Hello,
after learning a lot about the different resistor and capacitor types available (or rather I should say, after reading through a lot of marketing texts on products costing about 10000% of their industry standard competitors), I was worrying about the best way to go with my Aleph5-on-a-budget project. I already intend to spend a fair amount of money on the PSU, so I'd rather keep the spending to those few places where it actually makes a difference. So let's look at the schematics (I'm linking this pic from Holger Barske's website):
What I thought would make a bit of sense would be to use some high quality resistors and some high quality caps directly in the line of the input (R2,R3, R7, R9,R10,C5,C6 and C8). Now this might be a terribly naive attempt as I frankly have no real idea what adverse consequences a metal film vs a tantal film resistor (or an ordinary WIMA MKS5 cap vs a Mundorf MCap) might have on the signal qualities, and especially not on which place in the circuit those differences would be the most noticeable.
I could also imagine that the very low ohm resistors parallel to the output would be worthwhile to improve, but unfortunately it seems very hard to find ANY sub-1-Ohm resistors for me, not to mention high quality ones. Of course I could use 9x 1Ohm resistors to arrive at almost the same ohm rating, but I can hardly see me buying 20+ high quality resistors for €4 a piece in the near future...
By the way, (and again, please excuse my naivity) is this resistor arrangement (R22-25) representing the actual compensation for the "single-ended nature of air", as explained in those famous articles by Nelson Pass?
So would anybody who knows these amps (and it's obvious that some people on those boards do) care to give me some advice on how to spend my hard(ly) earned money the best way?
Chris
after learning a lot about the different resistor and capacitor types available (or rather I should say, after reading through a lot of marketing texts on products costing about 10000% of their industry standard competitors), I was worrying about the best way to go with my Aleph5-on-a-budget project. I already intend to spend a fair amount of money on the PSU, so I'd rather keep the spending to those few places where it actually makes a difference. So let's look at the schematics (I'm linking this pic from Holger Barske's website):
What I thought would make a bit of sense would be to use some high quality resistors and some high quality caps directly in the line of the input (R2,R3, R7, R9,R10,C5,C6 and C8). Now this might be a terribly naive attempt as I frankly have no real idea what adverse consequences a metal film vs a tantal film resistor (or an ordinary WIMA MKS5 cap vs a Mundorf MCap) might have on the signal qualities, and especially not on which place in the circuit those differences would be the most noticeable.
I could also imagine that the very low ohm resistors parallel to the output would be worthwhile to improve, but unfortunately it seems very hard to find ANY sub-1-Ohm resistors for me, not to mention high quality ones. Of course I could use 9x 1Ohm resistors to arrive at almost the same ohm rating, but I can hardly see me buying 20+ high quality resistors for €4 a piece in the near future...
By the way, (and again, please excuse my naivity) is this resistor arrangement (R22-25) representing the actual compensation for the "single-ended nature of air", as explained in those famous articles by Nelson Pass?
So would anybody who knows these amps (and it's obvious that some people on those boards do) care to give me some advice on how to spend my hard(ly) earned money the best way?
Chris
Hmm.. after reading through the Zen V2 pdf, I realized (as opposed to the last time I did so, when I stopped after getting the concept of constant current source as explained on the first page 
) the meaning of those 0.47 Ohm resistors - or at least I could somewhat relate what was described in the pdf to what I see in the Aleph 5 schematics
Uchi Deshi, which one would that feedback cap be in the schematics? R6 (680pF) by any chance? Because I already noticed that this one is missing in the PCB layout I'm using (BrianGT's), and I did already get worried about this a while ago...
Anyway, thanks for the replies so far! This is such a great forum!
Chris
) the meaning of those 0.47 Ohm resistors - or at least I could somewhat relate what was described in the pdf to what I see in the Aleph 5 schematics Uchi Deshi, which one would that feedback cap be in the schematics? R6 (680pF) by any chance? Because I already noticed that this one is missing in the PCB layout I'm using (BrianGT's), and I did already get worried about this a while ago...
Anyway, thanks for the replies so far! This is such a great forum!
Chris
I am not exactly shure how big your budget is but at any rate you'll find it pretty difficult to buy just a few "exotic parts" because you won't even get beyond the minimum order of most suppliers. A good supplier that has all the parts that you need would be schuro, here's my suggestion:
You can get pretty decent Metallband MPC71 5 Watt resistors for 50-60 cents (they also have manganin metal foils but they are already 4 EUR).
Next get their Vishay-Dale CMF-55-143, non-magnetic version !!!, for the signal path / feedback network at 50 - 80 cents: R7-10 (for single ended input), plus R52-54. Anything more exotic will cost ten times more.
As there are no caps in the signal path (let's not quibble about the definition) you can use WIMA for most foil caps, C6 Wima FKP2, C7 MKP4 or MKP10. C8 they don't have but you could create one out of a pair of twisted wires as explained in ZEN variation 4 (I think)
C5, 9, 10 you can use Panasonic-FC at 50 cents.
If you still have money left you can get more Vishay-Dale though it may not make a noticeable difference R4, R6 (not sure why you need both), R14, R21, R28-30, and so on.
You can get pretty decent Metallband MPC71 5 Watt resistors for 50-60 cents (they also have manganin metal foils but they are already 4 EUR).
Next get their Vishay-Dale CMF-55-143, non-magnetic version !!!, for the signal path / feedback network at 50 - 80 cents: R7-10 (for single ended input), plus R52-54. Anything more exotic will cost ten times more.
As there are no caps in the signal path (let's not quibble about the definition) you can use WIMA for most foil caps, C6 Wima FKP2, C7 MKP4 or MKP10. C8 they don't have but you could create one out of a pair of twisted wires as explained in ZEN variation 4 (I think)
C5, 9, 10 you can use Panasonic-FC at 50 cents.
If you still have money left you can get more Vishay-Dale though it may not make a noticeable difference R4, R6 (not sure why you need both), R14, R21, R28-30, and so on.
guys maybe something wrong with me, and maybe I have huge imagination ans so on. but parts really make big diference. very big diference. I agree that even with cheap cement resistors jamicon caps aleph 5 sound indeed good. but there are major improvements( OK some of you will find it minor) whern changing output resitors and capacitors , also PSU capacitors bring life to the amp. I experimented a lot I find that the best electrolytic capacitors to date(and most likely will bee) is siemens/epcos sikorell. they are very expensive but worth it. it costs about 700eur for 170 000uf and I tried and the sound was amazing. I also used elna silmic and it was huge improovemens in resoliution over jamicon. after burn in period however I found that elna silmic are muddy comparing with elna cerafine. now I am using black gate nx series.
and you may surprise but cables do make diferent in good systems.
just my few cents. just let spend wise him money. it is pleasure to do this I know and its not fair to say my 400eur aleph 5 on diet is as good as 1500eur aleph 5.
and you may surprise but cables do make diferent in good systems.
just my few cents. just let spend wise him money. it is pleasure to do this I know
and its not fair to say my 400eur aleph 5 on diet is as good as 1500eur aleph 5.
Well, I'm planning to walk the route of liquid cooling, so I think I'm pretty much covered in that area: Mosfets and other heat emitting devices will be sitting directly on two solid 250x150x5mm aluminium plates (1 per channel) or be connected to this using insulation-wrapped copper heatpipes, on the outsides of each of those plates there will be a 20mm thick plate of the same dimensions with coolant tunnels carved into them. I'll be using a garden water pump sitting in the next room (=garage) to get the fluids in motion, and a car radiator to get rid of the transported heat.
If I was better than I am (and if my dad was thinking more positively about running a bunch of pipes and tubes through the house), I would just dispose the water into our house's hot water reservoir and let the system run on cold tap water all the time. That would pretty much solve the efficiency problems of Class A and get rid of the heat problem at the same time I guess..
Chris
If I was better than I am (and if my dad was thinking more positively about running a bunch of pipes and tubes through the house), I would just dispose the water into our house's hot water reservoir and let the system run on cold tap water all the time. That would pretty much solve the efficiency problems of Class A and get rid of the heat problem at the same time I guess..
Chris
> I would just dispose the water into our house's hot water reservoir and let the system run on cold tap water all the time.
This is the best solution if your reservoir is large enough (and empty before you want to play music). But assume that you want to be able to play 5 hours, and say 1 litre a minute (which is nothing really). That would be 300 litres. (Electricity is probably more expensive than water. So worst case you can just dump it in the sink.)
> I'll be using a garden water pump sitting in the next room (=garage) to get the fluids in motion, and a car radiator to get rid of the transported heat.
Don't forget that your car radiator is designed to work on forced cooling. So don't forget to turn the fan on.
Patrick
This is the best solution if your reservoir is large enough (and empty before you want to play music). But assume that you want to be able to play 5 hours, and say 1 litre a minute (which is nothing really). That would be 300 litres. (Electricity is probably more expensive than water. So worst case you can just dump it in the sink.)
> I'll be using a garden water pump sitting in the next room (=garage) to get the fluids in motion, and a car radiator to get rid of the transported heat.
Don't forget that your car radiator is designed to work on forced cooling. So don't forget to turn the fan on.
Patrick
Well, a total loss water system sounds like a reliabilty or water bill$$$ problem IMO. I'ld stick with the closed system rather than risk a big leak with infinate supply of water.
I have tested some pure copper Heat Pipes for the Intel PIV and I'm happy with those for up to 80-100W (probably need at least 2-4) but, like the battery industry, these putor geeks are taking some less than high tech components up to today's more stringent requirements, at resonable mass produced costs...
Just 2 more cents that might help you save twenty Bucks...
Oh, Auto radiators come with crossflow (horizontal) and vertical flow paths. You can probably dispence with the fan with the verticle flow types... But then, it's not a car, you can just position it at your favorite angle also...
I have tested some pure copper Heat Pipes for the Intel PIV and I'm happy with those for up to 80-100W (probably need at least 2-4) but, like the battery industry, these putor geeks are taking some less than high tech components up to today's more stringent requirements, at resonable mass produced costs...
Just 2 more cents that might help you save twenty Bucks...
Oh, Auto radiators come with crossflow (horizontal) and vertical flow paths. You can probably dispence with the fan with the verticle flow types... But then, it's not a car, you can just position it at your favorite angle also...
Well, I honestly havent gotten that far myself yet. My two heat pipe units cost me $90.
There are countless discount putor suppliers. I have a Fry's Electronics nearby and their great for walking in and finding a deal.
As to the water system, there is an advantage there you may be overlooking. Once you have a water system, you can add one or two more modules at the amp without adding more pumps and radiators...
40 degrees??? I live in Arizona USA. It's Probably 40 Degrees outside at this moment
There are countless discount putor suppliers. I have a Fry's Electronics nearby and their great for walking in and finding a deal.
As to the water system, there is an advantage there you may be overlooking. Once you have a water system, you can add one or two more modules at the amp without adding more pumps and radiators...
40 degrees??? I live in Arizona USA. It's Probably 40 Degrees outside at this moment
Well, the car radiator can keep the engine well within the green temperature range when idling and slowly moving through a traffic jam for hours, and a car engine at idle produces, well, how much heat? Let's have a look: How do they say again in those ADAC car club magazines? The consumption of an engine is around 0.5l of gasoline / h at idle speed; 1 l of gasoline contains about 32MJ of energy, so for our 0.5l/h consumption, that equals 16000KJ/h, which equals 4.4 kJ/s. Taking the efficiency of the engine into regard (around 20-30%), that leaves us with at least 3.1kJ/s of heat. 1J/s=1W, so that equals 3.1kW of heat generated by the engine at idle, with a major part of it passing through the radiator - sure, after a while the additional fan kicks in, but I guess it would definitely be able to dispose a kW or two (just look at the sheer size and the surface area when compared to a standard electronics heatsink), and also, I have a few of those fans in my garage as well, and I wouldn't mind using them if the temperature runs too high.
As I already said, the tap water in-hot water out thing is a bit over my head, so I'll stick to the garden pump + radiator arrangement in the garage.
However, one (strikingly more skilled individual) could get rid of both the excessive water consumption and the danger of creating a massive leakage in case anything goes wrong by using a thermostat valve, a simple overpressure valve and a small auxilliary pump to create a circular water path around the amplifier - water goes through the amp's heatsinks, if it hasn't reached a certain temperature (40-50°C perhaps), the thermostat valves won't open for cool water from the tap. Once they open, cold water will stream in just enough to keep the temperature stable, and the hot water will exit through the overpressure valve to the hot water reservoir. If there is a leak anywhere in the circle between the valves, the thermostat's hot water input will run dry, and the thermostat would try to allow only hot water in, so that the tap water input would stay closed, reducing the possible leakage to the volume of fluid contained within the circle. As you can see, it would be very possible to run a stable temperature of pretty much anything above the temp. of tap water with such an arrangement, and if the water consumption would still be too high, one could still employ some more passive heatsinking to keep the cold water from flowing in through the thermostat.
Chris
As I already said, the tap water in-hot water out thing is a bit over my head, so I'll stick to the garden pump + radiator arrangement in the garage.
However, one (strikingly more skilled individual) could get rid of both the excessive water consumption and the danger of creating a massive leakage in case anything goes wrong by using a thermostat valve, a simple overpressure valve and a small auxilliary pump to create a circular water path around the amplifier - water goes through the amp's heatsinks, if it hasn't reached a certain temperature (40-50°C perhaps), the thermostat valves won't open for cool water from the tap. Once they open, cold water will stream in just enough to keep the temperature stable, and the hot water will exit through the overpressure valve to the hot water reservoir. If there is a leak anywhere in the circle between the valves, the thermostat's hot water input will run dry, and the thermostat would try to allow only hot water in, so that the tap water input would stay closed, reducing the possible leakage to the volume of fluid contained within the circle. As you can see, it would be very possible to run a stable temperature of pretty much anything above the temp. of tap water with such an arrangement, and if the water consumption would still be too high, one could still employ some more passive heatsinking to keep the cold water from flowing in through the thermostat.
Chris
Hello Folks,
While you are discussing "best parts" for an Aleph, could you please have a look at the following post which I put up just a few hours ago:
http://www.diyaudio.com/forums/showthread.php?postid=943655#post943655
By the way, where do you purchase these Dale-Vishay, Metallband, and Caddock resistors (and Riken while we are at it). I cannot source them in Australia (and I have spent quite a bit of time trying too) and they appear not to be on the Digikey or Mouser catalogues. The only interesting resistors I have been able to find are Vishay bulk metal foil resistors or naked bulk metal foil resistors from Texas Components.
Please note: these blokes are helpful and pleasant and sell small quantities too! (But I have not purchased anything from them yet. Gotta make sure my amp works before I put in such nice components.)
Regards,
George
While you are discussing "best parts" for an Aleph, could you please have a look at the following post which I put up just a few hours ago:
http://www.diyaudio.com/forums/showthread.php?postid=943655#post943655
By the way, where do you purchase these Dale-Vishay, Metallband, and Caddock resistors (and Riken while we are at it). I cannot source them in Australia (and I have spent quite a bit of time trying too) and they appear not to be on the Digikey or Mouser catalogues. The only interesting resistors I have been able to find are Vishay bulk metal foil resistors or naked bulk metal foil resistors from Texas Components.
Please note: these blokes are helpful and pleasant and sell small quantities too! (But I have not purchased anything from them yet. Gotta make sure my amp works before I put in such nice components.)
Regards,
George
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.