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

[rdenney]

I have not heard any different from Dylan. Therefore it is still assumed that the build will deliver mid September as previously announced.

Dylan, you are not under any pressure to prioritize my order just because it is being sent in for testing. I will wait in line like anyone else. To ask otherwise would be inappropriate.

For the record, I wasn't suggesting that. I'll wait for the test--I'm in no hurry. And, of course, it will have to fit in Amir's review schedule, which isn't exactly empty.

Rick "really just curious" Denney

 

[AdamG]

For the record, I wasn't suggesting that. I'll wait for the test--I'm in no hurry. And, of course, it will have to fit in Amir's review schedule, which isn't exactly empty.

Rick "really just curious" Denney

I know you were not, but it could be interpreted that way. Out of an abundance of caution.

 

[Lawyrup843]

Does anyone notice a difference between using the XLR TO XLR vs XLR to se(unbalanced) as connections? Just trying to figure out which way I want to go when I get my amp.

TIA

 

[anevard]

Wondering about level matching. I am waiting for some Buckeye 252s for my overheads and some 502s for my surrounds. My LCR will be powered by my vintage ATI 1506 bridged. It is unbalanced. My preamp is balanced and the Buckeyes are balanced.

I believe that the 502s and 252s have different input sensitivities, that are also different from the ATI.

Any thoughts on level matching all of this.

Andrew

 

[amper42]

Wondering about level matching. I am waiting for some Buckeye 252s for my overheads and some 502s for my surrounds. My LCR will be powered by my vintage ATI 1506 bridged. It is unbalanced. My preamp is balanced and the Buckeyes are balanced.

I believe that the 502s and 252s have different input sensitivities, that are also different from the ATI.

Any thoughts on level matching all of this.

Andrew

If you're using a Denon with Audyssey it will automatically level match the speakers/amps. There are two components that impact level matching.
1. The sensitivity of the speaker
2. The voltage gain of the amp
If all of your speakers have the same sensitivity (doubtful), then the 502 and 252 based amps would likely require 2db increase in levels compared to a standard A-B 28db gain amp.

If you don't have a receiver that offers automatic level matching (Audyssey/Dirac) then you'll want to do it manually with a sound level meter.

 

[Shanman]

Voltage gain in both modules is 25.5dB.

 

[DonH56]

Does anyone notice a difference between using the XLR TO XLR vs XLR to se(unbalanced) as connections? Just trying to figure out which way I want to go when I get my amp.

TIA

Probably won't matter unless you've a ground loop, but I'd go XLR if available for the better SNR and CMRR rejection plus ability to break a ground loop.

 

[anevard]

@Shanman @DonH56 Thank you for the replies.

To be more specific I am trying to determine the correct output sensitivity setting on a Monolith HTP-1 processor to balance between the balanced 252 and 502 class D modules and the unbalanced ATI 1506. Specs on the ATI are:

450 watts into 8 ohms
Gain 28dB
Input impedance 28,000 ohms

I realize that with Dirac, REW and my 30 year old Radio Shack sound level meter that I will be able to properly adjust the channel levels. However, I just want to start with the best possible input gain to the amps.

Thanks for all your insight.

 

[Shanman]

Well, I did a quick scan of the HTP-1 owners manual in pdf. A quick "Ctrl f" using the search word "amplifier" got me this on pg 14 which might help?:

"3. Volume: The Volume level is displayed in the center of the screen. The sample screenshot above shows -30dB as the Volume. The decibel (dB) value is relative to the amplifier input sensitivity, which can be configured on the CALIBRATION tab on the System Configuration screen in the Web GUI."

Looks like DIRAC will work the levels out during the System Config/Calibtation?

 

[amper42]

See page 48

Handling Unmatched Amplifiers
When 16 channels are in play, it’s not uncommon to use a selection of amplifiers that don’t exactly match. In a worst case, you may have 8 channels with balanced inputs and 6 channels with unbalanced inputs in addition to subwoofer(s). The Dirac calibration tool provides what is necessary to match these speakers. The amplifier with unbalanced inputs likely prefers to have a higher voltage drive suggesting you to increase the maximum output voltage. This makes the channels using a balanced amplifier too loud, so you should expect negative trim to be applied to these channels. If any of the amplifiers have adjustable gain, this can and should be the first line of adjustment to match the levels.
Levels can be measured using the Dirac tool.

 

[DonH56]

I'd stick with XLR, plumb everything, run Dirac Live, and enjoy. There is all sorts of lengthy analysis you could do but in practice most audio gear is made to be compatible to maximize sales if nothing else. As for gain differences, you also have to consider power differences, the sensitivity of your different speakers, distance from the listener(s), room effects, etc. -- any of which can swamp gain differences and level differences upstream in the system.

If you can adjust the gain settings of the HTP-1 (I am not familiar with it), then the usual goal is to adjust so that the level trims are within a few dB of 0 after all the calibrating. Dirac Live does not usually expose the final trim settings, but if everything is "in the green" at the start then you are fine. If one or more speakers are too high or too low during the initial DL volume-setting step, adjust at that time.

FWIWFM - Don

 

[anevard]

I'd stick with XLR, plumb everything, run Dirac Live, and enjoy.......

Again thank you all for the input. As for XLR, all will be XLR other than the subs and the LCR that are powered by the ATI 1506. My concern was over one specific setting in the HTP-1 and how to set it to balance between the balanced and unbalanced power amps.

The manual goes on to say the following. I wonder if I should be doing this with the unbalanced or balanced amps as there is only one global setting.

Andrew

 

[Buckeye Amps]

Again thank you all for the input. As for XLR, all will be XLR other than the subs and the LCR that are powered by the ATI 1506. My concern was over one specific setting in the HTP-1 and how to set it to balance between the balanced and unbalanced power amps.

View attachment 145471

Andrew

When mixing amps, you can split the difference. For instance, my NC502 amp wants around 2.7Vrms (8 ohm speakers) while the NC252 amp wants around 1.8Vrms...so I use 2.3Vrms.

In real world usage, there is pretty much no issues as there is still plenty of headroom left, even when listening at reference level (which I do often).

 

[Buckeye Amps]

So, some *BIG* news in the works: I am in the process of potentially hiring an employee. They would not be assembling the amps, so everything will still be put together to my standards. But my hopes would be to have someone help pre-wire/pre-terminate cables to speed up amp assembly. For instance, if I have extra wires made up, a 2ch amp assembly is roughly 1hr. But if I have to start from scratch it can take up to 2.5hrs.

The other goal would be to finally get a website going, which an extra set of hands would be beneficial for.

It is still very early in the process, so existing orders are not going to be sped up yet. But thanks to all you dedicated and appreciative customers, I should be taking the next step to grow more.

 

[DonH56]

In voltage, 28 dB of gain is 10^(28/20) ~ 25 V/V. The ATI is rated at 150 W into 8 ohms and that is sqrt(150 * 8) ~ 35 Vrms. To deliver full power you need to apply 35/25 ~ 1.4 Vrms. ATI does not state a different gain when bridged, though I'd usually expect another factor of two in there, but going with that 450 W into 8 ohms is 60 Vrms requiring 60/25 ~ 2.4 Vrms at the input. So now you have amplifier sensitivities of about 2.4 V (ATI), 2.7 V (NC502), and 1.8 V (NC252). That's about 3 dB, well within the trim range, and noise is probably low enough from any amp so it is not a big concern. The average is 2.3 V so that is probably reasonable.

HTH - Don

 

[anevard]

When mixing amps, you can split the difference. For instance, my NC502 amp wants around 2.7Vrms (8 ohm speakers) while the NC252 amp wants around 1.8Vrms...so I use 2.3Vrms.

In real world usage, there is pretty much no issues as there is still plenty of headroom left, even when listening at reference level (which I do often).

So now you have amplifier sensitivities of about 2.4 V (ATI), 2.7 V (NC502), and 1.8 V (NC252). That's about 3 dB, well within the trim range, and noise is probably low enough from any amp so it is not a big concern. The average is 2.3 V so that is probably reasonable.

Fantastic. Thank you all. That is where I will start from and see what Dirac sets as the trims. Just have to wait on the Buckeye amp delivery ;-)

 

[amper42]

You can go through these calculations and try the best to level match. Most people won't have an issue. However, if you are planning the setup in advance I would consider using the same amps for all channels or at least amps with the same gain.

I tried Purifi with Monolith 7x200 using Denon 4700 with Audyssey. It sounded fine with Stereo or Auro-3D but with Multi-channel Stereo the Purifi levels were a bit lower in some sections of the music. Moving back to Monolith for all channels resolved the issue. What I learned was Multi-channel Stereo playback may not always be as exact with amps of different gain levels - even after Audyssey has setup the initial level match.

 

[DonH56]

You can go through these calculations and try the best to level match. Most people won't have an issue. However, if you are planning the setup in advance I would consider using the same amps for all channels or at least amps with the same gain.

I tried Purifi with Monolith 7x200 using Denon 4700 with Audyssey. It sounded fine with Stereo or Auro-3D but with Multi-channel Stereo the Purifi levels were a bit lower in some sections of the music. Moving back to Monolith for all channels resolved the issue. What I learned was Multi-channel Stereo playback may not always be as exact with amps of different gain levels - even after Audyssey has setup the initial level match.

That makes no sense unless there is a bug in the processor or input levels (before Dirac Live and the amplifiers) are different for MCH playback.

Even if all amplifiers' gains are the same, the gain through the channels will be different to compensate for different speakers and speaker placement.

 

[amper42]

That makes no sense unless there is a bug in the processor or input levels (before Dirac Live and the amplifiers) are different for MCH playback.

Even if all amplifiers' gains are the same, the gain through the channels will be different to compensate for different speakers and speaker placement.

Obviously, different speakers/distances can impact level match. When I use all 28db gain amps with the Denon 4700 in multi-channel stereo mode (after Audyssey config) the sound level meter matches well as I move from speaker to speaker. However, with Purifi amp on fronts in multi-channel mode, fronts consistently measure 1-2db lower in various music passages compared to the Monolith amp powered speakers (7.2.4 setup). Audyssey level match shows compensation has been made for the 26.5db gain Purifi amp but the sound level meter still indicated a volume mismatch. Once I moved back to Monolith amps for all channels the issue disappeared.

Only in Multi-Channel stereo are all speakers playing the same source and simply duplicating it across five pairs of speakers. That's where you have the best opportunity to detect level match differences with a sound level meter.

 

[anevard]

Only in Multi-Channel stereo are all speakers playing the same source and simply duplicating it across five pairs of speakers. That's where you have the best opportunity to detect level match differences with a sound level meter.

Why would you not just run tones from REW or the Atmos test tone MP4s through each speaker and check the levels that way?

My understanding is that once the SPL level is properly matched from the speakers, the amp input levels should not matter unless there is clipping.

My issue was to ensure that I had the best level throughout the chain so that when the speaker output levels were properly matched, there would be no headroom issues with the amps.

I know it is not the perfect setup, but I felt that my ATI would provide the quality and the power I need for my LR NHT 3.3s and my C NHT Audiocenter-2. I have been using it in non bridged mode to power them for 25 years. Now with the addition of the Buckeye amps and the HTP-1 to replace my Pioneer LX701 receiver, I am looking forward to a whole new experience!