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Old 7th October 2009, 07:04 PM   #11
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Default No problem dear Ostry.... we use, down here, in brazil to enlarge specifications

It is possible that monster burns...you just point something possible...and you got the Brazilian spirit man.

Here..everything is enlarged...specifications here are peak, IHF, instantaneous, not continuous and those things..for sure they are this way....eheheheheh

regards,

Carlos
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Old 7th October 2009, 10:35 PM   #12
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Default This circuit will be tested tomorrow.... the supply voltage is more realistic

as my supply will drop to 82 volts under load.

I am using the Dx Standard schematic, to use the same board..this will turn more simple to builders..no special board.

Power now will drop to 340 watts into 8 ohms, and this is more reasonable to use 4 transistors...this will be more safe.... if people want more power, then include the fourth power transistor and connect 4 ohms speakers.

The input filter is in place...passive filter.... -3dB at 400 hertz..no losses into 5 hertz.

Sensitivity was adjusted and condensers are also more realistic, to save some money, and to reduce condensers size.

This gonna be tested tomorrow...wish me luck.

regards,

Carlos
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Old 8th October 2009, 12:08 AM   #13
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That looks interesting Carlos - I will certainly follow this tread closely.

Given the design parameters you described, it seems you are on the verge of creating the DXzilla - a monster that will smoke lots of Brazilian drivers.
This will certainly resonate with the "powerholics" as you call them.

I have never seen that driver you showed on the first posts - I remember Novik, Bravox and Selenium (the last two are still in business).
Please keep in mind that most drivers (I am aware of) available in Brazil are very inefficient just like most drivers intended for the MI guys (cheap and inefficient by design).

As for the components your friends sent me (to deliver to you)... I hope I can manage time to spend a couple of peaceful weeks in Brazil in the very near future.
That will be after a coordination meeting in Korea (for a project in Libya of all places) towards the end of this month.

Be well and get on with it!
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Old 8th October 2009, 06:58 AM   #14
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Default Yep... they like power, and i like to see them building and listening amplifiers...

and when build mine ones i feel even more happy..that feeling we have about "contributing to mankind"....doing something better than earn money only... feeding my big belly with food that we buy with money.... i am trying to feed my spirit, to become a better person.

They are very uneficient, yes, you have agreement Duda...not good alike US and UK drivers...ours is hard to move, have small compliance, heavy coils..and all that stuff is bad for our ears, results bad..... they make the driver tolerate power just turning them hard to move, and thick wire to the coils.... alike to make a car resistant, bullet proof, with thick armour, and then the car does not move, not power enougth to be fast and acelerate... this is the way they are building speakers, alike armoured vehicles...and they are doing this way because market is asking for that kind of stuff, to install in automobiles and with kilowatt amplifier (class D), they go pumping bass around.

The idea Duda, as i told you before, some monthes ago, and you agreed, is that we will have easy balance of bass, mids and treble...this will allow us to have better sound when we have not anecoic room and nor special microphones, also no spectrum analiser to check and equalize our speakers considering our rooms... this way, three knobs may do the job, and, building those amplifier with the same proportion of tones we have in normal music, we can set them same position to have a reference of what may be (more or less) the flat reproduction (not considering room acoustics and speakers..electricaly flat beeing considered the proportion, the ratio of tones that use to be 60 percent for basses, 30 percent for mids and 10 percent for treble).

Another advantage is that sending more simple waveform to the amplifier, or less complex waveform, the audio became better..speakers does not to have to follow complex movements, sometimes receiving "order" from the power amplifier to move forward to the bass while moving backwards for the treble tone.... not having too many frequencies to beat one each other, we will have better performance related harmonics and harmonic distortion.... we know, that simple orchestrations, not dense, not filled with several instruments and several singers same time, sounds much better to amplifiers...or they reproduce better...this is the point.

Other advantage that makes sound better is that you gonna be rid of passive crossover to the speakers, the filters, the ones we call in Brasil as "frequency dividers"...those inductors, resistances and capacitors that turns amplifier unstable...those things are not more used.

I love the passive filter, they are less precise and distorts more than active, but cheap and easy to make...for the future i will make them active too.... this way, to the amplifiers goes the frequency they are expecting to receive into their input... amplifier goes filtered to high frequency into the input, output and feedback line, avoiding high frequencies if they are not made to reproduce highs...this turns the unit safe.... against oscilations.... a slowered down amplifier..not needing to be fast as will reproduce only 1 to 300 hertz or a little bit more than that (bass unit).

I have found, building things in my home..that we have a lot of interaction into the supplies... each channel must have independent supplies, as noises and fluctuations of voltage goes messing the sound...so, this turns a little bit complex as supplies must be many...to a stereo TriAmp you gonna need 6 power transformers.... and i found that transformers with double output is no good too..the winding interact and core saturations are a problem too..so...there's a chance to folks to use all that junk of transformers they have...put them to work folks!... also use that buch of condensers you have collected througth the years, as those ones are doing anything , just laying down and scratching one against the others inside your junk box.

I am listening huge advantage into the quality..audio quality became better while using my BiAmp... and i hope the TriAmp will sound even better...i will be rid of some passive filters i am using into the output (mids and highs filter) and will be rid of power supply interations.

I am excited with that, and found that solution listening neighboor that have Panasonic BiAmp systems..they play more clear than others... even having worse circuit than some Sony, worse power amplifier chips and more dense circuit (more stages, a lot of buffers and electronic switches) they are playing even better sound... i have a lot of neighboors with many brands around...and the Panasonic plays better sound..... i think the BiAmp they use (subwoofer speaker, and double power amplifier..one for treble and other for basses).

So... alike the powder without smoke..... not a discovery, just to be attention about what is going on around my home.... the clever folks already have pointed the solution for us..we have just to follow them and do something about.

regards,

Carlos
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File Type: jpg SMD.jpg (499.1 KB, 264 views)
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Old 8th October 2009, 07:26 AM   #15
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Default Thank you, Greg Erskine (Gerskine at our forum) by your kind cooperation

Board was made by Greg.

I have installed the output transistors bellow the board, attached to the heatsink and connected to the board using 2 inches long wires... non parallel wires.

regards,

Carlos
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Old 8th October 2009, 02:40 PM   #16
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Default Simulator and real life is really different

The amplifier gave me a bad time.... i had to tweak a lot to make it work, a lot of changes were made..then i felt it ugly, too much hot (small Heatsink) and i decide to make another one to use 62 plus 62 (non loaded voltage).

Tomorrow i will listen this one..the other was not fine...supply droping a lot...no good supply, also i had not condensers enougth and this resulted that supply was not filtered in a decent way...well....no way to do that one with this transformer and without big condensers to 100 volts....for a while, lets go with lower power.

regards,

Carlos
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Old 8th October 2009, 04:40 PM   #17
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Quote:
I have never seen that driver you showed on the first posts - I remember Novik, Bravox and Selenium (the last two are still in business).
Please keep in mind that most drivers (I am aware of) available in Brazil are very inefficient just like most drivers intended for the MI guys (cheap and inefficient by design).
97dB sound efficient to me. The RMS rating on that driver is shown as 250W and the peak power is shown as 500W. Here is a link to the spec sheet.

http://www.oversound.com.br/index.ph...t=126&pro=3372
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Old 8th October 2009, 05:09 PM   #18
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Quote:
Originally Posted by Steve Dunlap View Post
97dB sound efficient to me. The RMS rating on that driver is shown as 250W and the peak power is shown as 500W. Here is a link to the spec sheet.

http://www.oversound.com.br/index.ph...t=126&pro=3372
Thanks Steve - I never heard of this manufacturer before...
Based on my experience with speaker manufacturers in Brazil for the last 20+ years, I have a hard time to believe the published specs.
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Old 8th October 2009, 05:46 PM   #19
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I didn't say I believed them. I just posted the link.
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Old 8th October 2009, 05:58 PM   #20
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Quote:
Originally Posted by dudaindc View Post
Based on my experience with speaker manufacturers in Brazil for the last 20+ years, I have a hard time to believe the published specs.
It's common practice for all manufacturers to use average SPL over the whole "ueasble" range for SPL 1M/1W. That includes the breakup peaks, which can be +10dB. Half-space reference sensitivity is easily calculated from T/S paramteters, and usually ends up some 3dB down from what's claimed based on average. It's probably about 94 dB, the same as similar drivers.

Some of the junk they put in "white van DJ speakers" can be really low efficiency - 88dB or even less and can have Qts over 1.0. Most of them are made in China. They also can be had for $20 for a 15" (so if you blow it it's no big loss). The ones Carlos is using aren't that bad - they're something like an Eminence Beta 15 or a bit up from that.
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