Peranders,
Special custom made on our request. The weight is lower as with a traditional transformer and becuase the wires are winded on a cirkel you need less length of wires (decrease copperresistance) and have much less mechanical noise......
Regards,
Jan-Peter
www.hypex.nl
Special custom made on our request. The weight is lower as with a traditional transformer and becuase the wires are winded on a cirkel you need less length of wires (decrease copperresistance) and have much less mechanical noise......
Regards,
Jan-Peter
www.hypex.nl
Bruno Putzeys said:
Put me on a waiting list for four of these modules
My Magnepan speakers are having those 20amps for breakfast (at about 2.5ohms in the woofers). I'm planning to biamp with a pair of UCD400 or bigger stereo amps - big transformers, etc.
What level of capacitance would you plan for in a totally overbuilt amp like this (my current Class A/AB monos have 180,000uF per channel and they seem to be "adequate" for the job when the going gets rough)? I'm thinking 1000va transformers and 40,000uF per channel, possibly a little more for the low end. Can one put too much capacitance in a power supply (I'd bypass the last set of caps with Auricaps)?
And while I am digging for PSU answers: Would a pseudo dual mono supply be beneficial in my setup (one channel drives mids and tweeter ribbon, the other the bass), or should I just build 4 mono blocks to be on the safe side? And if I do - is it easy to match the gain of these modules (or match gain between a UCD400 and a UCD700)?
And while I am lurking - do you expect that mother of all modules at 700-900w to be available before the end of the year maybe?
I'm glad I found out about these modules, because I had just given up on the ZapPulse for cost reasons and mostly lack of apparent DIY enthusiasm around it.
Another questions - do these amps need to be powered up all the time to perform at their best? My Class A/AB amps for example are supposed to be on all the time to sound their best when they are asked to dish out the amps...
Soft start - if I don't use one - what happens on the output at power up? Big thump? My speakers have no fuses left in them, so I can't afford that.
Chassis - is a full metal enclosure necessary, or would part metal and part ERS absorbing materials in strategic locations near the PCB suffice? I'm planning a chassis similar to Peter Daniel's Acrylic/heat-pipe gainclone...it's gotta look cool!
anway - keep the thread going - i'm taking notes about capacitor tweaks and other issues as I'm waiting for the big hitter modules to be released.
Peter
Hi,
Sorry for taking it off topic again but since it got bashed around here..
Paulmc was so kind as to answer some of my questions and I thought I'd pass them along.
"discrete analog input stage
with its own power supply, high common mode rejection, zero feedback,
output complimentary pair, decoupling components from the class D etc"
and
"Feedback in the HCA-2 is a bandwidth limited feedback around the Class D
stage that's pretty unique in my experience. Yes, it measures at the
output of the coil."
So that's all we're going to know.
Back on topic.
Pburke, that sounds crazy! Looking forward to seeing it.
I don't think the modules require soft start themselves, but with the kind of supply you're talking about though, wouldn't you really want to have soft start? What size breaker to you do you run that to?
Regards,
Chris
Sorry for taking it off topic again but since it got bashed around here..
Paulmc was so kind as to answer some of my questions and I thought I'd pass them along.
"discrete analog input stage
with its own power supply, high common mode rejection, zero feedback,
output complimentary pair, decoupling components from the class D etc"
and
"Feedback in the HCA-2 is a bandwidth limited feedback around the Class D
stage that's pretty unique in my experience. Yes, it measures at the
output of the coil."
So that's all we're going to know.
Back on topic.
Pburke, that sounds crazy! Looking forward to seeing it.
I don't think the modules require soft start themselves, but with the kind of supply you're talking about though, wouldn't you really want to have soft start? What size breaker to you do you run that to?
Regards,
Chris
Pburke,
Please check our website regular there we will inform everybody when we have some news. The UcD400 will be deliverable in about 6 weeks.
I can't answer all questions about quality of the sound, I have to leave this for Bruno.
The UCD400 will be a good choice because of the low outputimpedance (<0.010 Ohm) and high outpower for your "hungry" speakers
When you switch the amp on, it will be very silent no thumps pumbs or whatever. And we have no outputrelay
You don't need a metalcase for the shielding, EMI is low and below the official limits. But some heatsink will be nessecarry, for shure in the "future" heavier models like an UcD700 (900?)
...hm an UcD700, it's only in my mind at the moment. But it will be based on Bruno's 1.2KW 2Ohm design. But without the special preamplifier section. I will still use an opamp but I will choose the best what currently is available, any suggestions?
No time schedule yet.
The rest of the question I leaves to Bruno, if he has time to answer it.
Regards,
Jan-Peter
www.hypex.nl
Please check our website regular there we will inform everybody when we have some news. The UcD400 will be deliverable in about 6 weeks.
I can't answer all questions about quality of the sound, I have to leave this for Bruno.
The UCD400 will be a good choice because of the low outputimpedance (<0.010 Ohm) and high outpower for your "hungry" speakers
When you switch the amp on, it will be very silent no thumps pumbs or whatever. And we have no outputrelay
You don't need a metalcase for the shielding, EMI is low and below the official limits. But some heatsink will be nessecarry, for shure in the "future" heavier models like an UcD700 (900?)
...hm an UcD700, it's only in my mind at the moment. But it will be based on Bruno's 1.2KW 2Ohm design. But without the special preamplifier section. I will still use an opamp but I will choose the best what currently is available, any suggestions?
No time schedule yet.
The rest of the question I leaves to Bruno, if he has time to answer it.
Regards,
Jan-Peter
www.hypex.nl
Hi Ivan,
that was Bruno's replay to my question, since I used ceramics in parallel with Oscons in low voltage power supply. Based on results I got with this combination I agree with his answer. It is advantageous to have RC snubber directly across the switching FETs pair. I used 100n SMD foil capacitors with 1R to 4R7 resistor, but high ESR electrolyitic is even better idea.
Bruno,
Since blackgates datasheets are a joke, could you comment on ESR, ESL and ripple current capacity of those caps. Do they have any advantage over mainstream electrolyitics in non audio applications? For instance, OSCON datasheets are full of easily understandable improvements (lower voltage ripple and noise in SMPS, better quality picture in camera etc). And BTW, is it true that they are being discontinued?
Best regards,
Jaka Racman
that was Bruno's replay to my question, since I used ceramics in parallel with Oscons in low voltage power supply. Based on results I got with this combination I agree with his answer. It is advantageous to have RC snubber directly across the switching FETs pair. I used 100n SMD foil capacitors with 1R to 4R7 resistor, but high ESR electrolyitic is even better idea.
Bruno,
Since blackgates datasheets are a joke, could you comment on ESR, ESL and ripple current capacity of those caps. Do they have any advantage over mainstream electrolyitics in non audio applications? For instance, OSCON datasheets are full of easily understandable improvements (lower voltage ripple and noise in SMPS, better quality picture in camera etc). And BTW, is it true that they are being discontinued?
Best regards,
Jaka Racman
Yes you can overdo on caps, at least when the power supply is hard-rectified (normal supply without chokes). The current through the rectifiers becomes more and more spiky and the magnetic fields coming off the hookup wires and even mains cords can potentially start degrading the performance of the rest of the kit. Even if you can't hear the buzz directly, you do hear increased "veiling" of the sound stage. This is one of the reasons "audiophile" mains cables sometimes have an audible effect. I don't like it when mains cables start to make a difference.pburke said:
The 20000uF per rail that I have on my "esoteric amps" is really as far as I dare take it. I'm planning on a PFC supply to address this.
To me it would seem more logical to me to pair the woofers together on one two-channel amp and the mid/highs on the other, so that heavy bass content isn't seen by the mid/high amps (in so far as this should be a problem). Usually the performance loss on 2-channel amps (or performance gain on mono blocks) lies in the inherent impossibility of a 100% correct grounding scheme combined with ground referenced inputs. The UcD modules have differential inputs, so crosstalk over the ground connections is nonexistent.pburke said:
So far all my and JP's amp modules have the same gain regardless of power. I started doing this in order to facilitate comparative listening tests.
We're just setting up the first design round. Much will depend on other business.pburke said:
Most of the problem is solved if you keep all the small signal stuff powered up. It's completely solved if you use only the enable pin to turn the amp on or off. The whole issue is related to capacitors (the more caps in the amp, the worse the "warmup" behaviour), so you can leave them charged all the time but simply stop the amp switching when you're not listening. Since the power dissipation in idle is low, actually you can afford to keep the amps on all the time.pburke said:
You need a "soft start" circuit for charging the power supply caps without blowing the mains fuse. The amp itself is turned on/off using the enable pin and is nearly inaudible (a very, very quiet "tick" may be heard at the tweeters).pburke said:
You can use a plastic enclosure if you wish (except for cooling of course). Any EMI emanating from the amp is negligible (typically 20dB below any applicable legal limits). You can shave off another 10dB by simply mounting the board over a metal plate.pburke said:
The EMC performance of the UcD series is something we're very proud of, though so far we've forgotten to make a selling point of it.
A serious question warrants a serious answer so I went offline to do ESR measurements on some caps that happened to be lying round.Jaka Racman said:
47u 50V BG-NP 60m
47u 100V Panasonic NHG 250m
100u 16V Elna Silmic 220m
100u 16v Panasonic su 260m
100u 16v BG-STD 130m
100u 25v Elna Cerafine 80m
100u 50v Rubycon wxa 370m
100u 63V Elna RE2 150m
220u 10v OsCon 14m
220u 100V BG-STD 30m
470u 50V Multicomp (Farnell house brand) 40m
680u 35V BG-NP 21.5m
This shows that the BG's have lower than average ESR, but not out of their league. Claims of 10x lower ESR are highly exaggerated. Their use is not warranted outside of audio. It is quite obvious that the manufacturer quotes non-audio-applications in order to improve the sérieux of their image.
Ripple capability is simply a function of ESR, as in "how much power can I dissipate into the ESR before the cap overheats".
BG's ESL story is nonsense. Firstly, all elcaps I've measured simply have ESL corresponding to the distance between their pins and a fraction of their height. I've never seen any winding effects. I think cap manufacturers are smart enough not to attach one wire at the start of plate 1 and the other to the end of plate 2.
Secondly, if any winding effects were present, the magnetic field from the windings would not get further than the aluminium case (the case acts as a shorted secondary). This means that two caps placed in anti-series have no mutual inductance and therefore any "inductance cancelling" is fully nonexistent.
What I didn't quantify was that most capacitors of audiophile pretenses generally behaved simply as a capacitor and a series resistor, whereas more "mundane" types were rather like RCRCRC networks - distributed ESR and capacitance.
That suggests that in general purpose types, resistance of the actual aluminium foil is significant compared to the resistance of the electrolyte, whereas in the audio types only the electrolyte presents a significant resistance. This could go some way explaining the bulk of many audiophile caps.
Speaking of which. I remember trying to find a correlation between a cap's measured parameters and sound a few years ago. A preamp circuit was used where different power supply caps were used. I remained seated while my dad swapped out caps out of my sight. I took notes and after that he gave me the caps and a list identifying which was which.
Then I measured all of them and put all data into an excel sheet in order to find correlations (there is such a function in excel).
between the measurements and the subjective score.Well... nothing turned up, except one thing. There was a statistically significant correlation between "sound score" and physical size. The correlation was far from 1:1, but at least it was significant.
Strange eh? (It must be said that I didn't look at the foil capacitance thing then)
I mailed Black Gate and I got a very enigmatic reply:Jaka Racman said:
"We think that Black Gate production will stop by next year.
We have received rush orders for stocking at each customers."
I can't help wondering whether he hadn't simply deduced the first statement from the second.
