Tibo PA150 Power Amp…..very much a truly nice budget surprise!

[Schlippwhip68]

I popped back into the workshop this morning. Replaced the Douk P7 with the Fosi Audio P4 preamp armed with a Muses 02 and replaced the opa828 in the Ampapa Q1 dac with Ti opa1656.
Using the Fiio SR11 and iPhone with AirPlay as a source.

The result was quite a serious step up in soundstage detail, depth and width. Instruments became better located and vocals a touch fuller and more textured, more human. The opa828 soundstage can be a little narrow comparatively although marvellous at handling bass, I find the opa828 can ‘pinch’ the vocals slightly, giving a more narrow presentation. These op amps remind me of my old Rotel A11 Tribute where the soundstage is a more central than wide. Between the speakers is where all the all the Rotels action is but what’s there is extremely focused, tight and clean like the opa828.

The Fosi P4 with the solid state approach allows a typically cleaner more analytical sound than the P7 with the valves and to some degree this pays dividends with the PA150 and they work very well together.

Using the Fiio SR11 is a good reference source in this case. I am using the USB connection and if the amp is poor it will come through slightly veiled/muddy especially in the low frequencies as Airplay can get a little boomy on some systems.
This has not been the case with the Tibo PA150, the lows remain quite tight and defined. Vocals are clean, realistic and the highs precise, not splashy or faint but the overall sound remains balanced and quite immersive. I could use the PC here for a more detailed, cleaner source but to some degree I would be negating the budget end of this experiment which defeats the purpose of the test.

The Tibo PA150 did respond really well to these changes, revealing each incremental change like a more expensive transparent amplifier may do. Plenty of bass tones, mid range details and the same with the vocals and highs. The synergy of this change in components cleared portrayed through a set of Q Acoustics 5020 speakers and it’s another very good match, preferable for the greater overall more musical soundstage with this latest roll.

Freedom Cry - Scatered Few, sounds excellent!

 

[Svend P]

The opa828 can be a little narrow comparatively although marvellous at handling bass.

Amirm could measure no difference in "noise, gain or distortion" when switching op-amps. So chances are your perceived differences would not survive a proper blind test.

Does Op-amp Rolling Work?

When I post my last video on review of Douk A5 amplifier, I mentioned that rolling (changing) op-amp ICs in there is fruitless. I got have a dozen comments under that video in youtube asking why so I thought I experiment again with the A5. Note that I have done the same testing with both DACs...

www.audiosciencereview.com

 

[sergeauckland]

I popped back into the workshop this morning. Replaced the Douk P7 with the Fosi Audio P4 preamp armed with a Muses 02 and replaced the opa828 in the Ampapa Q1 dac with Ti opa1656.
Using the Fiio SR11 and iPhone with AirPlay as a source.

The result was quite a serious step up in soundstage detail, depth and width. Instruments became better located and vocals a touch fuller and more textured, more human. The opa828 can be a little narrow comparatively although marvellous at handling bass and pinch the vocals slightly.

The Tibo PA150 did respond really well to these changes, revealing each incremental change like a more expensive transparent amplifier may do. The synergy of this change in components cleared portrayed through a set of Q Acoustics 5020 speakers.

I'm not sure whether there should have been a smilie at the end of that post. That's the sort of deadpan humour I often engage in...
S

 

[Schlippwhip68]

I'm not sure whether there should have been a smilie at the end of that post. That's the sort of deadpan humour I often engage in...
S

If I may say considering the price of this little rig, it’s very good value. I mean let’s say the Fosi P4, SMSL SU1, Tibo PA150 and speakers of choice would give the user a very good and powerful Hifi experience for fairly little outlay and achieve a very acceptable level of fidelity. We could go mono as well but for myself that would be overkill but for anyone with a large room it would blow the ti3255 mono’s out of the pond!

There is plenty of headroom with the Tibo PA150 which just I don’t find on the Ti3255 chip based amps of late regardless of the manufacturer claims. The only recent Ti3255 amp that I found with any reasonable power is the Aiyima A70 but then the Tibo PA150 is also currently £40 cheaper than the Aiyima A70 on Amazon UK….its a no brainer!

I am not even half way on the Ampapa Q1 or Fosi P4 in regard to output and it’s already surpassed the other Ti3255 amps @ 80% output and the sound quality is with the PA150 is still there without any noticeable distortion regardless of current doubts in performance over the THD. Can’t grumble at that. A single PA150 will handle a medium sized room with ease (5x5x3 -W/L/H). I haven’t cranked it yet, so I cannot say what distortion levels would occur at high or even full volume but to be fair that would be extremely loud, too loud for my own environment.

50% on the Q1 dac and 1.00 o’clock on the Fosi P4 is plenty, a room fill and then some with a smallish room, 4x4x4m. In comparison the Rotel A11 Tribute would be near max volume at this level and would probably shut down after an hour or two. I was advised by Rotel not to play that amp at 70 for long periods i.e over an hour or two due to heat. The amp itself went up to 99, that’s why I sold the Rotel on.

I posted the earlier post a little early and had to edit it slightly, my apologies.

 

[RandomEar]

I am not even half way on the Ampapa Q1 or Fosi P4 in regard to output and it’s already surpassed the other Ti3255 amps @ 80% output and the sound quality is with the PA150 is still there without any noticeable distortion regardless of current doubts in performance over the THD. Can’t grumble at that. A single PA150 will handle a medium sized room with ease (5x5x3 -W/L/H). I haven’t cranked it yet, so I cannot say what distortion levels would occur at high or even full volume but to be fair that would be extremely loud, too loud for my own environment.

Again: This is not how power works! The Ti3255 amps may reach full power only at 95% volume on your DAC, while the PA150 might reach full power at 75% volume. That depends on the input sensitivity of the amps and the volume/voltage curve of the DAC. But the PA150 will - in this example - not get any louder past 75% volume, it will just saturate and the input can even start distorting. But the "evil chip amp" will get louder until it reaches full power at 95% volume (in this example).

In consequence, SPL at a random DAC volume level is not an indicator of amplifier power. It's even worse: The higher input sensitivity of the PA150 means your volume control will be less fine grained than on the Ti3255 amps with lower input sentivity. It's not a positive property.

The fact that you don't notice distortion is also not surprising: A THD of -62 to -72 dB on the PA150 is bad by any modern standard, but the audibility threshold for distortion is usually around -40 dB in controlled testing with music and maybe 10 to 15 dB lower with specific tests using pure tones. See for yourself here. So with -60 dB, you'll likely be just barely below the threshold for audible distortion in most listening scenarios. You may save £40 on the amp, but it also performs significantly worse.

 

[voodooless]

Output judgement by volume knob position is totally pointless. The amps has different gains, and the volume knobs may have different tapers (Lin/log/something else).

 

[audio_tony]

If anybody can investigate these photos and unveil some mystery as to whether this is Class D or Class A/B it might be helpfu.

It's class D as I said previously. The two grey blocks I highlighted are the output filters.

Other clues are the small heatsink (for the given output power) and the speakers are wired directly - there's no protection relays).

I suspect there might be some kind of driver IC on the underside of that PCB.

 

[sergeauckland]

It's class D as I said previously. The two grey blocks I highlighted are the output filters.

Other clues are the small heatsink (for the given output power) and the speakers are wired directly - there's no protection relays).

I suspect there might be some kind of driver IC on the underside of that PCB.

View attachment 501706

Not at all obvious, as there's no sign of the actual chip, although indeed it could be under the board. However, the 6 transistors on the heatsink could be output transistors, but are too small for the amplifier's power output. They could be power supply transistors, but then why 6? Unless there's a circuit diagram somewhere it's all speculation. If it is Class D, why have a linear power supply? Indeed even if it's AB, why have a linear supply...

S.

 

[audio_tony]

Not at all obvious,

You're right, it's not at all obvious. However the ferrite ring around the speaker cables is another class d giveaway. To meet with emissions specs, as much of the switching frequency as possible must be suppressed, and that's the purpose of this ferrite ring.

It is certainly a very unusual design though - I have a hunch it's based around the IRS2092 class d driver. I suspect that of the 6 devices we see on the heatsink, 4 are mosfets and two are the 15v regulators. The IRS chip is likely soldered to the underside.

The IRS2092 datasheet specifies 22uH inductors for the output filters - "Miden A 220"

 

[Joe Smith]

Kind of weird that it is not more obvious what the class is.

 

[Schlippwhip68]

Again: This is not how power works! The Ti3255 amps may reach full power only at 95% volume on your DAC, while the PA150 might reach full power at 75% volume. That depends on the input sensitivity of the amps and the volume/voltage curve of the DAC. But the PA150 will - in this example - not get any louder past 75% volume, it will just saturate and the input can even start distorting. But the "evil chip amp" will get louder until it reaches full power at 95% volume (in this example).

In consequence, SPL at a random DAC volume level is not an indicator of amplifier power. It's even worse: The higher input sensitivity of the PA150 means your volume control will be less fine grained than on the Ti3255 amps with lower input sentivity. It's not a positive property.

The fact that you don't notice distortion is also not surprising: A THD of -62 to -72 dB on the PA150 is bad by any modern standard, but the audibility threshold for distortion is usually around -40 dB in controlled testing with music and maybe 10 to 15 dB lower with specific tests using pure tones. See for yourself here. So with -60 dB, you'll likely be just barely below the threshold for audible distortion in most listening scenarios. You may save £40 on the amp, but it also performs significantly worse.

Ok, thanks for the input.

 

[Schlippwhip68]

Kind of weird that it is not more obvious what the class is.

A mystery is it not. Still, it’s got some serious poke and sounds decent for the money Joe.

 

[Method2Madness]

I love this post. So, so much.

 

[ThELiZ]

I'm using a couple of these amps. Seem to be absolutely fine. I use one of them for the rear heights and the other one in mono (300W RMS) to drive my tactile devices.

The most annoying thing about the amps (in a home theatre) is that it has an auto stand by feature... Which sucks when there isn't any LFE data for 10 mins or so and they shut off. If anyone knows how to defeat this, I'd love to know!