Inexpensive 5.1 amp?

[Nathan Raymond]

On my gaming PC, I have a 5.1 speaker setup, four Micca MB42x:

http://noaudiophile.com/Micca_MB42x_Bookshelf_Speakers/

and a Micca MB42x-C center channel as well as a powered Energy subwoofer (8" downfiring, flared front port, has both sub and speaker-level inputs). Sound source is a Creative Sound Blaster Zx:

https://us.creative.com/p/sound-blaster/sound-blaster-zx

Analog output is via three 3.5mm TRS jacks which I break out into RCA cables. For a time I was using an old receiver that had "6 Channel Direct" input (from the DVD/SACD era when that was a mainstream integrated receiver feature, sadly now a rarity) but the VFD was faded on it and it took up a lot of desk space. I tried a Weiliang Audio 5.1 amplifier from AliExpress (four TPA3116D2, claimed output power is 50W per channel measured at 4Ω), but it made a somewhat loud popping noise through all speakers when you first plug it in, regardless of whether the rotary power knob was in the on position or not, and it lacked much documentation and had some quirks (like three positions for the power knob, when only two seemed to do anything). Anyway, with the FX-Audio FX202A Class D Audio Amplifier 2 x 53W down to $40 on Parts Express, I picked up three of those. No pops, which is good, and according to the manual the specs are:

Chipset: TDA7492PE
Power Output: 53W+53W @ 4Ω, 40W+40W @ 8Ω
THD: 0.06%
SNR: -96dB
Frequency Response: ±2.5dB(20Hz~20KHz)

I was a bit disappointed that on one of the three units the volume knob "0" alignment was different, and while I hoped to be able to take it apart and adjust it so it was aligned the same, I could not find an obvious way to do that, so I'm just living with the difference right now. They don't take up much desk space, which is nice, but I did have to make room for three laptop-style AC-DC power supplies. Would be nice to have a single external volume knob, but I can set the volume knobs on the amps, leave them alone, and then use the Windows volume control as my master volume adjustment.

I also noticed that Parts Express caries the Sure Electronics AA-AB34181 6x100W TDA7498 Class-D Amplifier Board for $70:

https://www.parts-express.com/sure-...100w-tda7498-class-d-amplifier-board--320-307

It seems reasonably well regarded... from a sound quality perspective, would it be any sort of upgrade? Are there any cases out there that could easily house the AA-AB34181, ideally something nearly finished, like what GhentAudio has for the HypeX amps? Part of me would still like a single box to handle this task. One thing that concerns me about the AA-AB34181 being used for PC was this comment from a customer review on Parts Express:

"This is the second unit I purchased. The first had difficulty in handling the signal from my computer. It seems that a High definition audio device is a digital device which uses a 3.3v signal output, which the poor amp tries to boost with fatal results. Make sure of your settings before turning It on."

Does that mean I have to be careful with the Windows volume level if I were to plug the 5.1 analog outputs of the Sound Blaster Zx into the AA-AB34181? i.e. could I destroy it with too much output volume? Not sure I'd be happy with that risk.

Are there any other affordable solutions out there that don't suck?

 

[Neddy]

So this may be a bit 'off the wall', but I've had a remarkably good experience with this amp:
https://www.outdoorspeakerdepot.com/5-channel-amp-180w-osd-audio-xa5180.html
It's a bit more costly (~$400) than the options you mention (and I paid even less during pre-xmas sales), and is WAY heavy, but was very well packaged, shipped right away, and has both RCA and balanced inputs.
As near as I can tell (I use it only for surround channels) it sounds great, I've had zero problems with it, and it runs very cool.
I'm sure there are many other lighter and less costly options, too!

 

[WLVCA]

So this may be a bit 'off the wall', but I've had a remarkably good experience with this amp:
https://www.outdoorspeakerdepot.com/5-channel-amp-180w-osd-audio-xa5180.html
It's a bit more costly (~$400) than the options you mention (and I paid even less during pre-xmas sales), and is WAY heavy, but was very well packaged, shipped right away, and has both RCA and balanced inputs.
As near as I can tell (I use it only for surround channels) it sounds great, I've had zero problems with it, and it runs very cool.
I'm sure there are many other lighter and less costly options, too!

I own the same OSD amp and use it for home theater. Had it for about a year. Nice little amp - same as the Outlaw Audio 5000 for over $200.00 less

 

[Nathan Raymond]

So this may be a bit 'off the wall', but I've had a remarkably good experience with this amp:
https://www.outdoorspeakerdepot.com/5-channel-amp-180w-osd-audio-xa5180.html
It's a bit more costly (~$400) than the options you mention (and I paid even less during pre-xmas sales), and is WAY heavy, but was very well packaged, shipped right away, and has both RCA and balanced inputs.
As near as I can tell (I use it only for surround channels) it sounds great, I've had zero problems with it, and it runs very cool.
I'm sure there are many other lighter and less costly options, too!

Nice find! I've run across OSD's products before, but don't think I realized they had that amp. That's a pretty compelling option from price/performance perspective.

 

[IAmHolland]

Onkyo TX-SR393 can be had reasonably cheap, with full receiver capabilities. I can't speak to audio quality, I use the TX-SR494 in my garage, when working out. Not critical listening, background noise, filler, etc.

It's not exactly what you wanted, as you asked for an amp, but it'll work, and can be driven digitally.

 

[Nathan Raymond]

I am curious if anyone has any thoughts/experience with PC audio putting out 3.3v and destroying an amp like that Sure Electronics, or did that customer make some other mistake? Parts Express has the schematic linked and User's Guide on their website, and the User's Guide says this:

"K1 and K2 of SW1, SW2 and SW3 have been factory preset as ON to make sure weak gain of three channels. This can prevent chip from permanent damage caused by overheat when input signal amplitude is over range. On the other conditions of gain setting, it is recommended that the output signal amplitude is no larger than the power supply voltage once the input signal reaches the peak. For example, the maximum amplitude of the input signal is no more than 323mV RMS when power supply voltage is 36V, load impedance is 6 ohm and the gain is set at 37.6 dB. The other circumstances can be referred to the input sensitivity from TABLE 3-1 ELECTRICAL CHARACTERISTICS."

Looking at Table 3-1, the max input signal depends both on the gain switches and the DC voltage being fed to the Sure amp (which can be between 14V and 39V, with 36V being recommended). So with K1 ON, K2 ON if I'm reading that table right, the max amplitude of the input signal should be no more than 1286mV RMS with a 36V power supply. So then what happens if the max output voltage from a PC sound card is 2V RMS unloaded or higher?

 

[somebodyelse]

If the output level from the PC is to high you can make an attenuator to drop it to a suitable level to feed to the amp. The search engine of your choice will give a load of results for L pad attenuator calculators.

 

[Nathan Raymond]

Onkyo TX-SR393 can be had reasonably cheap, with full receiver capabilities. I can't speak to audio quality, I use the TX-SR494 in my garage, when working out. Not critical listening, background noise, filler, etc.

It's not exactly what you wanted, as you asked for an amp, but it'll work, and can be driven digitally.

So here's the funny thing about PC audio... I have three choices:

1) Use the analog outputs of my Sound Blaster sound card to get uncompressed low latency sound output and retain maximum compatibility with all sound APIs (Creative's ALchemy is able to put dll files in an app directory and intercept old 3D API sound calls and redirect them to Creative's semi-proprietary OpenAL architecture to retain EAX compatible for legacy titles) as well as compatibility with more modern sound APIs (it's worth noting that later versions of the now deprecated EAX APIs have similarities to Atmos and DTS:X in the sense that they are object-based APIs)

2) Use the optical digital or coax digital outputs on the Sound Blaster to put out a lossy encode of the 5.1 sound field as a Dolby Digital or DTS stream, which besides being lower quality than the uncompressed analog outputs will add some latency since the compression is done in realtime (I believe mostly on the CPU via the sound driver)

3) Don't use the Sound Blaster at all, and use the HDMI output of my video card and the sound card built into the video card (which doesn't have the ability to do any legacy 3D sound API processing, so old games would sound worse than they would on the Sound Blaster). On the plus side, if I ever wanted to add height channels and connect up at Atmos or DTS:X receiver, a very small number of modern PC games can actually produce a proper Atmos sound field, and the only way to experience that with the height channels is via HDMI and an Atmos receiver. I don't have an Atmos receiver right now, and if I get one, it's going in my living room, it won't be connected up to my gaming PC. Last time I checked, there weren't any PC games that supported Atmos that I really cared about enough to go through all the trouble of creating an Atmos setup for.

Anyway, receivers like that more entry-level Onkyo don't have 6-channel direct analog inputs, so the only way to connect a PC and get true 5.1 sound is via coax/optical (lossy) or HDMI (no Sound Blaster, no legacy API support), and I'm not really interested in those options. I find it super-frustrating that it seems like I'm left with either the multiple stereo amp solution (what I'm doing now), the DIY route (what I'm considering), or the 'audiophile' route of the discreet multichannel analog amplifier (there's also the high-end integrated receiver route, where some high-end receivers still have direct multichannel analog inputs, but that's both more expensive than the OSD amp and would be feature overkill while taking up too much space).

 

[IAmHolland]

I am curious if anyone has any thoughts/experience

Read the chip spec, it runs 3x TDA7498. https://www.st.com/resource/en/datasheet/tda7498.pdf

I have no experience, but my thoughts are that it will clip. Permanent damage from overheating, perhaps. Many of these devices tend to be marginally designed, with marginal heatsinks. It's purely cost driven.

Before it even gets there, it's probably going to have major distortion from an inadequate power supply. It, for sure, is not a 600W package and definitely not even remotely close to dissipating that much. Those wattages are also peak, and in no way RMS. I'd bet it's 1 channel driven peak voltages. Reasonably, I'd say you'd get no more than 20W RMS per channel out of that thing, if you're lucky and it doesn't burn up.

Since you're driving it with a soundcard, and a computer, you can just drop the volume to 50% and use the lowest gain setting.

 

[IAmHolland]

So here's the funny thing about PC audio... I have three choices:
2) Use the optical digital or coax digital outputs on the Sound Blaster to put out a lossy encode of the 5.1 sound field as a Dolby Digital or DTS stream, which besides being lower quality than the uncompressed analog outputs will add some latency since the compression is done in realtime (I believe mostly on the CPU via the sound driver)

Your commentary is very confusing.

You've not heard of pass through? I've run PC audio plenty of times, and your lecture is somewhat meaningless. Your source is going to be encoded in some way, already. It is digital.

Edit: Are you talking about the uncompressed digital streams on blu-ray? Just run HDMI. Legacy? I guess, but you can run onboard DSP processing.

Edit2: you can find old receivers/amps on craigslist. Many things "go out of style" quickly. Older multi-channel amps can be had fairly cheap. I'm sure you can find an old onkyo/pioneer with sacd inputs for cheap.

 

[HammerSandwich]

I own the same OSD amp and use it for home theater. Had it for about a year. Nice little amp - same as the Outlaw Audio 5000 for over $200.00 less

Outlaw measurements at Audioholics (without XLR in). Noise & distortion could be a little better. Power output's very respectable. Impressive value at $80/channel!

 

[Neddy]

Yes. I find it more than adequate for surround speakers, and having both input types makes it more versatile. Is a heavy thing tho.

 

[Nathan Raymond]

Your commentary is very confusing.

You've not heard of pass through? I've run PC audio plenty of times, and your lecture is somewhat meaningless. Your source is going to be encoded in some way, already. It is digital.

Edit: Are you talking about the uncompressed digital streams on blu-ray? Just run HDMI. Legacy? I guess, but you can run onboard DSP processing.

Edit2: you can find old receivers/amps on craigslist. Many things "go out of style" quickly. Older multi-channel amps can be had fairly cheap. I'm sure you can find an old onkyo/pioneer with sacd inputs for cheap.

PC audio is actually very confusing... I worked for a decade in the gaming industry for Rockstar Games, and gaming has been a pretty serious hobby of mine for three decades, so this is stuff I'm well versed in. Some web pages that cover this stuff in detail:

https://satsun.org/audio/setup.html

https://satsun.org/audio/index.php?sort=api

In short, a Creative Sound Blaster of some sort is needed to process EAX spatial/environmental audio in situations where games leveraged the proprietary Creative APIs for the most advanced effects. This has largely gone away in recent years because Microsoft changed their Windows architecture and stopped letting sound cards load their drivers into the kernel space and then later introduced their own XAudio2 API which includes X3DAudio which developers can use for true 3D spatial audio played back to an arbitrary number of speakers, and in Windows 10 they added HRTF processing as well so that can quality spatial audio on headphones is possible regardless of the brand of sound hardware - as long as games use the latest XAudio2 API. For those games, I can use any sound output (motherboard audio, Creative card, video card's sound card that outputs over HDMI, whatever, the sound field created and the effects I hear will be the same for the equivalent speakers/headphones as long as an additional HRTF isn't being applied by that playback device).

In the past, PC games that used proprietary Creative APIs always provided fallbacks to Microsoft's APIs, but they were inferior (often only stereo, and seriously lacking in effects and proper reproduction of environmental audio and spatial sound fields). My goal is max quality across the most titles in my library, which is why for 5.1 speaker playback at my desk, I use a Creative Sound Blaster Zx card. This sums up the legacy situation well:

https://videogameperfection.com/2013/02/27/are-pc-sound-cards-really-obsolete/

"Like many things in the world of PC gaming, PC audio is a heavily fragmented mixture of competing and legacy standards. Looking back over the history of Windows as a gaming platform, the change that caused the most amount of noise from gaming enthusiasts was when Windows Vista dropped support for hardware accelerated audio. Thanks to Microsoft’s change, anyone upgrading from Windows XP to Vista (or Windows 7 or 8) instantly loses surround sound in their older DirectSound titles. This includes any game that uses Creative Labs once super popular EAX hardware audio standard. Luckily for those of us who like to play older games, Creative Labs produced a program called ALchemy. This software fixes surround sound compatibility in many older games, allowing for full surround sound and other hardware accelerated audio effects to make a comeback. Creative Labs weren’t the only company to make software like this, Asus also produced a similar program for their Xonar range of sound cards. No such legacy compatibility software exists for HDMI audio from your graphics card however, so by using your video card for audio output, you limit your older games to stereo sound only."

Even if I wanted to go all HDMI audio (to gain uncompressed multichannel digital output, which you can't do over TOSLINK optical or coax), since my monitor is a 3440x1440 21:9 ultrawide, due to bandwidth limitations it drops to 50Hz over HDMI (I have it connected via DisplayPort to get the full refresh rate). While I could try using both my DisplayPort out and an HDMI out of my video card (with HDMI just for audio to a receiver), Windows would see the HDMI out as a second display even if no display is connected to the receiver, and while there are ways to potentially disable the display in software while retaining audio, it takes some fiddling to make it work since Windows really expects you to use HDMI primarily for video and not just audio.

At one point I did try searching for a device which could take the 5.1 analog outputs of my Sound Blaster, do an analog to digital conversion and embed a PCM 5.1 bitstream into an HDMI signal so that I could make use of a cheap lower-end receiver, but I never found anything that fit that bill, and I had concerns that it would add audio latency. So yeah, I care about old legacy APIs, and so a Sound Blaster with analog out is the only way to go.

Oh and in case you thought this all wasn't complicated enough, there have been a few modern games that have completely baked-in HRTFs into their sound such that their sound field will get very messed up if you try playing on speakers or gaming headsets that present themselves only as multichannel devices and have their own hardware HRTF. Hellblade: Senua's Sacrifice is one of those games:

https://www.polygon.com/2017/8/9/16120082/hellblade-binaural-audio-psychosis

It has phenomenal audio, as long as you listen on 2.0 headphones. Anything other than 2.0 will mess up the binaual sound field baked into the audio. Note that to get legacy EAX games to sound their best, you need set your Windows sound device to be 5.1 or 7.1 and then set your Creative Sound Blaster control panel to headphones so that the Creative drivers can get the 5.1 or 7.1 sound field and then apply the Sound Blaster HRTF which will create a binaural experience in realtime on headphones, and for this game, you need to make sure you change the sound device to be 2.0 in Windows and disable the Creative HRTF in their software for Hellblade to sound right. Likewise, I can't use these headphones with Hellblade:

https://usa.1more.com/products/1more-spearhead-vrx-gaming-headphones

The 1More Spearhead VRX work well in a lot of modern games since they present themselves as a 7.1 sound device to Windows, have a built-in motion tracking, and apply their own HRTF to the multichannel sound such that as you move your head, the sounds come from the right places (sounds in front of you continue to come from in front of you, i.e. the sound field isn't locked into your head movements like it is with most headphones). In a game like Hellblade, with it's 2.0 sound with baked-in HRTFs, I can't use the Spearhead VRX, so in cases like this, I need to use the headphone out on my Sound Blaster Zx (and give up on any head tracking while playing Hellblade).

 

[LBec]

You can get the boards cheap. A stereo Sure 2x100Watt 6 Ohm Class D AudioAmplifierBoard-TDA7498 (AA-AB32189) can be had for $30 however a decent power supply adds around $35 for 350Watts (Sure's recommended supply - Mean Well LRS-350-36). If you are looking at cost you are better of buying something already assembled unless you are into DIY for the fun.