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I'm currently using a Bryston 3B-ST amp and Magnepan MMG speakers. I'm so frustrated with noisy AC power and the inconsistency of my sound throughout the day that I'm planning to sell them and buy a battery-powered amp and efficient speakers. How will a good setup like that compare to my Bryston/Magnepan combo? Should I get ready for a big drop in dynamics and power/slam?
Follow Ups:
G do you have problems with hum? I had issues with dc offset out bush when I first got into tube amps which can be rectified. I think all said and done you are over reacting to your problem. You need to find a good mains conditioner there are lots of ones that will make your gear sound worse. Check Sac Thailand they are making something special for Aussies. Failing that when I moved into town I put up with low voltage for 2 years. I wish I didn't. I finally just rang up and complained and in a week they had my supply running of another feed at the end of the street. No more problems!. Give your power company a call. And failing that call a electrician get a new spur with a dedicated earth. Takes a lecy 2 hours to do. Good luck with it mate.
Howdy,
You said: "I'll be in Australia and due to shipping costs I should probably buy new there instead of shipping used from the US"
Indeed, shipping from the USA will cost a lot, and there will probably be some surprise customs charges on top. When shopping online, double the item cost for stuff <20 kg and forget about anything heavier.
I didn't notice if you said whether you are happy to DIY. If yes, some local companies worth looking at are:
Cannonsound - currently have 15" coaxials, 15" neos and other items on special. Good service. They recently sent me big 2" throat Selenium horns, by courier, for just $20.
Azura - horn builder (WA). He has answered my queries in the past, seems to make good gear and to be a business worth supporting. My 60cm round horn was influenced by his AH-340.
Etone - have a pair of reconed 18" Celestions for $500, other goodies
Finally: if you are in or near Melbourne for a while, I'm currently keen to sell on some surplus components (horns and such).
Hollow boy is there any particular reason why you ignored my question below regarding your old British drivers? And yet found the time to answer this question? Is there just a missunderstanding or did you make a special effort to insult me? If so how have I managed to offend you?
I didn't see the post you mention. You were replying to something from 2007.
Anyway: nope, I scrapped all those phenolic drivers.
-I didn't have many parts to match to their small throat size, making experimentation tricky
-I had enough projects on the go already
-I scored some B&C DE950 (2" exit) drivers pretty cheaply
If you found yours for free, great! Toys are good.
Thank you for your reply hollow boy I assumed you where emailed my reply thus the reason you came to the forum. Not to worry I am feeling a little unappreciated latterly. I try so hard to help as many peoples as I can here and yet I cant get a simple answer from a question I ask. Its a shame you scrapped them. They are standard small 1-3/8" size if they are like mine.Same as the WE555 I think. Standard for the time. phenolics with simple phrasings seem like a recipe for nice mellow sound. I have a small collection of these horns and drivers as most people don't bid against me when they come up on ebay. Some with phase plugs some with out. I even have a pair of dual throat 1-3/8 horns now and a very large set of very old WE like welded steel radials. Not supa large more like 250 to 300hz cut off welded in a boiler shop from a plan from 1/4 inch steel. Perhaps I am trying to hard I think I am going to fade awa
I'm trying to keep off the DIY path as much as I can just so I don't get sucked into another hobby I don't have time for. :) What would you suggest for turn-key gear in Oz?
Just the usual - PA / DJ sources, or selected stuff from Hi Fi shops. The PA market has many quite affordible passives. Usually if the bass drivers are are 30cm or more, efficiency is high 90s. Or search for JBL and other well regarded brands on ebay, and wait till something comes up locally.
The most turnkey solution would be to buy a one-box system: a speaker with internal amplifiers + rechargeable batteries.
Alternatively, you could go pretty DIY without actually building it yourself: a lot of the systems discussed here are essentially a big horn plonked on top of a big bass bin. You could clone one of these. Given a good set of plans, a carpenter could build a decent bass bin for you, and all you'd have to do would be to wire it up and bolt the horn driver together.
Howdy,
You asked: "How does a little T-amp produce enough power to drive the 15 inch woofer on a Cornwall?"
If you look at reviews of the Sonic Impact amp, you'll see people raving about how well they can drive big systems off batteries. I'm using an upgrade of that original amp (mains powered), from Trends Audio, and it is totally happy driving my 15" woofers. I'm currently using it to compare different stacks, with different impedances:
Right) pair of 15" (in parallel) + 2" HF driver on a round 60cm horn (P-Audio SN15B + B&C DE950)
Left) 15" coaxial (P-Audio 15CXHB)
...and there are no problems. Good and clean and loud. BTW, the sound of the different channels is more similar than you might think :)
Do my choices come down to T-amp SS or SET tube?
No. You could battery power a gainclone just as easy (actually, easier) than a SET amp. A couple of lead/acid batteries would give you +/-12V. With the LM3875, that would give you about 5W. Series a couple of batteries for +/-24V, and you would get about 28W. Plenty for a HE loudspeaker. This would also give you the power for an active crossover, as well. You could use car batteries, or the smaller sealed types from Panasonic (Parts Express has them). The current demands from the amps driving HE speakers would be fairly small, and you would probably get several days at least between charges, if you listen a lot.
It sounds like my choices for battery-powered amp are T-amp, Gainclone, or SET. That's nice, it's good to have some choices.
For the speakers, would Klipsch Heresy be a good place to start? I'll be in Australia and due to shipping costs I should probably buy new there instead of shipping used from the US.
What are "HE speakers"?
High Efficiency.
I found that the original T-amp was not very good, even when used with batteries. I later stepped up to a Charlize (DIYParadise), which was a fairly optimized design IMO, and used it with a 12V SLA. Not very good. I would try again with the newest units from Hypex, when they are available. My Gainclone experiments were consistently better than the Class-D stuff.
My very simple 2A3 SET beats them all IMO, if you can live with the power output -- an amp like this is best at 103db+, and even better at 107db+. Even better is my fully battery powered (B+ and heaters) 10Y-45 SET, when used on compression drivers.
I've used battery power supplies for triodes for about ten years now. It is not that big a deal. Just find surplus 1.5-2.5Ah batteries on eBay for $5 or less each. Put them in strings of four batteries to produce 50V. Charge in parallel on a fixed 55.2V supply. My present 400V supply (eight stacks of four batteries each) fits in a box about 24"x14"x8" and weighs about 100lbs. I would bypass the batteries with a cap of some sort. Batteries are not designed to pass AC.
I have found the same things, Gainclone is the nicest but still very far away from even a simple SET.
Still have not yet found the guts to go battery loaded SET, Have you been using batteries for 10 years already? are they the same batteries?
You have to charge every 50 volt pack separately I suppose.
How long can your batteries go for with full charge?
Very interesting!
I buy surplus batteries cheaply, and they tend to last about 3-5 years. The 50V stacks are charged in parallel on a single 55.2V fixed supply (a Mastech adjustable powersupply from eBay, set at 55.2V).The general rule for trickle charging is a charger with current delivery of 0.2x the capacity of the battery you are charging, thus a 1.2Ah stack would draw about 1.2A*0.2 or 240mA in charging current. I have eight stacks in parallel so that is 240mA*8 or 1.92A. The charger is a 3A charger so it works fine here, with a little headroom.
My present batteries are 1.2Ah I believe, which is rather small. In general, you should aim to discharge a battery by no more than 50% on a regular basis, so the effective Ah is 0.6Ah. My amps run about 100mA for both channels, plus another 50mA or so for the preamp, for a total of 150mA or so. Thus, you can expect about 4 hours of use from it to a 50% discharge. If you use something like a 300B at 80mA per channel, then of course you would discharge them faster.
If you can live with the large size, the 7Ah batteries seem to be a very good value. You can sometimes find them as cheap at $5 or so each. I would make boxes of 100V (two stacks) each and wire them in series. This would give you a lot more capacity, at the cost of larger size and weight of course.
I would again recommend using a bypass capacitor of at least 10uF, in the amplifier. You could even have a choke-capacitor combo. Batteries are not designed to pass AC.
I wouldn't necessarily say that you can't achieve similar effects with a standard wall power supply. However, to make a comparable wall-power supply would also take a lot of gear and money, and you would end up with something nearly as large and heavy IMO, and probably more expensive.
Very interesting NL, thanks!
I am about to start multiamping... so more batteries will be needed!
The Cornwalls and one of then little jobbies might be a happy combo. You'd get peaks to 103db with a 12volt tripath amp. You cold run a power opamp thingamajig with two 12V for 17watts that'd peak at about 110db. Not such a bad max.
he Cornwalls and one of then little jobbies might be a happy combo. You'd get peaks to 103db with a 12volt tripath amp. You cold run a power opamp thingamajig with two 12V for 17watts that'd peak at about 110db. Not such a bad max.> > >
Or you could upgrade to Khorns and get even more sound per watt.
How does a little T-amp produce enough power to drive the 15 inch woofer on a Cornwall?
A large driver does necessarily require more more; often the opposite is true. Sensitivity, loading, impedance and phase angles, and QTS are more helpful indicators.
A large, efficient, low QTS driver with appropriate loading is likely to require less power and damping to achieve similar volume levels than a small, inefficient driver in a tiny bass reflex enclosure... you should also experience less sense of constraint/unevenness/strain, even if extension is not as 'deep'.
Cheers.
BTW, the K33 is the same woofer as in a Cornwall, it will just play 6 db less loud vs. a Khorn.........so what?
I'm using a T amp (20 Watts per channel) on some FH-1 cabs with 15" Klipsch K33's, which are 104 db/w efficient. I'm also doing a 6 db boost at 60 Hz. to compensate for the rapid rolloff. My Audyssey is crossing them at 70 Hz. to a tapped horn sub.I only listen to music at 80-85b db (attached condo) to keep from pissing off my neighbors too much and to save my hearing for old age.
Paul Klipsch himself always recommended 20 W per channel and felt that 17 db of headroom was plenty for his home recordings of live symphonies. He used a 30 Watt/ch amp (Crown D-60) at his house when I was there.
Edits: 03/20/12
What would you recommend for an amp running from batteries and speakers (no biamp) for less than $3K?
Why don't you try the Redwine amp?
Yes, I think I'll try the Red Wine Audio Signature 30.2 or its successor. Great reviews for the 30.2.
Why no bi-amp? That is one of the most cost effective improvements you can make to your system. And when considering battery powered amps, can significantly improve your dynamic range.
Wouldn't biamping require an active crossover that plugs into the mains? I seek total isolation from the mains.
An active crossover could easily be battery powered (+/-12V), or, passive solutions also exist.
Used cornwalls or a DIY with cheapo tripath for under 800.00 if you can find them local. You might be able to get Altec Model 19s in you price range.
Worked good. Think they are out of business
big j.
"... only a very few individuals understand as yet that personal salvation is a contradiction in terms."
I'd suspect temperature, not just line noise. The Magnepan may have low resistance at DC. This can make the amp heat up from it's DC offset and lead to distortion. If you cap couple the amp to the speakers, the problem may go away. You can measure the dc offset out of the amp (both channels) at various points during the day to check.
I've seen a Bryston use as an industrial amplifier. The load was close to 4 ohms ac, but it less than 1/10 of that at dc. The amp had problems because its DC offset varied with temperature and into a low impedance DC load, the DC offset would cause the amp to overheat. The fix was to cap couple the amp to the load.
Try cap coupling through a series pair large (~> 10,000uF each) aluminum caps with the + terminals tied together with the Bryson amp going in one - terminal and the speaker to the other - terminal. Place a diode across each cap (Cathode (band) to the + terminal of the cap.)
Note: This type of load (4 ohm at audio and a low impedance at DC) is a challenge for any direct coupled amp. They were using a Bryston because their McIntosh tube amp finally died and they couldn't afford another McIntosh with a transformer output.
Play safe and play longer! Don't be an "OUCH!" casualty.
Unplug it, discharge it and measure it (twice) before you touch it.. . .Oh!. . .Remember: Modifying things voids their warranty.
The same sound quality variation problem I've had with my Bryston amp I've had with Outlaw 2200 monoblocks (which stayed very cool) and Quicksilver Mid-Mono monoblocks. Exact same symptoms with each amp.
It is also easy for power line noise to get in through the preamp.
Play safe and play longer! Don't be an "OUCH!" casualty.
Unplug it, discharge it and measure it (twice) before you touch it.. . .Oh!. . .Remember: Modifying things voids their warranty.
I actually just plug my Wavelength Proton DAC straight into the Bryston amp. Noise could definitely come in through the computer though which I suppose is the same idea. I do have the computer plugged into a Tripp Lite isolator just like the amp.
I haven't played with the Tripp Lite isolator. Some computer grade line filters improve RF noise at the expense of making audio noise worse. Others do quite well at blocking both audio and RF noise.
Try running wrapping the low level audio cables through one of these beads 3 to 5 times. Left and right should go through the center the same number of times on a stereo amp. Use separate beads for left and right if using monoblocks.
"http://search.digikey.com/us/en/products/LFB310190-000/240-2139-ND/571946"
Play safe and play longer! Don't be an "OUCH!" casualty.
Unplug it, discharge it and measure it (twice) before you touch it.. . .Oh!. . .Remember: Modifying things voids their warranty.
"Should I get ready for a big drop in dynamics and power/slam"
Wow, High efficiency speakers, mainly horns are the kings of dynamics and power slam! They own the brand!
I have listened to Magnepans and they are pretty bland...JMHO.
Actually get ready to meet dynamics and power slam!
As for amps:
I have tried a lot of amps and SET are the most dynamic, if your speakers can run on 2 watts, that is. If you try to run 89 db speakers with an 8 watt SET amp they will sound dull and lifeless. I am using a 1.5 watt amp right now with my 110 db horns and it is more dynamic than a 300 watt SS amp I was usng a while back... SS was very nice, very detailed, but cold and uninvolving. (Yes SS can also run 110 db horns)
And to answer you question directly: I have looked hard at the Battery aproach and I have tried a couple of circuits that could run on batteries: Mainly simple SS amps runing on 12 volts, they are nice but not on par with even a simple SET: imho. Gainclones, chip amps, T amps etc.
I was also pricing out a battery bank to get 450 volts for a SET amp!
But everyting is soundung so nice I just forgot about it...
Batteries can deliver tons of current - short a 12 volt battery with a large wire sometime if you question it !!
Amps run on batteries run dead quiet . Blackest background ever and amply dynamic
They still seems to lack something compared to well designed power supply.
Placing a good quality cap across the batteries to lower impedance seems to help
Simon
"They still seems to lack something compared to well designed power supply"Correct, you got it right. NO battery supplies for me !! SLM and saturntube (above) said it best by far !!
Jeff Medwin
Edits: 03/20/12
Car batteries are actually 13.8 volts when fully charged, but that can be up to 16 when over charged. Assuming a low of 12v, depending on amplifier design, and load impedance, you can pull quite a few peak watts from them without any ripple. After all they do start cars, don't they.
I don't get where ripples in batteries would come from, unless there is a momentary voltage sag under load, but I doubt that horn speakers would ever make that happen in a sane home volume level. I find that my speakers draw less that 0.02 watts most of the time, as measured on the woofer section (forget about measuring the mid and tweet horns). Even 20 db peaks only draw 2 watts, which for 6 ohms, is only about 3.5 volts of peak swing for less than 0.6 amps of peak current for a few milliseconds, usually about 1/2 a volt or less for most reasonably loud music.
.
If they can "deliver tons of current" then a cap would not lower impedance since it has to have extremely low impedance to deliver those tons. However, batteries do not produce pure DC. There is a noise element which may be reduced with a cap or other filtering.
.
Batteries can supply a lot of low frequency current; however, their impedance goes up at higher frequencies. The higher high frequency impedance is why the capacitor across them helps.
Play safe and play longer! Don't be an "OUCH!" casualty.
Unplug it, discharge it and measure it (twice) before you touch it.. . .Oh!. . .Remember: Modifying things voids their warranty.
.
I can't find any data to support what you said. Do you have any links?
How much does the impedance go up from 20 to 20K?
Thanks
.
Or you can just use batteries on the woofer amp.
and have a discontinuity of sound, if biamping a GOOD speaker, the amps MUST be exactly the same. A good system will use one amp, with the same time constant through it, and play it all !!! Look up a Serious Stereo 2A3 amp, as a start and a finish in amps.
Jeff Medwiin
I have to disagree, Jeff. I have bi-amped bunches of systems, and most of the time the amps are different. They all sound great. Of course, if you do have matching amps, so much the better. I do have to say though, I have never heard a SET amp with decent bass. Low bass is not a strong point of a SET design (the 'Single Ended with Slam' by Bruce Rozenblit may do it). I much prefer a decent SS amp up to about 300-500 Hz, and then go to tubes there in a bi-amped system.
"I much prefer a decent SS amp up to about 300-500 Hz, and then go to tubes there in a bi-amped system."
Hornloco
I had tubes. Prefer modern SS...........no transformers, bias, etc. to deal with, which is what you pay for. Love the even harmonics of tubes, but it's just a pleasant distortion.
.
I'd try an isolation transformer/regulator (i.e. Sola) and use
filters after that, before getting new gear. 12V is a last resort,
which I wouldn't attempt.
So this isn't usually done? There aren't many people using strictly battery-powered components and super-efficient speakers? What are the drawbacks?
I am using custom tripaths on my horns the price of energy is my motivation. I plan to use them more and more from the bass up. A battery tripath on horns is a awesome thing if done right. All these guys are biased to wards tubes. Half here prolly haven't even heard a tripath horn set up. imagine having worked on designing and building the best tube amps you can build for ten years like I have or double that in case of a lot of guys here only to find a sla tripath outperforms there tube amps? I wouldn't want to even know.Get it? Tripaths love horns they are not strong on anything much less or the smallest tripath chip I am referring too. I have not tried any bigger. Mine runns on a single large sla for 2 weeks before charging. You can get good sla's from ex government ups supplies often sold at auctions for scrap weight or less. I am considering building a sla powered dht preamp atm. Battery's rule. If your loaded try Jeff Roland amps.
That sounds awesome. I want in!
It's funny, with my old system I first picked the speakers (Magnepan MMG) and built everything around that until I realized that since they're so inefficient and require a beefy power amp, I can't do any real isolation from the mains. In my experience, the power source is ultra-critical and a noisy one will render everything else crap. I've tried every type of power conditioning except batteries and a regenerator, and neither of those are possible with an amp that can do the MMG's justice. That was my first real attempt at building a good system. This time I'm starting from the power source and building everything around that. Experience rules. :)
Specifically what would you suggest for battery-powered amp and horn speakers to start out? Say, less than $3K?
I built 2 gain clones either I wasn't good enough or they where not good enough. My little Chinese custom tripath amps beat them real easy. As did any of my tube amps. I found the gain clones where happier with SS speakers. IE current drive speakers as apposed to the tripaths that die quick when asked for current mine are similar to a strong 300b in power and drive. They love hi impedance hi efficiency loads. I want to try kit hiraraga class A amps someday.
.
Any amp that can drive the MMG's with enough power can't be put onto batteries and it's debatable whether or not a regenerator would be up to the task. A regenerator doesn't provide the real isolation from mains that batteries do though.
I'm talking isolation tranny, why not use that?. I have a 20A
unit, so that should be way more than enough.
I've tried Tripp Lite and BPT personally.
Hmmm, I don't see how noise can make it through the tranny,
since it's tunes to 50/60 Hz. Maybe an engineer can tell us.
I wouldn't think many are, if I was off the grid, I might
go that route, but otherwise a big NO. I have had no
problems with the grid AC here. But I admit, I'm on a dead-end
country road, with my own transformer on the utitlity pole. Nice!.So, I don't know what all the fuss is over AC noise, I've
never experienced it. I would think it could be filtered out
without alot of expense.
Edits: 03/18/12
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