Home |
Search |
Today's Posts |
#1
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock
PSUs. The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] The mystery is the sound, which is sort of peculiar. Hard to explain, but what is the source? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Not much to go on here, but thought I would throw this one out to you guys. Thanks again... Dave |
#2
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
"Wink" wrote in message ... I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock PSUs. The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] The mystery is the sound, which is sort of peculiar. Hard to explain, but what is the source? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Not much to go on here, but thought I would throw this one out to you guys. Thanks again... Dave Ought to work fine. Mark Z. |
#3
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
The mystery is the sound, which is sort of peculiar. Hard to explain,
but what is the source? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Just a guess, but: if you're dropped the rail voltage, you may also have disturbed the biasing of one or more of the amplifier's stages. The drivers or finals could now be running with a lower level of standing current... and if this is too low, the amp might be suffering from some amount of crossover distortion. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#4
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
In article , Wink
wrote: I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock PSUs. The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] The mystery is the sound, which is sort of peculiar. Hard to explain, but what is the source? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Not much to go on here, but thought I would throw this one out to you guys. Thanks again... Dave If this is one of those fancy amplifiers where the pull-up and pull-down are perfectly balanced, then it probably has minimal regulation on the bias currents. It will change sound if the average power supply voltage is too far off. 53V minus load drooping is probably out of normal operating range. -- I don't read Google's spam. Reply with another service. |
#5
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Interesting answers guys. That pa-3d driver card is designed to
operate over a wide voltage range. It is used in the DH-500 which has 90 volt rails. I'll have to talk John Hillig at Musical Concepts about this. The waveform is fully integrated at something like 17 V rails and 70 ma. idle bias. The card uses a single ended front end and I believe Cascoded current follower output device drivers. These blocks sound pretty good with Chemi-cons (not old stock Sangamos) at the 63 V design rail voltage Frankly though, I bought Clayton S-40, 50 W class A per channel, and it is verging on magical. I have doubts about whether my blocks will ever compete. Not the result I was seeking. Dave On Sun, 23 Mar 2008 12:35:17 -0500, Wink wrote: I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock PSUs. The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] The mystery is the sound, which is sort of peculiar. Hard to explain, but what is the source? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Not much to go on here, but thought I would throw this one out to you guys. Thanks again... Dave |
#6
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
"Wink" wrote in message
I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock PSUs. The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] Running 63 volt rated caps at 63 volts will probably not cause explosions, but it will shorten their useful life to spec, given other operating conditions are spec. Since you probably aren't running them as warm as spec, they will probably still live longer than spec. Furthermore, its not like electrolytics explode if run 1 volt over spec. They can probably take 20% or more overvoltage, with no undesireably results other than a somewhat shortened life. Bottom line, you could experiment for a few minutes or a few hours with rated power line voltage being appled, and nothing bad would happen. The mystery is the sound, which is sort of peculiar. And of course, being an unwashed amateur, you have no proper listening tests to back this up. With all due respect, which ain't much, why would anybody with a brain even comment on your random perceptions? You probably are scrunching up your ears every time you listen to these amps because you *know* about the *violence* that is going on inside. Come back when you've got evidence of something more electronic and technical than the state of your mind. :-( Hard to explain, but what is the source? Your state of mental stress due to your under-rated caps, which aren't all that under-rated? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Not to mention your obvious state of guilt and self-deinal. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Well, the Variac probably adds a little ESR, and may shift the harmonic content of the powerline measurably. But on balance, those are the sorts of thing that a well-designed power amp is supposed to take in stride. Not much to go on here, but thought I would throw this one out to you guys. If the origional caps were OK, then the added/replaced caps were acts of either futility or obsessive behavior. If they weren't OK, why didn't you get proper caps instead of inflicting this marginally-rated crap on your psyche? Seriously! As far as the bias-shift theory goes, the fact is that a well-designed power amp can't be allowed to suddenly fall apart because the rail voltages are 20% or whatever low. IME a lot of power amp output stages will do a credible job of amplifying when the rail voltage is 20% of spec. Not 20% low, but 20% of. Of course the power output will be only about 10% of spec, but what do you expect, power from no where? ;-) |
#7
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Why did you change the caps? Are the new ones larger? Trust me, the
electrons are not brand concious. They don't care what the label on the caps is. Brand X is just the same as Brand Y to an electron. Now labels and my teenage daughter, that's another story..... The voltage tolerance on your caps is going to have safety factor so you can run it at rated voltage. "Wink" wrote in message ... I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock PSUs. The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] The mystery is the sound, which is sort of peculiar. Hard to explain, but what is the source? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Not much to go on here, but thought I would throw this one out to you guys. Thanks again... Dave |
#8
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Arny Krueger wrote: Running 63 volt rated caps at 63 volts will probably not cause explosions, but it will shorten their useful life to spec, given other operating conditions are spec NO ! What kills capacitors is HEAT. The vast majority of that heat comes from the effect of ripple current, absolutely NOT applied voltage which merely affects the leakage current. A 63V rated cap is *designed* to be used at 63V. It will likely have a 'surge rating' of around 80V but that's rarely publicised these days. Graham |
#9
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote: I'm not running 800 bucks worth of 63 V lytics at 63 Volts. Not necessary. What a shocking waste of money ! Transistor amps by design (large degrees of negative feedback whether local, overall or both) and by virtue of the inherent high collector resistance of the active devices are very little affected by signal on the power rails. In any case, the AC voltage on the DC rails will be mostly 100/120 Hz ripple. And fitting Black Gates will make ZERO difference to that. At best you've simply not made your amp any WORSE by fitting BGs but it's an insane waste of money. What on earth did you expect it to do and most of all ** WHY ** ? Graham |
#10
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
jamesgangnc wrote: Why did you change the caps? Are the new ones larger? Trust me, the electrons are not brand concious. They don't care what the label on the caps is. Brand X is just the same as Brand Y to an electron. Now labels and my teenage daughter, that's another story..... Well ... different caps may have different ESRs which will slightly influence the ripple voltage but that's only a minor secondary effect compared to the capacitance value in this kind of PSU. The voltage tolerance on your caps is going to have safety factor so you can run it at rated voltage. Absolutely. Graham |
#11
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
"jamesgangnc" ) writes:
Why did you change the caps? Are the new ones larger? Trust me, the electrons are not brand concious. They don't care what the label on the caps is. Brand X is just the same as Brand Y to an electron. Now labels and my teenage daughter, that's another story..... The voltage tolerance on your caps is going to have safety factor so you can run it at rated voltage. I just reread that. So he changed the capacitors, and "made do" with lower voltage than needed, and now he's talking about getting a new transformer with a lower voltage to keep the capacitors safe. Even if there had been some value in changing the filter capacitors, it was silly to change them to lower voltage ones, and the moreso if that requires yet another change, the transformer. Plus, he thinks it sounds different with the variac. But if as some suggest that's because the unit is running at a lower voltage, then he'll still have that problem when he changes the transformer. Michael "Wink" wrote in message ... I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock PSUs. The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] The mystery is the sound, which is sort of peculiar. Hard to explain, but what is the source? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Not much to go on here, but thought I would throw this one out to you guys. Thanks again... Dave |
#12
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote: These blocks sound pretty good with Chemi-cons (not old stock Sangamos) at the 63 V design rail voltage Your obsession with capacitor brand is quite absurd. Look elsewhere for what's causing any apparent difference. Graham |
#13
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
A glorious response. Curious in light of previous helpful and cordial
ones, free of your compulsive cruelty. I'm not an objectivist Arny. I've tried to be, the scientist within compels it; but amps sound different, quite different frequently. ICs and cables: I've been a maximum skeptic for decades, using generics and zip cord. But recent experiments have shown that these items do indeed sound different, frequently meaningfully. It is distressing, looking for the physics, and the yet the conclusion is inescapable. I'm convinced that, though objectivists do not necessarily have inferior ears, they may have ears which are insensitive to things the subjectivists detect. Like my wife who can distinguish colors that look utterly the same to me. AB, ABX testing is useless. Sometimes amp problems/ strengths take weeks to emerge. The instantaneous nature of the AB test does not allow enough time for the ear-brain to acquire the target. This is not true of speakers generally because of the massive differences between designs. Sufficient differential for near instant target acquisition. Anyway, keep the responses coming. I need smattering of high quality, gratuitous immaturity in my day, and yours is of the highest quality. I'm not running 800 bucks worth of 63 V lytics at 63 Volts. Not necessary. Dave On Mon, 24 Mar 2008 09:27:16 -0400, "Arny Krueger" wrote: "Wink" wrote in message I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock PSUs. The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] Running 63 volt rated caps at 63 volts will probably not cause explosions, but it will shorten their useful life to spec, given other operating conditions are spec. Since you probably aren't running them as warm as spec, they will probably still live longer than spec. Furthermore, its not like electrolytics explode if run 1 volt over spec. They can probably take 20% or more overvoltage, with no undesireably results other than a somewhat shortened life. Bottom line, you could experiment for a few minutes or a few hours with rated power line voltage being appled, and nothing bad would happen. The mystery is the sound, which is sort of peculiar. And of course, being an unwashed amateur, you have no proper listening tests to back this up. With all due respect, which ain't much, why would anybody with a brain even comment on your random perceptions? You probably are scrunching up your ears every time you listen to these amps because you *know* about the *violence* that is going on inside. Come back when you've got evidence of something more electronic and technical than the state of your mind. :-( Hard to explain, but what is the source? Your state of mental stress due to your under-rated caps, which aren't all that under-rated? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Not to mention your obvious state of guilt and self-deinal. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Well, the Variac probably adds a little ESR, and may shift the harmonic content of the powerline measurably. But on balance, those are the sorts of thing that a well-designed power amp is supposed to take in stride. Not much to go on here, but thought I would throw this one out to you guys. If the origional caps were OK, then the added/replaced caps were acts of either futility or obsessive behavior. If they weren't OK, why didn't you get proper caps instead of inflicting this marginally-rated crap on your psyche? Seriously! As far as the bias-shift theory goes, the fact is that a well-designed power amp can't be allowed to suddenly fall apart because the rail voltages are 20% or whatever low. IME a lot of power amp output stages will do a credible job of amplifying when the rail voltage is 20% of spec. Not 20% low, but 20% of. Of course the power output will be only about 10% of spec, but what do you expect, power from no where? ;-) |
#14
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Michael Black wrote: Plus, he thinks it sounds different with the variac. But if as some suggest that's because the unit is running at a lower voltage, then he'll still have that problem when he changes the transformer. Absolutely correct. The entire plan is flawed from the ouset, although of course there is NO NEED to 'under-run' the caps. Graham |
#15
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote: Why did you change the caps? When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately a deadening of the sound. Simple reason for that, it's how the amp originally sounded when the Sangamos were 'fresh'. As caps 'die', their capacitance reduces and this affects the regulation of the power supply and consequently can influence how it treats large dynamics. All you did was restore the amp to 'original condition' but didn't like the result. If perhaps you'd fitted 3300 or 4700uF caps in place of 10,000uF you may have preferred how it sounded. Science DOES have the answers you see, but you really do need to know your onions and have LOTS of experience to understand this stuff. Random component substitution is one of the dumbest things out there but a lot of crooks make good money out of you from it. Graham |
#16
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Eeyore wrote:
Wink wrote: Why did you change the caps? When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately a deadening of the sound. Duh.... Simple reason for that, it's how the amp originally sounded when the Sangamos were 'fresh'. Why does that not make sense to 'audiophiles'...and by what objective measurement were the originals starting to 'die'? As caps 'die', their capacitance reduces and this affects the regulation of the power supply and consequently can influence how it treats large dynamics. All you did was restore the amp to 'original condition' but didn't like the result. If perhaps you'd fitted 3300 or 4700uF caps in place of 10,000uF you may have preferred how it sounded. Probably, but only if they cost at least $200 per cap.... Science DOES have the answers you see, but you really do need to know your onions and have LOTS of experience to understand this stuff. Random component substitution is one of the dumbest things out there but a lot of crooks make good money out of you from it. He should have new control knobs machined out of solid gold. Now THAT would provide some measurable change...opens up the soundstage and provides unimaginable depth and clarity to the imaging. Seriously, if the OP wants to use those 'bargain' $800 caps, perhaps he should build an entire new pair of blocs with those and the new transformers he's having custom built...and sell the originals. There are plenty of plans on the Web. Of course it sounds like money is not an object, so perhaps he could use the old ones as doorstops. jak Graham |
#17
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Why did you change the caps?
When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately a deadening of the sound. This has not changed much despite break-in, assuming electrolytic "break-in" actually occurs. (Of course the LC-200s have 3x the capacitance. Yes I've read esp's treatment on this.) I was going to continue with the MC caps when I built the monoblocks, but found a set of 4 - 63 V, 10 kufd FK series Black Gates for a "reasonable" price and thought I'd roll the dice. Are the new ones larger? Trust me, the electrons are not brand concious. They don't care what the label on the caps is. Brand X is just the same as Brand Y to an electron. Yes, of course. I expect Brand X could be labeled Fruit Loops and Brand Y, Captain Crunch. That would not make a difference. Differences in internal design, well...I suppose that COULD make a difference, but probably not. I think you've made such brand observations before, which make -- of course -- no sense whatsoever. The voltage tolerance on your caps is going to have safety factor so you can run it at rated voltage. Yes, I'm aware of this, but why do so if unnecessary? I was going to change the xfmrs anyway. Avel Lindberg has as a standard model a dual 40 V secondary unit of suitable physical dimensions. Seems logical since as pointed out the amp will operate properly over a wide range of voltages. It turns out that I'm not going with AL toroidals, but am having them custom made by a Canadian company -- Richard Sumner. I could specify any secondary voltage, but 40-0-40 gives 56.6 V calculated no-load, about 53 V under load at idle. A 10 Volt safety margin with negligible performance penalties. Dave "Wink" wrote in message .. . I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock PSUs. The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] The mystery is the sound, which is sort of peculiar. Hard to explain, but what is the source? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Not much to go on here, but thought I would throw this one out to you guys. Thanks again... Dave |
#18
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
"Wink" wrote in message
A glorious response. Curious in light of previous helpful and cordial ones, free of your compulsive cruelty. The kindest thing I can say to someone who is making decisions based on questionable information... I'm not an objectivist Arny. Neither am I. I've tried to be, the scientist within compels it; but amps sound different, quite different frequently. It always happens for a reason, and the reason often has nothing to do with amplifier performance. It often has to do with the circumstances of the listening evaluation. ICs and cables: I've been a maximum skeptic for decades, using generics and zip cord. But recent experiments have shown that these items do indeed sound different, frequently meaningfully. It is distressing, looking for the physics, and the yet the conclusion is inescapable. No such thing - try doing some reasonable tests. I'm convinced that, though objectivists do not necessarily have inferior ears, they may have ears which are insensitive to things the subjectivists detect. Interesting how the subjectivist's ears work the same when the sighted cues and other asymmetries are removed from the evaluation. Like my wife who can distinguish colors that look utterly the same to me. OK, so you are a little color blind. AB, ABX testing is useless. So how do you do a listening test? Any comparison of two pieces of equipment can be called an AB test. Sometimes amp problems strengths take weeks to emerge. If it is real, there is always a reason. The instantaneous nature of the AB test does not allow enough time for the ear-brain to acquire the target. Who said that an AB test has to be instantaneous? I've heard this straw man argument 100's of times. :-( This is not true of speakers generally because of the massive differences between designs. Sufficient differential for near instant target acquisition. Maybe yes, maybe no. Anyway, keep the responses coming. I need smattering of high quality, gratuitous immaturity in my day, and yours is of the highest quality. Actually, some of the original ABX crew is now well on their way to their 70s, and their immaturity is such that they have credibility in the audio industry that you probably don't even know exists. Immaturity, indeed. :-( I'm not running 800 bucks worth of 63 V lytics at 63 Volts. Not necessary. You paid $800 for the electrolytics for a power amp or two? Freakin' unbelievable. :-( |
#19
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
On Mar 24, 1:36*pm, Wink wrote:
Why did you change the caps? * When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately *a deadening of the sound. This has not changed much despite break-in, assuming electrolytic "break-in" actually occurs. (Of course the LC-200s have 3x the capacitance. Yes I've read esp's treatment on this.) I was going to continue with the MC caps when I built the monoblocks, but found a *set of 4 - 63 V, 10 kufd FK series Black Gates for a "reasonable" price and thought I'd roll the dice. Are the new ones larger? *Trust me, the electrons are not brand concious. *They don't care what the label on the caps is. *Brand X is just the same as Brand Y to an electron. * Yes, of course. I expect Brand X could be labeled Fruit Loops and Brand Y, Captain Crunch. That would not make a difference. Differences in internal design, well...I suppose that COULD make a difference, but probably not. *I think you've made such brand observations before, which make -- of course -- no sense whatsoever. The voltage tolerance on your caps is going to have safety factor so you can run it at rated voltage. Yes, I'm aware of this, but why do so if unnecessary? I was going to change the xfmrs anyway. Avel Lindberg has as a standard model a dual 40 V secondary unit of suitable physical dimensions. Seems logical since as pointed out the amp will operate properly over a wide range of voltages. * It turns out that I'm not going with AL toroidals, but am having them custom made by a Canadian company -- Richard Sumner. I could specify any secondary voltage, but 40-0-40 gives 56.6 V calculated no-load, about 53 V under load at idle. A 10 Volt safety margin with negligible performance penalties. Dave "Wink" wrote in message .. . I happened to snag a set of 63V/10,000ufd FK BG caps for my monoblock PSUs. The rail voltage with stock Hafler xmfr is ~ *63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts until I replace the Hafler trafos with lower sec V Toroidals. [Refer to "Hafler Monoblock Project..." thread] The mystery is the sound, which is sort of peculiar. Hard to explain, but what is the source? Of course there are 3 variables that have been changed: PSU caps from Chemicons to BGs, lower rail voltage (well within the operating range of the PA-3D driver board), and inclusion of the Variac twixt house mains and both amps. Should I expect some odd interaction between the Variac and existing Hafler power xfmr? Nothing obvious comes to mind. *Running stone cold, the 1500VA, Powerstat Variac has plenty of capacity. Not much to go on here, but thought I would throw this one out to you guys. Thanks again... Dave- Hide quoted text - - Show quoted text - Seems like a whole lot of time, effort, and money being spent to run a lower output stage voltage. To each his own. |
#20
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
"Eeyore" wrote in
message Wink wrote: I'm not running 800 bucks worth of 63 V lytics at 63 Volts. Not necessary. Did we read this right? Is this a typo? Was there an extra zero in that price? What a shocking waste of money ! Agreed. Transistor amps by design (large degrees of negative feedback whether local, overall or both) and by virtue of the inherent high collector resistance of the active devices are very little affected by signal on the power rails. Agreed. In any case, the AC voltage on the DC rails will be mostly 100/120 Hz ripple. And fitting Black Gates will make ZERO difference to that. Agreed. At best you've simply not made your amp any WORSE by fitting BGs but it's an insane waste of money. What on earth did you expect it to do and most of all ** WHY ** ? Graham, I don't think we should waste much time on a certifiable loonie who puts $400-800 worth of caps in a single amplifier. He's living in a different universe from the rest of of! |
#21
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
jakdedert wrote: Eeyore wrote: Wink wrote: Why did you change the caps? When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately a deadening of the sound. Duh.... Why the duh ? Simple reason for that, it's how the amp originally sounded when the Sangamos were 'fresh'. Why does that not make sense to 'audiophiles'... Because they mostly reject scientific reasoning, thinking that subjectivity is superior even though they can't explain why except by resorting to make-believe words and ideas. and by what objective measurement were the originals starting to 'die'? A good question. It would be VERY interesting to know what value they still had when removed. As caps 'die', their capacitance reduces and this affects the regulation of the power supply and consequently can influence how it treats large dynamics. All you did was restore the amp to 'original condition' but didn't like the result. If perhaps you'd fitted 3300 or 4700uF caps in place of 10,000uF you may have preferred how it sounded. Probably, but only if they cost at least $200 per cap.... For ordinary commercial 3300/4700 63Vs ? A few dollars each. I'm sure you can get them less than $10. Science DOES have the answers you see, but you really do need to know your onions and have LOTS of experience to understand this stuff. Random component substitution is one of the dumbest things out there but a lot of crooks make good money out of you from it. He should have new control knobs machined out of solid gold. Now THAT would provide some measurable change...opens up the soundstage and provides unimaginable depth and clarity to the imaging. LOL ! You've seen those wooden knobs for several hundred dollars each ? Graham |
#22
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
|
#23
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote: The rail voltage with stock Hafler xmfr is ~ 63 Volts so to avoid exploding my $$ BGs, I'm using a Variac to reduce the AC mains input for a rail Voltage of ~ 53 volts You first misunderstanding. If BG's ** EXPLODE ** with the rated voltage applied that simply shows that they're garbage. Competently manufactured electrolytic caps will not be troubled by as much as 20-25% overvoltage in fact as long as it's not continuous. Graham |
#24
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Arny Krueger wrote: "Eeyore" wrote in At best you've simply not made your amp any WORSE by fitting BGs but it's an insane waste of money. What on earth did you expect it to do and most of all ** WHY ** ? Graham, I don't think we should waste much time on a certifiable loonie who puts $400-800 worth of caps in a single amplifier. He's living in a different universe from the rest of of! I do like to (try to) explain to the crazies that there are actually perfectly 'sound' - lol - scientific reasons for what they appear to think are mysterious differences that they then attribute to component swaps or some kind of magick generally. It's a hard task but someone's got to do it ! Graham |
#25
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
"Eeyore" wrote in
message jakdedert wrote: Eeyore wrote: Wink wrote: Why did you change the caps? When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately a deadening of the sound. Duh.... Why the duh ? Simple reason for that, it's how the amp originally sounded when the Sangamos were 'fresh'. Why does that not make sense to 'audiophiles'... Because they mostly reject scientific reasoning, thinking that subjectivity is superior even though they can't explain why except by resorting to make-believe words and ideas. and by what objective measurement were the originals starting to 'die'? A good question. It would be VERY interesting to know what value they still had when removed. As caps 'die', their capacitance reduces and this affects the regulation of the power supply and consequently can influence how it treats large dynamics. All you did was restore the amp to 'original condition' but didn't like the result. If perhaps you'd fitted 3300 or 4700uF caps in place of 10,000uF you may have preferred how it sounded. Probably, but only if they cost at least $200 per cap.... For ordinary commercial 3300/4700 63Vs ? A few dollars each. I'm sure you can get them less than $10. http://search.digikey.com/scripts/Dk...?name=P7511-ND Price = $8.15 in lots of one. Oops! They are 80 volt parts. ;-) Science DOES have the answers you see, but you really do need to know your onions and have LOTS of experience to understand this stuff. Random component substitution is one of the dumbest things out there but a lot of crooks make good money out of you from it. He should have new control knobs machined out of solid gold. Now THAT would provide some measurable change...opens up the soundstage and provides unimaginable depth and clarity to the imaging. LOL ! You've seen those wooden knobs for several hundred dollars each ? I have seen some incredible glowing testimonials for them. |
#26
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote:
A glorious response. Curious in light of previous helpful and cordial ones, free of your compulsive cruelty. I'm not an objectivist Arny. I've tried to be, the scientist within compels it; but amps sound different, quite different frequently. ICs and cables: I've been a maximum skeptic for decades, using generics and zip cord. But recent experiments have shown that these items do indeed sound different, frequently meaningfully. It is distressing, looking for the physics, and the yet the conclusion is inescapable. I'm convinced that, though objectivists do not necessarily have inferior ears, they may have ears which are insensitive to things the subjectivists detect. Like my wife who can distinguish colors that look utterly the same to me. Actually there is a possible scientific explanation for this: a small number of women can actually see far more colors than the usual 16 million or so. I forget the details, but their retinal structure is actually different. Jerry |
#27
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
"Wink" wrote in message
A new stock DH-200 or 220 doesn't sound dead. Neither does a used one in good shape with commodity power supply caps @ $10 each. Science has the potential to have all the answers. It doesn't follow that is has all the answers currently. But audio isn't rocket science and it isn't high energy physics, either. We've got all the answers we need to understand why things sound different. The trough job is getting true believers to do proper listening tests. I think YOU think you know what you're talking about, but really don't. Prove it. And I suspect you know this. Doesn't follow, |
#28
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Jerry Peters wrote: Wink wrote: A glorious response. Curious in light of previous helpful and cordial ones, free of your compulsive cruelty. I'm not an objectivist Arny. I've tried to be, the scientist within compels it; but amps sound different, quite different frequently. ICs and cables: I've been a maximum skeptic for decades, using generics and zip cord. But recent experiments have shown that these items do indeed sound different, frequently meaningfully. It is distressing, looking for the physics, and the yet the conclusion is inescapable. I'm convinced that, though objectivists do not necessarily have inferior ears, they may have ears which are insensitive to things the subjectivists detect. Like my wife who can distinguish colors that look utterly the same to me. Actually there is a possible scientific explanation for this: a small number of women can actually see far more colors than the usual 16 million or so. I forget the details, but their retinal structure is actually different. Precisely. If you actually look in enough detail, you'll find the scientific exaplanation. The audio subjectivists don't even try looking though. They see and hear only what they want to believe. It's like a religion. Graham |
#29
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote: A new stock DH-200 or 220 doesn't sound dead. We only have your word for that. When did you last hear one in *ORIGINAL* condition with PSU capacitors at their orignal value ? Science has the potential to have all the answers. It doesn't follow that is has all the answers currently. In this instance science most certainly DOES have the answer. Your old caps had reduced capacitance through aging. That's why new ones of the correct originally specified value sounded different. That would be the case regardless of the brand name on the can. Graham |
#30
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote: I think YOU think you know what you're talking about, but really don't. And I suspect you know this. I'm a pro-audio designer who's worked with some of the best in the busines and I'm something of an expert about amplifier design. I suspect you need to get a life and stop believing voodoo nonsense. You'll find you have a lot more spare cash too. Graham |
#31
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote: Why does that not make sense to 'audiophiles'...and by what objective measurement were the originals starting to 'die'? Loss of bass control. Serious enough to be quite objective. I initially thought the surrounds on the woofers were coming unglued. That sounds like something more serious. Do you really know what you're doing poking around inside amps ? What ELSE did you touch (possibly inadvertantly). Seriously, if the OP wants to use those 'bargain' $800 caps, perhaps he should build an entire new pair of blocs with those and the new transformers he's having custom built...and sell the originals. There are plenty of plans on the Web. Of course it sounds like money is not an object, so perhaps he could use the old ones as doorstops. This is what I've done Jak, using John Hillig's driver cards. The caps and xmfrs are the final additions. All that remains of the original 220's are chassis, mosfets, and xfmrs. Why on earth are you wasting your time mucking about with an ancient amp ? Technology has moved on although I confess I have a soft spot for mosfet amps. When really well designed and set up they have miniscule (high order) crossover distortion compared to bipolars. Indeed one of my own mosfet designs had vanishingly low THD and most of what could be measured was 2nd harmonic which is sonically the least intrusive. Graham |
#32
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote: Seems like a whole lot of time, effort, and money being spent to run a lower output stage voltage. To each his own. 63 V BGs were available for a deal, albeit a relative deal -- no question. 80 V versions are gone. This is the only reason I'm lowering the rail voltage. They'll be totally fine at 63V. At least you can then rule out bias variations caused by the lower voltage operation. Graham |
#33
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
A new stock DH-200 or 220 doesn't sound dead.
Science has the potential to have all the answers. It doesn't follow that is has all the answers currently. I think YOU think you know what you're talking about, but really don't. And I suspect you know this. Wink wrote: Why did you change the caps? When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately a deadening of the sound. Simple reason for that, it's how the amp originally sounded when the Sangamos were 'fresh'. As caps 'die', their capacitance reduces and this affects the regulation of the power supply and consequently can influence how it treats large dynamics. All you did was restore the amp to 'original condition' but didn't like the result. If perhaps you'd fitted 3300 or 4700uF caps in place of 10,000uF you may have preferred how it sounded. Science DOES have the answers you see, but you really do need to know your onions and have LOTS of experience to understand this stuff. Random component substitution is one of the dumbest things out there but a lot of crooks make good money out of you from it. Graham |
#34
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Why does that not make sense to 'audiophiles'...and by what objective
measurement were the originals starting to 'die'? Loss of bass control. Serious enough to be quite objective. I initially thought the surrounds on the woofers were coming unglued. Seriously, if the OP wants to use those 'bargain' $800 caps, perhaps he should build an entire new pair of blocs with those and the new transformers he's having custom built...and sell the originals. There are plenty of plans on the Web. Of course it sounds like money is not an object, so perhaps he could use the old ones as doorstops. This is what I've done Jak, using John Hillig's driver cards. The caps and xmfrs are the final additions. All that remains of the original 220's are chassis, mosfets, and xfmrs. |
#35
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Eeyore wrote:
wrote: Seems like a whole lot of time, effort, and money being spent to run a lower output stage voltage. To each his own. It's completely NUTS. Quite bizarre, to spend all that money on caps that are so incorrect that he thinks he needs variacs... |
#36
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Seems like a whole lot of time, effort, and money being spent to run a lower output stage voltage. To each his own. 63 V BGs were available for a deal, albeit a relative deal -- no question. 80 V versions are gone. This is the only reason I'm lowering the rail voltage. |
#37
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Eeyore wrote:
jakdedert wrote: Eeyore wrote: Wink wrote: Why did you change the caps? When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately a deadening of the sound. Duh.... Why the duh ? Duh = 'obvious'. If the caps were actually 'dying', then replacing them would improve the sound...same point you made below. Simple reason for that, it's how the amp originally sounded when the Sangamos were 'fresh'. Why does that not make sense to 'audiophiles'... Because they mostly reject scientific reasoning, thinking that subjectivity is superior even though they can't explain why except by resorting to make-believe words and ideas. and by what objective measurement were the originals starting to 'die'? A good question. It would be VERY interesting to know what value they still had when removed. As caps 'die', their capacitance reduces and this affects the regulation of the power supply and consequently can influence how it treats large dynamics. All you did was restore the amp to 'original condition' but didn't like the result. If perhaps you'd fitted 3300 or 4700uF caps in place of 10,000uF you may have preferred how it sounded. Probably, but only if they cost at least $200 per cap.... For ordinary commercial 3300/4700 63Vs ? A few dollars each. I'm sure you can get them less than $10. Yeah, but 'ordinary' capacitors for a few bucks each don't 'sound as good'. $200 caps--identical in every way, but for appearance and price tag--'sound' better...or so the OP would have us believe. Science DOES have the answers you see, but you really do need to know your onions and have LOTS of experience to understand this stuff. Random component substitution is one of the dumbest things out there but a lot of crooks make good money out of you from it. He should have new control knobs machined out of solid gold. Now THAT would provide some measurable change...opens up the soundstage and provides unimaginable depth and clarity to the imaging. LOL ! You've seen those wooden knobs for several hundred dollars each ? Oh year...then there are the 'magic rocks' that you put in each corner of the room; the speaker cable towers, the wall *outlet covers* (of all damn things!), the...ad nauseum. jak Graham |
#38
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Wink wrote:
A new stock DH-200 or 220 doesn't sound dead. Science has the potential to have all the answers. It doesn't follow that is has all the answers currently. I think YOU think you know what you're talking about, but really don't. And I suspect you know this. I suspect you pay a lot of money for nothing. Probably you have a lot of money to spend on nothing. Fine. You just won't get much sympathy for snake-oil hawkers in a forum of objective audio (mostly) professionals. You've taken the word (or falling for the BS...your choice) of people who are simply taking your money and laughing behind your back. Then you come here and try to convince us that the Emperor's New Outfit is so exquisite that only you and a select few like you, with Certified Golden Eyes (ears)--and lots of money--can perceive it. Trouble is, that people who really do know--can't...and they're laughing, too. OTOH, it's your money. 'Spend it wisely' probably never entered your lexicon. You'd probably get a lot more mileage out of it if you gave it away to somebody who could actually use it, as opposed to enriching pseudo-scientific, alchemist charlatans. YMMV.... jak |
#39
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
jakdedert wrote: Eeyore wrote: jakdedert wrote: Eeyore wrote: Wink wrote: Why did you change the caps? When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately a deadening of the sound. Duh.... Why the duh ? Duh = 'obvious'. If the caps were actually 'dying', then replacing them would improve the sound...same point you made below. 'Improve' depends on subjectivity. Make different for sure. It seems the OP felt it was inferior despite the fact, that's how the amps were designed. However his later comments make me think he may have disturbed something else if the sound really deteriorated badly. Graham |
#40
Posted to rec.audio.tech
|
|||
|
|||
Effect of Variac on Monoblocks
Eeyore wrote:
jakdedert wrote: Eeyore wrote: jakdedert wrote: Eeyore wrote: Wink wrote: Why did you change the caps? When the stock Hafler 10 kufd Sangamos started to die several years ago, I replaced them with Musical Concepts 80V, 27 kufd LC-200s made by Chemi-con, and noticed immediately a deadening of the sound. Duh.... Why the duh ? Duh = 'obvious'. If the caps were actually 'dying', then replacing them would improve the sound...same point you made below. 'Improve' depends on subjectivity. Make different for sure. It seems the OP felt it was inferior despite the fact, that's how the amps were designed. However his later comments make me think he may have disturbed something else if the sound really deteriorated badly. Graham His later comments make me think he wouldn't know if his amp was bad or good. The only subjective measurement unit he's presented (beside ps voltage) is US Dollars ($). More$ = Better sound. Many more$ = Much Better Sound. jak |
Reply |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Variac as a Troubleshooting Aid | Vacuum Tubes | |||
fa jefferson variac | Marketplace | |||
Variac and New Amp | Vacuum Tubes | |||
Variac | Vacuum Tubes | |||
Variac | Vacuum Tubes |