[speedcenter]

Interesting approach (I love batteries in my DAC and soon will move my CD transport to batteries). I assume those are UCD180 modules? What kind of playing time do you get from those 8 7.2ah cells in the supplies?

My speakers are very inefficient and probably draw a lot of juice, so I am somewhat on the fence if I should approach a project like this (18ah cells are pretty cheap at Gruberpower.com), plus I am not sure how to build a charger that would deal with batteries in a series configuration that gets me 60volts for the UCD400s I would want to build.   I suppose that can be researched, though.  Five 18ah cells would give me 90ah total and I'd be building these as monoblocks with one set of these cells per channel - anyone can tell me how long you'd be able to fire some big Mangepan speakers with those? My Odyssey Mono Extreme amps I'm using now are pretty good at handling the speakers, but they get rather warm when pushed. The cost of 10 of these batteries is about equal to a pair of decent transformers, but it's still cheaper than going with some Plitrons and really high-end parts throughout. Very tempting.

Peter

[JoshK]

Gordy is powering his UcD 400s with this, not 180s.  That is due to the voltage rails being 54VDC, which is closer to the UcD400 spec.   He says he gets around 12+hrs driving his 86db speakers.   Magnepans are basically resistive loads, so I am not sure it would be any different.

[Gordy]

Hi Speedcenter,

Josh is absolutely correct, I'm using the 400ST modules and the one time I checked I was still at 49.1v and 49.9v after 12+ hrs of use.  The battery system, as orig. configured, was designed to shut down and re-charge automatically at 42v to prevent deep discharging of the batteries.  I'm only presuming that would give me about 24 hrs. or so if I were to run it that deep.

The 48v/54v set up is as high as you can go, as a 5 battery system would take you to over 67v which will put the modules into the protection mode. I haven't built them yet, but I do have everything here to build the ac power supplies for a comparison, but fully expect the same results as with the 3886 amps!  

Add into your savings the cost of those $$$ power cords as well

Gordy

[Occam]

Add into your savings the cost of those $$$ power cords as well.  

But Gordy, have you tried different powercords on the chargers to see whether they effect the sound quality?

[Gordy]

Yes!   I found that unshielded cords let far too much dirty 'lectric into the batteries and gunked them all up

[speedcenter]

Hi Speedcenter,

Josh is absolutely correct, I'm using the 400ST modules and the one time I checked I was still at 49.1v and 49.9v after 12+ hrs of use.  The battery system, as orig. configured, was designed to shut down and re-charge automatically at 42v to prevent deep discharging of the batteries.  I'm only presuming that would give me about 24 hrs. or so if I were to run it that deep.

The 48v/54v set up is as high as you can go, as a 5 battery system would take you to over 67v which will put the mo ...

cool - never thought of it that way (I was thinking of regulating the batt power to exactly the highest value the UCD400 allows).

4 of the big 13ah batts should be enough then I guess - they clock in at about 13.1 V fully charged.  What I would need to design is a fancy switch that when I power down the amp will let me switch them from series to parallel config. Then I just fire up the recently aquired Vectra surplus charger and a half hour later they are back to full tilt, turn them back to series config, and continue to listem.  This can probably be achieved with a few smart DPDT switches set up in a way that I can only charge the batts when I turn the thing off.

Very cool - this whole battery discovery has pushed me over the edge, I am gonna order a pair of these 400s to build me the first pair.

Power cords? darn - what am I going to do without those? I have about $50 invested in two fat VenHaus style DIY cords  The cool thing is that I now don't even need to install the dedicated AC circuits I had planned for my amps!

But wait - I can probably still sink an unheard of amount of cash into the DC connections between amp and battery box -  Neutrik Powercons are just way to mundane to consider here, although a cryo job and some silver wiring will probably do the the job for me  

what are you doing for "soft start" with the battery power? Is that still an issue like it is with AC power?

I am pretty amazed that you get that much playing time from the UCDs, but then again, we're talking 400watts into 4ohms here at peak, which I feel isn't going to be that much of a drain on the battery during regular listening levels. My DAC currently pulls about 0.5 continuous amps from a single 7.2ah SLA battery, and that thing will run easily for 8 hours before things go too low to sound right.  For the amps I'll use 18.2ah batteries, which will give me a total of 72.8ah per channel, which even with a non-stop diet of Paul Oakenfold remixes should last for a few hours of bass thumping.

I plan to build a total of 4 channels of UCD 400s for my speakers if I actually find myself liking the sound of the first pair. 4 channels will let me drop the power-robbing passive crossover in the speakers, possibly gaining even more efficiency, even if I should power both channels from the same batch of batteries on each side of the system.

Well, that's my summer project - I just need to finish two DACs and a new tube preamp before I can start with this.

Peter

[Gordy]

Hi Peter,

"4 of the big 13ah batts should be enough then I guess -"

In order to get the +/-48v required you'll need 8 batteries total.  Here is the Audio Karma thread where "our own" Gone Fishin' describes the wiring/grounding for a +/-24v gainclone system, you just double up for 48v. http://audiokarma.org/forums/archive/index.php/t-15565.html  He was kind enough to help me out with my Q's while I was building my chip amps!  The run times I quoted were for 7ah batteries!

"What I would need to design is a fancy switch that when I power down the amp will let me switch them from series to parallel config. Then I just fire up the recently aquired Vectra surplus charger and a half hour later they are back to full tilt, turn them back to series config, and continue to listem. This can probably be achieved with a few smart DPDT switches set up in a way that I can only charge the batts when I turn the thing off."

That's exactly how mine is wired! It'll depend on your layout as to what type of switches you will need, of course.  With the original outboard modules layout I used 2 - 4pdt 25a KNN toggle switches, as one pole killed the 120ac to the chargers/fans.  Occam pointed these out to me...
http://www.mouser.com/index.cfm?&handler=data.listcategory&D=*633s43f*&terms=633-s43f&Ntt=*633s43f*&Dk=1&Ns=SField&N=0&crc=true
 I also needed 2 - spst switches for the standby's, but my modules are in seperate chassis.  There was the very slightest of power up "ticks" when I had the ground hard wired (if an alligator clip is hard wiring...lol) early on, so I decided to go with the mute...

HTH...
Gordy

[Kevin P]

You don't need to get crazy on the PS to get great results.   I think a lot of people like to throw money at them.  

The simplest of supplies as suggested by Hypex works extremely well with these things.

[JM]

You don't need to get crazy on the PS to get great results.   I think a lot of people like to throw money at them.  

The simplest of supplies as suggested by Hypex works extremely well with these things.

I have been tweaking my amp now that it is mostly broken in and, IMO, the power supply has a significant sonic impact on the overall presentation. The modules will probably sound good with a simple PS, but I'm convinced that some extra filtering will help reduce distortion and improve resolution. The extra cost is relatively low if one uses industrial parts.
EMI seems to be an issue too. I've been playing with ferrites and they do clean up the sound. The trick is to find the right combination and placement. Too many ferrites can kill the dynamics and shrink the sound stage.
Overall I'm very happy with these modules. They sound really good: very resolving and dynamic.

[Kevin P]

I have been tweaking my amp now that it is mostly broken in and, IMO, the power supply has a significant sonic impact on the overall presentation. The modules will probably sound good with a simple PS, but I'm convinced that some extra filtering will help reduce distortion and improve resolution. The extra cost is relatively low if ones uses industrial parts.
EMI seems to be an issue too. I've been playing with ferrites and they do clean up the sound. The trick is to find the right combination and placemen ...

It's like anything.... one persons significant sonic impact is another's insignificant sonic impact.    A lot depends upon the speaker load, room, connected equipment etc....   If you are building your own amp you can play with parts experimenting on what sounds best in YOUR system.   If you build something for other people you have to make intelligent choices and call it good enough at some point.

[speedcenter]

Hi Peter,

"4 of the big 13ah batts should be enough then I guess -"

In order to get the +/-48v required you'll need 8 batteries total.  Here is the Audio Karma thread where "our own" Gone Fishin' describes the wiring/grounding for a +/-24v gainclone system, you just double up for 48v. http://audiokarma.org/forums/archive/index.php/t-15565.html  He was kind enough to help me out with my Q's while I was building my chip amps!  The run times I quoted were for 7ah batteries!

"What I would need to desig ...

I never thought of the +/- 48V  d'oh! I guess the smaller batteries will do fine, now that I will have 8 of them per channel...

I've done some research and found a great fully automatic 48V charger from Soneil - $185, but it eliminates all kinds of problems with the wiring. I may just spend the extra cash on that once I get the unit done. During testing, I'll just manually wire/recharge them with a 12V unit. Wiring all these toggle switches just seems to invite trouble.  getting the polarity wrong on any of this kinda scares me after I've already sent some wiring up in smoke with my single battery powered DAC  

reading the gainclone thread, I saw that he recommends smaller capacitors for the battery supply - does this translate to the UCDs? i.e. instead of the 10,000uF use something like 220uF? I'm not sure if that's a good idea, since I always thought the caps are the big power reserve for instant-demand. On the other hand, based on my melted wiring experiements, I know that batteries can deliver huge current very quickly. what have you done regarding those caps?

Peter

[Occam]

You don't need to get crazy on the PS to get great results.   I think a lot of people like to throw money at them.

Absolutely Kevin! And you don't have to use the typical POS toroidal transformer which lets all sorts of crap in (and out). Use 2 of these dual bobbin ($40 retail) transformers, each providing 175va @28v AC, one for each rail of your UCD180(s), and you've got the start of a fine powersupply.

http://www.bgmicro.com/prodinfo.asp?sid=078189814814814869201136182&prodid=PWR1164&page=1&cri=signal+transformer&stype=3

and if you call BGmicro, tell Tammie that Paul sent you and she'll put up to 4 of these $9 transformers in a $8 PriorityMail box. Your postman will love you.

[JM]

It's like anything.... one persons significant sonic impact is another's insignificant sonic impact.    A lot depends upon the speaker load, room, connected equipment etc....   If you are building your own amp you can play with parts experimenting on what sounds best in YOUR system.   If you build something for other people you have to make intelligent choices and call it good enough at some point.

Kevin,
I just don't understand the reason for your previous statement.
I'm sure the Hypex modules sound good with a simple PS, but that's not the reason we're here. We want more than just good.
We are all struggling to extract the most from our systems, that's I believe the main reason we are DIYers and crazy audiophiles. And that we actually spend time in the discussion forums sharing our experiences so that others can learn and may be able to contribute with different ideas.

[speedcenter]

I am in the camp of the overbuilt=better crowd. With power amps, you are listening to the power supply - that's what drives your speakers. The rest just modulates the output of that supply.


Anyway - so back to the battery supply.  Gordy, here's what I have in mind for each monoblock, although I am not sure if I can keep the ground wires connected to the amps while switching to charge. This diagram is based on the gonefishing description and assumes I have 48V smart chargers for each monoblock that is always on and charges the amps the moment I toggle the DPDT switch that disconnects the batteries from the amp module and links it to the charger. To be safe that switch could be one of the 4DPDT you pointed out, cutting the negative rail and 0V rail as well - I think I'd prefer that.  

 


given these batteries are $7.25 a piece, this isn't such a bad deal.


Anything horribly wrong with this setup?

Peter

[Occam]

Kevin,
I just don't understand the reason for your previous statement.

Kevin said -

If you build something for other people you have to make intelligent choices and call it good enough at some point.

Julien - I thought Kevin gave a superb and honest answer. Actually, one of the least self serving statements I've ever heard from a vendor, which only increases my respect for him. Kevin is trying to earn a living, and there is simply a point of diminishing returns. The folks who know me know that I've no problem, and actually enjoy antagonizing vendors over technical issues. While I do enjoy yanking Kevin's chain, the man is a straight shooter. For each increment of $50 increment in a $700 product, he probably looses about 25% of his potential market (yes, I'm pulling those numbers out of thin air) I'd hazard to guess that Kevin's pricing is a the very low end of bill of materials cost to retail. He simply has to make a rational business decision, that sadly doesn't necessarily jibe with our desires.......

[JM]

Julien - I thought Kevin gave a superb and honest answer. Actually, one of the least self serving statements I've ever heard from a vendor, which only increases my respect for him. Kevin is trying to earn a living, and there is simply a point of diminishing returns. The folks who know me know that I've no problem, and actually enjoy antagonizing vendors over technical issues. While I do enjoy yanking Kevin's chain, the man is a straight shooter. For each increment of $50 increment in a $700 product, he prob ...

Occam,

I never questioned Kevin's integrity or honesty. But I felt I should express my opinion since he was making a statement and not giving an opinion.
The statement in question is: "You don't need to get crazy on the PS to get great results."

[Kevin P]

Occam,

I never questioned Kevin's integrity or honesty. But I felt I should express my opinion since he was making a statement and not giving an opinion.
The statement in question is: "You don't need to get crazy on the PS to get great results."

Hey... no reason to argue over my integrity.    

I'm just giving you my opinion.   When opinion transforms into fact is a philosophical question that I'm unwilling to tackle at this moment.

[Occam]

Julien,

My comment on Kevin's response was in no way meant to imply that you questioned his integrity or honesty. I was simply stunned by Kevin's candor in these times of vendors proclaimed 'absolutely no expense spared'. I found it so refreshing, I forgot to put parentheses around a parenthetical statement. If I inadvertantly gave you any offence, I sincerely apologize.

What I meant to convey was that IMO, within Kevin's market there is little price elasticity.
This is quite different for the masochistic DIYer who might be willing buy surplus transformers and accept  the limited availabilty, the larger chassis required, the increased potential for hum..... all for some specific benefits. All of these constraints could be suicidal for a profit making business, but merely a pain in the arse for a hobbyist.

[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.

[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. Worse, there is often AC on that ground. The only way this would work is if the chargers voltage is floating, without a ground reference.

3. Unless you can find a 96v charger (which I've never seen) I believe you'll need 2 48volt chargers or a dual bank charger.

4. 7ah batteries at $8ea might indicate old batteries that have not been maintained 'at charge' and might have constrained lifetime and performance.

My enthusiasm for high power battery powered amps was based soley on that availability of $25 (plus shipping) packs including batteries, chargers and chassis. At that price the risk of less than optimally conditioned batteries was, for me, a non-issue. As these are all gone, the idea is far less appealing and costly. At $120 [EDIT-actually $150, I forgot the cost of the 2 4pdt switches] all in for a dual rail +- 48v battery powersupply, the project was, for Gordy and I, minimal risk and worth a 'flyer'. This is no longer the case. Gordy and I worked together on configuring the supply for his UCD400s, and to be honest, the above comments have exhausted my 'expertise'.
I'm not saying you won't be wildly successful in your implementation, but I've not seen on this board the requisite knowledge upon which you can draw.

FWIW,
Occam