Any news on UCD700?

raediant

Member
2005-09-15 10:51 pm
UcD700

My 1st post here. Have reviewed UcD400Q&A (phew). Run a pair of B&W800s which soak up 500w rms per channel. Am looking to replace huge aging Nakamichi PA-7 amp, so looking for more power than UcD400 can offer.

Saw you might be considering a bridged UcD400 product. If one UcD400 works best into nominal 4ohms, each amp in the bridged pair would see 2ohms, not 4. This would increase the current needed beyond limits. Not a good idea. Am pleased to see 90v on the job. This implies a single more powerful amp, not a bridged pair? Also would allow mad dogs to consider bridging two UcD700. I'm not quite sure what would happen if one tried to bridge a pair of already bridged amps (ie 4 amps total) !!!
Also, overall probably a cheaper way to go?
Cheers Bruce.
 

ghemink

Member
2004-06-14 2:26 pm
Japan
Re: UcD700

raediant said:
My 1st post here. Have reviewed UcD400Q&A (phew). Run a pair of B&W800s which soak up 500w rms per channel. Am looking to replace huge aging Nakamichi PA-7 amp, so looking for more power than UcD400 can offer.

Saw you might be considering a bridged UcD400 product. If one UcD400 works best into nominal 4ohms, each amp in the bridged pair would see 2ohms, not 4. This would increase the current needed beyond limits. Not a good idea. Am pleased to see 90v on the job. This implies a single more powerful amp, not a bridged pair? Also would allow mad dogs to consider bridging two UcD700. I'm not quite sure what would happen if one tried to bridge a pair of already bridged amps (ie 4 amps total) !!!
Also, overall probably a cheaper way to go?
Cheers Bruce.


The UcD700 seems to be unbridged as it uses a 90V supply, for a bridged amp, a lower supply could be used. So you should be able to bridge them. In general, you can not bridge an amp that is already bridged. Although I think remember seeing a trick somewhere on the net where they did it, I remember it was a very dirty trick so I did not consider it as a desired solution. I think they used a floating power supply that was modulated by an amp or something like that.

Gertjan
 
As promised hereby a measurement of the first two protos, who are at the moment working by one of my customers.

The power is really huge out of this new version! In a bridge setup we have something about 1.8kW in 4 ohm:D

Next week we receive a small pre-production batch, when we have done all our tests and everything is still ok, the product is ready for the first production batch. In about 6 weeks from now the amps must be on stock.

Regards,

Jan-Peter
 

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Hi Gertjan,

My reasons are that I need an amp that is stable into 3ohms and ease of construction. I originally had thought about bridging two UCD400's but the impedences could be a problem ie. a bribged amp generally sees half the impedence of the load. I also need about 600w into that load as a minimum.

Regards,
Jam
 
jam said:
Hi Gertjan,

My reasons are that I need an amp that is stable into 3ohms and ease of construction. I originally had thought about bridging two UCD400's but the impedences could be a problem ie. a bribged amp generally sees half the impedence of the load. I also need about 600w into that load as a minimum.

Regards,
Jam


classd4sure said:
Depending how much power you require it could still be ok.

Sure each amp see's half the load, but together they push twice the current, what's the problem? Just make sure you build a supply that can deliver it.

Regards,
Chris


If the max current is 30A, then at 3 Ohm with 90V out, you get 30A peak. 90V RMS at 3 Ohm would be about 1350W. Not bad I would say. Of course you may not get the 90V out because the supply is 90V. So maybe you get 80V out. Would still be more than 1000W in 3 Ohm.

Sounds like smoking eardrums to me :)

Gertjan
 
Originally posted by Jam;
Hi Jan Peter,

I would like to know prices, how the UCD 700 is different from the 400, max current output and if it is a full bridged amp...............if not do you plan to offer one.

The answers are as follows;
- price will be EUR 200.00 standard version, with AD8620 upgrade EUR 230.00.
- max. current will be 28A piek.
- recommended working voltage is 90VDC, overvoltage set at 95VDC.
- needs a seperate dual 12V supply for the buffer stage.
- needs a seperate 15V driver voltage for the power fet's.
- we will have a special power supply with Slitfoil 4x10,000uF/100V dual fast recovery rectifiers and seperate 'audiophile' supplies for the buffer stage.
- price for UcD700 HG supply EUR 250.00.
- mono 750VA transformer, price +/- EUR 100.00
- stereo 1200VA transformer, price +/- EUR 135.00
- will be on stock beginning November.

It's still a single ended amplifier, no plans yet for a bridged version. However you can bridge two UcD700 for a 1.5-1.8KW amplifier....

The design is much more complex as an UcD400, we use now a special design around the power fet's with schottky diodes, to avoid the problems of fast switching at higher voltages. The design is made on a 4-layer PCB.

Last week we have test the amplifier against our UcD400AD, and the sonic performance is again a step further...... ;)

Al prices are ex. VAT and transport. For export out of EU we do not have to add the VAT.

Cheers,

Jan-Peter
 
Jan-Peter said:




Last week we have test the amplifier against our UcD400AD, and the sonic performance is again a step further...... ;)

Al prices are ex. VAT and transport. For export out of EU we do not have to add the VAT.

Cheers,

Jan-Peter


Congratulations with the newest addition to the UcD series.

With respect to sonic performance, is it really better? If so, what is the main reason? and how would you describe the sonic difference? Would be nice for us tweakers to know:)

Best regards

Gertjan
 
Originally posted by Gertjan;Congratulations with the newest addition to the UcD series.

With respect to sonic performance, is it really better? If so, what is the main reason? and how would you describe the sonic difference? Would be nice for us tweakers to know:)

Thanks....:angel:

Yeah, what's the difference?? I am not that good to describe difference in sound. But directly your hear a very steep solid bass performance, a very detailed mid, and a sweeter high end as we were used to. I was personally quite impressed....:bigeyes:

To tell you the truth I don't know why this amp sounds better as the other UcD modules. Perhaps because we use standard seperate power supplies for the buffer stage??

We have to wait for more input from other reviewers...

Jan-Peter
 
Jan-Peter said:


Thanks....:angel:

Yeah, what's the difference?? I am not that good to describe difference in sound. But directly your hear a very steep solid bass performance, a very detailed mid, and a sweeter high end as we were used to. I was personally quite impressed....:bigeyes:

To tell you the truth I don't know why this amp sounds better as the other UcD modules. Perhaps because we use standard seperate power supplies for the buffer stage??

We have to wait for more input from other reviewers...

Jan-Peter

Hello Jan-Peter,

I see, so we have to wait a bit until the first users start to show up here. Personally I think that that larger number of parallel decoupling caps on the board could be beneficial. I can hardly believe that the sound can be much better. But I will not try it for the time being as I would need too many amps for my active system, have not even finished my active system with all the UcD400 amps that I have (8 of them), now using only 2 for the woofers and still using UcD180 for mid and tweeters.

On your web-site, you mention that you are working on an SMPS for the UcD modules, that sounds very interesting, guess it will not be for the DIY market???

Best regards

Gertjan
 
I see, so we have to wait a bit until the first users start to show up here. Personally I think that that larger number of parallel decoupling caps on the board could be beneficial. I can hardly believe that the sound can be much better.

Me too, but the difference is quite serious.... You hear the sonic difference in a few seconds.....;)

But I will not try it for the time being as I would need too many amps for my active system, have not even finished my active system with all the UcD400 amps that I have (8 of them), now using only 2 for the woofers and still using UcD180 for mid and tweeters.
Your setup is a 3-way active system, so this is already sounding SOO MUCH better. I would keep it as it is now, but in future?

On your web-site, you mention that you are working on an SMPS for the UcD modules, that sounds very interesting, guess it will not be for the DIY market???

Indeed, to risky because of the high voltage and direct connected to the mains voltage.

Jan-Peter