[beppe61]

Dear Sirs,

looking at the Hypex site I found the two modules:
180AD  and  180ST.
I understand that the only difference is in the brand and model of the input op-amp.
Am I right ?
What about the differences in the sound?
Which is the best choice?
Besides I heard of some mods that can be carried out on the modules, in particular caps substitution.
Is there any thread dealing precisely with this subject?
My intention is to buy two 180 and powered them with just one 500VA transformer + high current diode bridge from IRF + 2 Siemens Sikorel 15.000uF/100 V that I already have.

Thank you so much for any kidn suggestion.

Kind regards,

beppe61

[StevenACNJ]

All the info you are looking for is located @ DIY Audio.

Link:

http://www.diyaudio.com/forums/forumdisplay.php?forumid=49

There are several long threads but all the info is there.

[beppe61]

All the info you are looking for is located @ DIY Audio.
Link:  
http://www.diyaudio.com/forums/forumdisplay.php?forumid=49
There are several long threads but all the info is there.

Dear Sir,
thank you so much fro your very kind and valuable reply.
Do you have a direct experience of this module?
What is your opinion?

Kind regards,

beppe61

[Gordy]

Hi Beppe61,

Be sure to adjust the "number of days" on the DIY site's page index!  This thread http://www.diyaudio.com/forums/showthread.php?s=&threadid=58873 is now 75 days old and way back on page 7 or so.

Enjoy!

[Kevin Haskins]

The AD version uses an Analog Devices AD8620 opamp on the input.   The ST version is now using an Brown Burr OPA 2134 opamp.  

Both are excellent opamps.   The sound differences are not huge and there is plenty of room for personal preference.   Go read any thread at DIYAudio about opamps and you will see there are a number of opinions about which sounds the best.    I'd say the differences are minimal but if you want the "best" specifications and your pocketbood supports it go for the AD8620.  

Your room and loudspeakers will have a far larger influance on the final sound of your system.   I'm taking a 2-channel system to CES and I'm using the stock base model UCD-180STs.   The reason I'm doing so is that I know the room/loudspeaker interface will dominate how my system sounds at the show.   Not one opamp in the entire amplification scheme.  

I'd not encourage you to do tweaks unless you enjoy tweaking.   Your not going to gain that much over the basic modules and you risk damaging them and your speakers if you goof.  

The so called modifications are really very minimal.   A couple parts substitutions and bypassing the DC blocking caps.   Just understand if your source has any DC transient it will be amplified and possibly damage your speakers.   It's a risk you take when removing DC blocking.

[beppe61]

Dear Mr. Haskins,

please excuse me but only now I understand your are the owner of DIYCABLE company.
First of all my most sincere congratulations for your great creations !
Then thank you so much for spending your time giving such valuable advice to me.
It is very kind of you.

>  The AD version uses an Analog Devices AD8620 opamp on the input. The ST version is now using an
Brown Burr OPA 2134 opamp.
Both are excellent opamps.
The sound differences are not huge and there is plenty of room for personal preference.
Go read any thread at DIYAudio about opamps and you will see there are a number of opinions about which sounds the best.
I'd say the differences are minimal but if you want the "best" specifications and your pocketbood supports it go for the AD8620.
Your room and loudspeakers will have a far larger influance on the final sound of your system.
I'm taking a 2-channel system to CES and I'm using the stock base model UCD-180STs.

If the Standard module is good enough for the CES is even too much for my system.
I wish you the greatest success for your products at the CES !
You could very well be the “Pioneer” of an audio revolution.
I will read with the utmost interest any report about your partecipation.

>  The reason I'm doing so is that I know the room/loudspeaker interface will dominate how my system sounds at the show. Not one opamp in the entire amplification scheme.

Very interesting point I often overlook. The listening room. It could be the weakest link in my current set-up.

>   I'd not encourage you to do tweaks unless you enjoy tweaking. Your not going to gain that much over the basic modules and you risk damaging them and your speakers if you goof.

You have convinced me to not touch anything.
Plain stock and standar. Let’s say “nature”.

>  The so called modifications are really very minimal. A couple parts substitutions and bypassing the DC blocking caps. Just understand if your source has any DC transient it will be amplified and possibly damage your speakers. It's a risk you take when removing DC blocking.

Ok. No mods no problems.
Dear Mr. Haskins,
thank you very much again for your extremely kind and valuable consultancy.

Kind regards,

beppe61

[skrivis]

The so called modifications are really very minimal. A couple parts substitutions and bypassing the DC blocking caps. Just understand if your source has any DC transient it will be amplified and possibly damage your speakers. It's a risk you take when removing DC blocking.

I can't actually think of any good reasons for removing coupling caps, nor for a "DC" amp or preamp.

[beppe61]

The so called modifications are really very minimal. A couple parts substitutions and bypassing the DC blocking caps.
Just understand if your source has any DC transient it will be amplified and possibly damage your speakers. It's a risk you take when removing DC blocking.

I can't actually think of any good reasons for removing coupling caps, nor for a "DC" amp or preamp.

Dear Sir,

I have experience that a low quality cap in series with the signal influences the sound not for the better.
And good ones are usually very expensive and quite big (PP et similia).
It is a very important component indeed.
Of course removing it can cause some problem.

Kind regards,

beppe61

[skrivis]

Dear Sir,

I have experience that a low quality cap in series with the signal influences the sound not for the better.
And good ones are usually very expensive and quite big (PP et similia).
It is a very important component indeed.
Of course removing it can cause some problem.

Kind regards,

beppe61

<sigh>

http://sound.westhost.com/articles/capacitors.htm

[beppe61]

When I mean bad cap I mean the electrolytics can also go bad with time.
They are not "stable" as film caps are.
I have a vintage (25 years old ) amp and I should replace all the electrolytics.
I relaced for instance an electro cap in series with the tweeter with a PP cap and I heard improvements.
Maybe it is just me tough.
To end I would never use a electrolytic cap in series with signal.
Of you course your are free to do this and anything else you like.

Kind regards,

beppe61

[Kevin Haskins]

Dear Mr. Haskins,

please excuse me but only now I understand your are the owner of DIYCABLE company.
First of all my most sincere congratulations for your great creations !
Then thank you so much for spending your time giving such valuable advice to me.
It is very kind of you.

Hey... no problem.   Thanks for the nice words.   You will be very happy with the Hypex amps.   Bruno did a great job on these.

[beppe61]

[/quote]
Hey... no problem.   Thanks for the nice words.   You will be very happy with the Hypex amps.   Bruno did a great job on these.[/quote]

Dear Mr. Haskins,

I wish you again all the best for your products at the next CES.
Thank you very much again for your exquisite kindness.

Kind regards,

beppe61
Torino
ITALY

[guest1632]

Dear Sir,

I have experience that a low quality cap in series with the signal influences the sound not for the better.
And good ones are usually very expensive and quite big (PP et similia).
It is a very important component indeed.
Of course removing it can cause some problem.

Kind regards,

beppe61

Hi Beppe61,  Well, from what I read on the DIY forums, get the one with the AD8620. Now if you are aware of what is up the electronics chain, you can try shorting out the input caps. The "offset" voltage appearing at the output is very low. Shorting the imput caps, would give you the knowledge of whether keeping them or removing them would be worth the time. Unless, you go the Channel Islands route, or get the Stan Warren UCD amp, don't think you will go to much wrong here. Just some simple ideas to try.

Ray

[beppe61]

Hi Beppe61,  Well, from what I read on the DIY forums, get the one with the AD8620. Now if you are aware of what is up the electronics chain, you can try shorting out the input caps. The "offset" voltage appearing at the output is very low. Shorting the imput caps, would give you the knowledge of whether keeping them or removing them would be worth the time. Unless, you go the Channel Islands route, or get the Stan Warren UCD amp, don't think you will go to much wrong here. Just some simple ideas to try.
Ray

Dear Mr. Bronk,
thank you so much for your very kind and valuable advice.
Now I have another problem: will the UcD 180 power module be powerful enough to drive adequately my "hungry" Dynaudios?
From the data sheet I understand they are current limited at 10A max.
Then only time I heard my Dynaudios sounding nice was with two little monos able to deliver 22A of peak current each !
They are very demanding speakers in term of current.
Bedises the UcD 400, limited at about 20A, could be a wiser choice.
Do you have any direct experience with these modules?
Which speakers are you using ?

Thank you very much indeed.
Kind regards,

beppe61

[guest1632]

Dear Mr. Bronk,
thank you so much for your very kind and valuable advice.
Now I have another problem: will the UcD 180 power module be powerful enough to drive adequately my "hungry" Dynaudios?
From the data sheet I understand they are current limited at 10A max.
Then only time I heard my Dynaudios sounding nice was with two little monos able to deliver 22A of peak current each !
They are very demanding speakers in term of current.
Bedises the UcD 400, limited at about 20A, could be a wiser choice.

Hi Again,

Well, Kevin could give you a little more info on this. Never played with either the Modules or the Dynaudio speakers. Probably the UCD400 would be the wiser choice.The definite key is a good stout power supply. That's all I can tell you for now.

Ray

[beppe61]

Dear Mr. Bronk,
thank you very much for your kind reply.
Let me please be more precise between the lines.

>  

Hi Again,
Well, Kevin could give you a little more info on this. Never played with either the Modules or the Dynaudio speakers.

By now I have tested a lot of amp with these speakers and most of them have failed to drive adequately.
The bass is slow and soft.
If you have ever listened to the bass from a JBL speaker, it is exactly the opposite.
The woofer in the JBL seems made out of wood, in the Dynaudio out of rubber !
To make a Dynaudio woofer sound like a JBL one I think something like a Krell is needed (high current delivery).
I heard the Dynaudios sound fine with two old (1990) UK monos 45W/8 ohm each but with a peak current of 22 Ampere.

>  Probably the UCD400 would be the wiser choice.

I start to think the same. Max peak current in the order of 20 A.
I understand that the UcD400 is also used in a pro amp for bass players (high current demand).  So it should be just fine.

>  The definite key is a good stout power supply.

That is what I thought.  But now I understand that most of commercial amps use some kind of current limiting circuits in order to safeguard the ouput devices from breaking-down for stress.
In my case this has very bad consequences in term of sound.
Maybe a wiser choice would be to abandon these hungry speakers.

>  That's all I can tell you for now.
Ray

Dear Mr. Bronk,
thank you so much again.
If you are aware of high current amp kits please tell me.

Kind regards,

beppe61

[guest1632]

Dear Mr. Bronk,
thank you very much for your kind reply.
Let me please be more precise between the lines.

>  Dear Mr. Bronk,
thank you so much again.
If you are aware of high current amp kits please tell me.

Kind regards,

beppe61

Well, since you likve in Italy, you might do well to get all of the stuff through Bruno who makes the Hypex kits. If memory serves me right, he lives in Belgium. You want at least a 500 or 600VA transformer for the UCD400's. I don't know what the limiting factor would be, but a to big transformer, and it will slow down the amp. Go up to the DIY audio forum and read all the comments on the power supplies for the UCD stuff. Stan Warren is using a 600 VA transformer in his application of the hypex stuff. Those Dyn speakers are supposed to be find units. Power limiting is already built in to the modules, with no sound degradation at all. It's there to protect the modules. Again, check out the DIYaudio forums. A lot of good stuff there.

Ray

[beppe61]

>  

Well, since you likve in Italy, you might do well to get all of the stuff through Bruno who makes the Hypex kits.
If memory serves me right, he lives in Belgium.
You want at least a 500 or 600VA transformer for the UCD400's.

Dear Mr. Bronk,
I have to say that Ucd 400 power modules are very high in my most wanted list.
The 20 A max peak current should be just fine for me.
I am just waiting for the presentation and feedback from the next January CES where there will be a lot of products based on these modules.

>  I don't know what the limiting factor would be, but a to big transformer, and it will slow down the amp.

For me a slow amp is an amp with low damping factor and current delivery.
We perceived the slow movement of woofers out of control.

>  Go up to the DIY audio forum and read all the comments on the power supplies for the UCD stuff.

I read about different choices between toroidal and EI transformer.
But I understand that a nice powerful toroidal should be just fine.

>  Stan Warren is using a 600 VA transformer in his application of the hypex stuff. Those ...

The fact that a lot of very talented audio designers have selected these UcD modules as a base for their products speaks for itself.

Thank you very much indeed again.
Kind regards,

beppe61