 12b4.
The output devices were also rewired with Van Den Hul CS16 wire which I believe is silver coated high grade copper with a teflon covering. The orginal wire was real cheapo.
Please contact me privately at hugot@icon.co.za. There are other issues I would like to discuss off-line.
Thanks.
Jozua
Hi Still4given,
the 15003/4 is the real Klone part.
But I don't think it gets the best performance out of the topology.
Transistors have moved on since the 80s and faster, higher gain, more linear at high current, better matched devices may improve performance in some areas but at the expense of reliability.
These newer devices are nearly always less robust.
The exception is the 21193/4, but it only moves a very small way towards the speed/gain available now.
the 15003/4 is the real Klone part.
But I don't think it gets the best performance out of the topology.
Transistors have moved on since the 80s and faster, higher gain, more linear at high current, better matched devices may improve performance in some areas but at the expense of reliability.
These newer devices are nearly always less robust.
The exception is the 21193/4, but it only moves a very small way towards the speed/gain available now.
No, I don't update the WIKI, thats up to you to mark that you paid. PayPal is very good about making sure that funds are delivered and thats one of tha main reasons I prefer to use them. I am compiling a list of those who have paid and will post that list here over this holiday weekend at some point. I am still awaiting several pay by mails to arrive too.
Mark
The 21194/21193 are a step better towards audio applications but as AndrewT mentioned not a massive improvement compared to what's available currently. TO3-case transistor technology does not advance much anymore, so these are probably one of the best straight-swops for the 15003/4's available. Once you go for flatpack TO3-P, the MJL21194/21193 is one of the slowest choices available compared to the likes of MJL4281/4302 et al.
[BTW the 21194/3 is a rare case where the higher number indicates the NPN.. got reminded the hard way with a 300W subwoofer amp fired up at full power arghh]
One of the few advantages of the slower transistors is that that the wiring isn't as critical, and you can get away with long wires such as on the original KSA heatsinks.
It would however be a good experiment if somebody would take the time to evaluate some of the transistors using this particular amp side-by-side to get an insightful idea of what works well. At low bias this should not be too difficult to swop out flatpacks and e.g. using only 4 per channel.
[BTW the 21194/3 is a rare case where the higher number indicates the NPN.. got reminded the hard way with a 300W subwoofer amp fired up at full power arghh]
One of the few advantages of the slower transistors is that that the wiring isn't as critical, and you can get away with long wires such as on the original KSA heatsinks.
It would however be a good experiment if somebody would take the time to evaluate some of the transistors using this particular amp side-by-side to get an insightful idea of what works well. At low bias this should not be too difficult to swop out flatpacks and e.g. using only 4 per channel.
The speed of the output stage...
...may ultimately be a less important parameter than the gain linearity.
As reported in his book, Doug Self tests a small selection of transistors in his output stage and their contribution to distortion. His findings were pretty conclusive, the 3281/1302 were the best but the 21193/4 pairs were not a lot worse. However, IMHO, the most important thing he found was that more transistors were better than less transistors. Whichever transistors you use, keeping them in their 'comfort' zone works best of all...ie if one pair is good for 8 ohms, then 2 pairs are needed to get similar results for 4 ohms, 4 pairs for 2 ohms etc. Once you have 'enough' more don't help...
For a beginner building this amp transistors that are much faster could lead to other problems...long cables leading to a remote output stage with 40MHz transistors might not be the perfect recipe...
This may be a situation where building the amp and getting it working perfectly with older/slower parts, then swapping the new spiffy parts in would allow better diagnosis of oscillation etc.
Stuart
...may ultimately be a less important parameter than the gain linearity.
As reported in his book, Doug Self tests a small selection of transistors in his output stage and their contribution to distortion. His findings were pretty conclusive, the 3281/1302 were the best but the 21193/4 pairs were not a lot worse. However, IMHO, the most important thing he found was that more transistors were better than less transistors. Whichever transistors you use, keeping them in their 'comfort' zone works best of all...ie if one pair is good for 8 ohms, then 2 pairs are needed to get similar results for 4 ohms, 4 pairs for 2 ohms etc. Once you have 'enough' more don't help...
For a beginner building this amp transistors that are much faster could lead to other problems...long cables leading to a remote output stage with 40MHz transistors might not be the perfect recipe...
This may be a situation where building the amp and getting it working perfectly with older/slower parts, then swapping the new spiffy parts in would allow better diagnosis of oscillation etc.
Stuart
On the two KSA 50s that I built, I used MJ15003/4 for the one and MJL4281/4302 flatpacks on the other. To be honest, I really can't hear any difference between the two. I'm sure they probably measure differently but I sure can't hear any difference.
I have plenty of all three devices to go with for this KSA 100 so I guess I'll wait and see how folks like their choice before I build the back end. I have two tunnels that I can use for the TO3 devices but I also have some heat sinks that will work with the flat packs so I guess I have some decisions to make.
Blessings, Terry
I have plenty of all three devices to go with for this KSA 100 so I guess I'll wait and see how folks like their choice before I build the back end. I have two tunnels that I can use for the TO3 devices but I also have some heat sinks that will work with the flat packs so I guess I have some decisions to make.
Blessings, Terry
Hi,
Doug Self did show (very well) that using "low droop" transistors helps the low impedance distortion.
He also showed that 1pair could be outperformed (distortion wise) by 2pair when halving the load impedance.
The same series of experiments and the published data still showed that distortion into a 4ohm load using low droop AND 2pair gave a worse distortion performance than 1pair into 8ohm.
I wonder why he did not publish a 3pair comparison.
It may have shown that a further pair could have improved the 4ohm performance just that bit more.
Now, when we extrapolate that information to a KSA100 with it's reputed low impedance driving ability, then why stop at 4pair (To3)? when 6pair or maybe even 8pair of the less robust 247/264 devices may well work very well or even better (if you need the ultra low capability).
That then prompts the obvious question: will either the 4ohm or 8ohm performance improve once above 4pair? I'm guessing the answer might be yes and opting for a 6pair output stage to drive 8ohm.
Doug Self did show (very well) that using "low droop" transistors helps the low impedance distortion.
He also showed that 1pair could be outperformed (distortion wise) by 2pair when halving the load impedance.
The same series of experiments and the published data still showed that distortion into a 4ohm load using low droop AND 2pair gave a worse distortion performance than 1pair into 8ohm.
I wonder why he did not publish a 3pair comparison.
It may have shown that a further pair could have improved the 4ohm performance just that bit more.
Now, when we extrapolate that information to a KSA100 with it's reputed low impedance driving ability, then why stop at 4pair (To3)? when 6pair or maybe even 8pair of the less robust 247/264 devices may well work very well or even better (if you need the ultra low capability).
That then prompts the obvious question: will either the 4ohm or 8ohm performance improve once above 4pair? I'm guessing the answer might be yes and opting for a 6pair output stage to drive 8ohm.
Well for a totally no-holds-barred version of the KSA100 I'm going to build for Jozua later this year the plan is to use 8 pairs on a massive heatsink originally intended for an Aleph-X, and experiment with different voltage rails and bias settings by ear. Adding/removing pairs is easy enough when using 1-pair TO3-P PCB modules.
still4given said:
Terry,
If you enjoy a rodeo show on your lawnmower in the back garden, will you still enjoy it as much if you drove the thing to Aspen, during a snowy winter ?
The loudspeakers you have are an easy load for an amplifier, they don't need racetrack rear suspension.
If you had loudspeakers that sound different if they are raised 5 inches higher or 10 inches closer to the wall, ask 1 amp of current one moment and 5 amps the next, then you'd keep hearing differences. And go nuts !
MJ21194/3 are surprisingly good, there are better ones.
I have some of those speakers...
...and my wife tells me I'm already nuts...
Apogee duetta signatures, after 10 years of ownership I can get them just right in only 10 hours or so of listening, spread over a week or two...
A few years ago I used them to bait a friend who sells mass-fi, he had bought into the 'high current' designation that Sony, Denon et al used for a while. I commented that perhaps the little NAD4020 I had was actually, really high current, and after a little talking smack the game was on.
Turns out that Duettas like snacking on mass-fi, and relays are nowhere near fast enough to be used to protect electronics...after 4 'kills' he agreed perhaps that the 20w/channel receiver I'd been using for comparisons was a little better than he'd given it credit for...
Stuart
...and my wife tells me I'm already nuts...
Apogee duetta signatures, after 10 years of ownership I can get them just right in only 10 hours or so of listening, spread over a week or two...
A few years ago I used them to bait a friend who sells mass-fi, he had bought into the 'high current' designation that Sony, Denon et al used for a while. I commented that perhaps the little NAD4020 I had was actually, really high current, and after a little talking smack the game was on.
Turns out that Duettas like snacking on mass-fi, and relays are nowhere near fast enough to be used to protect electronics...after 4 'kills' he agreed perhaps that the 20w/channel receiver I'd been using for comparisons was a little better than he'd given it credit for...
Stuart