AndrewT
2 amperes
my question is.
for a given total bias on the output stage, for example, say 2 amps
the current available is only the available 2 amps, minus losses eg Re's(emitter resistors etc)
whether it is push/pull or single ended.
Is this correct?
allan
2 amperes
my question is.
for a given total bias on the output stage, for example, say 2 amps
the current available is only the available 2 amps, minus losses eg Re's(emitter resistors etc)
whether it is push/pull or single ended.
Is this correct?
allan
PARTS GB UPDATE...
I re-ordered (4 orderes) all the parts that didn't fit last weekend and 3 of them arrived during the week. The Jap transistors for Jan's boards are still in transit.
A few items from both Mouser AND Digi-Key were not "in-stock" ie backordered.
They had a 5 day lead time so they should be here next week.
I'm trying fellas... Just keep in mind that your getting these parts SIGNIFICATLY below the cost of ordering them yourself.
I re-ordered (4 orderes) all the parts that didn't fit last weekend and 3 of them arrived during the week. The Jap transistors for Jan's boards are still in transit.
A few items from both Mouser AND Digi-Key were not "in-stock" ie backordered.
They had a 5 day lead time so they should be here next week.
I'm trying fellas... Just keep in mind that your getting these parts SIGNIFICATLY below the cost of ordering them yourself.
Those parts that I managed to find over here (and still not all) would cost me somwhere between 250 and 300$ so I'm not complaining.
Just in case of confusion
Only one amplifier
edited version
AndrewT
2 amperes
my question is.
for a given total bias on the output stage, for example, say 2 amperes
the current available is only the available 2 amperes, minus losses eg Re's(emitter resistors etc)
whether it is push/pull or single ended.
Is this correct?
allan
Only one amplifier
edited version
AndrewT
2 amperes
my question is.
for a given total bias on the output stage, for example, say 2 amperes
the current available is only the available 2 amperes, minus losses eg Re's(emitter resistors etc)
whether it is push/pull or single ended.
Is this correct?
allan
Hi Awpagan,
that's the fundamental difference between single ended and pushpull.
A single ended amplifier can drive a load upto but not exceeding the bias current sourced(or sunk) from the active output device. As soon as the load is driven beyond this Iq limit either one of the crest peaks will clip.
A pushpull amplifier can drive the load upto twice the Iq limit before the topology reverts to classB (one output device cuts off).
so Iq=2A gives a max classA output of just below +-4A into the load. Then the pushpull circuit is usually capable of driving more current upto the output device, driver stage and PSU limit, whichever comes first. This classB current can be many times the classA limit.
Now what has this got to do with you requoting my question about reactive loading on that special case of single ended topology that I referred in post5194? Are you trying to confuse the issue?
that's the fundamental difference between single ended and pushpull.
A single ended amplifier can drive a load upto but not exceeding the bias current sourced(or sunk) from the active output device. As soon as the load is driven beyond this Iq limit either one of the crest peaks will clip.
A pushpull amplifier can drive the load upto twice the Iq limit before the topology reverts to classB (one output device cuts off).
so Iq=2A gives a max classA output of just below +-4A into the load. Then the pushpull circuit is usually capable of driving more current upto the output device, driver stage and PSU limit, whichever comes first. This classB current can be many times the classA limit.
Now what has this got to do with you requoting my question about reactive loading on that special case of single ended topology that I referred in post5194? Are you trying to confuse the issue?
jacco vermeulen said:
Better not mention Metaxas around here 😉
As far as sound difference, I'm real skeptic when it comes to sound of electronics. Not saying it doesn't exist, but let's say that blind test is a very good friend to your wallet.
Marketing mechanism ? If a regulated front end helps sound (we know it does help distortion figures), few measly bucks to construct it is nothing in grand scheme of things of megabuck amplifiers.
And let's not forget that even Golden Ears praised KSAs, Pass designs, and 1001 others that DON'T use regulated front end.
Bratislav
PS I'd take any Pass amp (including Thresholds) over anything Metaxas ever made. Ditto for Krell. And I'm not alone (some people around here would use much harsher words, I assure you)
awpagan said:
Well, here's my take on answers :
1. Adequate. Yes, we can fire up simulators and get the PSRR to two decimal points, but what's the point ? KSA 50 remains one of the most commonly accepted 'great' amps. It is on everyone's top whatever list. For a good reason - it IS good. Yes, without regulated front end. Even people like Pass like it 😎
2. Depends on your power supply. Large, low ESR capacitors and small decoupling non-electrolytic caps close to the output devices are your friend.
3. LM 317 and 337, despite what people say, are great devices. These designs stood ultimate test of time - engineers still use them. And engineers are not stupid.
Can you do better - of course you can. You want shunt regulator ? Go ahead, it is not that difficult. You want one better ? Use batteries. But keep things in perspective. At the other end of your ultra regulated ultra low distortion amp (or even BOTH ends if you use turntable 🙂), sits a very primitive electromechanical device that will distort several orders of magnitude more.
Want more controversy ? Some people actually prefer amps that show more distortion. In my big amp distortion figures definitely went south when I removed output stage from the feedback loop. Guess what ? I prefer it this way.
4. Regulated will of course give you less ripple. Even LM317 (which is by the way used in Silicon Chip ULD and class A amps, and these achieve astonishingly low noise/distortion figures) is an improvement over unregulated. Shunt regulator will go one better. Serial followed by shunt again. Batteries. Batteries with several Farads of capacitance followed by few millifards of polypropilene caps followed by slightly less amount of silver mica followed by an array of your favourite snake oil cap (Rel, Multi, Wonder ...). There's no limit to it (except your bank account 🙂 ).
But think agin - if you really want ultimate in power supply ripple rejection, you should not build KSA 50. Look at Greg's killer amp for example. Or Rod Eliott's designs. Or AKSA. Or even better - Silicon Chip ULD is now for sale for peanuts at Altronics. And it is twice the power of KSA50.
Me ? I'm happy with my unregulated, primitive, inefficient mostrosity
😀 😀 😀
Bratislav
Bratislav said:
I heard the Ksa50 many many years ago, I did really like it, but was way out of my price range. Let alone the system it was connected to.
Also heard the Ksa100 when it came out later, as well as a few later Krells, always preferred the Ksa50 to my ears.
I am NOT looking for ultimate PSRR, just asking what it was like in the kas50.
Distortion figures on amps are one thing but some amps just sound good.
Did build P3b amp, was nice amp, sounded better biased Class A.
Now scraped for parts.
Did build Silicon Chip ULD amp, very clean and accuate but sterile sound.
Trying mods to get the music back, long term project for testing ideas seen on this and other forums.
But there 15Watt Class A very nice little amp.
up'd volts and bias solen input caps still in use, just sounds good.
My regulated question started because i have a variety of caps around but different volts and ufarads
not enough similar ones for dual mono
but i have reg'd psu that i can easily mod for voltage and current.
Hope this explains a bit better.
AndrewT
seems I'm having difficulty in expressing this in the way you can understand
I'm not trying to annoy you please don't take it the wrong way.
As for reative loads?
Arn't all speakers a reative load to some degree?
allan
Boy howdy! Be careful there Rbstag with that three letter abreviation... I'm NOT trying to open a can of worms here...... Now I know its an abreviation but the sensitive members here will always take it the wrong way.... you might end up in the sin bin like I did for using it.......
.Mark
(Somewhere near Page, AZ., but I'm not sure exactly where)
P.S. You regulator guys have the scheme of things all wrong... you should be thinking "shunt regulator". Over in tubes I learned that pass transistor based regulators are not really a good thing..... A giant shunt ought to generate a good kilowatt or so for ole Gregie.....
Actually I love these big 'monster' amplifiers -
because I can place my small efficient designs on them like a pedestal and blow them away. Haha. The look on those agents faces is priceless!!
BTW jacco, my 10/12 yo kids have taken to the putting together
of kits like fish to water, freeing my time for design and teaching them skills along the way. Maybe a future in electronics.
Cheers,
Greg
because I can place my small efficient designs on them like a pedestal and blow them away. Haha. The look on those agents faces is priceless!!
BTW jacco, my 10/12 yo kids have taken to the putting together
of kits like fish to water, freeing my time for design and teaching them skills along the way. Maybe a future in electronics.
Cheers,
Greg
amplifierguru said:
But you have to put your small efficient designs in study boxes.
Or they'll melt.
allan
Hi awpagan,
Rather than dance around the maypole or build a sacrificial wicker man, I accept the inevitable and insulate my amps against climate change, localised to their immediate environment by ensuring they have more than adequate heatsinking and accurate thermal tracking,
Cheers,
Greg
Rather than dance around the maypole or build a sacrificial wicker man, I accept the inevitable and insulate my amps against climate change, localised to their immediate environment by ensuring they have more than adequate heatsinking and accurate thermal tracking,
Cheers,
Greg
awpagan said:
Greg, Before you are put into the same bin as workhorse, I think it is wise to realize that the audio world has been the graveyard of countless "good ideas" and "good measuring amps" that never made it ...., I am sure folks here respect your designs, on the flip side we all know whose amp are better known and more sought after... Blowing your own trumpet is one thing, rubbing people's noses into it is another...
You can learn a thing or two from Pavel (who we all know is not a Dan fan, yet his criticism is contructive and he helps people regardless, thats why he is respected not condemned for the same line you tow. Granted he walks on a fine line... 😉 )
This thread is for people who want to make and enjoy the Krell KSA, if that does not meet your fancy, no sweat we all have our preferences and opinions,
Cheers,
K-Ampy out.
awpagan said:
{Abreviated}
A number of Yanks, Aussies, Kiwi's and a bunch of other food items had a talk on regulation on a Leach thread.(makes me think of a bug)
It started as a suggestion to supply low current voltage to the front end of the amplifier, some read the possibillity in it to do the whole enchillada regulated.
No way a regulator is going to solve the lack of proper capacitors for the required normal powersupply of the KSA50.
Single ended amplifiers like Alephs do not like highly reactive loads. My Quad ESLs do a 60 degree shift, the Aleph Os was not a great companion for electrostats.
Audio magazines in Germany used to add cubic diagrams of the voltage capability of amplifiers, in relation to impedance and phase shift, to amplifier test articles. Single ended amplifiers have very poor voltage stability, current giants like Krells and Thresholds had close to flat voltage planes from -90 to +90 degrees.
(question : the name the Japanese give their country is Nippon, does that make them Nipponese or Nips ? There is an old brand called Nip in Japan)
John Cheese signing off.
Pinkmouse BOM
Al, Troy and Mark,
I've been getting orders put together for my PinkMouse boards, and have made some modifications to Troy's BOM. I would appreciate any comments. Some changes I made:
C104 was moved to line 1 with C303 etc. to match pin spacing.
For C105/106, the Mouser part number was for a 7.5mm lead spacing rather than 11mm. I couldn’t find a 47pf cap with 11mm, so I reverted to a 330pf cap.
The Mouser hyperlink for C303 etc. went to a .01uf cap instead of 0.1uf. I changed to a Digi-Key selection.
I added alternate parts numbers from Jameco for some diodes and transistors.
I put in Mark’s selection of MJL21193OS and MJL21194OS for the output devices (TO264 in place of TO3)
The Mouser hyperlinks for R101 thru R125 were for .25W instead of .5W. I changed those part numbers, but not the hyperlinks....yet.
Robert
Now I can't get the .zip BOM to attach....any hints?
Al, Troy and Mark,
I've been getting orders put together for my PinkMouse boards, and have made some modifications to Troy's BOM. I would appreciate any comments. Some changes I made:
C104 was moved to line 1 with C303 etc. to match pin spacing.
For C105/106, the Mouser part number was for a 7.5mm lead spacing rather than 11mm. I couldn’t find a 47pf cap with 11mm, so I reverted to a 330pf cap.
The Mouser hyperlink for C303 etc. went to a .01uf cap instead of 0.1uf. I changed to a Digi-Key selection.
I added alternate parts numbers from Jameco for some diodes and transistors.
I put in Mark’s selection of MJL21193OS and MJL21194OS for the output devices (TO264 in place of TO3)
The Mouser hyperlinks for R101 thru R125 were for .25W instead of .5W. I changed those part numbers, but not the hyperlinks....yet.
Robert
Now I can't get the .zip BOM to attach....any hints?
jacco vermeulen said:
Jacco,
talking about ESLs, I remember well around the KSA50 time (early 80s) much smaller amp achieved almost a cult status with ESL 57s - Bedini 25/25. I've seen/heard one driving stacked THREE pairs of ESLs. And it seemed very easy to clone - simple straighforward circuit, plain vanilla parts (2N3055!). Much smaller than KSA too, no fans (but running very hot).
No regulated front end either 😉
Bratislav
Re: Pinkmouse BOM
Email it to me directly and I will zip and link.
The Dale RN60 resistors are all 1/4 Watt. It was discussed and agreed upon earlier.
rjkdivin said:
Email it to me directly and I will zip and link.
The Dale RN60 resistors are all 1/4 Watt. It was discussed and agreed upon earlier.
Hi Rjk,
have another look at the PCB and BOM.
C103 0.3inch pitch
C104 0.4inch pitch
C105 & C106 0.4inch or 0.6inch pitch.
0.6inch would suit axial and 0.4inch may suit something.
but DO NOT use 330pF instead of 47pF.
C303 is 470uF on BOM and 100nF 0.3inch pitch on PCB.
i.e. PCB labelling has swapped component nos. But schematic and BOM agree. Just keep the schematic/BOM numbering and accept the mislabelling on the PCB. It is very obvious from the component outlines and pitches which component fits it's correct location.
Stay with 250mW resistor size, to fit the PCB. Many current 500mW and 600mW metal film are made to the 250mW size.
Larger resistors can be persuaded to fit but require the lead bending very close to the resistor body. This is very bad practice. A short straight from the body and then a gentle bend to fit the PCB is much preferred. As far as I can tell all the PCB (low power) resistor pitches are 0.5inch and this is adequate for the 250mW size.
Please do not post your replacement BOM until all these issues are resolved with Pinkmouse and Mark. It will only confuse the new group buyers waiting in the wings.
have another look at the PCB and BOM.
C103 0.3inch pitch
C104 0.4inch pitch
C105 & C106 0.4inch or 0.6inch pitch.
0.6inch would suit axial and 0.4inch may suit something.
but DO NOT use 330pF instead of 47pF.
C303 is 470uF on BOM and 100nF 0.3inch pitch on PCB.
i.e. PCB labelling has swapped component nos. But schematic and BOM agree. Just keep the schematic/BOM numbering and accept the mislabelling on the PCB. It is very obvious from the component outlines and pitches which component fits it's correct location.
Stay with 250mW resistor size, to fit the PCB. Many current 500mW and 600mW metal film are made to the 250mW size.
Larger resistors can be persuaded to fit but require the lead bending very close to the resistor body. This is very bad practice. A short straight from the body and then a gentle bend to fit the PCB is much preferred. As far as I can tell all the PCB (low power) resistor pitches are 0.5inch and this is adequate for the 250mW size.
Please do not post your replacement BOM until all these issues are resolved with Pinkmouse and Mark. It will only confuse the new group buyers waiting in the wings.
BOMs
Hi Andrew,
Thanks for the input. Troy had already told me that the 250mW resistors were agreed upon and would work fine. I am going to be emailing my revisions directly to him for review (as soon as I get his direct email).
Some of your comments seem to relate to an older BOM than Troy's corrected one (like C303 for instance).
I'm interested why it is important to maintain 47pf for C105 and C106 when it is listed as 33-330pf for the Jan BOM, 47pf for the Al BOM, and 390pf on the schematic? I'm not arguing with you....just curious! I must have missed some posts that discussed this value.
Was there ever a revised schematic posted for the Pinkmouse boards? All I have is Jan's schematic from the Delta Audio site. It doesn't even have C303/4 as far as I can tell.
Robert
AndrewT said:
Hi Andrew,
Thanks for the input. Troy had already told me that the 250mW resistors were agreed upon and would work fine. I am going to be emailing my revisions directly to him for review (as soon as I get his direct email).
Some of your comments seem to relate to an older BOM than Troy's corrected one (like C303 for instance).
I'm interested why it is important to maintain 47pf for C105 and C106 when it is listed as 33-330pf for the Jan BOM, 47pf for the Al BOM, and 390pf on the schematic? I'm not arguing with you....just curious! I must have missed some posts that discussed this value.
Was there ever a revised schematic posted for the Pinkmouse boards? All I have is Jan's schematic from the Delta Audio site. It doesn't even have C303/4 as far as I can tell.
Robert