andrewhockley
pfm Member
Has anybody used the Hypex Class D modules? If yes, any comments on the sound quality etc? I bought a stereo pair of UCD700s largely based on reviews and would be interested to hear any first hand exerience
Hypex modules
- Thread starter andrewhockley
- Start date
andrewhockley
pfm Member
I'm trying to use the UCD700s to drive a very low impedance, very inefficient load. Main problem to date is just getting hold of components - caps and transformers in particular as it needs very large power supplies. So budget is overrunning and it's a bit of a leap of faith as to whether its going to work at all, let alone deliver the sound quality I'm hoping for.
Don't know anything about CAP 6 and Hypex.
Don't know anything about CAP 6 and Hypex.
MarkW
Full Speed & Pagan
Hi Andrew
I have a pair of UCD180s, together with the psu from Hypex, been up and running since early this year.
Very good, much sweeter and (unlike a T-amp) not wearing on the ears over time, even at enthusiastic levels. I currently lack a pre-amp, so my UCD amp is out of use until I build myself a passive attenuator (driving the system flat out is unlikely to win domestic approval).
Even with the UCD180ADs and the least grunty PSU arrangement, it's a truly impressive amp, bettering the Naim amps I used before by a big margin.
As long as you have a suitable case, the build is also very straightforward. So I urge you to get to it and enjoy what must count a one of the major bargains in the audio world right now.
Mark
I have a pair of UCD180s, together with the psu from Hypex, been up and running since early this year.
Very good, much sweeter and (unlike a T-amp) not wearing on the ears over time, even at enthusiastic levels. I currently lack a pre-amp, so my UCD amp is out of use until I build myself a passive attenuator (driving the system flat out is unlikely to win domestic approval).
Even with the UCD180ADs and the least grunty PSU arrangement, it's a truly impressive amp, bettering the Naim amps I used before by a big margin.
As long as you have a suitable case, the build is also very straightforward. So I urge you to get to it and enjoy what must count a one of the major bargains in the audio world right now.
Mark
andrewhockley
pfm Member
MarkW said:
Soldering iron is itching, but I still only have half the caps and no transformers - can't even lay the case out until I know how big the transformers are so it's very frustrating.
Andrew H
martin clark
pinko bodger
Andrew - what do you need, voltage wise? I may have just the bits you're looking for, from a project I've abandoned (no time /inclination to complete). Four large Philips PSU caps, bridge rectifiers and a whopping gurt toroidal giving 39-0-39V twice, about 700VA.
andrewhockley
pfm Member
Thanks martin, that's a very kind offer, but I've already paid for the caps (16 off 100v 33k Kendeils - size of baked bean tins - 7 received before Kendeil went on holiday), and the transformers have been on order with Les W for a couple of months - so hopefully should be getting them soon.
I'm really hoping these amps will deliver the goods.
I'm really hoping these amps will deliver the goods.
PigletsDad
My intelligence test came back negative.
You will absolutely have to have some kind of soft-start circuit - otherwise the in rush current at turn on is going to blow fuses.
martin clark
pinko bodger
And bleeder resistors across the caps. 2500J stored is a frightening amount of energy... enought to hoist Andrew about 35m vertically!
andrewhockley
pfm Member
Should be somewhere around 2kva per transformer, each driving one speaker (not 100% sure whether it will be a stereo amp per speaker or mono per speaker - both are possible with the speakers. Tempted to build as stereo amps as the cost won't be significantly more). Les wasn't 100% sure what size the factory would be able to deliver given the other specs, so I'm waiting to see what turns up really.
andrewhockley
pfm Member
Yes, I've got the Hypex soft start modules.PigletsDad said:
And yes I know this is a very large power supply but it's about the right size using Hypex recs for the speaker load I'm looking at.
And yes this is going to be a very very careful build indeed.
martin clark
pinko bodger
I'm curious to know what you have in mind to soak up all this power; the only things I can think of are panels - Apogee, maybe?
andrewhockley
pfm Member
Yes, Martin, Apogee Scintillas, one of the most difficult Apogees to drive. The load drops way below 1Ohm, and they are also pretty inefficient. So a bit of a radical departure for me.martin clark said:
martin clark
pinko bodger
They can make you see stars, too... 
Make that very inefficient. Not only are they bipolar suffering baffle cancellation, but the magnetic circuit is very lossy (poor BL product) - even by the standard of ribbons - which is partly where the amazing bass comes from, and mostly where all the amps' output goes...
Make that very inefficient. Not only are they bipolar suffering baffle cancellation, but the magnetic circuit is very lossy (poor BL product) - even by the standard of ribbons - which is partly where the amazing bass comes from, and mostly where all the amps' output goes...
ron
Tweaker
I've got a pair of the UCD180's, I have been running these for almost a year now.
They was fairly good as standard (they had all totally standard grade parts)
The psu and especially the earth wiring seems to make quite a difference to its sonics, I tried a pair of cap6 which was ok but the UCD's sound better with dual secondary transformers and dual rectifiers instead of the centre tapped single rectifiers type used on the Cap6 which sounds spot on with the NCC200.
The only thing I don't like about my UCD is its input stage, I'm not a big fan of the AD8620 so I've been hunting for a nice discrete input stage to build, a folded cascode type with cfp buffer was recommended but I've not found anything yet I tried disconnecting the input stage altogether and fed the modulator direct from my passive attenuator, obviously the gain was greatly reduced but the sound was much better!
If theres a few more UCD users on PF it would be nice to start up a modding/building experience thread, these things have potential
I use a pair of 620vA Holden and Fisher transformers with 2 x 0-30 secondarys on each.
A snubber across the secondarys
Dual rectifiers for each using MBR10100 schottkies with 2 x 6800uf BHC ALP20 caps on each rail.
Current mods are bypassed the electrolytic caps used as coupling after the AD8620, fitted CRD's on the AD8620's output, changed the amps output filter caps from 680nf to 470nf
I'm sure the UCD700 would have no trouble driving those Apogee Scintillas
They was fairly good as standard (they had all totally standard grade parts)
The psu and especially the earth wiring seems to make quite a difference to its sonics, I tried a pair of cap6 which was ok but the UCD's sound better with dual secondary transformers and dual rectifiers instead of the centre tapped single rectifiers type used on the Cap6 which sounds spot on with the NCC200.
The only thing I don't like about my UCD is its input stage, I'm not a big fan of the AD8620 so I've been hunting for a nice discrete input stage to build, a folded cascode type with cfp buffer was recommended but I've not found anything yet
I tried disconnecting the input stage altogether and fed the modulator direct from my passive attenuator, obviously the gain was greatly reduced but the sound was much better!If theres a few more UCD users on PF it would be nice to start up a modding/building experience thread, these things have potential
I use a pair of 620vA Holden and Fisher transformers with 2 x 0-30 secondarys on each.
A snubber across the secondarys
Dual rectifiers for each using MBR10100 schottkies with 2 x 6800uf BHC ALP20 caps on each rail.
Current mods are bypassed the electrolytic caps used as coupling after the AD8620, fitted CRD's on the AD8620's output, changed the amps output filter caps from 680nf to 470nf
I'm sure the UCD700 would have no trouble driving those Apogee Scintillas
PigletsDad
My intelligence test came back negative.
There may be an issue at the top end.
The output filter (which is inherent in class D amp) will have a frequency response that will drop off as the load impedance goes down. I don't know the numbers, and seem to remember that the Apogee load is not so brutal at HF as lower down, but there might be an issue with HF rolloff happening early enough to be audible.
The output filter (which is inherent in class D amp) will have a frequency response that will drop off as the load impedance goes down. I don't know the numbers, and seem to remember that the Apogee load is not so brutal at HF as lower down, but there might be an issue with HF rolloff happening early enough to be audible.