Buckeye Amps: Purifi 1ET6525SA (the successor to the 1ET400A)

[KMO]

I just checked and I am hearing at that new Purifi 7040 needs 75 volts to reach full rated power but the power supply from Hypex smps 1200a400 only puts out 64 volts, while the smps 1200a700 puts out 85 volts, which would be too much. How does this reach rated power with the Hypex smps 1200a400, even in a mono mode, if the voltage output is below that required for full power?

Oops, delayed post - this didn't go through earlier. Some people have already said some of this. Nevertheless...

Rated power is at the nominal 70 volts (the 70 in its name). 75V is the "absolute maximum" voltage - you wouldn't want to be feeding it that.

But given the 63V of the SMPS1200A400, the graph in the 1ET7040SA datasheet suggests you'd get 200W(8ohm)/400W(4ohm)/750W(2ohm) at that supply voltage, rather than 250/500/900.

My understanding was some other suppliers are turning to non-Hypex power supplies.

Note that most people supplying the 1ET400A may not be quite getting its rated power out either - it's nominally 65V, but it's usually driven with one of Hypex's slightly lower 63V supplies.

Mind you, both datasheets have graphs that don't precisely match the headline power specs if you look very closely. On that graph you see the headline 227W@8ohm and 425W@4ohm at 65V and 63V respectively, suggesting slightly inconsistent testing for the headline numbers, or some deviation between a "theoretical" graph and real life.

 

[KMO]

For example if my AC line voltage is 225VAC, and at other place 240VAC what do you expect?

My first thought is you'd probably want a 230V PSU proportional to line voltage, and nominally 70V. Then you'd be on-spec at 230V, and you'd be varying between 67V to 73V from 220V to 240V. You'd be out-of-spec on the 1ET7040SA once you hit 247V volts though, exceeding 75V.

Apparently nominal tolerance on mains is actually quite lax in a lot of places. One bit of googling suggests 217-253V for UK, and it's not the worst. So the 75V absolute maximum isn't leaving you quite enough slack for the nominal 70V.

The 1ET400A is a lot better - it has the same 75V absolute max, but given 65V nominal you'd have to hit 265V on the mains to overdrive it. Shouldn't be possible without a mains fault, and you're probably out of spec on the PSU by that point too. (Would be on the SMPS1200A400).

If I was a 1ET7040SA builder, I'd probably want to prod Purifi about its 75V max. Don't think it's high enough to totally safely fit a 70V supply.

Edit: And the recommended max is even tighter at 73.5V. At that point, you just can't be using a "proportional to input" supply, at least not with a nominal 230V = 70V. Getting rated power out of this module is going to be tricky...

 

[goryu]

My first thought is you'd probably want a 230V PSU proportional to line voltage, and nominally 70V. Then you'd be on-spec at 230V, and you'd be varying between 67V to 73V from 220V to 240V. You'd be out-of-spec on the 1ET7040SA once you hit 247V volts though, exceeding 75V.

Apparently nominal tolerance on mains is actually quite lax in a lot of places. One bit of googling suggests 217-253V for UK, and it's not the worst. So the 75V absolute maximum isn't leaving you quite enough slack for the nominal 70V.

The 1ET400A is a lot better - it has the same 75V absolute max, but given 65V nominal you'd have to hit 265V on the mains to overdrive it. Shouldn't be possible without a mains fault, and you're probably out of spec on the PSU by that point too. (Would be on the SMPS1200A400).

If I was a 1ET7040SA builder, I'd probably want to prod Purifi about its 75V max. Don't think it's high enough to totally safely fit a 70V supply.

Edit: And the recommended max is even tighter at 73.5V. At that point, you just can't be using a "proportional to input" supply, at least not with a nominal 230V = 70V. Getting rated power out of this module is going to be tricky...

Indeed, but other than the fact that these 1ET7040SA modules aren't going to meet their rated power with the Hypex supply, the important take away is that unless you have 2 ohm loads to drive, the 1ET7040SA isn't going to do anything for you that the cheaper and better performing 1ET400A won't do. It also bears mentioning that the 1200a400 supply does allow the 1ET400A to reach rated power, at least in the US, where the mains is a nominal 120V, not the 115V as speced in the Hypex data sheet.

I agree that until manufacturers start supplying the 1ET7040SA modules with a different smps, it won't be producing rated power with the Hypex 1200a400 supply though in fairness for those needing more power at 2 ohms, it will still produce nearly double at that load in comparison to the 1ET400A.

 

[Buckeye Amps]

After some follow-up with Purifi:

While the SMPS1200a400 does not provide the recommended +/-70V, it currently comes "closest" to what the 1ET7040SA can handle.

I am updating my specs on the mono 1ET7040SA to acknowledge more realistic power output due to the lesser voltage. Never was my intention to mislead and I appreciate the error being pointed out.

 

[EdW]

My first thought is you'd probably want a 230V PSU proportional to line voltage, and nominally 70V. Then you'd be on-spec at 230V, and you'd be varying between 67V to 73V from 220V to 240V. You'd be out-of-spec on the 1ET7040SA once you hit 247V volts though, exceeding 75V.

Apparently nominal tolerance on mains is actually quite lax in a lot of places. One bit of googling suggests 217-253V for UK, and it's not the worst. So the 75V absolute maximum isn't leaving you quite enough slack for the nominal 70V.

The 1ET400A is a lot better - it has the same 75V absolute max, but given 65V nominal you'd have to hit 265V on the mains to overdrive it. Shouldn't be possible without a mains fault, and you're probably out of spec on the PSU by that point too. (Would be on the SMPS1200A400).

If I was a 1ET7040SA builder, I'd probably want to prod Purifi about its 75V max. Don't think it's high enough to totally safely fit a 70V supply.

Edit: And the recommended max is even tighter at 73.5V. At that point, you just can't be using a "proportional to input" supply, at least not with a nominal 230V = 70V. Getting rated power out of this module is going to be tricky...

It does seem that the Purifi amplifiers deserve better power supplies than the Hypex unregulated units. Perhaps that’s why March audio have their own SMPS which I imagine are regulated since they run from 100-240V.

P501 Mono-Block Power Amplifier - March Audio

The P501 is a Purifi 1ET7040SA based mono-block amplifier. This simply elegant product is milled from solid aluminium with a tough anodized treatment. Exceptional fit, finish and build quality. Class leading technical and subjective audio performance.

www.marchaudio.com

Not sure what rail voltages result though but Alan March claims 250W/8 Ohm which suggests around +/-70V
His IET400 amps also use a regulated supply but their power output suggests a supply nearer the +/-65V nominal. Perhaps just by adjustment of the regulator control voltage?

 

[goryu]

It does seem that the Purifi amplifiers deserve better power supplies than the Hypex unregulated units. Perhaps that’s why March audio have their own SMPS which I imagine are regulated since they run from 100-240V.

P501 Mono-Block Power Amplifier - March Audio

The P501 is a Purifi 1ET7040SA based mono-block amplifier. This simply elegant product is milled from solid aluminium with a tough anodized treatment. Exceptional fit, finish and build quality. Class leading technical and subjective audio performance.

www.marchaudio.com

Not sure what rail voltages result though but Alan March claims 250W/8 Ohm which suggests around +/-70V
His IET400 amps also use a regulated supply but their power output suggests a supply nearer the +/-65V nominal. Perhaps just by adjustment of the regulator control voltage?

Not sure if I would say "better", perhaps "more appropriate to their capabilities". Disappointing that Purifi keeps turning out drivers and amps but has yet to deliver on the promised smps for their amps.

 

[MicroAudio]

March audio uses the MICRO AUDIO SMPS products, that are designed to fulfill their custom requirements.

Also, other OEMs

Thank you

 

[Espiritiv]

What is the current wait time on one of these 1ET400A 3CH amps? Would a 5CH be an option (or even fit) in the Rack Mount case?

 

[Espiritiv]

After some follow-up with Purifi:

While the SMPS1200a400 does not provide the recommended +/-70V, it currently comes "closest" to what the 1ET7040SA can handle.

I am updating my specs on the mono 1ET7040SA to acknowledge more realistic power output due to the lesser voltage. Never was my intention to mislead and I appreciate the error being pointed out.

Don't forget to update the other part of the website to match the product pages.

 

[Buckeye Amps]

What is the current wait time on one of these 1ET400A 3CH amps? Would a 5CH be an option (or even fit) in the Rack Mount case?

I am about 9-10wks lead time.

No options past 3ch at this point

 

[bkdc]

The 1ET400a CAN handle 2 ohm loads. Output is purely thermally limited. The 1ET7040SA has beefed up thermals (and hopefully cooling) to improve performance when driven at 2 ohms. But I suspect the biggest issue (not for transient crazy loads) for sustained output is the ability of the chassis to cool the board. I’d be willing to pay significantly more for a completely different case/chassis with greater mass (larger heat sink) and large fins.

 

[Meanpeak]

Not sure if I would say "better", perhaps "more appropriate to their capabilities". Disappointing that Purifi keeps turning out drivers and amps but has yet to deliver on the promised smps for their amps.

Better?

Yes Micro audio is better, I had a Hypex supply died after 2 months of use, and Hypex refused to fix it and asked me to return it. I turned that down and dropped it into the trash.
I heared many stories about Micro audio technical support, they even send you free unit if you are under warranty and you just pay shipping.

I bought one SMPS from them in replacement for the Hypex, its a top notch quality product.

 

[goryu]

Better?

Yes Micro audio is better, I had a Hypex supply died after 2 months of use, and Hypex refused to fix it and asked me to return it. I turned that down and dropped it into the trash.
I heared many stories about Micro audio technical support, they even send you free unit if you are under warranty and you just pay shipping.

I bought one SMPS from them in replacement for the Hypex, its a top notch quality product.

Your opinion. Plenty of happy Hypex customers. Sorry you had a bad experience.

 

[Buckeye Amps]

I'm going to steer this back on topic:

I've updated my power ratings to reflect the slightly underpowered SMPS1200a400 being used. At the very least I will always try to be honest and transparent to my customers.

That being said, it should be reiterated that 750w vs 950w is splitting hairs in real world usage. I'm happy the mistake was pointed out so i could fix it. But I also wouldn't stress too much as a consumer (whether my amps or competitors).

 

[thegeton]

Just received my Buckeye Amps Purifi 1ET400A 2 Channel amp and got it set up in the intended system. I was using another Buckeye (NC252MP) as a place holder until the Purifi version arrived. Needless to say it sounds transparent just like the NC252MP, and I love it.

However, it will allow that system to stay clean and get much louder than the NC252MP. Much louder.

Bluesound Node 2i -> Topping D70s -> Schiit Freya S -> Buckeye Amps Purifi 1ET400A -> Revel M16 + Emotiva SE12

Thanks @Buckeye Amps !!!

 

[Rottmannash]

We have a similar chain. Am waiting for my 3 ch Buckeye Purifi but it will be used for HT only. I have a VTV Purifi in the 2 ch system which is Node 2i>D90 SE>Freya+>VTV>F208s.

 

[thegeton]

@Buckeye Amps - quick question: the Purifi QSG section on Auto Sense states that "Auto sense circuit uses Channel 3 for operation." What channel is used for a 2 channel amp?

 

[Buckeye Amps]

@Buckeye Amps - quick question: the Purifi QSG section on Auto Sense states that "Auto sense circuit uses Channel 3 for operation." What channel is used for a 2 channel amp?

Channel 2 (closest to the IEC power socket)

When I do my next batch of cases I'll fix the numbering so channel 1 is always closest to the IEC socket on all versions

 

[thegeton]

Excellent build quality.

 

[Buckeye Amps]

I am halfway through August backorders. Flying through backorders (got 8 done over the weekend). Will be caught up soon and hopefully at the point of having amps on hand for same day sales at some point before the end of the year