UcD700 Q&A

[lucpes]

I'll take the freedom to post the UcD700 preview pic from the Hypex website and let more knowledgeable (Hypex?) people post comments:

An externally hosted image should be here but it was not working when we last tested it.

First thing that comes into mind is 'Err..., is that T-heatsink-thingie turned 180 degrees?'

Another things I'd like to find out: availability, supply voltages, power, current limiting, connectors, opamps, etc.

 

[wytco0]

Good to see that there is a picture available and I noticed that the high spec power supply is now showing as available and can be ordered.

My Amp cases arrived this week and I was planing to buy 2 new Ucd400's to instead of resuing my Ucd180 amp to build a new amp but now I think I might wait for the Ucd700's.

Upgraditis seesm to be even worse in the diy world than it was when I used to buy stuff

 

[ghemink]

I'll take the freedom to post the UcD700 preview pic from the Hypex website and let more knowledgeable (Hypex?) people post comments:

An externally hosted image should be here but it was not working when we last tested it.

First thing that comes into mind is 'Err..., is that T-heatsink-thingie turned 180 degrees?'

Another things I'd like to find out: availability, supply voltages, power, current limiting, connectors, opamps, etc.

Wow, that looks like a pretty beast. Large amounts of decoupling on board and 3 mosfets per rail in parallel? Probably quite a bit bigger than UcD400.

Best regards and thanks for posting the pic

 

[sx881663]

Re: Re: UcD700 Q&A

Wow, that looks like a pretty beast. Large amounts of decoupling on board and 3 mosfets per rail in parallel? Probably quite a bit bigger than UcD400.

Best regards and thanks for posting the pic

ghemink,
The real question is what is the function for all those extra connections? This opens some very interesting possibilities. Maybe some kind of add-on module can be connected?
Roger

 

[wytco0]

I thought those power connectors looked too small on the Ucd400 and they look the same on the 700 are they really up to the job? the 180 had much meatier connectors.

 

[lucpes]

I thought those power connectors looked too small on the Ucd400 and they look the same on the 700 are they really up to the job? the 180 had much meatier connectors.

The power & speaker connectors are right near the heatsink, more than adequate in size. The revision of the UcD400 currently available has the same power connectors, as does the UcD180.

The smaller 4 pin connector must be same as on the other UcD's (balanced input and /On).

<guessing>

As for the 10 pin connector near the 22uf/63V ? Philips coupling caps I can only speculate that it has something to do with the opamp

If the 3 pin connector is direct input for the UcD control module itself a big thanks to Bruno for that

</guessing>

 

[ghemink]

Re: Re: Re: UcD700 Q&A

ghemink,
The real question is what is the function for all those extra connections? This opens some very interesting possibilities. Maybe some kind of add-on module can be connected?
Roger

Hi Roger,

Maybe those extra connections are there because it is a prototype.

All those power supply decoupling caps seem to be 220uF 100V. Wonder why not 470uF 100V as on the UcD400. Of course there are 6 of them per rail, so total 1320uF per rail. Maybe some of them are used behind the resistor. On the UcD400, you have a few coils in the power rails, then the 470uf caps, than a smal resistor (R005=5mOhm (really that low??) or 50mOhm?) and then 10uF 100V that is decoupling the power mosfets together with some small chip caps (100nF???). This cap is 22uF on the UcD180, at least on the old ones that I have. Was thinking of a possible tweak of the UcD400 to replace the 470uF caps with 100V 1000uF, size would fit, however, the caps would be longer, so they would be sticking out higher than the heatsink.

Best regards

Gertjan

 

[Bgt]

any word on pricing???? These are awsomely looking (and sounding?).

 

[wytco0]

lucpes, Ah yes I see them now I only noticed the small one which I though wre like the ones on the 400, I guess the 400 has been upgraded a bit since the first version.

I am definately going to wait before deciding which ones to get hopefully the 700s will be at least as good as the 400's

 

[Jan-Peter]

We are working on the Uc700.......

Some answers on all questions (some can be prelimenary!);
Absolute maximumvoltage 90VDC (overvoltage protection)(all components rated voor 100V)
Working voltage 85VDC.
Outputpower +/- 700W in 4 ohm.
Outputpower +/- 900W in 2 ohm.
Outputpower +/- 450W in 1 ohm.
Maximum outputcurrent will be 30A piek.
Opamps AD8620 or OPA2134 (just as the UcD400).
Connector for bypassing input elcos, or even bypassing the input opamp. This is the small 3-pin connector. So you can use an own designed preamp.
Power fets Philips PSMN057-200+schottky diodes+flybackdiodes.
Decoupling caps 2 x 5 x 220uF/100V.
4-layer PCB, design is quite complex..........
Avalability after summer holiday (august/september).
The same sonic performance as the UcD180/UcD400, or even better because of the higher power..... Or,
better sonic performance because the low power voltage comes from a seperate power supply (10pins connector)
Price......not yet available.

Proto works quite ok.......

Regards,

Jan-Peter

 

[Lars Clausen]

Jan-Peter why did you choose AD8620 for the special edition UcD, and OPA2134 for the standard UcD?

AD8620: 0.008% THD (@ 3V RMS x1 - from figure 19).
OPA2134: 0.00008% THD (hundred times better).

Shouldn't it be the other way around???

 

[Jan-Peter]

The sonic performance is better.......

Jan-Peter

 

[Lars Clausen]

Does this mean, that you acknowledge that the sound can be better even though the THD is (considerably) higher?

 

[lucpes]

Connector for bypassing input elcos, or even bypassing the input opamp. This is the small 3-pin connector. So you can use an own designed preamp.

First, a big thanks for the answers and for the good work so far

In the UcD180 Q&A thread you have mentioned that the input impedance of the UcD modulator is 1.8K (if one is to bypass the opamp section). Did this value change in the new 180/400 versions or the 700? It's a tad bit on the low side for use say with tube preamps or with some pro gear which has output impedances in the hundreds of ohms region.

 

[Jan-Peter]

Below a certain level of THD there can be sonic difference whereby the lowest THD doesn't have to sound the best......

Our idees is not to have a low THD at 1kHz but to have a FLAT THD across the whole audio bandwidth. So the THD must be the same at 100Hz / 1kHz / 10kHz.

The most amplifier has a fast rising THD response above 1kHz, we don't like this. Besides some good tube amplifiers, or amplifiers without feedback...They have a constant loopgain/THD curve.

AND, a flat frequency response load independ. Because of the UcD post-feedback technology we can achive our goals.....

In the UcD180 Q&A thread you have mentioned that the input impedance of the UcD modulator is 1.8K. Did this value change in the new 180/400 versions or the 700? It's a tad bit on the low side for use say with tube preamps or with some pro gear which has output impedances in the hundreds of ohms region.

The modulator is unchanged......all UcD modules do have exactly the same modulator. Altough we have changed some values to increase the maximum voltage of the modulator pcb to 100V.

Jan-Peter

 

[Lars Clausen]

Jan-Peter: But does the input buffer not solve the problem of low input impedance of the modulator, as asked by our Romanian friend ( Tots Romani sunt prieteni mie ) ?

 

[Jan-Peter]

The design of the modulator is not changed so also not the input impedance.....

The extra connectors are as follows;
10pins:
12V for the gate drivers.
+15V / -15V for the buffer opamp and logic.

Second 10pins:
Bypass input 22uF capacitor.
Bypass input buffer opamp.

3pins:
Input for signal DIRECT to the modulator. Advantage you can use your own high sofisticated preamplifier.....
Watch out, input impedance is 8.2k and 1.8k.

Jan-Peter

 

[ghemink]

Does this mean, that you acknowledge that the sound can be better even though the THD is (considerably) higher?

Hi Lars,

This is a very tricky question from your side. It seems you almost want to say that a certain competing Class D amp has higher distortion than UcD but sounds better than UcD?

I think the explanation later on from Jan-Peter makes sense (flat THD over frequency instead of super low THD at low frequencies and rising at high frequencies).

Best regards

Gertjan

 

[goudey]

thermal issues, mounting

A few questions about working with the ucd700 (for Jan-Peter or Bruno). Maybe it is too early for the final answers, if so then let us know.

The heat sink appears to have an odd attach point. Is this an artifact of it being a prototype, or is this intended? What are the heatsink requirements, and what mounting orientation and ventilation schemes are recommended?

Are the overall dimensions known, or known approximately?

The ucd400 is a great amp, working well with my electrostatic panels. If the sound quality of the ucd700 is as good as that of the ucd400 the added power (2.4 dB additional SPL) may make a difference.

 

[hpsxr]

UcD700HG

About the plug to the connector type 4-pin MOLEX KK series, the crimp housing is 0,1" 4way, 0,156" 4way, 0,2" 4way or is 2,5 mm 4way (like farnell number 143094) ?

About the connectors type 1/4" FASTON, the crimp terminal female can have a tab with of 6,35 mm (like farnell number 488392 wich is very interesting) ?

Will be UcD700HG with HxR ready, to sell in future ?

Thank You
Hugo