[Rafael Gonzales]

I plan on building Hypex 400 monoblocks in a single chassis with one IEC inlet.

I want to use either a Hypex 500va transformer on each channel or a Hypex 250va on each channel.

Which transformer would you recommend?

Can I use a - SINGLE - Softstart module to control both transformers (assuming I use the 500va transformers)?

Thank you in advance.

Rafael

[mgalusha]

I suggest the 500va transformer for each channel. Even if they were 100% efficient each channel would need a 400va transformer (actually more), so the 500va would be my minimum choice.

The data sheet for the soft start module says it can handle up to 1500va with a maximum of 6A continuous. It's unlikely you will draw more than a few amps continuously unless you are driving inefficient speakers at high power levels.

Are you going to use their power supply modules or design your own? Your questions leave the impression you are fairly new to projects such as this and if I'm correct I suggest using their power supplies and reading all the app notes from Hypex. This won't be a cheap project so gathering all the knowledge possible before plunking down the cash will be worth your time.


Edit - I just now saw the transformers on their site and that they suggest the 250va for the 400 module. Personally I prefer larger transformers but following the manufacturers directions is never a bad thing.

[Folsom]

I like going over sized on the transformers. I also like running higher voltage on the rails and then putting a higher shunt value on the input so essentially you are needing more volume from source for it to get loud, but will never over drive it because of the larger shunt value (and ears bleed at some point). This equals a bit lower distortion but it depends on efficiency of speakers if you want to do that. Then again I have never seen the schematics of this amplifier.

Greater potential equals more headroom, a somewhat advantage to have on tap for dynamic music is my understanding after learning more about tube vs. solid state and some functions of why people think tubes are louder (voltage can have a lot to do with it).

I think monoblocks are smart because it eliminates problems with grounding and RF that I can not seem to freaking kick in my not monoblock amplifier. This is assuming separate chassis for each...

[Rafael Gonzales]

mgalusha & destroyer,

Thank you very much for your replies. 

The feedback on the transformers and the softstart was very helpful.  I will be using the 500va transformers after your recommendations.

mgalusha, I will be using the power supplies from Hypex.  In fact, I will be using all of their plug 'n play components.  And your observations were very astute.  I have no clue about schematics or electrical design.  I did build my Audio Note DAC 1.2 and later modded it with interstage transformers, caps, resistors, etc.  I have also modded my preamp to some degree.  But in all instances, I had help online in forums like these.  (I can paint by numbers pretty well, if you know what I mean).  If someone tells me what to do, I have been very successful doing it so far.  I can solder well and I am typically a perfectionist.  Everything has worked flawlessly...but I don't have a clue why!  I only have a very basic understanding.  I simply have had no personal exposure to electronics or diy audio hobbyists in my area.  My only option is to read in forums like this and try to learn what I can.  So I greatly appreciate your feedback!

[richidoo]

Raphael,
I bought a pair of 1000va from diycable. Price has gone up in 2 years since, but it's still a great value for lots of good features. 40-0-40 for UcD400.
http://www.diycable.com/main/product_info.php?cPath=140_141&products_id=597

If you are in Europe, Hypex might be cheaper when you include shipping cost.
Rich