HI, Did you happen to find out what the value of the original ceramic cap was? It would seem to me that by replacing that cap with a different type with the same value and voltage, you wouldn't have to change anything else. Could be wrong here.
Ray
Ray
transformer usage
Hi all,
Just a curious question, assuming you use either of the two UCD Hypex power supplies, I can get one big 1KVA transformer for both channels, along with 2 secondaries and a 12V for the aux supply. Versus buying 2 500 or 600VA and making 2 separate mono amps. I'd still be using 2 bridges and separate supplies using the 1 big gtransformer. Besides cost as a negative, what positives would I be gaining. The Monos would be in the same chassis.Thanks for the imput.
Ray
Hi all,
Just a curious question, assuming you use either of the two UCD Hypex power supplies, I can get one big 1KVA transformer for both channels, along with 2 secondaries and a 12V for the aux supply. Versus buying 2 500 or 600VA and making 2 separate mono amps. I'd still be using 2 bridges and separate supplies using the 1 big gtransformer. Besides cost as a negative, what positives would I be gaining. The Monos would be in the same chassis.Thanks for the imput.
Ray
Transformer question.
Ray,
I personally prefer the dual mono approach. The sound staging is better due to less cross talk. The sound stage becomes confused when there is high frequency cross talk and instrument placing wanders or is smeared. This is more important in giving a life like presentation than having more grunt for the bass as with one much larger transformer. Another consideration is weight and speaker cable length. Both clearly favor the dual mono setup. Which would you want to move 1- 60 lb amp or 2- 35 pounders?
I would recommend separate chassis for the amps to gain the above advantages including separate power cords.
Roger
Ray,
I personally prefer the dual mono approach. The sound staging is better due to less cross talk. The sound stage becomes confused when there is high frequency cross talk and instrument placing wanders or is smeared. This is more important in giving a life like presentation than having more grunt for the bass as with one much larger transformer. Another consideration is weight and speaker cable length. Both clearly favor the dual mono setup. Which would you want to move 1- 60 lb amp or 2- 35 pounders?
I would recommend separate chassis for the amps to gain the above advantages including separate power cords.
Roger
Hi Ric,
Not at all. Simply expressing my view. If you feel I "won all the rounds" then I guess you're in agreement with those views.
This is a DIY audio forum and not a commercial advertising venture to not discuss what secrets you supposedly have, that's a very poor level of contribution, in my view.
I don't believe I've belittled you personally or wished you any ill will, nor is it my intention to do so with your products.
I'm sorry that you seem to feel it's the next cold war, but at the same time, it is good to see that you've the ability to be so analytical after all, and I'm very proud to have been a contributing factor in that level of your personal development.
As far as your hopes of my becomming a servant, I give freely here.
No charge.
Chris
Not at all. Simply expressing my view. If you feel I "won all the rounds" then I guess you're in agreement with those views.
This is a DIY audio forum and not a commercial advertising venture to not discuss what secrets you supposedly have, that's a very poor level of contribution, in my view.
I don't believe I've belittled you personally or wished you any ill will, nor is it my intention to do so with your products.
I'm sorry that you seem to feel it's the next cold war, but at the same time, it is good to see that you've the ability to be so analytical after all, and I'm very proud to have been a contributing factor in that level of your personal development.
As far as your hopes of my becomming a servant, I give freely here.
No charge.
Chris
Bgt said:
Hi,
Valide concerns I think. I'll have a closer look at the rest of the regulator circuit before going ahead with adding another tantalum near them, of smaller value, which is what I planned to attempt next.
I trust there'd be provisions to limite max current draw, and so far it's been just fine. Will post those findings when I get it done.
It's been an extremely worthwhile tweak thus far.
Regards,
Chris
Dear Chris:
Thanks for sharing. SMT is still out of my skills 🙁
Another homework...
I will wait to play with separate opamp PS.
Sorry to intrude between the "big dogs" 😀 , but Chris, I'm sorry but I do feel an unnecesary degree of bad vibrations and sarcasm from your part over Rick. He started sharing a good amount of interesting experiences and well intentioned advices. It is true that letting know about some worthy secrets of a
non-divulgable kind is like "counting money in front of the poor", like we say around here. It's OK, we got it. No need to mention it further I think.
Please, these UCD threads were very peaceful. Let's maintain them like that
Agree.
Not to mention that monoblocks are cool!
😀
You tell your friends: those boxes next to the speakers...oh yeah...those are my monoblocks 😉
Good night to all UCD fans.
M
Thanks for sharing. SMT is still out of my skills 🙁
Another homework...
I will wait to play with separate opamp PS.
Sorry to intrude between the "big dogs" 😀 , but Chris, I'm sorry but I do feel an unnecesary degree of bad vibrations and sarcasm from your part over Rick. He started sharing a good amount of interesting experiences and well intentioned advices. It is true that letting know about some worthy secrets of a
non-divulgable kind is like "counting money in front of the poor", like we say around here. It's OK, we got it. No need to mention it further I think.
Please, these UCD threads were very peaceful. Let's maintain them like that
Agree.
Not to mention that monoblocks are cool!
😀 You tell your friends: those boxes next to the speakers...oh yeah...those are my monoblocks 😉
Good night to all UCD fans.
M
Re: Re: some secrets are not secrets
Hi Mike,
Thanks for the measurements. Nice to know we have about 330nF there. I agree that open loop performance is important. For UcD that would be true as well as the open loop gain is not so high. It also shows that those 470uF caps are potentially very important for the sound of the amp. That 330nF is an impedance of about 40mOhm at 20kHz, if the ESR of the caps on board is significantly lower than that, than those caps could probably have a large effect on the sound. If ESR is higher, than the path of least impedance would be through the beads to the main power supply caps. What one could get is that depending on signal frequency, the path of lowest impedance would be through the beads towards the main power supply caps (lower frequencies) while it would be the caps on the UcD board for higher frequencies. Maybe this gives undesired effects? For an active system, I may want to try to avoid this type of switching over effect. So choosing different caps and sizes for the tweeter and midrange amp for example. This opens up a whole range of tweaking possibilities, interesting.
Next time when playing with the caps, I'l try to do so some measurements on the power rails with a square wave at the input so that any resonances should quickly show up in the form of ringing.
Best regards
Gertjan
Portlandmike said:
Dam Gertjan, good guess.
I just measured the resonance of one ferrite bead and a 820uF 16V FC (it was laying around)
It was not a very hard null, so it was kind of a hack guess.
I don't often come up with accuracy to 4 signficant digits, but a resonance of 820uF and one ferrite bead came out to be 5.56kHz, or 1.000E-6. Kind of wierd aside!
So, the inductance on the UcD400 is actually 1/3rd of that since it is three in parallel.
So the UcD400 inductance in the supply is 330nH!
The stock resonance is 12.8kHz (That would be a dip!)
Bigger caps raises the Q.
Lower ESR raises the Q ( of depth of the dip)
I think that's not perhaps as important as the anti-resonance stuff that is set by the parasitics like ESL ESR and the 100nF, bypass at the fets. Note, there is a shunt R of 5m0 in series with that.
As I've said before, I see know way that the actually impedance of the bypass cap can have any direct affect at the bass frequecies. 470uF has a impedance of 3.4 ohms at 100Hz where as the supply mains have an impedance an order of magnetude less. For sure ESR shouldn't matter at 100Hz as its orders of magnetude less.
btw, I'm not saying that more on board cap doesn't have sonic differences in the bass.
I'm wondering if its got more to do with anti-resonance stuff, and the spikes distortion on the open loop response of the amp.
I believe open loop response is very important when it comes to how an amp sounds although I can't prove it technically besides listening experience. That's one of those, they measure the same but sound different things.
This brings me to another tweak topic. Has anyone played with adding a zobel on the output to compensate for there tweeter and speaker wire inductance at LC resonance?
Mike
Hope this helps.
Mike
Hi Mike,
Thanks for the measurements. Nice to know we have about 330nF there. I agree that open loop performance is important. For UcD that would be true as well as the open loop gain is not so high. It also shows that those 470uF caps are potentially very important for the sound of the amp. That 330nF is an impedance of about 40mOhm at 20kHz, if the ESR of the caps on board is significantly lower than that, than those caps could probably have a large effect on the sound. If ESR is higher, than the path of least impedance would be through the beads to the main power supply caps. What one could get is that depending on signal frequency, the path of lowest impedance would be through the beads towards the main power supply caps (lower frequencies) while it would be the caps on the UcD board for higher frequencies. Maybe this gives undesired effects? For an active system, I may want to try to avoid this type of switching over effect. So choosing different caps and sizes for the tweeter and midrange amp for example. This opens up a whole range of tweaking possibilities, interesting.
Next time when playing with the caps, I'l try to do so some measurements on the power rails with a square wave at the input so that any resonances should quickly show up in the form of ringing.
Best regards
Gertjan
Hi Roger,
Using 1 transformer with dual secondaries, and everything else after that mono, why does it sound better with 2 transformers? I am not questioning that so much as to wonder why does it work that way. Is there a reactance between the two secondaries?
Ray
Using 1 transformer with dual secondaries, and everything else after that mono, why does it sound better with 2 transformers? I am not questioning that so much as to wonder why does it work that way. Is there a reactance between the two secondaries?
Ray
tantalum caps
Hi, On that tantalum cap replacement, that might be worth reporting that to Bruno. This way he can confirm your findings, and find the correct value, and do an upgrade Is this a surface mount cap? How did you get to it past the Urethane. Other than cheap, don't know why he would have used a ceramic cap. If it's like a disc ceramic cap, temps and moisture can vary the value of the cap.
Ray
Hi, On that tantalum cap replacement, that might be worth reporting that to Bruno. This way he can confirm your findings, and find the correct value, and do an upgrade Is this a surface mount cap? How did you get to it past the Urethane. Other than cheap, don't know why he would have used a ceramic cap. If it's like a disc ceramic cap, temps and moisture can vary the value of the cap.
Ray
ray bronk said:
Ray,
There is a great deal of coupling between the separate windings as they share a common core and are capacitively coupled as well. It always amazes me how much signal voltage/current is cross coupled. If you think of one secondary as the input and the other as the output you have high quality unity coupling. Having separate secondarys is still a very desirable thing as the low frequency garbage and line byproducts are greatly attenuated by not sharing a common ground. However the only way to reduce the HF cross talk is to have entirely separate transformers. This still leaves the path through the power lines which are common. This is one reason that power line filters work. We tend to think of only the crap coming in but there is a definite channel to channel or component to component path here. The HF path is effectively shorted with line filtering.
I know most setups have far from perfect grounds and these do have signal current in them, both high and low level. In other words the power supply ground is not quite the same as the amps ground and is even more different from the other channel’s grounds. Any power supply coupling of signal eventually gets into these grounds and is coupled into the opposite channel and that way as it looks like part of the signal.
This simplistic explanation is only the tip of the iceberg on ways signals get cross coupled. Even dual mono amps are no guarantee of no cross talk. All you have to do is run the cables together and the grounds will cross couple at high frequency. This is mostly true with single ended cables and not balanced.
Roger
transformer and grounding
Hi Roger and anyone else who cares to comment,
Now, we have two amps, with the supplies, and separate transformers, and the whole bit. Why would it make a difference putting them in a separate box, versus putting a shield between the two amps, and of course wiring the 110 imputs in parallel with each other. The first set would be in the same box. Now as total separate monoblocks, it would seem to me that you will be encountering the same stuff just by hooking them both as separates to the same power line. So how much of a real world difference would I hear using a mono block versus 2 monos in the same box?
Ray
Hi Roger and anyone else who cares to comment,
Now, we have two amps, with the supplies, and separate transformers, and the whole bit. Why would it make a difference putting them in a separate box, versus putting a shield between the two amps, and of course wiring the 110 imputs in parallel with each other. The first set would be in the same box. Now as total separate monoblocks, it would seem to me that you will be encountering the same stuff just by hooking them both as separates to the same power line. So how much of a real world difference would I hear using a mono block versus 2 monos in the same box?
Ray
there's one "real world" advantage to monoblocks often overlooked: You can use extremely short speaker wires and longer interconnects. It is dramatically easier to build a high quality IC than a similarly long speaker wire. If you put both channels into a single chassis you are losing that benefit unless you are biamping with 2x2 channels. The balanced inputs on the UCDs really are asking for long ICs (if your sources is true balanced).
Apart from that, there may not really be a significant difference between a total dual mono build in a single chassis compared to the same parts in separate boxes. Maybe minor magnetic field issues with the big transformers in close proximity.
Peter
Apart from that, there may not really be a significant difference between a total dual mono build in a single chassis compared to the same parts in separate boxes. Maybe minor magnetic field issues with the big transformers in close proximity.
Peter
It all comes down to proper wiring layout and place of the grounding point. And there are so many views on grounding a system. And don't forget what a preamp can do to your soundstage/crosstalk/dynamics. Doing this faulty may ruin your effort of making the power amp. super wide. Tuning a system in a way you get the least crosstalk/best soundstage is the best.
This can be quite time consuming.
This can be quite time consuming.
Secrets?
Hi all,
Well, now that we got the transformer issue out of the way, on to this ceramic cap business.
First of all, how do you get to it without destroying the amp, getting under that Urethane coating? Now, if I read the posts correctly, changing the value of that cap will either heighten the resonance peak or lower the resonace, and broaden it. Now, with all that in mind, would you use the same value, or are you saying to just ditch those filter caps, and just change out the caramic cap to an undetermined value? Sorry, perhaps a little dense.
Ray
Hi all,
Well, now that we got the transformer issue out of the way, on to this ceramic cap business.
First of all, how do you get to it without destroying the amp, getting under that Urethane coating? Now, if I read the posts correctly, changing the value of that cap will either heighten the resonance peak or lower the resonace, and broaden it. Now, with all that in mind, would you use the same value, or are you saying to just ditch those filter caps, and just change out the caramic cap to an undetermined value? Sorry, perhaps a little dense.
Ray
Monoblock advantage?
Let’s not forget the advantage of dual power cords and separate ac wiring. I know it all seems like picking nits but power amps draw high current in peaks to replenish the storage caps. The more we do to reduce ripple voltage and improve overall regulation the higher these currents will be. Even the resistance of a power cord becomes quite significant in limiting these currents. Having 2 means ½ the resistance and ½ the loss. This translates into sonics with less compression and a more real dynamic presentation. With the peak currents the 1Kw transformer can draw this is significant! Where else would you be able to make an improvement like reducing resistance 50% or more?
Roger
Let’s not forget the advantage of dual power cords and separate ac wiring. I know it all seems like picking nits but power amps draw high current in peaks to replenish the storage caps. The more we do to reduce ripple voltage and improve overall regulation the higher these currents will be. Even the resistance of a power cord becomes quite significant in limiting these currents. Having 2 means ½ the resistance and ½ the loss. This translates into sonics with less compression and a more real dynamic presentation. With the peak currents the 1Kw transformer can draw this is significant! Where else would you be able to make an improvement like reducing resistance 50% or more?
Roger
to monoblock or not to monoblock
Hi roger,
ok, now your point is valid. So I ask, is the sonic difference between having 2 mono amps in the same box with two transformers etc., versus as actual monoblocks that big of a difference audiblly speaking. Now I am not at the moment discussing the speaker cable and interconnect issue.
Ray
Hi roger,
ok, now your point is valid. So I ask, is the sonic difference between having 2 mono amps in the same box with two transformers etc., versus as actual monoblocks that big of a difference audiblly speaking. Now I am not at the moment discussing the speaker cable and interconnect issue.
Ray
Sound value?
Ray,
You can’t separate these things as they are a package. I have never tried in the past, no reason to. From past experience I would say using the dual power cords would be a noticeable improvement. You have an opportunity with your setup to try it both ways and give us a report.
Roger
Ray,
You can’t separate these things as they are a package. I have never tried in the past, no reason to. From past experience I would say using the dual power cords would be a noticeable improvement. You have an opportunity with your setup to try it both ways and give us a report.
Roger
Sound Value
Hi Roger,
Well, don't have the "setup" yet. I suppose I can see the difference with 2 transformers, and whether it would be worth the difference to mount both in a separate case, can't say for sure. Will have to see about that. Now, for the questions I asked about why so big of transformers since the modules I understand don't draw that much current? Can you shed some light on that?
Ray
Hi Roger,
Well, don't have the "setup" yet. I suppose I can see the difference with 2 transformers, and whether it would be worth the difference to mount both in a separate case, can't say for sure. Will have to see about that. Now, for the questions I asked about why so big of transformers since the modules I understand don't draw that much current? Can you shed some light on that?
Ray
Which one is better for UcD? Balanced signal or single-ended one.
Hi!
Sorry for changing to another topic!
I find Bruno posted the above sentences in page 8 of this thread. Because of my poor English, I don't fully understand what is "in most cases the inverting input is used as a kelvin sense ". Did Bruno hint there is no different feeding UcD balanced or single-ended source signal? Will the gain or power of UcD become half when input signal change from balanced to sigle-endded? Does anybody compare the sonic difference between balanced and sigle-endded input?
Thanks!
Bruno Putzeys said:
Hi!
Sorry for changing to another topic!
I find Bruno posted the above sentences in page 8 of this thread. Because of my poor English, I don't fully understand what is "in most cases the inverting input is used as a kelvin sense ". Did Bruno hint there is no different feeding UcD balanced or single-ended source signal? Will the gain or power of UcD become half when input signal change from balanced to sigle-endded? Does anybody compare the sonic difference between balanced and sigle-endded input?
Thanks!
Re: Which one is better for UcD? Balanced signal or single-ended one.
Hi xman,
I don't think he was hinting that there's no difference. He was most likely simply saying it will work either way, without having to resort to other means.. simple.
Yes gain will be reduced accordingly. I correct for that with my audiodock, one click of the mouse. You can also do it by changing one resistor on the module.
I have used the modules both ways, single ended in several configurations, like floating which is virtually differential but without the advantage of a shield. Having had it grounded produced a rather wicked ground loop so I never used it in the usual single ended sense.
I just used monster cable for those interconnects.
I then went to microphone cable and true differential. Can honestly say, no noticable difference in sonics whatsoever. One possible reason for not hearing a difference is that the rest of the setup may not have yet been optimal. That should stress yet again the importance of proper wiring. I think if you do hear any difference with input cables or single ended to differential it will no doubt be a vvvvvery minor one.
Since we're on about wiring, I can understand having less ESR and more current capability in dual mono with the use of dual power cords, however I'm not convinced it would be much of a benefit, I'd think ideally they'd be plugged into the same outlet to minimize loop area between them, and that should also encorporate the source's plug for the same reason... that'll give you a better soundstage than using different outlets with different loop area over to the electrical panel where they eventually become joined anyway.
Unless maybe you're the sort to run optimal runs to the breakers. I can't say I've tried either way to know though.
This seems to make something like Roger made, line conditioner with multiple outlets, a fairly usefull product, from a grounding and line filter perspective, given that said filters are of the variety that will not pollute the ground, I trust they are.
As for me, I have done a manner of A/B testing whereby I play the amp at high volume, and swap the power cord from the wall outlet to a 2$ super budget computer power bar while it's still playing, that also takes the power cord down a number of wire gauges, and no doubt the built in outlets are of very poor quality.
I repeated this test a good number of times and got a second opinion as well, there was absolutely no audible difference. So I'm of the opinion that with a healthy supply the cord and mains etc will not and should not be audible.
Peter:
"The balanced inputs on the UCDs really are asking for long ICs (if your sources is true balanced)."
It's been said you're better off to go with longer IC's in place of longer speaker wires, but I can't see why it would be "asking" for longer IC's as though it would be a requirement towards better performance, surely keeping them as short as possible would be the optimum choice.
Regards,
Chris
xman737 said:
Hi xman,
I don't think he was hinting that there's no difference. He was most likely simply saying it will work either way, without having to resort to other means.. simple.
Yes gain will be reduced accordingly. I correct for that with my audiodock, one click of the mouse. You can also do it by changing one resistor on the module.
I have used the modules both ways, single ended in several configurations, like floating which is virtually differential but without the advantage of a shield. Having had it grounded produced a rather wicked ground loop so I never used it in the usual single ended sense.
I just used monster cable for those interconnects.
I then went to microphone cable and true differential. Can honestly say, no noticable difference in sonics whatsoever. One possible reason for not hearing a difference is that the rest of the setup may not have yet been optimal. That should stress yet again the importance of proper wiring. I think if you do hear any difference with input cables or single ended to differential it will no doubt be a vvvvvery minor one.
Since we're on about wiring, I can understand having less ESR and more current capability in dual mono with the use of dual power cords, however I'm not convinced it would be much of a benefit, I'd think ideally they'd be plugged into the same outlet to minimize loop area between them, and that should also encorporate the source's plug for the same reason... that'll give you a better soundstage than using different outlets with different loop area over to the electrical panel where they eventually become joined anyway.
Unless maybe you're the sort to run optimal runs to the breakers. I can't say I've tried either way to know though.
This seems to make something like Roger made, line conditioner with multiple outlets, a fairly usefull product, from a grounding and line filter perspective, given that said filters are of the variety that will not pollute the ground, I trust they are.
As for me, I have done a manner of A/B testing whereby I play the amp at high volume, and swap the power cord from the wall outlet to a 2$ super budget computer power bar while it's still playing, that also takes the power cord down a number of wire gauges, and no doubt the built in outlets are of very poor quality.
I repeated this test a good number of times and got a second opinion as well, there was absolutely no audible difference. So I'm of the opinion that with a healthy supply the cord and mains etc will not and should not be audible.
Peter:
"The balanced inputs on the UCDs really are asking for long ICs (if your sources is true balanced)."
It's been said you're better off to go with longer IC's in place of longer speaker wires, but I can't see why it would be "asking" for longer IC's as though it would be a requirement towards better performance, surely keeping them as short as possible would be the optimum choice.
Regards,
Chris
- Status
- Not open for further replies.