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[Gallium Nitride amplifier] Impressions of the Mini Gan 5 by Premium Audio, pictures / video inside

Doodski

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daniboun

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That's a impressive and comprehensive list. Did you make that?

It comes from ASR. I got it from a thread. super useful anyway :)
 

MaxBuck

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No. Absolutely incorrect. Transparent means you can see through it. Light. Not sound. Not electricity and certainly not audio equipment. The term is not remotely applicable to HiFi gear and never will be.
I see no reason why "transparency" can't relate to sound equally well as to optics. Transparency is used with respect to communications.
 

pjug

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We want to have as many definitions as we can imagine
1632088236549.png
 

restorer-john

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I see no reason why "transparency" can't relate to sound equally well as to optics.

It can, I'm just being recalcitrant. :)

To me it's just a lazy person's adjective used in a blanket manner with no specifics. Someone declares a DAC "transparent", but that means nothing in reality does it?

If I declare my amplifier "transparent", what does that tell you, specifically? Nothing about its power output into all loads, frequency response, distortion, crosstalk, features, build quality, price, warranty, fit, finish or features.
 

antcollinet

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It is just one element of the description (just as power output doesn't tell you anything about distortion, FR, crosstalk, features - or even transparency :))

It tells you specifically that what appears at the speaker terminals is pretty close to (or audibly exactly) identical (excluding gain) to what you shove up it's jacksie.:D

Just as the light exiting one side of a transparent window is pretty close to (or visually exactly) identical to what goes in the other side. :cool:
 

JuliaCoder

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Is GaN going to become price competitive someday soon or is it something that can't be made cheaper?
 

AudioJester

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If you don't take the full advantage of high switching frequencies (>1MHz), then using GaN FETS will give you no advantage besides a slight efficiency boost, due to lower Rds-on. It will not add more "details" or improve any audio parameter for a switching type of an amp... BTW, are those actually gold plated heat sinks??? I just hope you didn't use audiophool-grade contact cleaner instead if a thermal paste to attach those floating heat sinks...

Is the capability of higher switching frequency another one of these urban myths? I mean does it actually lead to audible sonic differences?
 

Doodski

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It tells you specifically that what appears at the speaker terminals is pretty close to (or audibly exactly) identical (excluding gain) to what you shove up it's jacksie.

That's the formal designation of amplifier linearity. Retaining the signal to be the same from input to output.
We here at ASR also refer to linearity as the, "Doubling of wattage for each halving of impedance too." But linearity for the amp as a entire unit is input to output integrity.
 

restorer-john

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It is just one element of the description

It's a subjective catch all. There is no line on a meter or number on a dial where a "transparency" light turns on. One person's view is different to another's. No detail on which characteristics are included or excluded. No detail on respective weightings of contributing factors.

It's a buzzword thrown around by people trying to sound intelligent, but it has the opposite effect.
 

Doodski

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Is the capability of higher switching frequency another one of these urban myths? I mean does it actually lead to audible sonic differences?
The bandwidth or frequency response of a decent transistor is so good that more bandwidth is maybe just splitting hairs when it's used for audio. It's like OP amps with >MHz bandwidth being use for audio applications and the splitting hair differences when people OP amp roll.

EDIT: For class D higher freq transistors/FETs for switching is a plussy.
 
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restorer-john

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Is the capability of higher switching frequency another one of these urban myths? I mean does it actually lead to audible sonic differences?

Less dead time. The period where the device is neither fully off nor fully on. Leads to less device disipation and better waveform fidelity.

I'll take a faster device over a slower device in any application. After all, you can slow/bandwidth limit a fast device, but you can't speed up a slow one and retain linearity. (sure, you can help devices switch faster)
 

MaxBuck

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If I declare my amplifier "transparent", what does that tell you, specifically? Nothing about its power output into all loads, frequency response, distortion, crosstalk, features, build quality, price, warranty, fit, finish or features.
Transparency would communicate, to me, lack of audible distortion and no objectionable noise. Certainly nothing about features, build quality, price, color, physical dimensions, P/E ratio of its manufacturer's stock, factory location or any other extraneous stuff. In other words, a component that @amirm approves of from a measurement perspective.
 

Doodski

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Less dead time. The period where the device is neither fully off nor fully on. Leads to less device disipation and better waveform fidelity.

I'll take a faster device over a slower device in any application. After all, you can slow/bandwidth limit a fast device, but you can't speed up a slow one and retain linearity. (sure, you can help devices switch faster)
Now that we are on a transistor topic @restorer-john what makes those expensive big Sanken transistors and the like better for audio use? If the bandwidth is enough then what else is going on?
 

Raindog123

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GaN power electronics does make noticeable difference in modern highly-integrated _RF_ devices. Compared to “conventional” (SiGe, GaAs) transistors/integrated devices, it offers (a) higher power efficiency, (b) both higher operation temperature and thermal conductivity (thus less demanding heat management), and (c) higher operation voltages and current densities (leading to miniaturization with high power).

GaN‘s can also operate at higher RF frequencies and offer [RF] wide-band linearity. But we are talking GHz bands and frequencies here, irrelevant to [kHz-class] audio equipment... Bottom line, none of the GaN features would/can offer any improvement to audio hifi. It can offer miniaturization of higher-power devises, but the amp in discussion - with its dimensions - is not the case.
 

restorer-john

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Now that we are on a transistor topic @restorer-john what makes those expensive big Sanken transistors and the like better for audio use? If the bandwidth is enough then what else is going on?

Sanken have the LAPTs, which are essentailly a multi/diffused emitter technology, which, if I recall correctly was first used by Fujitsu on their RET (ring emitter transistor) output devices around 1979. Very fast, very linear with very low beta droop at high currents and no real downsides.

1632099102086.png


The first Fujitsu RETs I remember turned up in the range topping Pioneer SA-9800 integrated.

Prior to that, the NEC T0-3 EBT (emitter ballast transistor)s had been incorporated into the Kenwood LO-7m power amplifiers:
1632099343959.png
 

Doodski

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Sanken have the LAPTs, which are essentailly a multi/diffused emitter technology, which, if I recall correctly was first used by Fujitsu on their RET (ring emitter transistor) output devices around 1979. Very fast, very linear with very low beta droop at high currents and no real downsides.

View attachment 154462

The first Fujitsu RETs I remember turned up in the range topping Pioneer SA-9800 integrated.

Prior to that, the NEC T0-3 EBT (emitter ballast transistor)s had been incorporated into the Kenwood LO-7m power amplifiers:
View attachment 154464
The Sanken 150C junction temp sounds pretty good. Could boil some water very effectively at that rate. :D I'm not up to speed on what junction temps are usually rated at but I do know that thermal runway generally commences at around 85C-105C from what I've read. Substituting transistors and selecting them is not something I've had to do because I provided warranty service and so was only permitted to use factory spec parts and order from the service manual or use service bulletins/MODs sheets.
 
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