"The Wire AMP" Class A/AB Power Amplifier based on the LME49830 with Lateral Mosfets

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A

AP2

Banned
Joined 2009
IanAS said:
When you say 'on load' do you mean quiescent current or full power into 8 Ohms? My pal, below, gets very little rail drop at full power, IIRC he say maybe 1 volt, which would appear to be better than these SMPS are doing at much less power. And his 300Watt mono blocks make about 1000W into 2 ohms continuous using sine wave with no visible clipping. Mine should be bit better as he has 750VA toroids from the same people at the same time that I got the similar spec 1000VA made by and I'll have a bit more capacitance. I like the idea of the 'regulated' rails with this SMPS but I think I'll need a bigger one?

±55V equates to not much power for a mosfet amp. My bipolar amp is only about 100W with it's ±50V rails.

That's OK if you have efficient enough speakers, but I don't. My Hafler might be making perhaps 220W or so (RMS per channel into 8 Ohms) and the VU meter someone gave me flashes it's 200Watt light from time to time without the music seeming particularly loud. Maybe it's faulty, I don't know. But a pal with similar speakers made his own VU and that indicated upper power (about 220Watts) nearly all the time at normal listening level in his sound proofed and well damped room from a beefier and better amp he made that was similar to that Hafler. He went up to 300Watts after that with the same boards and two more mosfets, but two bigger Tx instead of the one, and the transient response was far better.
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all of us have been through this speech, about how much current is required in your case. when you say that you need 80V and have measured a decrease of only 1V under load with your transformer. This means that you need to 1500w (dissipation on the load). calculate you please.
How about having a reactive load heavy, assumed min. 3.2 R.
The reality is very different in my opinion.
A measure with dynamic load .. no? please show.
I do not want this thread to focus on a debate that has been widely addressed.
two words only.
@ 230Vac a DPS-500 / S at + /-68V allows my mosfet Amp (4 mosfets per side) to deliver at 1kHz 450W (4R) 400W (4R) at 120Hz; 750w (2R) 1kHz.
these data are simply demonstrable. now, you calculate, how much power (or what would happen), at 80V


regards
 
A

AP2

Banned
Joined 2009
IanAS said:
Thanks AP2, so the DPS-500 is what I'd need for the 'medium' power amps, not the DPS-600.

They'd be better than the Meridian 605s as they are ±63 rails rated as 150W. I'm perhaps asking too much of those amps really for louder listening with these speakers.
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Hi, sorry for simple...old concept explanation.

In an active system (multi-way) is cheaper and easier to decide the powers involved in the design of the amp / psu.
In systems with passive crossover (I am referring to the high-end of course), the design of the amplifier should be sized (and consequently the psu) referring always to the lowest load, 2R or less. (independant that we think not use)
This is the first reason for the trade price higher.
Continuing with this philosophy (used by old), and in case of smps with fast transient response, there is a new problem to be solved, which does not have a linear psu in case of overload.
(An audiophile perfectly perceives the inadequacy of current (voltage drop effect in the audio and does not want this).

When happens the overload?

Always when listening with passive crossover, ( impedance changes with the sound envelope)

well, this is to say that the DPS-500 has been developed to ensure performance in the range of 800w but that does not means two 400w amps each, except that the system is a multi-way active.
 
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lolo

lolo

Member
Joined 2010
AP2 said:
I'd be curious to know what happened to everyone else with the DPS-600 GB
...I hope it went well.

For additional filtering capabilities, 5000uF per side is the maximum stated on the datasheet,
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Nothing happened on my side unfortunately. It's not the lack of enthusiasm but too many personal problems since last year (car, wife, house, family, you can name them all..) :eek:
Still hopping to start building in a month or so, however I am planning on changing job "soon", so.. :(

I believe I also asked for the added cap bank, which did not come.. never mind.
 
A

AP2

Banned
Joined 2009
lolo said:
Nothing happened on my side unfortunately. It's not the lack of enthusiasm but too many personal problems since last year (car, wife, house, family, you can name them all..) :eek:
Still hopping to start building in a month or so, however I am planning on changing job "soon", so.. :(

I believe I also asked for the added cap bank, which did not come.. never mind.
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Hello Lolo..I'm sorry that you have some problems, but these days, who does not?
Regarding the additional capabilities, I have not received your request or you sent to my old email?
@ moderators:
how can I replace my personal email linked to the forum?

Regards
 
M

multisync

Member
Joined 2008
I made the SE version and used a low pass on the input and mounted a zobel on the output on the binding posts. The amplifier has a wide bandwidth and amplified what looked like the carrier of an AM radio station as seen on the scope as well as amplifying noise from CFL lamps. I used 60khz for the low pass and 10ohm and .1uf for the zobel
 
R

Robert F

Member
Joined 2005
multisync said:
I made the SE version and used a low pass on the input and mounted a zobel on the output on the binding posts. The amplifier has a wide bandwidth and amplified what looked like the carrier of an AM radio station as seen on the scope as well as amplifying noise from CFL lamps. I used 60khz for the low pass and 10ohm and .1uf for the zobel
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Thanks, I was delaying putting mine on the 'scope until I was ready to play with the feedback cap etc. Mine is SE in too but I have used the values for balanced and shorted the - input at the phono socket so that I can convert to balanced in without having to take the board out. Did you insert the cap for the low pass across the phono socket or elsewhere?
 
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BiswajitKundu2007

Member
Joined 2013
Dear All,
Any body can help me that i'm using the LME49830 and MOSFET IRFP240/IRFP9240 for amplifier, so I want to protect the MOSFET pair as well as speaker without using Zener diode. Bcz when I using zener diode at Gate and Source at MOSFET pair I see that when playing a high peak music frequently very large current draw from power supply and distorted the sound quality, I selected the Gain 28.9dB and power supply +/-55V, speaker load 8E/15W.
 
opc

opc

Member
Joined 2004
Paid Member
Hi Back,

I'm a little confused... the back of the IC is indeed tied to V-, so you should be reading 0 ohms between the back of the IC and the V- pin. What you want to make sure of is that the back of the IC (V-) is not in any way making electrical contact with the heatsink itself, which is at GND potential once soldered to the board.

You may need to scrape some of the oxide coating off the sink to get a good reading, but you definitely want to measure infinite resistance between the pad of the IC and the heatsink.

Have you already soldered the IC into the board?

Cheers,
Owen
 
B

back

Member
Joined 2005
hi owen
yeap i soldered it.i have open circuit between heatsink (or gnd) and v-.but if i reverse the probes and put the black at v- and red at gnd then i have a reading of 650ohm with nothing else on the board.is it normal?
i guess it is and i measure the inside resistance of the chip between gnd and -v.
 
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