@acko - AHA! Makes perfect sense. Appreciated.
@benb and @acko - as a relative novice to all of this... I also wonder if that's where some driver / speaker manufacturers come up with their "recommended" amplifier power. Sure, if it's 300W PMPO, I may need that for some of my speakers, but any "real" 25W amp drives most of them just wonderfully to reasonable levels.
Still trying to learn about "crest factor" mentioned above. Just when I think I know something...
@benb and @acko - as a relative novice to all of this... I also wonder if that's where some driver / speaker manufacturers come up with their "recommended" amplifier power. Sure, if it's 300W PMPO, I may need that for some of my speakers, but any "real" 25W amp drives most of them just wonderfully to reasonable levels.
Still trying to learn about "crest factor" mentioned above. Just when I think I know something...
Need to check but this PMPO may have crest factor taken into account. At least the Japanese labels it clearly on their products so as not to confuse or mislead. I remember during my younger days building a JLH 10W rms class A amp and friends laughed about with their 200W (pmpo) mini-compos🤩
… try explaining rms, peak, pmpo 🤣
… try explaining rms, peak, pmpo 🤣
Last edited:
That’s about right for a wolverine. Decent amps ( that means housing and a proper PSU etc) are not cheap.
Over at ASR, two developments:
It ran ~ 10 V RMS / 110 Hz into a 4.0 R dummy load fine (hence about 25 W) for a few minutes, with the dummy load and the amplifier getting warm to the touch but not hot. Increasing to 15 V RMS caused the protection to trigger instantly. Starting at 10 V output voltage and increasing the input by 1 dB at time made the protection kick-in 2-3 seconds after the output voltage had been increased to 11.6 V (33 W).
After that, the amp would not switch on again after input, output and power had been removed (1 - 1 blink code = supply voltages abnormal). This persisted after 15 minutes and after 2 h when the amp had completely cooled down to 20°C. According to the manual, this means the amp is damaged and should be returned to Topping.
- PMA used a RCA to TRS adapter, so he may have been driving only one side of the BTL amplifier. He is trying to borrow the amp again for some more testing.
- I ran tests on a unit that was already "last stock" at a German Amazon warehouse in early October, so may have been from one of the first production runs. I used a symmetrical signal into the balanced input (TRS to TRS):
It ran ~ 10 V RMS / 110 Hz into a 4.0 R dummy load fine (hence about 25 W) for a few minutes, with the dummy load and the amplifier getting warm to the touch but not hot. Increasing to 15 V RMS caused the protection to trigger instantly. Starting at 10 V output voltage and increasing the input by 1 dB at time made the protection kick-in 2-3 seconds after the output voltage had been increased to 11.6 V (33 W).
After that, the amp would not switch on again after input, output and power had been removed (1 - 1 blink code = supply voltages abnormal). This persisted after 15 minutes and after 2 h when the amp had completely cooled down to 20°C. According to the manual, this means the amp is damaged and should be returned to Topping.
I'm sorry to hear that and was wondering if you tried using a lower gain level.
In the spirit of contributing to issue solving and not knowing if it has already been said I was just wondering if you tried using a lower gain level.
The protection issue was also reported in this thread and in the same page it seems that with a medium gain the power reaches 86W.
Hoping you can get what you need out of them.
By the way, the highlighted procedure seems to me a bit particular, though...
May I ask what the sensitivity of your speakers is? How are you driving the B100? Cinch or TRS input? If TRS, with a true balanced signal or with an adapter?
^ Thank you! Always good to 'RTFM', which admittedly... I did not. But...
My pre-amp is set to 0dB gain (at the moment) b/c I didn't want to over-drive the B100. Source will output a clean 4Vrms through balanced output at 0dBFS. Many times I drive an amp straight from the source (old AKM D90). I am particularly averse to clipping, so I tend to do everything I can to avoid it. Plus, it's only on rare occasions that I need a lot of voltage swing.
Basic table using Vrms / Wrms
I don't think I've ever seen a 0dBFS signal in music. Assume 6dB of digital headroom, and I think that's on the low side. So, I should be at max output from the DAC at 2Vrms (assuming I ever understood that properly). Main point here is that I'm not running a "hot" source or running anything into the amp that should run it into protection from an input standpoint (I think).
So, on medium gain - I would think... that I could run the pre-amp with zero attenuation and have zero issues with the B100 going into protection from an over-voltage / over-current either in or out. Max conceivable output should be 13V2rms. More realistically, it's more like 6V6rms. So, that leads me to thermal (which the manual shows as the code). That also gets me to over 25W into 4R which is below the current rating of the power brick (4A). I can nearly get to 25W into 2R with that voltage output while still staying below the current rating of the brick.
I am in MN, USA. The units are in my basement on an open-top rack. The ambient temp is ~20C. So... let's call that 'normal'.
Again... this was just my noodlings the other day... I may have some (or all) of that wrong re: my assumptions.
Tekton DI are 'rated' at 98dB / 2V8rms / 1m. 4R nominal. Never seen a decent published impedance curve. My gut says they're rated fairly ambitiously. If someone has a reliable source for a plot, I'd be grateful. I generally think they might dip to 2R in the bass region. One of these days, I'll learn to measure it.
Vandersteen 3A - 86dB / 1W / 1m. 6R nominal. 4R published min. Link to Stereophile measurements
As a side note - if these had worked out well, I may have purchased another pair to use with a pair of Nelson Pass inspired SLOBs. 4 Identical amps would have been nice, and I had hoped for a small form-factor. However, the cross-over needs a SE in/out... so... that also puts a kink in my idea.
Quick pics of the mess. 🙂 They're playing now... again... they sound 'nice to me'. I've got the DIs hooked back up.
Cheers!
Edited to fix table import. Also... to note that I could have calculated things into 16R, but I don't think we're running into voltage issues... gut says it's thermal / overload into lower impedances.
Edited again to add - I hooked up the Vandy's b/c they're closer to my brother's 2Ce in characteristics than the Tektons. Since I ran them into protection with the Tektons... I was concerned. They ran into protection at lower listening levels (as expected) with the Vandys. Thus, I still have the amps and have not sent them to my brother yet. He'd be far less tolerant of little hiccups like this.
The units are both set to medium gain. Gain should be 10.4dB (Balanced) => ~3.3X More info and assumptions below.
My pre-amp is set to 0dB gain (at the moment) b/c I didn't want to over-drive the B100. Source will output a clean 4Vrms through balanced output at 0dBFS. Many times I drive an amp straight from the source (old AKM D90). I am particularly averse to clipping, so I tend to do everything I can to avoid it. Plus, it's only on rare occasions that I need a lot of voltage swing.
Basic table using Vrms / Wrms
| Output Power (Watts) | Load | Output Voltage (RMS) | Output Current (RMS) | Output Voltage (Vp) |
| 25 | 8 | 14.1 | 1.8 | 20.0 |
| 25 | 6 | 12.2 | 2.0 | 17.3 |
| 25 | 4 | 10.0 | 2.5 | 14.1 |
| 25 | 2 | 7.1 | 3.5 | 10.0 |
I don't think I've ever seen a 0dBFS signal in music. Assume 6dB of digital headroom, and I think that's on the low side. So, I should be at max output from the DAC at 2Vrms (assuming I ever understood that properly). Main point here is that I'm not running a "hot" source or running anything into the amp that should run it into protection from an input standpoint (I think).
So, on medium gain - I would think... that I could run the pre-amp with zero attenuation and have zero issues with the B100 going into protection from an over-voltage / over-current either in or out. Max conceivable output should be 13V2rms. More realistically, it's more like 6V6rms. So, that leads me to thermal (which the manual shows as the code). That also gets me to over 25W into 4R which is below the current rating of the power brick (4A). I can nearly get to 25W into 2R with that voltage output while still staying below the current rating of the brick.
I am in MN, USA. The units are in my basement on an open-top rack. The ambient temp is ~20C. So... let's call that 'normal'.
Again... this was just my noodlings the other day... I may have some (or all) of that wrong re: my assumptions.
The two pair I've used so far are -
Tekton DI are 'rated' at 98dB / 2V8rms / 1m. 4R nominal. Never seen a decent published impedance curve. My gut says they're rated fairly ambitiously. If someone has a reliable source for a plot, I'd be grateful. I generally think they might dip to 2R in the bass region. One of these days, I'll learn to measure it.
Vandersteen 3A - 86dB / 1W / 1m. 6R nominal. 4R published min. Link to Stereophile measurements
As a side note - if these had worked out well, I may have purchased another pair to use with a pair of Nelson Pass inspired SLOBs. 4 Identical amps would have been nice, and I had hoped for a small form-factor. However, the cross-over needs a SE in/out... so... that also puts a kink in my idea.
TRS. True balanced / differential.
Quick pics of the mess. 🙂 They're playing now... again... they sound 'nice to me'. I've got the DIs hooked back up.
Cheers!
Edited to fix table import. Also... to note that I could have calculated things into 16R, but I don't think we're running into voltage issues... gut says it's thermal / overload into lower impedances.
Edited again to add - I hooked up the Vandy's b/c they're closer to my brother's 2Ce in characteristics than the Tektons. Since I ran them into protection with the Tektons... I was concerned. They ran into protection at lower listening levels (as expected) with the Vandys. Thus, I still have the amps and have not sent them to my brother yet. He'd be far less tolerant of little hiccups like this.
Last edited:
@ Itsall: are you still exhiting shutdowns, especially with the Tektons?
@ all: Update from pma:
https://www.audiosciencereview.com/...ping-b100-amplifier-review.57036/post-2149901
with RCA --> RCA, he got 54 W at 61.5% duty cycle into 4 R without shutdown, and had a shutdown after unspecified time with 94 W at 61.5%.
Note that 54 * 61.5% = 33.2 W which led to self destruction after 2 s in my specimen. Maybe mine was either an early production unit or somehow dodgy.
Alltogether, those are numbers I think I could live with, especially with a 4th order HP and a separate sub.
@ all: Update from pma:
https://www.audiosciencereview.com/...ping-b100-amplifier-review.57036/post-2149901
with RCA --> RCA, he got 54 W at 61.5% duty cycle into 4 R without shutdown, and had a shutdown after unspecified time with 94 W at 61.5%.
Note that 54 * 61.5% = 33.2 W which led to self destruction after 2 s in my specimen. Maybe mine was either an early production unit or somehow dodgy.
Alltogether, those are numbers I think I could live with, especially with a 4th order HP and a separate sub.
^ When wifey wakes up... I can push the Tektons a bit. They were the first issue with protection... then I hooked up the Vandys. DIs are back in. I can't measure output, but I'll give you a subjective gut feel and hold my phone's cheesy dBSPL tool at listening position.
They're a delight at "don't wake wifey" levels. It's only (with the DIs) at levels that I'd call "loud". However, with the DIs ("party speakers") I reach those levels semi-regularly. With the Vandy's they'd have been unacceptable (to me). They ran out of juice for 'loud rock' at reasonable listening room distances. I reach those levels on a daily basis.
I hope that makes some semblance of sense. Mainly... I'll repeat the behavior again and report back.
Edited for clarity - need more coffee. 🙂
Edited again to add - My gut says with a separate sub... most people will be fine depending on impedance characteristics / sensitivity of what else the B100s need to drive.
They're a delight at "don't wake wifey" levels. It's only (with the DIs) at levels that I'd call "loud". However, with the DIs ("party speakers") I reach those levels semi-regularly. With the Vandy's they'd have been unacceptable (to me). They ran out of juice for 'loud rock' at reasonable listening room distances. I reach those levels on a daily basis.
I hope that makes some semblance of sense. Mainly... I'll repeat the behavior again and report back.
Edited for clarity - need more coffee. 🙂
Edited again to add - My gut says with a separate sub... most people will be fine depending on impedance characteristics / sensitivity of what else the B100s need to drive.
correction to my post #189: Pavel got 54 W into 8R, not 4 R. His reply also shows the whole test cycle. Those 60% are only reached in the last ~20 s of the test sequence.
^ I fully admit that I'm not versed in "duty cycle".
So, wifey is awake and hasn't started conference calls yet.
Here's some 'reference' points. This is all with NIOSH SLM app on an iPhone and a complete dolt at the controls. So, grain of salt. Song will be noted as something "typical" that I might listen to at that level. I ran each for about 20s or so during a "normal" part of the song. Readings were 'reset' between each b/c it averages. So scientific, I know. <sarc>
With DIs -
Had tunes at my 'normal quiet' level. At listening position (WAY off axis at the computer) about 2m from the left driver and 4m from the right.
Frank Sinatra "Witchcraft" - I tried to get the horns b/c that section 'seems' loudest to me.
At chair -
Doesn't hold it, but glancing - max instantaneous level - ~70dB(A)
LAeq - 66.4dB
LMax - 75.2dB
LCPeak - 87.4dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Screen shot attached b/c I really don't have a clue what I'm doing.
Same song 1m (est) from left speaker ear height sitting -
Doesn't hold it, but glancing - max instantaneous level - ~80dB(A)
LAeq - 79.3dB
LMax - 89.0dB
LCPeak - 99.6dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Went to my 'good seat' which is situated ~5m from the speakers / centered. Moved level to 'normal quiet' by ear at that position.
Witchcraft again
LAeq - 67.1dB
LMax - 75.3dB
LCPeak - 90.3dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Back to 1m from speaker - at the speaker it's not "LOUD", but I'd probably not listen at that level that close for too long... just not my idea of 'correct' for that song.
LAeq - 84.5dB
LMax - 92.3dB
LCPeak - 103.5dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Went to my workbench - about 6m from the speakers off axis to right.
Witchcraft again
LAeq - 72.6dB
LMax - 82.4dB
LCPeak - 94.0dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Back to 1m from speaker
LAeq - 86.3dB
LMax - 91.0dB
LCPeak - 106.3dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
That's pretty loud at the speaker.
That's 'quiet ' at various places that I normally sit or work along with what things look like around 1m from the speaker.
No protection.
-----------------------------------------------------------------------------
Quickly! Did something to show what I MAY do on occasion if people are over. Plus... wifey may smack me over the head with a headset (and she's a floor up and on the opposite side of the house).
Song - Bela Fleck - Flight of the Cosmic Hippo - (b/c I know it has bass)
Went into protection at at about 1:10s (1 blink then 5 blinks) into the song on a bass drum kick. Took a quick video of 'error code'. Oddly... only right channel this time. Was this 'loud', yes. Was it ludicrously loud, no. Do I expect to be able to go to '11', yes. Was I able to hit pause on the SPL app to capture properly before I hit pause on the music, no.
Did a reset of both amps (just in case)... and knowing about where this song kicks it in... wanted to repeat it so I could get numbers.
LAeq - 75.7dB
LMax - 88.0dB
LCPeak - 107.3dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Again, that's at "the listening chair". Didn't want to try it again at the speaker. Screenshot attached. Oddly... the left amp went into protection this go around.
Hope that helps.
Not going to intentionally send them into protection again. I'll wind up keeping them, so I don't want to damage them.
Note in all screenshots the meter is "paused" but still shows the active "instantaneous" reading. Those aren't really relevant in the screenshots, when I remembered to look down at the phone and remember the instantaneous posted highest peak I saw... I jotted it above.
tl;dr - yep, even with DIs, they still go into protection under an atypical for some, but expected for me, use case.
Edited to add since above is pretty darn long - at 1:13 in or so... the bass drum kick will send the amp(s) into protection at a level I find "loud". I don't often listen that loud, but I sometimes listen louder. Also, that song is streamed from my NAS burned from CD. I don't use level correction (sometimes) in Roon. So, one other practical consideration is even if I keep the level down enough for THAT song to not go into protection, I'd almost guarantee that any song I stream from Qobuz if I don't have levelling on will put the amp(s) into protection if it comes after Flight of the Cosmic Hippo from my NAS.
Once again, I hope that makes sense from a practical / use case scenario.
Edited once again - For those keeping track. D90 into Iron Pumpkin with gain at 0dB into B100 at medium gain. All balanced.
So, wifey is awake and hasn't started conference calls yet.
Here's some 'reference' points. This is all with NIOSH SLM app on an iPhone and a complete dolt at the controls. So, grain of salt. Song will be noted as something "typical" that I might listen to at that level. I ran each for about 20s or so during a "normal" part of the song. Readings were 'reset' between each b/c it averages. So scientific, I know. <sarc>
With DIs -
Had tunes at my 'normal quiet' level. At listening position (WAY off axis at the computer) about 2m from the left driver and 4m from the right.
Frank Sinatra "Witchcraft" - I tried to get the horns b/c that section 'seems' loudest to me.
At chair -
Doesn't hold it, but glancing - max instantaneous level - ~70dB(A)
LAeq - 66.4dB
LMax - 75.2dB
LCPeak - 87.4dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Screen shot attached b/c I really don't have a clue what I'm doing.
Same song 1m (est) from left speaker ear height sitting -
Doesn't hold it, but glancing - max instantaneous level - ~80dB(A)
LAeq - 79.3dB
LMax - 89.0dB
LCPeak - 99.6dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Went to my 'good seat' which is situated ~5m from the speakers / centered. Moved level to 'normal quiet' by ear at that position.
Witchcraft again
LAeq - 67.1dB
LMax - 75.3dB
LCPeak - 90.3dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Back to 1m from speaker - at the speaker it's not "LOUD", but I'd probably not listen at that level that close for too long... just not my idea of 'correct' for that song.
LAeq - 84.5dB
LMax - 92.3dB
LCPeak - 103.5dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Went to my workbench - about 6m from the speakers off axis to right.
Witchcraft again
LAeq - 72.6dB
LMax - 82.4dB
LCPeak - 94.0dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Back to 1m from speaker
LAeq - 86.3dB
LMax - 91.0dB
LCPeak - 106.3dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
That's pretty loud at the speaker.
That's 'quiet ' at various places that I normally sit or work along with what things look like around 1m from the speaker.
No protection.
-----------------------------------------------------------------------------
Quickly! Did something to show what I MAY do on occasion if people are over. Plus... wifey may smack me over the head with a headset (and she's a floor up and on the opposite side of the house).
Song - Bela Fleck - Flight of the Cosmic Hippo - (b/c I know it has bass)
Went into protection at at about 1:10s (1 blink then 5 blinks) into the song on a bass drum kick. Took a quick video of 'error code'. Oddly... only right channel this time. Was this 'loud', yes. Was it ludicrously loud, no. Do I expect to be able to go to '11', yes. Was I able to hit pause on the SPL app to capture properly before I hit pause on the music, no.
Did a reset of both amps (just in case)... and knowing about where this song kicks it in... wanted to repeat it so I could get numbers.
LAeq - 75.7dB
LMax - 88.0dB
LCPeak - 107.3dB
TWA - N/R
Dose - N/R
Projected Dose - N/R
Again, that's at "the listening chair". Didn't want to try it again at the speaker. Screenshot attached. Oddly... the left amp went into protection this go around.
Hope that helps.
Not going to intentionally send them into protection again. I'll wind up keeping them, so I don't want to damage them.
Note in all screenshots the meter is "paused" but still shows the active "instantaneous" reading. Those aren't really relevant in the screenshots, when I remembered to look down at the phone and remember the instantaneous posted highest peak I saw... I jotted it above.
tl;dr - yep, even with DIs, they still go into protection under an atypical for some, but expected for me, use case.
Edited to add since above is pretty darn long - at 1:13 in or so... the bass drum kick will send the amp(s) into protection at a level I find "loud". I don't often listen that loud, but I sometimes listen louder. Also, that song is streamed from my NAS burned from CD. I don't use level correction (sometimes) in Roon. So, one other practical consideration is even if I keep the level down enough for THAT song to not go into protection, I'd almost guarantee that any song I stream from Qobuz if I don't have levelling on will put the amp(s) into protection if it comes after Flight of the Cosmic Hippo from my NAS.
Once again, I hope that makes sense from a practical / use case scenario.
Edited once again - For those keeping track. D90 into Iron Pumpkin with gain at 0dB into B100 at medium gain. All balanced.
Last edited:
Even though I couldn't follow it completely in its entirety. as it deserved, it is great post imo, in every sense, descriptive and analytics.
However, snce Google Translate sometimes gives incomprehensible (to me) translations sorry if I ask, but if I understood correctly, you decided to keep the two Topping, if so, I'm happy for you from a sound point of view and also because this way you also saved a lot of energy and resources.
Anyway, please note that in attached pictures of the two power amps, the speaker cables of the right channel seem reversed.
^ Apologies. I type a lot.
Oversimplifying, but...
They sound very nice (to me) at all volumes where they work. They 'stop working' at a level that (to me) is not acceptable for an amplifier that the manufacturer would like us to think is "100W". Given that there really is no working standard (at least in the USA) for this, I can't call the claim deceptive, but ... it seems very careful.
There may be a standard for amplifier power in the USA (again) soon, from what little I understand. That will hopefully help.
So, I don't feel "cheated", but I certainly can't recommend these amps to people if they feel like they need a "100W" amplifier.
It is too much of a pain to send them back to the retailer, and I can use them for other things. So, I will keep them. If I could take them back to a local store and get all my money back, I would.
Other people may feel differently about the power claim.
My goal was to post (hopefully) useful information to others that may be considering them. They could work really well for some people. They just will not work well for me, in this application. So, I'll find something else to do with them.
Cheers!
Oversimplifying, but...
They sound very nice (to me) at all volumes where they work. They 'stop working' at a level that (to me) is not acceptable for an amplifier that the manufacturer would like us to think is "100W". Given that there really is no working standard (at least in the USA) for this, I can't call the claim deceptive, but ... it seems very careful.
There may be a standard for amplifier power in the USA (again) soon, from what little I understand. That will hopefully help.
So, I don't feel "cheated", but I certainly can't recommend these amps to people if they feel like they need a "100W" amplifier.
It is too much of a pain to send them back to the retailer, and I can use them for other things. So, I will keep them. If I could take them back to a local store and get all my money back, I would.
Other people may feel differently about the power claim.
My goal was to post (hopefully) useful information to others that may be considering them. They could work really well for some people. They just will not work well for me, in this application. So, I'll find something else to do with them.
Cheers!
Last edited:
Tell me about it! 😀
It's not you, it's a limitation of mine that I can't read (the translations of Google) for too long.
However, just out of curiosity, why are the right amp cables colors reversed?
Yes, and you did it well.
Their protections are probably sensitive to speakers with (very) low impedance.
It becomes progressively harder to design amps with decent output power and low distortion and noise. This happens because things like common impedance coupling, larger signal related EM radiation, PSU ripple etc all become progressively more intrusive and require mitigation in higher power amps.
Separately, I can’t help think that some of the products - and especially those reviewed on ASR - are designed to perform exceptionally well at Amir’s 5W Sinad test regime. In other words they are gaming the test regime. Is a Topping really better than a Benchmark ABH2?
Modern speakers are generally very inefficient and claiming the average output power of a music signal is 1W misses the fact that you also have to reproduce crescendos without distortion.
The relentless focus on single digit ppm distortion is tiresome when other things like power delivery and the ability to drive real world loads are more important. Distortion is not the most important amplifier parameter. It simply has to be below the threshold of hearing. Adequate power, ability to drive complex loads and freedom from hum etc are more important.
OH! I forgot to answer that in your earlier post. They were/are reversed at the amp on that channel. They are/were wired in phase though. The DI's don't have a clear + - on the back (that these tired eyes can read). They're very small and in the same color as the backing. I should mark them with a white pen. When I hooked up that channel first, I realized I did backwards at the speaker... Dark corner of the room, and I was lazy. So, I just connected the amp the same for that side. 🙂
If you zoom in, you can barely make out the + / -
I went back and swapped both... just to be proper. Thank you. 🙂
Hi Bonsai, Ostrippers post sparked my interest. Im curious what designs hes referring to.
What designs are you referring to?
Cheers
and vs Wolverine, Mod x86 etc. perhaps we should create a list to correlate what is ‘objectively’ tested by ASR with real world performance🙂