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Buckeye Amps: New US based Hypex multichannel amplifier builder, line-up announcement!

nstzya

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The 4 channel NC502MP would be plenty of power for the setup, however the Denon AVR6700 only provides 1.5Vrms, meaning you'd not be getting full headroom/power with the 502's. However, reading up it seems the AVR6700 can provide up to 4Vrms if no internal amps are used.

Why would the 6700’s preamp section put out different Vrms if the internal amps aren’t used? Is this common behavior of AVR’s?

If it was me, I would get the 6 channel NC252. You can externally bridge it at any time for your usage but still resell it as a 6 channel amp. And the NC252's would be better suited for the lower Vrms of the 6700

So did you conclude that the input sensitivity remains the same when bridged?
 
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Why would the 6700’s preamp section put out different Vrms if the internal amps aren’t used? Is this common behavior of AVR’s?
So did you conclude that the input sensitivity remains the same when bridged?

No idea if that is common behavior. For the 6700 I am going off a Sound and Vision review in which it was stated that if internal amps are bypassed the Vrms is around 4.5.

I still haven't gotten my answer on the bridging actually. Still open to someone's input on that.
 
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Updating my sales page with an unfortunate update:

Due to the time it takes to assemble the 6 and 8 channel amps, I will be increasing the price some. Until now I haven't factored labor into the costs. But now that I have the build process as streamlined as I can and with the increase in orders, I have come to find that the 6/8 channel amps are not as simple as scaling up in terms of time compared to the lower channel counts. For instance, a typical 8 channel NC252MP is around 6-7 hours of work. My goal was always to be able to do one amp a night but especially during a busy day in lab or a week of experiments, they are more of a time sink.

The increase won't be substantial and it will still be priced to be competitive as always. Anyone with a pending order is not affected nor is anyone I have already quoted.

I really apologize for this. I intended to keep prices fixed unless EUR to USD ever changed drastically (for buying the actual modules) but with the new cases I have coming along with the logo and future website, I anticipate orders to increase or at least stay around this level of interest.

Thank you everyone for everything so far!
 

mdsimon2

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Thanks! I have that part of the equation down. My confusion is when bridging. For a normal 252, Hypex uses the ohms and power of one of the channels to calculate the input sensitivity (so their datasheet example is sqrt(150*8)/10^(25.6/20) = 1.82Vrms

But when bridging, each channel of the amp now see's half impedance. So if I bridge a 252 and use it to power a single 8ohm speaker, technically each amp on the module is seeing 4ohms but combined the overall impedance is 8ohm @ 500w. Do I use 500*8 for the sqrt() now? Or 500*4? Or 250*4 (since each module is outputting max power of 250w)?

125W x 2 @ 8 ohms
input sensitivity = sqrt(125*8)/10^(25.5/20) = 1.7V

250W x 2 @ 4 ohms
input sensitivity = sqrt(250*4)/10^(25.5/20) = 1.7V

500W x 1 @ 8 ohms
input sensitivity = sqrt(500*8)/10^(31.5/20) = 1.7V

Input sensitivity is always calculated on a per channel basis. As long as power doubles in to half the impedance the input sensitivity will be the same. Input sensitivity for 8 ohms bridged will always be the same as the input sensitivity in to 4 ohms stereo.

Just for demonstration let's say power does not quite double in to 4 ohms and you only get 200W x 2 @ 4 ohms (400W x 1 @ 8 ohms).

200W x 2 @ 4 ohms
input sensitivity = sqrt(200*4)/10^(25.5/20) = 1.5V

400W x 1 @ 8 ohms
input sensitivity = sqrt(400*8)/10^(31.5/20) = 1.5V

IMHO gain is a much more useful concept than input sensitivity.

Michael
 
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thepiecesfit

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Not sure this will help anyone with the 17" cases. I wanted to cool my unit and noticed the AC infinity fans did not align with the cut outs for ventilation. Easy fix was to reverse the top panel so the fins are closer to the rear. Now the three fans are directly on top of the fins when the AC infinity is flush with the front of the amp. Cruising happily at 84F.
BuckeyeAmp.jpg
 

AdamG

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Not sure this will help anyone with the 17" cases. I wanted to cool my unit and noticed the AC infinity fans did not align with the cut outs for ventilation. Easy fix was to reverse the top panel so the fins are closer to the rear. Now the three fans are directly on top of the fins when the AC infinity is flush with the front of the amp. Cruising happily at 84F.View attachment 116531

Great idea unless,
Buckeye Amps
designed the cutouts to be precisely placed over the area/zone that generates the majority of heat. Any difference Buckeye? Will rotating the top cover 180 degrees matter ?
 
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Great idea unless, designed the cutouts to be precisely placed over the area/zone that generates the majority of heat. Any difference Buckeye? Will rotating the top cover 180 degrees matter ?
They are positioned to cover most of the PSU section of the modules. However, if using a cooling solution such as the AC Infinity the position isn't as important.
 

thepiecesfit

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Great idea unless, designed the cutouts to be precisely placed over the area/zone that generates the majority of heat. Any difference Buckeye? Will rotating the top cover 180 degrees matter ?

IMO the case could benefit from having the same venting pattern as the 19". The 502 gets quite toasty and could use all the venting holes it can get. I'd argue that a multi channel config in 17" and 19" in the 502 at least should have active cooling.
 

AdamG

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IMO the case could benefit from having the same venting pattern as the 19". The 502 gets quite toasty and could use all the venting holes it can get. I'd argue that a multi channel config in 17" and 19" in the 502 at least should have active cooling.

I have a 3 module 502 amp (6 ch). While I do employ an Aircom on top with back venting. The Aircom temp sensors barely exceed +6 degrees above ambient/room temperature. That comes out to average of 82 to 84 degrees Fahrenheit operating temperature at top of amp case. So with nothing stacked on top and ample space to breath. An argument that cooling is not required can be supported.

I prefer to keep all my amps cool using Aircom units. But it’s just a preference and not a requirement in this case. These class D amps do really run fairly cool.
 
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I have a 3 module 502 amp (6 ch). While I do employ an Aircom on top with back venting. The Aircom temp sensors barely exceed +6 degrees above ambient/room temperature. That comes out to average of 82 to 84 degrees Fahrenheit operating temperature at top of amp case. So with nothing stacked on top and ample space to breath. An argument that cooling is not required can be supported.

I prefer to keep all my amps cool using Aircom units. But it’s just a preference and not a requirement in this case. These class D amps do really run fairly cool.
I am the same. I have run the amps without my Aircoms just to test them and while they got hot, they are not the same level of hot as an A/B amplifier with active cooling (even something like my low powered Emotiva BasX still got very hot).
But I run the Aircoms just to keep temps as low as possible.
 

rvsixer

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Why would the 6700’s preamp section put out different Vrms if the internal amps aren’t used? Is this common behavior of AVR’s?
See the ASR 6700 reviews here for clarification. With the amps off, max SINAD is at 1.5V preout, and decreases as preout voltage goes up (but still a respectable SINAD 92 at 4.4V). With amps on, clipping bleeds over to the preouts. AFAIK Denon is the only current AVR manufacturer that allows you to (very thankfully) circumvent this issue (some older class D Pioneer AVR's I used back in the day also allowed turning off individual amps).
 

thepiecesfit

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I have a 3 module 502 amp (6 ch). While I do employ an Aircom on top with back venting. The Aircom temp sensors barely exceed +6 degrees above ambient/room temperature. That comes out to average of 82 to 84 degrees Fahrenheit operating temperature at top of amp case. So with nothing stacked on top and ample space to breath. An argument that cooling is not required can be supported.

I prefer to keep all my amps cool using Aircom units. But it’s just a preference and not a requirement in this case. These class D amps do really run fairly cool.

I've done some testing with and without the Aircom and while it doesn't appear to get as hot as some equipment I've used in the past, the bottom of the unit felt very toasty after watching Avengers End Game at -10dB. The top was hot towards the rear but nothing like underneath. With the Aircom active on auto 2 fan speed in a similar scenario the bottom never got past warm to the touch. Can it work without it? Sure, but having everything nice and cool can only extend it's life and potentially improve it's function. I'm not sure if anyone has ever measured the effects of heat on audibility but would be an interesting test to see. I'll continue to buy these Aircom units like you as I feel they are a great value, provide peace of mind equipment protection.
 

Lancastrian

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I have a 2-channel Buckeye NC502MP on order and would like your thoughts on a topic which I think would apply to all amps, and perhaps also to other electronics. For context, I'm building a great room measuring 37' x 21' x 8.5'. A family room is on one end and a kitchen on the opposite end. My 2.1 or 2.2 entertainment system will be on the 21' FR wall. A meter main combo will be located on the other side of the wall. I intend to wire two dedicated 15 or 20 amp circuits for the power amp - total cable length for each circuit will be about 5' from the breakers (two circuits in case I go with monoblocks in the future). Would 20 amp circuits be overkill? Any thoughts on optimizing this set up, i.e., commercial grade receptacles, etc.?
 

DonH56

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If you are having the work done (or doing it yourself) the incremental cost for 20 A is probably insignificant. I might spring for hospital-grade outlets, just run-of-the-mill variety, but doubt it really matters..
 

DWPress

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Where I live in the US 20A is code for wall receptacles and 15 is for lighting circuits only.
 
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The original 12"x12" case inventory is now used up and will be replaced with the first of my newer case designs. Designated Small, this case is 7" wide by 12" deep and features the new Buckeye Amps logo. Pictures will be updated once it arrives. The idea is to try and offer an even lower footprint case for stereo builds without having to go the Ghent route. Construction/material and overall look is still the same. Cost will be the same, also
 

dutchboy

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For what it's worth I'm using the 4 channel NC502MP with my Denon X4400H and I can play -10dB from reference, calibrated with an SPL meter and it sounds clean. I only needed to add +1.5dB from my old amp for the LCR trims likely to account the amp gain 27db vs 25.6. I am 12 feet away from my speakers rated at 88dB 1/watt meter at 8ohms. My ears can't tolerate much louder I'm usually at -15dB. This is without LR amp disconnect. YMMV
How do you have it plugged in? How many speakers are you powering with it?
 

geekpryde

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Why do the hypex modules not specify a 6ohm rating? Seems to me that would be more common than 2ohm.
 
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geekpryde

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The original 12"x12" case inventory is now used up and will be replaced with the first of my newer case designs. Designated Small, this case is 7" wide by 12" deep and features the new Buckeye Amps logo. Pictures will be updated once it arrives. The idea is to try and offer an even lower footprint case for stereo builds without having to go the Ghent route. Construction/material and overall look is still the same. Cost will be the same, also

Can't wait to see how it came out. By materials staying the same does this mean aluminum or steel? I think you said at one point your were adding/ changing to steel.
 
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