How to: Build your own Hypex UcD amps

Gordy · « **Reply #80 on:** 12 May 2005, 03:55 am »

Thank you, Occam, for covering the chargers and the need for switched/isolated grounds! My pics don't really show them, but I'm using two 48v chargers for my supplies, hence the two Neutrik PowerCons.

I'm of a slightly different mind than Occam on the value aspect. Having spent a good amount of time comparing the battery ps's vs. the diode/cap ps's with balanced power, I don't find the batteries wanting in any aspect and definitely superior in noise floor reduction. Where do you draw the $ line?

Peter, I haven't tried playing with capacitance yet, but yes, I'll be starting with 4 - 100uF caps. Actually, I've some 50's I'll try on the 3886's until the 100's arrive for the UcD's. I'm planning on trying rc snubbers as well, eventually.

Quote from: JoshK

Peter/Gordy,

Is there a way to calculate the instantaneous current available from such a battery PSU as Peter outlined? I guess this is my only concern with regards to going full monty battery powered. Of course, most of my listening media has little in the way of dynamics, I still choose to not limit myself.

Hi Josh! You're asking the wrong person

for calculations! Until I'm corrected, I'm of the belief that a full 7amps is available and I'm looking at the batteries as big a$$ caps and vice versa. Somebody please jump in and correct me here, a 35 year old HS diploma doesn't take one very far...

Occam · « **Reply #81 on:** 12 May 2005, 03:14 pm »

Quote from: Gordy

.....
I'm of a slightly different mind than Occam on the value aspect. Having spent a good amount of time comparing the battery ps's vs. the diode/cap ps's with balanced power, I don't find the batteries wanting in any aspect and definitely superior in noise floor reduction. Where do you draw the $ line? ...

Dunno where that line is drawn. The point I was trying to make is that when you can do the esoteric (SLAs) for less money than the mundane (transformers, diodes and bridges), its a no brainer.

I'm still trying to decide what to do with my 2 bargain basement 48v battery systems. I bought 2 Teac LP7000s in anticipation of experimenting, but given Gordy's most excellent experiences, it seems a waste and now can't decide between using one to power my AKSA 55 or tread the path that Gordy has blazed and do the UCD400s. (or maybe just sell them for my cost, but I'm unsure whether anyone would be interested

)... or simply move on as I've just taken delivery of 77 double shielded 500va+ balancing transformers with slightly funky voltages.

For my purposes, I've no sonic issues with SLA powered amps.
I do have one specific issue with SLAs aside from their bulk and weight, and that is their environmental issue of disposing of lead. The US now finds it cheaper to export dead lead batteries to China, rather than comply with our own environmental regulations. Just great.... we're now exporting both democracy and brain damage. But there are technologies which do address this issue by extending both the life and performance of SLA/Gel Cells, desulfation chargers. What principally causes the failure of these batteries is the formation of sulphur salts within the batteries. Any wharehouse operation that uses forklifts, etc... as a matter of course uses desulphating chargers, not out of any environmental concerns, but economic self interest. Do a google seach on 'battery desulphate'. It works, its proven, and for those using a 12v charger, its not incrementally that much more expensive that a non-desulphating charger. And it typically extends useful battery life by a minimum to 2 to 3 times.

As to why our government doesn't mandate such chargers for ups, emergency lighting, etc....oops

, I don't allow discussion of politics/religion on this board.

JoshK · « **Reply #82 on:** 12 May 2005, 03:27 pm »

I'd be interested if you decide to sell them!! Me, me, me!

Gordy · « **Reply #83 on:** 12 May 2005, 04:17 pm »

I've sent off some Q's about the 48v MaxiPulse 3000, thanks P'Occam!

I've checked Ebay once again, the "missing" 80 APS units haven't shown up...

Slightly OT, after waiting 2 weeks for an invoice from PercyAudio I received a note saying that the entire backlog of requests had been deleted and he was starting fresh... So this a.m. I called in an order to Angela Inst. in Annapolis MD. and my supply caps are on their way! I'll probably put them in the AC/battery supplied chip amps for a faster burn in and simultaneously see how they affect the battery supply

Time to go head off to work...

speedcenter · « **Reply #84 on:** 12 May 2005, 08:44 pm »

Quote from: Occam

Peter(Speed),

A number of issues -

1. I don't believe its common practice to charge SLA batteries in parallel, unless they are charged with multiple bank chargers, which are actually multiple chargers which individually control the voltage ramping, but share a common underlying powersupply.

2. You really need a 4pdt switch to also lift the ground(s). Inevitably, the ground is tied to other grounds via the interconnects on the amplifier, and mains ground which rarely sits at a real earth ground. Wor ...

check the prices on those batteries - if you are paying more you are buying from the wrong source. www.gruberpower.com just as one example.

Interesting about not being able to do the charging in parallel - why not? it's just a bigger battery at that stage. I'll be testing this with two 12V 7.2ah tonight. Two 48V chargers are rather beyond my budget - that's 4 185 dollar chargers for two monoblocks, and at that point even the fanciest AC supply is cheaper to build

I understand about the grounds - that's hwat I am doing on my DAC, but there it's just one battery and all I needed was a simple DPDT. I'd rather avoid buying.

regarding a question earlier - instant current delivery? probably more than an AC supply can do unless there are large capacitor banks involved. My current amp manufacturer claims 120amp peak output, which it can only do due to 180,000uF per channel. I see no reason why you couldn't do something similar with a battery supply.

speedcenter · « **Reply #85 on:** 12 May 2005, 08:57 pm »

Quote from: Occam

Dunno where that line is drawn. The point I was trying to make is that when you can do the esoteric (SLAs) for less money than the mundane (transformers, diodes and bridges), its a no brainer.

well, I am not looking at the batteries for cost reasons. It helps to keep the cost reasonable, but I've essentially had it with AC power and all the expense that goes into cleaning it up. Dedicated coircuits, cryo outlets, fancy power cords, isolation transformers, Line filters, Auricap filters, better power supply caps, etc etc - that adds up and it just doesn't ever get good enough. With batteries, there are other issues, but at least the noise factor of the power supply should be pretty much optimized. If it costs less than 50% more than a nice AC supply, I'm ready to try it.

speedcenter · « **Reply #86 on:** 12 May 2005, 09:08 pm »

Quote from: Occam

What principally causes the failure of these batteries is the formation of sulphur salts within the batteries. Any wharehouse operation that uses forklifts, etc... as a matter of course uses desulphating chargers...

FYI, the 48V charger I have in mind:

http://
http://soneil.com/Completesets/4808SRF(Rev03).15-Jul-03.pdf

quote from page 5: "De-sulfation of battery: The charger will remove loose sulfation and increase the battery life."

Vinnie R. · « **Reply #87 on:** 12 May 2005, 10:57 pm »

Quote from: speedcenter

It helps to keep the cost reasonable, but I've essentially had it with AC power and all the expense that goes into cleaning it up. Dedicated coircuits, cryo outlets, fancy power cords, isolation transformers, Line filters, Auricap filters, better power supply caps, etc etc - that adds up and it just doesn't ever get good enough..

A'men...Preach ON!!!

JoshK · « **Reply #88 on:** 12 May 2005, 11:29 pm »

Gordy,

How are the dynamics with the battery PSU? On something of large scale orchestral are the dynamics at all limited in any way that you can tell by using batteries. I know you haven't yet made the comparison to your soon to be AC PSU, but in relation to other amps you've tried, how would you rate it?

Gordy · « **Reply #89 on:** 13 May 2005, 02:30 pm »

Hi Josh,

Comparing the batts and tranny/cap supplies with my bridged 3886 amps directly (I've a 4pdt switch which adds wiring, both have same disadvantage) I've noticed no loss of dynamics or congestion at all. Subjectively, maybe more dynamic as the noise floor is dramatically lowered compared to the non-BPT fed ac supply. I'm running North Creek Borealis speakers, which are Scan Speaks and they're 86dB insensitive

and a Django preamp, which is a line level tx-102 tranny preamp. However, as I've mentioned in PM's, I'm in an apartment, 15 x 15 room with 15 x 13 dining room "L" connected, doubt I've run 'em over 85-90 average dB's, mostly less. I'm intimately familiar with dB levels, so that's pretty accurate.

One other thing: I have been simultaniously burning in a newly moded BG 'laden' battery dac as well. With about 80-85 hrs. on the dac and 110-120 on the amps things are really starting to open up, especially after the 60-70 hr. point on the dac! I stopped comparing the straight out Denon to the dac awhile ago...

The BG caps for the batts arrived this am, less than 24 hrs. from Angela's!!! They're going in the chip amps today for 100 hrs. or so, guess the UcD's will be off until Tues. or so...

Occam · « **Reply #90 on:** 13 May 2005, 03:13 pm »

Speed,

Thanks for the link to Gruberpower. Their products and prices appear to be excellent.

With regards to the soneil 48v you're considering buying -
http://soneil.com/48v_Chargers.htm
from their pdf the full quote on page 5 is -

Quote

De-Sulphation of battery: The charger will remove loose sulfation and increase the battery life. (Hard sulfation cannot be reversed).

Now here I was thinking that it was only 'high end audio' marketing that attempted to blow smoke up our collected arses

. What they're actually saying is that their charger cannot remove hard suphation. Any charger (including the switching chargers that came with Gordy's and my bargain basement battery packs) removes loose sulphation. The very process of discharging a SLA generate lead sulphate on both the anode and cathode of a battery, and the standard process of recharging reverses that loose sulphation; its how SLA batteries work. When I referred to desulphation, I was referring to hard sulphation which is generally the cause of battery demise. Do that Google search for more information......

JoshK · « **Reply #91 on:** 13 May 2005, 03:26 pm »

Thanks Gordy,

I guess, I have had this mental preconceived bias that battery power = less dynamics. I am glad to hear that isn't the case. This makes me really want to try the battery route even if the $25 special that I missed out on is gone. But first, I just need to finish what I already got going.

That is what I love about DIY. I am not committed to anything and can change and experiment with whatever I wish at any time without having to do major overhauls and lots of $$$.

dr_minky · « **Reply #92 on:** 16 May 2005, 03:09 am »

Quote from: JoshK

I guess, I have had this mental preconceived bias that battery power = less dynamics. I am glad to hear that isn't the case.

From my experience with the t-amp this WAS the case - the sound from a battery supply was much smoother and more refined, but it took a noticeable hit in dynamics..
..Until I added electrolytic caps in parallel with the battery supply (at the amp end). Doing this improves not just the dynamics, but all aspects of the sound improve. I'd say its definitely worth a try on the ucd!

Gordy · « **Reply #93 on:** 16 May 2005, 03:47 am »

Excellent!, thank you Dr Minky. I have some cooking in a chip amp now, I'll give them a try starting about Wednesday. May I ask what capacitance(s) have you tried??? Thanks

speedcenter · « **Reply #94 on:** 16 May 2005, 02:32 pm »

Quote from: Gordy

... have been simultaniously burning in a newly moded BG 'laden' battery dac as well. With about 80-85 hrs. on the dac and 110-120 on the amps things are really starting to open up, especially after the 60-70 hr. point on the dac! I stopped comparing the straight out Denon to the dac awhile ago...

The BG caps for the batts arrived this am, less than 24 hrs. from Angela's!!! They're going in the chip amps today for 100 hrs. or so, guess the UcD's will be off until Tues. or so...

Well, now you're talking. I'm into the battery thing because of my recent DAC building projects. About a year ago I built a DDDAC1543, pretty much by the book. It was darn good out of the box, but as usual, I felt I could tweak it a little. My current version is "BG-laden" as you call it, has 16 DAC chips in it instead of 8, custom regulators for the clock, etc.

The unit is currently being rebuild again to add USB input and tweak some more areas. It's also usable as a passive preamp and as a headphone amp (directly off the DACs, no tubes, no opamps - directly to the headphones through two blackgate 220uF nx, with passive 24 step Elma attenuator out of the signal path next to it).

In short - I am extremely happy with this DAC and am getting interested in applying the same concept to other components. My transport will be next, where I'll be converting some of the lower voltages to battery power. Meanwhile I'll keep an eye on those UCDs and learn a little more about the battery supply issues once you have to deal with +/-48 volts

Peter

dr_minky · « **Reply #95 on:** 17 May 2005, 07:57 am »

Quote from: Gordy

Excellent!, thank you Dr Minky. I have some cooking in a chip amp now, I'll give them a try starting about Wednesday. May I ask what capacitance(s) have you tried??? Thanks

Well, on the t-amp 1800-2200uF seemed to do the trick (more than was neccessary probably, but not too much to cause loud speaker pops). Remember the t-amp is only a 15 watter. I would start by throwing on a pair of 4700uf or 10000uf (1 between the + rail and ground, and another between the - rail and ground), and add another pair in parallel, listening as you go. I don't think the exact value is too critical - keep adding if it helps the sound...stop if are getting worried about pops and inrush currents. For a totally uniformed guess, I reckon 2 pairs of 10k's would probably do the trick.

Al Garay · « **Reply #96 on:** 18 May 2005, 11:20 pm »

Anybody looking for caps for their UcD400 or toroids for their UcD180s, I have the ones that mac recommended for sale.

Caps (5) for $45
http://www.audiocircle.com/index.php?topic=19124

Toroids (4) for $80
http://www.audiocircle.com/index.php?topic=19125.msg168413#168413

SOLD everything in record time. Thanks.

Gordy · « **Reply #97 on:** 22 May 2005, 05:35 am »

Thanks Doc!

Sorry it took so long to get back to you with that! I've made up two boards with two 4.7K caps and two 100uF caps each. The 100's are there because that's about what the gaincard people over on DIYaudio seem to be recommending with batteries, less is more... The 4.7's are now wired in with 4pdt switches so I can directly compare straight batteries vs. the caps in line. I'll swap the amps back in tomorrow...

I did have the 4.7's in for about 30 hrs. total of run time before wiring in the switches. I had the UcD's out for a week as I was forming the 100uF BG's in the chip amps 24/7, so the following very preliminary comment is made with no direct comparison with batteries alone. Dr. Minky's comments seem to be right on, they seem to now have better jump, are even more expansive sounding and maybe slightly less hard during piano crescendos (been a while since I've heard that anyway) but with a very slight lose of fine detail... maybe! Hopefully I'll know better in the next coupla days.

Occam has kindly sent me some more 4.7K caps, so I can go higher eventually! I also have a whole slew of used Chemicon 6.8's, but nothing in the 1.0 - 2.0K range. Would Panasonic FC's be appropriate? I can pick up 10 of them for $18 if going up does prove to get grungier.

Suggestions or pos. criticisms would be very helpful!

Thanks much

dr_minky · « **Reply #98 on:** 24 May 2005, 07:38 am »

Another thing worth playing with is bypassing (wiring in parallel) the large electrolytic caps with small value film caps. This may help with cleaning up the higher frequencies. It also supposedely makes the electrolytics behave more like they were film caps (to a point), negating some of the inherent disadvantages of electrolytics..

Again, playing with size would be the key..possibly one 1/100th of the size of the electrolytic and/or one 1/1000 the size, or something in between.

JoshK · « **Reply #99 on:** 12 Jun 2005, 12:17 am »

Out of curiousity, how many folks here would be interested in trying to organize a group buy on UcD modules? If I was nuts enough to organize it, how many people would want in? How many units?

P.S. they also offer completed PSU boards now too, so those that don't want to solder or attempt a PSU themselves can still build their own amps, just buy the module, the PSU board, connectors, transformers and a case and you are good to go. They do sound quite good.