Bratislav,
Thats an interesting concept that I never thougth of..... I suppose it never dawned on me because our power here in Utah is pretty good most of the time. This looks like the sort of circuit that would normally be part of an AC conditioning box thats available from many different manufacturers. Those input caps.... how does one calculate how large they need to be based on how much current draw one needs? I may want to implement this same thing in my KSA-50 as well.
Thanks!
Mark
Thats an interesting concept that I never thougth of..... I suppose it never dawned on me because our power here in Utah is pretty good most of the time. This looks like the sort of circuit that would normally be part of an AC conditioning box thats available from many different manufacturers. Those input caps.... how does one calculate how large they need to be based on how much current draw one needs? I may want to implement this same thing in my KSA-50 as well.
Thanks!
Mark
Not sure that i'm going to bother for a DC mains blocker.... I have 2 or 3 toroids running now with no filter whatsoever and they are dead silent...
I'm on the corner of a street so i have 2 different phases 🙂 different circuits 🙂
It sounds like it might work, my ripple current will be fairly high though potenitally i guess?
Hmmmm.....
*ponders*
I'm on the corner of a street so i have 2 different phases 🙂 different circuits 🙂
It sounds like it might work, my ripple current will be fairly high though potenitally i guess?
Hmmmm.....
*ponders*
Mark A. Gulbrandsen said:
Mark,
pretty simple - calculate you steady current draw from the mains, and apply the safety factor. Say your KSA50 draws 300W idle (that is more than generous for a 50 watter!), that is less than 3 amps from 115V (we have advantage of higher voltage, 240V AC in Oz so current drawn is less than half). I'd look at capacitors with at 8A ripple current or thereabouts. You can use several of them in paralel if no singe units have that much oomph.
Bratislav
Algar_emi said:
I still don't see this. As far as I understand diodes D1 and D2 are just in parallel with the top half diode bridge and the bottom half diode bridge resp.
So I would assume that these two diodes of the bridge are already taking care of the spikes (well, what's left of the spikes after filtering by the electrolytic caps). Did ML really use these additional diodes?
Steven
Sreven, this idea is not coming from ML, but from Susumu Tanaka. You can find it on JAES : " New Biasing Circuit for Class B Operation ", Vol. 29, No. 3, 1981 March 😎
Why didn't Krell (Dan A.) use current sources in LTP instead of resistors?
Does this result in less musical amp?
Tom
Does this result in less musical amp?
Tom
Upupa Epops said:
Hi Pavel,
Tanaka is about the non-switching class AB biasing scheme. I know, but that was not the subject.
I was refering to the CLC power supply with anti-spike diodes. D1 and D2 in post #1341. Algar_emi said in post #1339 that he got this idea from ML.
Steven
not just the LTP...
The latest publically available incarnation of the KSA100 amp has a lot more changes than just the constant current sources, including but not limited to multiple driver sets, pre-drivers, different biasing points etc...it's not really the same
...and on the strength of the commentary here, the result, sonically speaking, is one step below the more pedestrian earlier version...
It would be cool if one of our constructors could report if they ever have an opportunity to give us first hand feedback on a comparison...
Given the success we have had with the 50, for 100w+ into 8ohms, I'd probably forgo the ability to drive 1ohm loads with impugnity, and got to more outputs with higher rails, more idle current etc.
Stuart
The latest publically available incarnation of the KSA100 amp has a lot more changes than just the constant current sources, including but not limited to multiple driver sets, pre-drivers, different biasing points etc...it's not really the same
...and on the strength of the commentary here, the result, sonically speaking, is one step below the more pedestrian earlier version...
It would be cool if one of our constructors could report if they ever have an opportunity to give us first hand feedback on a comparison...
Given the success we have had with the 50, for 100w+ into 8ohms, I'd probably forgo the ability to drive 1ohm loads with impugnity, and got to more outputs with higher rails, more idle current etc.
Stuart
DC Blocking, ML Style
So this is what this part of the circuit is doing 🙂
Here a part of a ML20.5 amp power supply. I was wondering what was the function of all these parts at the input. SO I guest MOV.1, C104, C101-102, R100-102 and BR4 are there to block the DC at the transfo primary. Very fancy😱 but it is ML after all.
Thanks.
So this is what this part of the circuit is doing 🙂
Here a part of a ML20.5 amp power supply. I was wondering what was the function of all these parts at the input. SO I guest MOV.1, C104, C101-102, R100-102 and BR4 are there to block the DC at the transfo primary. Very fancy😱 but it is ML after all.
Thanks.
Attachments
I've waited a bit to see how the problems unfold on the forum before finishing my KSA50 - just need to figure out the optimum size for C105/106 (seems like there is no definite answer yet) and mount it to the heatsink.
On another topic, most threads I've seen on amplifier design eventually states that it is "not the best amp than can be built". I find this intriguing as I don't think I've ever seen one that claims to be the best by a large amount of people. Keeping valve designs out of the picture, what do you people (Stuart, Mark et al) consider to be the ultimate diy solid-state amp (of which all the parts are obtainable and with a final component cost of say no more than $3000? So far the following seem popular:
- Aleph X
- Lindsey-Hood
- Stan Curtis
- Self
- Leach
Pierre
On another topic, most threads I've seen on amplifier design eventually states that it is "not the best amp than can be built". I find this intriguing as I don't think I've ever seen one that claims to be the best by a large amount of people. Keeping valve designs out of the picture, what do you people (Stuart, Mark et al) consider to be the ultimate diy solid-state amp (of which all the parts are obtainable and with a final component cost of say no more than $3000? So far the following seem popular:
- Aleph X
- Lindsey-Hood
- Stan Curtis
- Self
- Leach
Pierre
PWatts,
It really is more dependent on what speakers you want to drive and to what level and dynamics you like to go. There are too many variables and I certainly agree with Nelson that different fine amplifiers (of which all those you listed are very fine) are just like different fine wines. What do I like about the KSA-50? Its low end response for sure, its extreme detail and resolution without being the slightest bit harsh or brittle, It is extremely dynamic and doesn't behave like a 50 watt amp, its very stable too at least after about 150 hours of on time, andvery easy to construct. Makes me miss my KSA-80B even more! Its been gone for about 5 years now
.
I'm still not 100% sure about C105 & 6 but with the stated value in there the amp performs and sounds extremely good. I did take a brief look at a 10 khz square wave and its a bit rolled off for my tastes, but again the amp sounds REALLY good. One thing for sure is that you can eliminate C107 & 8 completely. The original KSA-50's did not have these caps at all, nor did the 100. They ARE in mine at the moment and don't seem to really make any difference audibly if they are left in or out.
BTW: I don't consider any tube amp to be the ultimate.... and I've owned ALOT of them over the years! They are simply not worth the effort involved any longer. Solid state really does have more to offer......
It really is more dependent on what speakers you want to drive and to what level and dynamics you like to go. There are too many variables and I certainly agree with Nelson that different fine amplifiers (of which all those you listed are very fine) are just like different fine wines. What do I like about the KSA-50? Its low end response for sure, its extreme detail and resolution without being the slightest bit harsh or brittle, It is extremely dynamic and doesn't behave like a 50 watt amp, its very stable too at least after about 150 hours of on time, andvery easy to construct. Makes me miss my KSA-80B even more! Its been gone for about 5 years now
.I'm still not 100% sure about C105 & 6 but with the stated value in there the amp performs and sounds extremely good. I did take a brief look at a 10 khz square wave and its a bit rolled off for my tastes, but again the amp sounds REALLY good. One thing for sure is that you can eliminate C107 & 8 completely. The original KSA-50's did not have these caps at all, nor did the 100. They ARE in mine at the moment and don't seem to really make any difference audibly if they are left in or out.
BTW: I don't consider any tube amp to be the ultimate.... and I've owned ALOT of them over the years! They are simply not worth the effort involved any longer. Solid state really does have more to offer......
PWatts,
maybe we should ask if there is any way to improve on the KSA-50 as we have built it. Should we throw away our Randy Slone and D. Self books and trust this as the best incarnation?
PS. any chance of more PCB's for sale?
Tom
maybe we should ask if there is any way to improve on the KSA-50 as we have built it. Should we throw away our Randy Slone and D. Self books and trust this as the best incarnation?
PS. any chance of more PCB's for sale?
Tom
aleph...and DIY Meet
Trust no-one...the books aren't wrong, but sometimes an accidental local maximum can occour in the way components interact to yield something much better than the sum of the parts would imply...tweaking is easy and if you like the results better you know the answer.
I can't vouch for the aleph-x, but the aleph even moderately biased is a very nice amp indeed, as the bias increases I believe it will sound better and have more authority with extreme loads. Chances are it is not going to slam a pair of apogees around the way a krell does. I have not tried the krell with the duetta's I own, but as soon as I do I'll get back to you all...
In fact if any one in the SF bay area and thinks getting together for a weekend day would be good I'd be happy to host it at my house, I know of just one person so far in my 'vicinity', but I have parking for perhaps 10 cars, and a pretty big (25'x50'x20') room, so speak up if a day in April would be worth having a DIY meet...if there is any interest we can fire up another thread...
Stuart
Trust no-one...the books aren't wrong, but sometimes an accidental local maximum can occour in the way components interact to yield something much better than the sum of the parts would imply...tweaking is easy and if you like the results better you know the answer.
I can't vouch for the aleph-x, but the aleph even moderately biased is a very nice amp indeed, as the bias increases I believe it will sound better and have more authority with extreme loads. Chances are it is not going to slam a pair of apogees around the way a krell does. I have not tried the krell with the duetta's I own, but as soon as I do I'll get back to you all...
In fact if any one in the SF bay area and thinks getting together for a weekend day would be good I'd be happy to host it at my house, I know of just one person so far in my 'vicinity', but I have parking for perhaps 10 cars, and a pretty big (25'x50'x20') room, so speak up if a day in April would be worth having a DIY meet...if there is any interest we can fire up another thread...
Stuart
Al...
...if you wanna make the trek, I'll get Balti flown in fresh from Brick lane, just a mile down the road from where I used to live in the east end. Here in Santa Cruz We have a local nice indian restaurant, but not up to the standard of the one you showed us...
And if you wanna make it over I can give you heatsinks & caps to try and get through security...
Tom, I have one spare board, possibly more, if you can find someone with another, or convince Troy to part with one, you're set, no muss no fuss...alternatively we can trade if you have interesting parts...drop me an email.
Stuart
...if you wanna make the trek, I'll get Balti flown in fresh from Brick lane, just a mile down the road from where I used to live in the east end. Here in Santa Cruz We have a local nice indian restaurant, but not up to the standard of the one you showed us...
And if you wanna make it over I can give you heatsinks & caps to try and get through security...
Tom, I have one spare board, possibly more, if you can find someone with another, or convince Troy to part with one, you're set, no muss no fuss...alternatively we can trade if you have interesting parts...drop me an email.
Stuart
I finally had time tonight to work the 2nd supply in and get it running true dual mono. The difference is astounding! Really allows the dynamics in the music to jump out and grab you...... or slap you if thats the case. This ain't no 50 watt amp, thats for sure! Also realized by this addition was much improved low end distortion, now pinpoint, almost 3D soundstaging which is the best I've heard in my system from any amp. Both toroids are 769 VA surplus units I bought several years ago, and the caps are 58,000 50 volt jobs. This is all pretty close to what the original KSA-50 had except that these trannys are quite a bit larger in VA rating. I can really see whay so many reviewers still use these amps.......
Attachments
There's a guy selling a "Lot of 22 stereophiles" on ebay, one of those has the original review of the KSA-50, if anyone is interested.
K-
Mark, set-up looks nice, got a larger pic:?
K-
Mark, set-up looks nice, got a larger pic:?
Well, I have to size it so it fits in the file space allowed on this site. I suppose I can e-mail you a larger file tonight if you like....
MArk
MArk