Balanced line stage and attenuators and seperate power supply chassis, diy not to save money, but to build it the way I want it. R core transformers, CRC power supply 240,000 uf, Jung regulators as pre regulators, fet shunt regulators, discrete jfet/fet line amp designed by Erno Borbely
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High gain and high NFB Opamp can measure pretty well or at least based on some basic measurements.
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Hi Andy,
Let go of the issues we had in the 80's and before. Back then I was using a THD analyzer (HP 339A) and an HP 3585A spectrum analyzer hung on the output of that to sort out issues. I was pretty successful back then and its so much easier today with current equipment. Averaging readings took forever back then, but it was the only way to drop the noise floor enough to see the distortion products.
Today's well equipped test bench is far different than what we had in the 70's and 80's and even the 90's. There are many members here that can confirm what I have said. All these highly skilled people do the same thing I do, and we always listen to what we have done out of habit and just to confirm what the instruments told us. I have done work on equipment and sent it home with the client, and their reports have agreed with what I told them (later) about what they would hear. Pretty scary stuff to the "design by ear" crowd.
-Chris
That's why I specified the instruments I did. We can measure below your ability to hear issues these days. You will not find a preamp (or any equipment) that measures well on my bench but doesn't sound good. However, there are plenty of pieces of audio gear that are supposed to sound good that measure poorly. I have improved many and in fact I am often paid to improve equipment. Real improvements that can be measured and those measurements have always agreed with the client's listening tests.
Let go of the issues we had in the 80's and before. Back then I was using a THD analyzer (HP 339A) and an HP 3585A spectrum analyzer hung on the output of that to sort out issues. I was pretty successful back then and its so much easier today with current equipment. Averaging readings took forever back then, but it was the only way to drop the noise floor enough to see the distortion products.
Today's well equipped test bench is far different than what we had in the 70's and 80's and even the 90's. There are many members here that can confirm what I have said. All these highly skilled people do the same thing I do, and we always listen to what we have done out of habit and just to confirm what the instruments told us. I have done work on equipment and sent it home with the client, and their reports have agreed with what I told them (later) about what they would hear. Pretty scary stuff to the "design by ear" crowd.
-Chris
This computer style soundcard designs you could buy at the asian markets, maybe even the price will be competitive or will beat your DIY price.
They do real cheap, not comparable with the usual high end prices we know.
I think, for that gear no one needs DIY. If you want three PSU, just buy three and your finished.
Btw, to use 240.000uF means brute force designs. Use much of it and it helps a lot, thats the thought behind that. But much uF isn't good, especially for a PSU. Every cap stores energy, that makes it a sloooooow PSU. No one wants that. There are far better technical solutions than the usual take much uF and its a better PSU. Its just a nice thought, but never worked out. For me, its just a bad design.
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The next type computer soundcard design. B. Oring. Can be seen on every audio fair, onehundredthousand times the same. They all sound (nearly) the same.
Can't see the need either. Certainly not if you connect it through a wire to another box.
If what you said is right, then any preamp measured by your equipment should sound exactly the same, since you claimed that the measurements are all below the threshold of human hearing.
As an owner of several Krell products (from the glory age of massive uF), several Counterpoints and a Le Monstre (diy), I would challenge that statement, lots of uF is very very very good, it makes for amazing sounding amps, better than any amp I have heard with a whimpy PSU anyhow.
If you know of an incredible sound low uF amp that can hold up to a Krell, or Le Monstre, I am happy taking a listen, just point me in the direction....
I will say that when it comes to power supplies for power amplifiers, bigger is better. And it is a fact that the secret to the Krell (which is an antique now) is its power supply. And with a bigger power supply comes obligatory bigger heat sinks. Other than these attributes, is it really that spectacular by today''s standards?
I have a Nakamichi receiver rated (I think) 50 watts RMS into 8 ohms. It has an enormous power supply for such a modest rating. It sounds like it too; the power amplifier never wheezes and even has headroom at 8 ohms. It sounds way more powerful than my buddy's budget "100 watts x 2 @ 8 ohm" budget Sony receiver driving the same speakers in the same room. In fact, a virtue of this receiver is that it can drive speakers with atrocious impedance curves with no sweat.
As a learning exercise, I polished a few turds I pulled out of the dumpster. I took an old Pioneer receiver (early 90s) that was rated (I think) 65 watts RMS @ 8 ohms. Quick testing showed it had about 3 dB headroom @ 8 ohms, promising. It sounded terrible. Wheezy and thin distorted bass is what it offered. Low volume listening was terrible. Loud volume listening was excruciating. Now I know why it hit the dumpster, because everything worked.
I replaced the big antique power supply capacitors with capacitor arrays. I built boards that would stand up where the old caps were and put a 5 capacitor array on each board. I used plastic nuts and bolts to stabilize the boards (bolted them together). I soldered two huge MKP caps (0.33 uF/600 volts) on the bottom of the board across each pair of output transistors where they go to the power supply.
I safety tested it and did a listening test. This was a huge improvement. The bass was back in a big way. The sound was clearer and the unit provided a big punch.
Then I hotwired around the equalizer (terrible) and all the digital crap, so it was just a power amp with RCA inputs. I was stunned. This was a very nice, clean, punchy power amplifier. I actually used it that way for about 3 years. I still have it.
Cliff notes: When it comes to power supplies, size matters.
I have a Nakamichi receiver rated (I think) 50 watts RMS into 8 ohms. It has an enormous power supply for such a modest rating. It sounds like it too; the power amplifier never wheezes and even has headroom at 8 ohms. It sounds way more powerful than my buddy's budget "100 watts x 2 @ 8 ohm" budget Sony receiver driving the same speakers in the same room. In fact, a virtue of this receiver is that it can drive speakers with atrocious impedance curves with no sweat.
As a learning exercise, I polished a few turds I pulled out of the dumpster. I took an old Pioneer receiver (early 90s) that was rated (I think) 65 watts RMS @ 8 ohms. Quick testing showed it had about 3 dB headroom @ 8 ohms, promising. It sounded terrible. Wheezy and thin distorted bass is what it offered. Low volume listening was terrible. Loud volume listening was excruciating. Now I know why it hit the dumpster, because everything worked.
I replaced the big antique power supply capacitors with capacitor arrays. I built boards that would stand up where the old caps were and put a 5 capacitor array on each board. I used plastic nuts and bolts to stabilize the boards (bolted them together). I soldered two huge MKP caps (0.33 uF/600 volts) on the bottom of the board across each pair of output transistors where they go to the power supply.
I safety tested it and did a listening test. This was a huge improvement. The bass was back in a big way. The sound was clearer and the unit provided a big punch.
Then I hotwired around the equalizer (terrible) and all the digital crap, so it was just a power amp with RCA inputs. I was stunned. This was a very nice, clean, punchy power amplifier. I actually used it that way for about 3 years. I still have it.
Cliff notes: When it comes to power supplies, size matters.
Categorically, Yes the Krell's are still amazing, I have heard very little that comes even close to my KSA150, including certain $30k class D offerings and alot of modern stuff. You want to better even an old KSA50 from 1983, you have to spend a lot of money today.
Beg to differ. Only had the KMA160 and the KSA250 and while excellent in some areas they were pretty bad in speed, high frequency resolution and air. Could i live with that sound today? No way, except for bass duties. The only Krell preamp i had was even worse. Spent a couple of weeks updating the amps with known good sounding caps and termination and achieved only a very modest improvement.
Sounds like your Krell's were broken. Come over and have a listen. bring your favorite amp and we can play around with that.
Pass KorgB1 being a wonderful example of a great sounding amp even in the lowest spec with smps. Treat it well and it really sings
And I agree with you. Although they may not compete with today's equipment in terms of THD+N and speed, they deliver the power the power and dynamics that's lacking in some consumer grade (and better) amplifiers (especially in integrated products like receivers). That's because weak power supplies collapse under demand. This allows manufacturers to use smaller heat sinks. If you want to know how much power the engineer really intended the amplifier to provide reliably, then just look at the heatsink. What do the heatsinks look like in the Krell? What do the heatsinks in my buddy's "100 watts x2 into 8 ohms" receiver look like? The Krell can deliver its rated power all day without dynamic compression, excessive distortion, or overheating.
My Nakimichi is rated 0.1% THD. My buddy's budget receiver is rated so low it's academic. Guess which one sounds better? (Guess which one has a more honest specification?) You don't have to guess why. Dynamic compression is more audible than 0.1% THD, to my ears. How about yours?
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