View Full Version : Advice on a power supply for amp 6
bull041161
15-Oct-10, 23:54
Hi can any one help i need a decent power supply for my amp 6 sneaky i have a torodial transformer which puts out 2x 25 volts so would i just use one side of the transformer and a voltage reg or rectifier. Allso what value smoothing caps should i use i was thinking about an out put of 14 volts any advice would be great. Please nothing too difficult as im a novice
Unfortunately 2x25VAC is just too high for this little amp.
After rectification and smoothing caps, you are looking at over 36VDC which is not practical to cut down to 14V with a Linear VR.
On the other hand, that transformer would be great to use with an AMP11 kit.
My suggestion for a very simple solution is to purchase a laptop SMPS "power brick".
It is a fully enclose complete solution with no further construction required. Just plug it into the completed and cased sneaky and away you go!
Something like this would be 'killer':
http://cgi.ebay.com/Power-Supply-Adapter-Kogi-L7CH-LCD-Monitor-12V-4A-/230348299271?pt=Laptop_Adapters_Chargers&hash=item35a1d41c07
bull041161
16-Oct-10, 13:04
Hi scratchy do you think the lap top supplys are any good i just thought the amp 6 is a top class amp and may benifit from a good power supply. I used a plasma tv power supply on my last amp 6 and found i was getting mains interferance
That power supply is fine for the AMP6, only you then could just as well have taken the AMP6-B because you don't need the rectifier, regulator and smoothing cap any more. Actually these parts only work negative to a power supply that already outputs dc voltage.
I would recommend to buy a different transformer, or unwind the one you have now to match the voltage... Something like 12Vac or 15Vac would be great. If you want to unwind it please ask for some more advise, I have done it many times...
That power supply is fine for the AMP6, only you then could just as well have taken the AMP6-B because you don't need the rectifier, regulator and smoothing cap any more. Actually these parts only work negative to a power supply that already outputs dc voltage.
I would recommend to buy a different transformer, or unwind the one you have now to match the voltage... Something like 12Vac or 15Vac would be great. If you want to unwind it please ask for some more advise, I have done it many times...
V-bro, Bull has the AMP6 - Sneaky which is the replacement for AMP6-B.
There is no Rectifier or VR on this board, hence my recommendation for a DC PS solution.
Please nothing too difficult as im a novice
AArgh, why off course, Jan mentioned this a while ago that he would discontinue the 'regular' AMP6...
bull041161
16-Oct-10, 22:00
Hi all thanks for replys what do you think best way to go buy a brick type power suply or would the amp benerfit from makeing a power supply or not worthe the hassle
Please tell me what happened related to these posts:
http://www.41hz.com/forums/showthread.php?2487-41hz-amps-v-other-quality-amps&p=22185#post22185
http://www.41hz.com/forums/showthread.php?2487-41hz-amps-v-other-quality-amps&p=21306#post21306
etc..
What did you use on your other amp-6-basic (sneaky same specs)? Is that 12V-4A smps-'brick' broken?
bull041161
17-Oct-10, 00:37
Hi i did use a plasma tv power supply but i was going to make one so i could up the voltage to give the amp a bit more power but some of the power supplys dont allways put out the said voltage for instance i put my volt meter on a regulated power supply it shoud have read 14 volts but was puting out 16,5 volts thats what really puts me off buying a ready made power supply incase i blow my amp. The old post youhave seen was my old hifi system it was very sad but i had to sell it to rais some cash. Thats why i had to buy a new amp. I have been useing a bench top power supply that sounded ok but the transformer si huming like mad and drives me mad. So i am useing that power supply to run the opamps in my moded marrantz 67
Aha. I see now: a bad experience. Yes, can always happen.
But it was about a year or more ago, and that smps stuff gets better all the time.
Just try again, for couple of pounds.
bull041161
17-Oct-10, 01:19
Hi will try another one then my speakers that i was useing in the old system wasn't as sensative as the diy tannoys i have now so 12v should be ok
I would like my amp6s to run off a power supply that has an accessible switch (not the wall plug) and gives the best quality to match the money and investment I have put into my stereo chain (Caiman+PLLXO+4-way active open baffles). This thread seems to suggest any laptop smps will do, but like Bull I wonder if something like this dual output linear supply below would make a difference!?
http://www.itemaudio.co.uk/item_power_supply.html
•230V AC > 12.8V DC Converter
•Linear regulated 4 amp power supply
•Peak output current: 6A
•Load regulation: 130mV
•Line regulation: 320mV
•Low ripple and noise
•Dual 2.1mm outputs
•Overload and short-circuit protection
•Dimensions:
160mm (D) x 160mm (W) x 90mm (H)
•Weight: 2800g
•CE Approved
•12 month UK warranty
Seems perfect to get the last percent of perfection out of the amp.
However (there's always a 'however') I closed the url when I read: 2.8 kg + 70+10 P+P Pounds.
(this seems like a 13.8V supply for home CB's to me)
A small smps 12-14V 3-4A will get the job done 90-95%, for 250g + 10 Pounds (incl. P+P)
If you have amp6, not amp6-basic, best setup is with just a toroid of 12Vac OR a smps and leave the regulator/caps out.
Not much difference, but £70 inlcudes the £10 P&P so the way I look at it is that the £60 is for two PSU's, and no DIY necessary. Then again, can I run two amp6bs off one SMPS?
If I understand correctly, the linked linear PSU is so light it must be so weak as to be poor value.
Slightly seperate issue if I may;
Admittedly, I originally wanted two amp9s but am nervous that the extra power may not be necessary, and I may sacrifice some sound quality. I want absolutely perfect vocals for example from my carefully arranged audio system. When I saw this dual power supply I thought I could just buy two more amp6s, giving me two per channel, and two PSUs at £130. Am I crazy sticking with the amp6bs? Should I go with the two amp9s and then go back to looking for a 24V supply?
Well, the ad looks to me as P+P is not included, but OK.
It's still 6A, even if it has two jacks. (and it is still expensive!)
The TA2020 on the amp6b's seem to offer better sound quality than the TAA4100A on a amp9b, if I read a lot of post correctly, so you should be OK with those. For me, I like both.
For good quality, you get:
-6basic: 2x10Wrms + 0.03%THD @ 4ohm @ 13Vdc
-9basic: 4x40Wrms + 0.01%THD @ 4ohm @ 25Vdc
How much power do you need? OR How sensitive are your speakers? AND How loud does it need to be?
In home, the amp6basic should suffice mostly, so if you already have them, OK. (got it too, sort-off)
A 12-14V - 4A smps will suffice, even for 2x amp6basic.
If you find it won't (it gives 50W continuous power, but this is music), then get another one to power separately.
Simple.
Or find a real powerful one if you think you really need to (you don't). This:
http://cgi.ebay.co.uk/13-8V-350W-25A-Switching-Power-Supply-CCTV-RADIO-/180552192410?pt=UK_BOI_Electrical_Test_Measurement _Equipment_ET&hash=item2a09bfd19a
-can power at least 8x amp6basic for less than 30 Pounds.
In-any-case: Tripath amps are great, you will never be disappointed.
(don't forget to use a mute-switch to avoid thump-on)
If you test an amp6basic at quite LOUD level, try to measure the (average) current from the PS, don't be surprised if it is under 500mA.
Thanks, for your input FFF. If you were to go to the shopping cart on that site the pricing then becomes clear but given your comments I will give up on that. In fact, with the amp6b limited to 10watts low distortion I suspect the amp9 might be a better bet.
I am bit stuck for describing the sensitivity of my DIY speakers having done no modeling nor measurements. It is all done from forum research and playing test tones. It is hard to judge the power requirements from the muddy bass sound currently because I am using a Denon AV Receiver as a preamp until I get my Caiman pre/DAC fixed and I drastically changed these speakers recently. Let me give a run down and a picture (damn, I need a URL?) in the hope the kind people here can sway me one way or the other on the amp6/amp9 decision;
All drivers run open baffled on a 4 way, currently 3 way active using three stereo amps (2Xamp6b, 1XTA10.1).
Neo3PDR planar-magnetic tweeter
Monacor 4" 91db
Monacor 8" 91db
2XAlpha 15s 15", paralleled for 4ohms
So I will drive the lot with four amp6bs or two amp9s. I am leaning toward the amp9bs now since my open baffle is built with efficiency being the main compromise (small/no baffle, first second order crossovers).
OK, I could not manage an attachment so a glance at my Avatar may help. The 8" has changed (was a B200) and the top two drivers are visible above the baffle.
I will admit here and now that speakerbox design is not my thing, I just try some things.
Others are much better at that.
But I do know now that an OB design is completely different and bit hard to design at all. Still I have found a calculation (a spreadsheet I believe) that gave my OB the OK (yes!!). (url in listing, read on).
Also others pointed me to documents, like Krilli, Scratchy, V-bro. Read the OpenBaffle forum-thread.
Basically, when I see your OB, I have the feeling the baffle is too small, it might need twice the width and should be tilted more. Maybe that is the bass-problem?
I do think the efficiency of the OB is lower than in normal box, but I'm happy with it.
Now, the eminence-alpha-15 is rated 97dB, you use 4 (2 per ch.). If you'd get 93dB per chassis then still ~96dB.
You can get 10-15W into 2 alpha's, which could be OK, but I think baffle is problem. (get some wood out of shop)
An amp9b has more reserve (on 24V, that is) to make them really run, about 24V/6A ps.
If you have amp6b's (TA10=TA2024=~smd TA2020) now, maybe
- input signal weak so amp cannot max out
- input gain on amp set to low for your stuff
- try amp6b or TA10 on them (which one is more sensitive? but 41hz-amp6b is better)
- pre-amp is weak
- run that spreadsheet: http://www.t-linespeakers.org/index.html On bottom, Downloads, line with "17_09_03 Thorsten Loesch Open Baffle Spreadsheet" to check baffle (check it per woofer=alpha)
- I assume you don't use cross-overs = quad amping with line-level filter (active/passive), otherwise the cross-over are no good?
For the other speakers, some more details would be nice to find them on the web (just 'Monacor' aint much).
(you can dump pictures into a public Album on your profile page. log-in and click your name on the top of the page)
If you need more power and the amp to be NOT smd, then an amp10 or amp15 is the next best thing.....but you want 2x4ch....Xpensive.
Both very good and only need a power-toroid.
With AMP-9-BASIC you cannot set the gain, you need the pre-amp to provide adequate signal.
But is very low-cost power (one per 'side'). Both amp9basic and assembled not in stock now...typical.
Don't really know if the speakers influence each other? Not my thing. I only have the woofer as OB.
Test a bit more.
What would really help is to get some serious power for the sub drivers.... The baffle size is OK, I've seen smaller. The trick is not so much in the baffle size itself, it's in making a good balance within all the loss...
The loss caused by roughly 80% of the total driver diameter radiation pattern being dipole. That 20% is the path towards the ear, so NEVER lift the baffle off the floor! This should make a FIRM contact there to ensure the longest waveforms to be able to reach your ears without meeting the back wave. This is why the system works AT ALL. If this path is 'broken' there would be no lower frequencies whatsoever....
Then the trick is to adjust the OB correction filter to the loss in order to make the response curve flat there. This is less hard than you'd think. Usually done by a 6db filter at a really low frequency to start bending the curve more flat, then sometimes followed by another 6db if necessary (depending on the upper crossover frequency, which should be low, preferrably not above 500hz) Then to be followed usually by a 12db filter which is the actual crossover towards the next driver in line.... Here's where most of the sub driver efficiency is wasted, or better said "put to good use". Here's why the next drivers in line should best be lower efficiency unless inevitable, off course this can also be adjusted by driving them active and turning a few volume knobs... But the beauty of a good design is in my opinion by going for the least of adjustments and pulling it off with passive speaker filters, resulting in a simple system that connects to any stereo amplifier with just two wires.... (I can hear a few guys thinking dream on, but hey, this IS possible! ;))
I have noticed that using a passive speaker filter here is actually beneficial due to the resistance of the coils raising the Qts of the driver, which is almost always too low (designed for popular closed or vented speaker systems) Another parameter that is SO unlike all other systems and seems skewed, but logically is not. A lot of guys like to DCX the crap out of an OB to make it flat, this often doesnt work very well due to that. If you understand well what's happening and patch the slight flaws right on the wounds it's way more effective than mopping the blood from the floor, obviously.
Then loss, compensating this well takes two things. A high efficient driver is most important, take two if the listening height allows it. Then power, you can not quickly have too much. A few hundred watts would be most welcome there. This only counts for the subs off course! AMP9-B can do this reasonably well, for me it was satisfying enough in a small room driving two 15" woofers and two QUAD ESL-57 treble panels. It was even very magical and I've had a lot of sound engineers and enthusiast coming over who were more than impressed. So if your budget doesn't allow for more I'd say go for it. It's probably a better choice for your application. Although you might also have great results combining the AMP6 for the high range, they do sound a little more sweet and have a little bit lower noise floor. Adjusting the two to match nicely is easily done by adding a potentiometer on the amplifier inputs.
For the mid and high range it's less important.
Then radiation pattern, a lot of OB diy designs tend to forget high frequencies have a really hard time to crawl their way around objects, hence these drivers tend to beam quite narrow. This can be adressed to bu placing another driver in the back side radiating backwards, and the same dipole radiation pattern will occur! Don't fool yourself in to thinking you can solve this by playing with an opened up tweeter, some have a resonant chamber which can be removed, but it doesn't work really well. These tweeters are designed to operate in a well sealed closed chamber, opening it up completely ruins the efficiency and response curve. Let's say it'll just sound bad....
I'd love to see some more pics of your set up!
I love many of the drivers in the palette of Monacor, but I'm just as curious as FFF to find out which ones you are using?
Good to chime in into thread V.
Just heard that Krilli does very interesting speaker designs too.
SeanC, you do run the OB a couple of feet away from the wall? Helped me too.
And yes, more power always helps of course. How big is the room?
I was only so vague because I did not expect such generous interest in my project. I would be delighted to share more. I must first say that these have been in the making for about three years (mostly alphas, B200, and neo3PDR), but it is only in the last couple of days that I have been truly excited by these. Forum posters talk about been fooled into believing real musicians are in their listening room and before yesterday I never truly experienced that. The two Monacors and some Xover changes made a world of difference. There is nothing drastically wrong with these speakers at the moment but I want to take them further.
Structure
The baffle width is a compromise but worth the theoretical advantages and improved WAF. From the picture you can see the 4" driver is behind the tweeter. I am planning on trimming some metal of the aluminum supports so that the cones can sit between the supports, lining up the acoustical centers, and hopefully resolving supposed diffraction issues.
Drivers
Neo3PDR, tonight replaced the back cup due to the sensitivity loss on the current Xover, and the underdamped issues such as an 8khz notch. I can hear an improvement. I believe this is what Vincent referred to in his above post. Funny coincidence that!
Monacor MS-100CHQ - 4ohm - 90db
http://www.monacor.de/typo3/index.php?id=56&L=1&act=8&act_sub=23&artid=5258&spr=EN&typ=u
Monacor SP-8/150PRO - 8ohm - 93db
http://www.monacor-ost.com/catalogue-product.phtml?id=7376&Comp=0&Hier=6&MainKtg=62&SubKtg=679
Eminence Alpha15s - 8ohm - paralleled to give 4ohm
Xover
The PLLXO changes regularly and as Vincent suggests, for a long time I crossed 67Hz/6db, supposedly reducing some of the open baffle hump this narrow baffle would give the woofers. I am doing something a little different at the moment as shown below. According to MJK, in a non EQ'ed design such as mine, the woofers need to up to 10dbs more sensitive than the mid/tweeters.
As Vincent points out, the balance is the key, and on 31octave test tones, the sound is very close to flat now, with some padding (10K line level) on the upper two drivers (sharing a channel).
Amp6b - 15" LP - 200Hz@12db (might go back to around 67Hz/6db - just worried about propping up the 8" losses).
Amp6b - 8" BP - 200-850@6db
TA10.1 - 4"+Neo3PDR in series (8ohm) HP - 5khz@12db (these have to be padded down with a 10k resistor in line).
Speaker level cap on Neo3PDR - 8khz@6db
Might seem a bit strange at the top but it is working great! No reverse connections made to allow for phase. Not too sure how that works anyway. Amp6b beats my TA10.1 for grunt easily based on it driving my FR125s sealed speakers.
1038103910401041
Room
Speakers are easily moved, usually a meter from the wall if I want a nice listening session, but I have not experimented with this much. The living room is 5x4mtrs with some four DIY fibreglass panels (safely done) to bring down reverberation (brick walls, wood floor, etc.). However, as you may notice in the photo, the fourth wall is nearly all missing extending the room another 4 meters into the extension and open to the rest of the house. Sometimes I place the speakers before the opening giving 5 meters behind the speakers. This is theoretically preferable. That will be the permanent arrangement if I ever get a projector!!!
I see now that the edge of the alpha's are close to the edge of the baffle and you have no sides at all on the baffle.
Truly, I believe that kills the bass, it is just too open.
WAF is a problem?
If you cover the baffle with cloth/wood matching the curtains/floor, does that help? Can you trade her in maybe?
I have my OB's slanted back by about 10-15' and have a triangle of wood from the tip to the baseplate, like in the OB-article. (projects). Also my baffle is wider and I have only 1 woofer in it.
My OB works from 20-200Hz.
I suppose the 4"Neo must be reverse connected? Give it a twist then, to test.
Rest of speakers is more complicated, not sure what to say yet about those.
I see now that the edge of the alpha's are close to the edge of the baffle and you have no sides at all on the baffle.
Truly, I believe that kills the bass, it is just too open.
This is not a problem, there is no real NEED for side flanges. The only thing this changes is the baffle step correction point, which needs to be compensated for anyway. So if you want a slim looking design, the only difference is the OB correction filter needs to work at a higher frequency...
I rather see a problem in the four way set up, and the way the top-midrange driver is mounted. Midrange drivers are hard to implement in an OB system anyway, because they too suffer from bafflestep. You just made it harder on yourself adding those.... You get four baffle step problems, a whole bunch of phase shifts, the crossover matching itself which is already hard....MAN!
If you want to make such an impressive system work well you NEED to measure, get a piece of software like Fuzzmeasure and a dual channel sound card, a Behringer measurement mic and for a reasonably low budget you can analize all such problems and get them by the balls. (or not and discover something will NEVER work, which is also interesting)
Fuzzmeasure can measure a frequency response graph, waterfall (decay), impulse, impedance, phase.... You can even measure thiele and small parameters of drivers with a few tricks....
That was my conclusion also Vbro. I have downloaded a range of software but am looking at getting the hardware on the cheap, phantom power to an "Omnidirectional Back Electret Condenser Microphone Cartridge" as per SL uses. I may have to get something ready made if that proves too difficult for me although the link below looks promising. I'll just need to mod for mono rather than stereo somehow? I'll try asking the seller.
http://www.felmicamps.co.uk/products/diystereomicroph.html
http://www.panasonic.com/industrial/components/pdf/em06_wm61_a_b_dne.pdf
Mind you, despite the blind design, it sounds awesome already through an AV recevier as preamp!!! When I said "muddy" bass, that was been picky. Another reason I am committed is that for a long time I had the same alphas, B200, Neo3PDR set-up as others, which is well regarded. It does not come close to what I am listening to now, so the Monacors are staying. Maybe I hit the right formula already, perhaps more by accident, and the measurement system will only confirm that. Wish me luck.
FFF, I have seen similar claims about open baffle 20Hz that on closer inspection have proven to be distortion from 40Hz tones and other such issues. Such people then put a high pass on their woofers at about 40Hz. I have resolved myself to going without sub-bass, despite loving my movies, and I think the neighbours will thank me for it. I rewatched Batman on blu-ray the other day and the minigun sounds incredible like it did when I heard it at the cinema.
Vbro, this speaker is part inspired by StigErik with his no baffle mid/tweeter, and more recently JohnKs passive NaoNote, which is very close to my arrangement. I would like to know what you mean by a problem with "the way the top-midrange driver is mounted". Is it the lack of a baffle. For example, I thought I was simplifying my life by reducing the BSC requirements, i.e. narrower baffle, less high frequency reflections to pad down with a filter!? A more elegant mechanical rather than electrical solution is it not?
I meant that it gets the 20-200Hz part, not that it can actually do it, can test it some day, I suppose.
In that calculation (any good? it does NOT take a given efficiency into consideration.):
When I change the baffle-width to mine (80cm+2x15cm sides=110cm), response goes up 3dB.
However, my cheap speaker-OB with Vas=700L seems to get better results than an Alpha.....twice as expensive.
2x Alpha are about the same, but 4x the total cost. funny.
FFF, I was reading a description of your system the other day somewhere. Was it even on this forum I'm wondering. I look at DIYAudio a lot. What woofer are you using? What part of the result is superior? Is it the low frequency extension?
This:
http://www.41hz.com/forums/content.php?243-Open-Baffle
and this:
http://www.41hz.com/forums/showthread.php?2308-Active-open-baffle-speakers&highlight=open+baffle
Too much hassle on diyaudio.com, 100's of opinions don't really help.....
Sound is open, strong, fullfilling, good belly-lows
Superior: bloody cheap.
Speaker (UK): http://www2.conrad-uk.com/goto.php?artikel=329479
Just hit me: my baffle size = 80x120cm =8:12 =4:6 or 2:3 = 'golden cut' ?
And it is slanted back such, that the base plate is 40cm deep: 40x80x120= 1:2:3
Might be just, by accident, be the perfect size ;)
With the perfect speaker.
Measuring with an 'unknown' or better said uncalibrated microphone is fairly pointless, you can never be certain if you are adjusting your system to false data then....
There is a plugin for Fuzzmeasure to have the whole measurement system calibrated to the Behringer measurement mic. Why make it hard on yourself for a few tenners?
The lack of baffle is a step too far. There was a whole article about this in the German magazine K&T which described a breathtaking looking speaker on the front of the magazine, but reading through the pages which described the design it became clear that this doesn't really work. It's like making a saloon table with just two legs.... If there is no output left whatsoever there's nothing possible any more with compensation....
http://www.visaton.de/vb/attachment.php?attachmentid=5765&d=1270584531 http://www.audio-direkt.de/Webshop/shop/images/kut1003.jpg
What FFF mentioned is partly true, the larger you make the baffle the less compensation is necessary. It's a trade off between looks and practicality. When there is the possibility the ideal open baffle would be to have speakers built in to the wall, with the back side still open towards another infinitely large space/room. This would mean you need NO compensation whatsoever...
This is just theory, because in practise the magic evolves much from the back wave, so we don't actually want that fully eliminated. Bottom line is that there is quite a big margin for the baffle size, when you go by the gut feeling the baffle size is almost always well within the region of compensatability....
Those speakers look almost like Gradient's Helsinki speakers: http://www.gradient.fi/models/helsinki
But Gradient's speakers do work, they do have baffles...
I saw those before, but then not with the glass bit I believe....
It seems he's made a reasoning error there, usually low frequencies radiate in a circular pattern all the way around a speaker box, but with a dipole there is almost no output towards the sides. This system would strongly depends on room reflections to have some kind of low frequency response... Which is not really gonna work out...
Seems like the next in the line of speakers where the eye wanted more than the ear....
I would really like to do some measurements. I am going crazy playing endlessly with xovers. Vbro, I assume you mean the Behringer ECM8000 mic, about £38 here. I'm betting the soundcard is not cheap. Any specific recommendations for sound-cards or whatever will connect the mic to my imac please?
Is Fuzzmeasure worth the paying for rather than the free REW?
Regarding the baffle, theoretically, for ideal polar response, my baffles are TOO BIG for the 8" and the Neo3, been more than the 2.2 times wider than the driver radiation area. The The acoustic xovers are targeted to avoid the dipole peak, thereby avoiding filters to resolve that issue. Then again I am mostly spouting theories I only half understand!!!
Thats the mic... We used an Alesis dual channel I/O sound card for the Megamini measurements, its a great quality:
http://www.inta-audio.com/b-stock-c234/alesis-io-2-usb-sound-card-b-stock-p2516 You need the I/O function to be able to output the test tone and input the measurement with the mic simultaneously....
I am not sure if the Fuzzmeasure version was shareware or paid for or cracked. I have a friend and he had it on his Apple laptop. I don't have an Apple system myself, sadly Fuzzmeasure only runs on Apple...:( But if you have an Imac, you're good to go!
2.2 times driver radiation area, LOL. There are PA midrange drivers covering the same frequency area as tiny hifi drivers... This is not precise at all. What works is to calculate the wavelength of the lowest frequencies to play... Or use the software "The Edge"...
I don't want to pretend I have built dozens of Open Baffle speakers, I too run down the lane of experimenting with it. But I did learn you get nowhere without measuring to test whether your ideas match with reality. The whole trial and error method with measuring is so much more effective! I can understand you getting tired of experimenting!
I see the 2010 model drops the SPDIF and goes a bit cheaper for 80£, but goes at Maplin, delivery only, for £60inc del (damn, price went up again, must have been a mistake);
Alesis iO2 Express 24-Bit USB Recording Interface
http://www.maplin.co.uk/Module.aspx?ModuleNo=506557
So, £60 soundcard+£38 mic, cost of software, some cables. Not cheap but tempting, especially if I ever got something like Minidsp xovers, and then I could room eq.
Euhh, SeanC,
You said in a post here that it -does- already sound awesome, do you need assurance about it or do you want to tweak it to absolute perfection? Which seems hard with the OB, especially if the OB will not be in the perfect position at -all- times.
And no furniture close to it, ever.
Some power-reserve seems to be nice, so we already concluded that an amp-9-basic per OB would be best and convenient. (you could wait till assembled ones are available in shop again if you want easy-peasy too)
For filters, you can make an active filter board with some opamps and tweak that.
For levels, a pot per amp-channel will do.
You only need to decide what the frequency range will be for each speaker with some test-tones maybe.
Otherwise, this can all be very time-consuming and Xpensive.
That's why I keep it simple: an OB for 20-200Hz and the 2way Magnat-100 for 200Hz and up. Pretty good.
Active filter is 18 or 24dB @ 200Hz and a 12dB filter in that Magnat.
Maybe I or V-bro can run some tests on our OB's with diff. amps at diff. supply voltages?
Or other tests that will help/support you?
Very kind offer FFF.
You read my mind. It does sound great, and thinking aloud in this thread has helped me appreciate the faults in my xovers. I will hold off on measuring equipment and put my money towards the amp9bs (pre-assembled). In the end I realised the glaring errors yesterday and a final fiddle fixed these speakers;
- low bass (around 150Hz) was too boomy, voices were coming from the alphas 2Khz peak, and a 67hz/12db LP returned a clean sound.
- Neo3PDR open baffled lost too much sensitivity when running off the same padded PLL LP as the 4".
- 4" was crossed crazy high to pad it down, but a 21k resistor on the PLLXO padded it down which allowed a return to a sensible 1300hz@12db HP.
Somehow these xover points and the padding were in the original plan, were tried days ago, did not work, but on return something was different and now it is perfect. Maybe returning the Neo3PDR to monopole contributed, but I think the 200Hz/12db LP on the 15's was responsible for a lot of my woes.
I found leonardaudio.com last week and wish I'd seen it years ago. Very easy to understand, and summarises the info I spent years slowly piecing together from other sources (go to "subject index" for lots of great topics).
http://www.lenardaudio.com/education/06_x-over.html
As you say FFF, who cares? It sounds great on music, and flat on my test tones track, so that is enough of a measure for now without bleeding more money in to this hobby. When I started a few years ago I put an FR125s onto a small pine open baffle and blindly thought that would be the end of it.
Thanks the Vbro and FFF for your help. A couple of amp9bs are next, perhaps some NTE-4s, and a 24V smps or a toroid if I feel brave playing with high voltages.
It is not so much the frequency response I am worried about, because if it was only that then speaker designing would be a laugh. It's phase shifts and bafflestep I am MUCH more worried about. The hardest part is they all influence each other, so what you think you hear, symptoms may have a whole other cause or come from a totally different disease than the obvious. This is where measurement systems make achieving perfection SO much easier, without it it is doubtfull you'll ever achieve perfection at all. Most often you don't even come that close and the fatigue, dried up budgets and WAF (!) call a halt to projects, drain the fun out of it and you might never make an attempt any more after a while. That's how projects remain unfinished....
You are LUCKY you already have the Apple, and off cheap compared to having to buy one on top of it. Then simple measurement systems that could only do FR and impedance used to cost €10.000+ back in the 80-ties and early 90-ties..... THIS IS DAMN CHEAP!!!
You have a point Vbro. I have not heard speakers better than my own so I do not know what is possible. The computer might be smarter than me in that respect. This free software works on mac and PC and is very popular (Room Equalization Wizard). It also has ECM8000 calibration files.
http://www.hometheatershack.com/forums/REWv5_Beta/
Another thing that put me off was the thought of having to learn to use the software, measuring technique and all that, but thinking about it now, using it may help me understand the principles better. I will persevere with the measuring route in time.
Update; I watched a couple of movies this evening, and I think I am hearing phase cancellation. Whatever it is, it is wrong. I'll have to get serious about measuring or go back to the 3-way.
Get the measurement system, measure each driver individually and then the whole system and you should know pretty well what to do....
I'm afraid a three way system has advantages, as a matter of fact if a two way system can cut it I would recommend that. You see, it is not my intention to give you the impression the system will ever be 100% perfect. There will always be compromises. The more drivers you pull out of the hat in a system the more problems will arise to be dealt with and there is no way you will be able to address them all. Perhaps when you're lucky. Like when the chosen drivers will have natural phase alignment. But this is an illusion, because this will only be at one point and away from this axis there will still be phase differences.
Now there is a lot possible, and I previously mentioned the word perfection and I meant nothing other than the design quality. Perfection in terms of having made the best compromises.
Well, I'm sure you'll discover a lot of new things when you're able to measure...
Hi, just checking out amp6 sneaky from the shop.
About the power supply I'm going to use a smps mean well, with an adjustable voltage, so if use the 12v version can go up to 13,6 and if I get the 15v version can go down a bit to 14,2v. My question is, these meanwells have various ranges of amperage in the same voltage. What is the recommended amperage? What happens if it's a 12v 8,5A or 12,5A? Will that burn the amp? Sorry I'm not engineer, and my physic basic studies at school are "to far away to remember":p
Thanks.
V-bro: I'm going to do the amp6 basic, maybe later I'll take the challenge to do amp1. I need also a more powerful amp as I sold my tk2050 amp board, didn't like it much, a bit dull.
I was thinking of the nes-100-12 or eaven the nes-100-15. They are 8,5Amperes and 7A respectively. There are very convinient because they have 2 inputs and I need to share the smsp with a preamplifier.
http://www.meanwell.com/search/NES-100/NES-100-spec.pdf
Which do you think, if possible, is more suitable to get the maximum power of amp6?
A TK2050 amp sounding dull??!?? Well, I gotta hand it to you, my brother bought a Muse TK2050 amp that I can't get used to either, maybe due to the digital volume control or tone controls, but it sounds quite horrible!!!
I can assure you that AMP4 or AMP11 are way beyond that and sound nothing short of breathtaking!
A TK2050 amp sounding dull??!?? Well, I gotta hand it to you, my brother bought a Muse TK2050 amp that I can't get used to either, maybe due to the digital volume control or tone controls, but it sounds quite horrible!!!
I can assure you that AMP4 or AMP11 are way beyond that and sound nothing short of breathtaking!
Do you know about the amperage smps that is necessary for amp6? Those mean well with 8,5 or 7 amps is ok?
Hi, just checking out amp6 sneaky from the shop.
About the power supply I'm going to use a smps mean well, with an adjustable voltage, so if use the 12v version can go up to 13,6 and if I get the 15v version can go down a bit to 14,2v. My question is, these meanwells have various ranges of amperage in the same voltage. What is the recommended amperage? What happens if it's a 12v 8,5A or 12,5A? Will that burn the amp? Sorry I'm not engineer, and my physic basic studies at school are "to far away to remember":p
Thanks.
3-4A is more than enough for the AMP6 - 12Vx3A= 36W
This amp is only rated for 25W output at 12V, so you will have plenting of breathing room with one of these.
And there's no risk of burning an amplifier with a too powerful power supply: the amp draws power, the power supply does not push it into the amp. So no problems as long the input voltage is within the limits.
Sorry guys, the more I continue with building the amp the more questions I have.
Related to the power supply, the mean well I mentioned has 2 channel output, so I could feed both the amp and the preamp from the SMPS. I mean that there is v+ v+ and v- v- at 12v and 8,5 amperes each.
If I use a single SMPS with only one output in 12V, can I wire the two boards into the same v+ and v-?
Thanks for your kind help, and for the other replies.
I promise some pictures of the boombox I'm doeing.
John
This is a single output PS. It's output is a max of 8.5A, regardless of how many output terminals it has.
They are all fed from the same source.As for feeding a preamp from the same source, that depends entirely on the type of preamp you have and it's voltage requirements. This PS has plently of power to run both, if that's what you're asking.
I can't really see what you are building from over here..... ;)
Hi, first thanks.
Secondly, I'm doeing a boombox if that is what is called. For the boombox I'm using a pair of bandor loudspeakers miniatures. Also a preamp and the 41hz amp6. Everything ordered and on it's way to Spain and hopely by the end of this week.
The only part I haven't ordered yet is the power supply, and I prefer it in the same box, not an external one like many people do. Is just a matter of more comfortable to carry the boombox.
The preamp and the amp can be fed with the same voltage up to 14v max.
The thing is I have a space limitation, I would like to keep it as small as possible.
The meanwell nes 100 I linked before is a 12V dc smps, and it has 2 terminals for the outputs. There are also other smps like this one wich is 12v and 4A with only one Output like his meanwell NES 50 12 http://www.meanwell.com/search/NES-50/NES-50-spec.pdf it only has 5 screws. 2 for the ac mains, 1 for the ground and 2 for the output V- V+
Where as the NES 100 12 has 7 screws. The sama as before but the 2 extras are another V- V+ http://www.meanwell.com/search/NES-100/NES-100-spec.pdf
I was just wondering if the NES 50 12 i could use the two screws V-V+ to feed the amp6 and preamp. The advantage of the nes 50 12 is that is more compact.
Also I've seen this one but not very sure if this is only for batteries: http://www.meanwelldirect.co.uk/public/ranges/pdfs/r1332/r1332_3.pdf
Thanks for the help
John
You are better off with the nes 50 12 in this case.
As mentioned, there number of terminals has no bearing on the output power of the amp.
The nes 100 just added 2 more output terminals in parallel to the existing output (V+ & V-).
You can quite easily run both amp and pre-amp off one set of terminals, and the nes 50 has plenty of power for this application.
Powered by vBulletin® Version 4.2.0 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.