UCD180 questions

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#742
UrSv is quite right! I would need two of those and I suspect, I would have to rob a bank, (which I never would do) to afford one, let alone two.

Then I also read the DEQX has digital attenuation, which I've read, is not so good to do and then I also suspect it would be a problem trying to daisy-chain the volume on two DEQX.

So, I'm afraid that one is out of my league.🙁

BR
Roland
 
#744
I am experimenting with passive volume control using a Dact 8 deck device. I can then use balanced all the way from source to amp. You can also get various things from www.goldpt.com and they have a wealth of info in their docs section about building passive preamps, and how to calculate everything.

You can also get a remote control for the Elma switches (ie the dact and goldpoint devices) from Bent audio.

Perhaps this is something for you to think about?
 
#746
The DEQX PDC2.6P preamp model has got multichannel analog volume control with BB PGA2310 devices and the units can be daisychained via a RS232 port. I have owned the standard version and own the preamp version at the moment. All I can tell is that the difference between the digital volume control and the analog volume control is not that big and mostly noticed at very low listening levels. The digital volume control is not as bad as you might think.
 
#748
paradigm said:
OK, but there is still that tiny issue of what two of those gadgets would cost me.

If you know the price, please give it to me gently.

BR
Roland
Click to expand...

With Pre option it would be about USD 3500 each if NOT bought in Sweden in which case it would be about USD 4500 each. That's USD 7000+ for two which is tad bit more than 2 DCX and 1 DEQ...
 
#750
UrSv said:


With Pre option it would be about USD 3500 each if NOT bought in Sweden in which case it would be about USD 4500 each. That's USD 7000+ for two which is tad bit more than 2 DCX and 1 DEQ...
Click to expand...


If you limit yourself to a 3-way system then you need only one. Since your filters can be steeper with the DEQX than in a conventional system, you could use your drivers more to the limits. So probably you will find that 3-way is enough. However, if you have already a 4 or 5 way and you don`t want to give that up, then you would run in high costs. But note, I think the PDC is not awfully expensive for what you get. It is a complete preamp with analog colume control and with a remote. It has the digital crossovers for 2x3 channels, it has the speaker correction and it will (hopefully) have the room correction. This is a very nice one box solution. People that have used it can`t live without one anymore, at least I can`t.

Best regards

Gertjan
 
#751
ghemink said:



If you limit yourself to a 3-way system then you need only one. Since your filters can be steeper with the DEQX than in a conventional system, you could use your drivers more to the limits. So probably you will find that 3-way is enough. However, if you have already a 4 or 5 way and you don`t want to give that up, then you would run in high costs. But note, I think the PDC is not awfully expensive for what you get. It is a complete preamp with analog colume control and with a remote. It has the digital crossovers for 2x3 channels, it has the speaker correction and it will (hopefully) have the room correction. This is a very nice one box solution. People that have used it can`t live without one anymore, at least I can`t.

Best regards

Gertjan
Click to expand...

I mostly agree and would love to have one. However, just like Paradigm I'm on the 4/5-way route for which the price suddenly is way to high. I have a friend who has one and will hopefully be able to test it one day.

Edit: Sorry for this OT persistance. I'll refrain from further violations of the topic.
 
#753
Bruno Putzeys said:

If you mean two transformers for two channels (=mono blocks), I find this does make a small (imho worthwhile) difference in "lateral resolution" of the stereo image.

For the power supply caps, ordinary grade Elna LP5 are fine. My experience using black gate caps in the power circuit is not very good. Cerafines are fine for the medium sizes (470u 25V etc). Cerafines can be ordered from http://www.schuro.de/preisl-elna.htm
Don't be tempted to try out the Silmics. They s*ck (or st*nk if you will).

The AD8620 (plus J511 from out to -12) is the first IC op amp that I can listen to without wanting to go back to my discrete op amps straight away.

Hooking up a UcD module to a supply, preamp and speakers is about as simple as it gets. If you intend to make changes to the stock module it's a good idea to make sure you know what you're doing.
Click to expand...


Hi Bruno

do you use the A8620 with coupling caps or without ?
And with J511 do you put an isolating resistance ?

alain
 
#756
classd4sure said:
Current regulator diode, so we have provisions for the "class A" biasing tweak on it now? Is this featured on all models?
Click to expand...
I'm not exactly sure if it's done on the current version (JP?) but the intention was to have 4 footprints (SST511, sot23) on the PCB layout ie. two "up" and two "down", so the tweakaholic could add them (up or down depending on which type of op amp is used, but of course not all four!).
 
#759
Jan-Peter said:
Bruno,

You mix up now two projects. The UcD180 Hypex version and the "special UcD180 version" of our OEM customer ***.

In the special OEM is version is placed a SST511. There is also a leaded version of the SST511, quit easy to solder this by hand as an interesting mod.

Regards,

Jan-Peter

www.hypex.nl
Click to expand...


Hello Bruno, Jan Peter,

What is the talk about j511 or SST511? Is this about adding a FET (two FETs I assume) after the AD8620 acting as a source follower so that the AD8620 does not see the relatively low input impedance of the UcD module itself? If true, sounds like a very interesting modification since most opamps don`t really like to drive low impedances.

Best regards

Gertjan
 
#760
ghemink said:


Is this about adding a FET (two FETs I assume) after the AD8620 acting as a source follower so that the AD8620 does not see the relatively low input impedance of the UcD module itself?
Click to expand...
No, just biasing one of the output transistors off to remove power rail modulation on the rail that has worst PSRR.
Placing a follower after an op amp (inside or outside the loop) is not a panacea. I've often heard the sound degrade, so it's not something you'd "just do".
 
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