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

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MarkB1

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Joined 2005
IanAS said:
Though my PC (that operates my sound card) uses a Seasonic X400 SMPS and still benefits massively from a 10mm2 mains cable to the super spur and also from the PC chassis being tied separately to a good earth, and I care not a rats a*se biscuit for the BS from those people with no experience who choose to follow the figments of their imagination and talk down to, rather that take notice of, the practical realities that many many experienced people know so well.
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IanAS said:
I ran out of editing time. That last sentence is aimed squarely at the noobs who, with nil idea what they're talking about, slag off big mains supplies and in parallel condescend to a whole lot of people who are more knowledgeable and possibly more capable.
/rant
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Never been more proud to be a "noob" in my life. :p
 
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IanAS

Member
Joined 2004
AP2 said:
www.audiopower.it/datasheet/DPS500-52_EN1_5.pdf

i'm sorry, but not know a smps for 4 class A-B amp or 8.(for audiophile use)
know a dedicate version dps-600 for good mono-block.
Or dps-500/S for an amp with 4 devices mosfet per rail on 3R load (full range) instead of 5Kg of trafo.
But if i find better or big (one smps for two big amps), then inform you.

Regards
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Thanks :)

So this was designed for a class D amplifier and has been 'pressed into service' for this class A/B? But it needs a bit of further development to make it fully compatible with versions with more output devices?
 
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pieter t

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tribute-audio.nl
exp4nder said:
Owen, can you please clarify the reason for the removal of the temperature compensation network (that is present in the datasheet) ? Will it not be unstable without it? Excuse me if i am wrong, i haven't read many data...
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If you allow me to answer (but Owen will confirm I guess): the Wire Amp output stage has fets; the compensation network can be important when the output stage has BJT's which can be sensitive to current drift when getting too hot. Fets do not have these problems.
 
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IanAS

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Joined 2004
AP2 said:
Not is important how many devices you have.
tell me total bias current per rail and output current (vs. load) you need.
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Bias is related to number of devices. From what Owen measured I'm guessing it would be 720mA bias for 4 pairs of devices. Though we use less, only 400mA for 4 pairs and about ±90V rails for the MOSFETs and my Meridian 605 amps use only 240mA for three pairs and are ±63V so one of your SMPS would go OK in those M605 or if I 'cloned' them.

I'm not sure how to suggest an output current requirement. My pals Tannoy D700's apparently drop to 2 Ohms at places but are generally higher and about 93dB. A 6 or 8 MOSFET 300W/Channel Perreaux amplifier gripped those adequately, a similar amp did mine also. It's not about the wattage, just low volume the benefit of that hulking brute is obvious. He's now using an Audia Flight 50W / channel Class A which also grips them. My larger speakers are about 6 Ohms and about 87dB. The lower the impedance the amp's PSU, output stage, mains supply, the more grip, slam, focus, clarity, imaging the speakers deliver.

In the data sheet it's mentioned the SMPS beats 47,000uF of caps. But caps are day and night apart for the same value. The Elna Standard vs. the Nichicon GS grade 4 are a world apart of bass depth, loudness, grip and slam and also superb vocal clarity. 40,000uF of the former are insipid and weak and of the latter, mighty. Which type did your SMPS beat?

Thanks :)
 
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AP2

Banned
Joined 2009
IanAS said:
Bias is related to number of devices. From what Owen measured I'm guessing it would be 720mA bias for 4 pairs of devices. Though we use less, only 400mA for 4 pairs and about ±90V rails for the MOSFETs and my Meridian 605 amps use only 240mA for three pairs and are ±63V so one of your SMPS would go OK in those M605 or if I 'cloned' them.

I'm not sure how to suggest an output current requirement. My pals Tanoy D7's apparently drop to 2 Ohms at places but are generally higher and about 93dB. A 6 or 8 MOSFET 300W/Channel Perreax amplifier gripped those adequately, mine also. It's not about the wattage, just low volume the benefit of that hulking brute is obvious. My larger speakers are about 6 Ohms and about 87dB. The lower the impedance the amp's PSU, output stage, mains supply, the more 'grip and wallop' the speakers deliver.
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has already used a DPS-500 / S for this type of mosAmp (8 mosfets). up to 800mA bias,limited at + /-68V 20Amp repetitive peak. yes just brute fast..but one per amp.
 
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hochopeper

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IanAS

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The current flows from one rail, through a N channel, through a P channel, to the other rail. That's one pair.

These double die Alfets have two dies in parallel in each. So two Alfets is two pairs.

One Alfet on it's own is no pairs, just two half's.

Each pair needs at least 80mA. Each die in each Alfet needs that minimum of 80mA.

I don't really recall, but I think Owen said 360mA for the working amplifier. That would be 180mA per pair, ie, 180mA for one die in each Alfet 'pair' and 180mA for the other die in each 'pair'.

That's as clear as mud! But the best I can do :)
 
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back

Member
Joined 2005
IanAS said:
The current flows from one rail, through a N channel, through a P channel, to the other rail. That's one pair.

These double die Alfets have two dies in parallel in each. So two Alfets is two pairs.

One Alfet on it's own is no pairs, just two half's.

Each pair needs at least 80mA. Each die in each Alfet needs that minimum of 80mA.

I don't really recall, but I think Owen said 360mA for the working amplifier. That would be 180mA per pair, ie, 180mA for one die in each Alfet 'pair' and 180mA for the other die in each 'pair'.

That's as clear as mud! But the best I can do :)
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it`s ok.

i understand now but i didn`t know those are double.
 
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IanAS

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Joined 2004
AP2 said:
has already used a DPS-500 / S for this type of mosAmp (8 mosfets). up to 800mA bias,limited at + /-68V 20Amp repetitive peak. yes just brute fast..but one per amp.
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:)

With ±68 we might run into clipping with friends with bigger low efficiency speakers in their soundproofed listening rooms but for my other pals and myself that might do (in a mono block driving a passive crossover) as these days I have keep the volume down a bit. If I get the active cross over sorted then I'd have to get another pair of SMPS I guess.

± 85 would be better though. Is that too much?
 
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back

Member
Joined 2005
IanAS said:
:)

With ±68 we might run into clipping with friends with bigger low efficiency speakers in their soundproofed listening rooms but for my other pals and myself that might do (in a mono block driving a passive crossover) as these days I have keep the volume down a bit. If I get the active cross over sorted then I'd have to get another pair of SMPS I guess.

± 85 would be better though. Is that too much?
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at 85volt you will run out of current at lower loads.

do you plan to add extra alfets?
 
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AP2

Banned
Joined 2009
I think is better that you know well this smps,or ask table of voltage/power output
dps-500/S decrease 3V @750w(burst). not 15V
at 80V (3R) repetitive peak is 2kw.
at 68V (8R nominal) you have 750w (just when you up volume and is clean. (i suppose load decrease 3,2R with audio enveelope) tannoy or B&W or sonus faber..think other good full-range.
 
qusp

qusp

Member
Joined 2009
uh oh, IanAS has started talking like the borg again, enlisting the weight of so many audiophiles behind his voice. me, i just have this one and this experience rather than many in parallel

also rather happy at this point to be noob

reads like we are all of a sudden talking about a different amp in this thread
 
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