[TonyRoma]

Hi, i had a problem with this amp and the SR1a where i would get distortion in one channel at higher volumes, i sent videos of the problem to Topping and the retailer with no Joy so i returned the amp to the seller and got a refund after a lot of messing about and having to pay return shipping. The unit i had was a very early release with the original firmware.

 

[Buckie]

Hi, i had a problem with this amp and the SR1a where i would get distortion in one channel at higher volumes, i sent videos of the problem to Topping and the retailer with no Joy so i returned the amp to the seller and got a refund after a lot of messing about and having to pay return shipping. The unit i had was a very early release with the original firmware.

That could make sense, that they try to avoid distortion by cutting off the signal. My Callia which has analog volume control does distort after a certain threshold. Hmm. This is all good and well, but what about 17x2 watts of power...

 

[TonyRoma]

Not sure how accurate their power specs are but i had to go really high on the volume for the sr1a and thats when it distorted, im now using Schiit gjallarhorns which have ample power for these phones.

 

[SageM]

A little story about VM1-a.

I bought a second-hand VM a while ago.
When I received it, it didn't work (nothing to do with its first owner with whom I had a perfect transaction.)

I asked Raal for help and the same day David got back to me and put me in touch with Danny.
So I was able to talk to Danny, which was both great(I mean: Wow! a talk with Danny himself) and horrible because speaking English is a real torture for me.
Danny asked me for several tests and when he couldn't find a cause, referred me to Dragan from Solaja Audio.

After sending Dragan photos of the inside of the VM1-a, which revealed nothing, he asked me to send it to him.
Dragan immediately found out what was wrong.
A hole had been drilled in the VM's frame, damaging it.
Probably Customs wanted to check if there was anything illegal inside.(there seems to be some kind of sand inside to insulate components).
Dragan was able to repair it and send it back to me.

But on his return, when I switched it on, there was an immediate smell of burning.
This time it was me who, in the excitement of getting the VM back, must have connected a tube wrong.
It was a real nightmare, but once again, Dragan found the solution by sending me a new card which I was able to install easily.

So today I'd like to say a very big thank you to David, Danny and Dragan of course.
They did everything they could to help me, even though it's a second-hand VM and they didn't have to.
They are talented people, who design fantastic products, but they are also extremely thoughtful and generous people.

And so I can confirm that music through the VM1-a/SR-1a is incredibly beautiful.

Thank you for sharing this story and so kind are your words about our concern for your situation. I've been involved, professionally, in audio for over 45-years and never seen anything so crazy as customs drilling a hole into a power transformer! Crazy! I must complement you for being so patient and cool under such circumstances. Very best wishes, Danny McKinney RAAL-requisite

 

[nfandi]

That could make sense, that they try to avoid distortion by cutting off the signal. My Callia which has analog volume control does distort after a certain threshold. Hmm. This is all good and well, but what about 17x2 watts of power...

Buckie do you still have a need for this question to be answered or is it now resolved?

 

[Buckie]

Buckie do you still have a need for this question to be answered or is it now resolved?

Good day! I absolutely do need to have this answered. I've contacted Topping about it and they've avoided answering the question for several emails and after I asked them directly they chose to be silent. Specifically, I asked, what are...
1. Maximum peak power in watts
2. Maximum sustained power in watts
per channel on balanced output.

 

[nfandi]

Good day! I absolutely do need to have this answered. I've contacted Topping about it and they've avoided answering the question for several emails and after I asked them directly they chose to be silent. Specifically, I asked, what are...
1. Maximum peak power in watts
2. Maximum sustained power in watts
per channel on balanced output.

Ok, first off I am not technical nor do I understand much about electronics, BUT, I’ve owned the Raal SR1b and CA1a since 2022 and read every thread and posting I could find about them. So here’s my thoughts. Most headphones use voltage drive and watts is the usual term used for the amplifiers we use to drive them. The Raal’s are very different in that they present a virtually zero impedance to an amplifier and they are current-drive, not volts. The interface box you are using presents a more friendly impedance to your amplifier and it converts the volts into the amps that the CA1a needs. So far so good. Dynamic music such as Orchestral Classical or Bass Heavy music such EDM etc creates huge demands for power. I’ve looked at the ASR review of the A70 and also at the manufacturers specification and they both have something missing that seems to me to be very important. I see no info about Impulse Response, Rise Time etc. This is the ability of the amplifier to cope with sudden demands for power, power that the CA1a most needs to give its bass response or it’s amazing fast transient responses to things like drum hits. I think the CA1a is via the interface box is pulling more power than the A70 can sustain and hence it keeps trying to go into shutdown or self-protection mode. This is not about 17 watts continuous power into an easy load, this is about the sudden need for more amps brought on by the dynamic range in some types of music.
I might be completely and utterly wrong and would be very happy if someone could correct me. But I saw that nobody had tried to answer your question and so I thought I would at least try.

 

[Polygonhell]

Good day! I absolutely do need to have this answered. I've contacted Topping about it and they've avoided answering the question for several emails and after I asked them directly they chose to be silent. Specifically, I asked, what are...

The odds are Topping are the only ones that can answer the question.
Transformers aren't magic, they convert Voltage into Current and Vice Versa, having said that they also won't present a static load, and it will vary to a point with frequency response.
If I had to guess the issue is that Toppings quoted power figure is a peak figure quoted for a 1000Hz Sine Wave, and it can't sustain anything like that number for any duration, and as has been pointed out Bass frequencies require more energy to reproduce.
It could be as you speculated an issue with a badly designed protection circuit, but without knowing what it's doing, it's hard to say, if it's protecting the amp from say drawing too much current, they can't just disable it.

The problem is quoted power figures may bot be based on any standard, Ifi for example has been quoting power based on an amps ability to reproduce a single cycle of a sine wave at the given amplitude into a fixed load, leading to grossly inflated figures for amps like the Diablo.

You really don't even need the recommended 3W to drive the Raal's, I can drive the Raal's from a 2A3 amp I designed and built, which has a power output of ~3W into 8 Ohms, probably closer to 2 into 16, and 1.5 into 32, but it's not a peak rating, it will sustain that power out all day.

 

[Buckie]

Well, it's exactly the lack of standard that is the culprit here. 17 watts measured what way, exactly? If I would pry, Topping could answer with a similarly nonsensical value for sustained power which in the end would tell me nothing. Perhaps if I could measure the power at my end somehow, playing a specific tune, but even then that would not help me make an informed decision on what amplifier to buy instead, given that their specs are so misleading.

It's also interesting that I drove VM1-a's Ultra-Linear past its rated 15 watts – I knew because audible distortion appeared at very loud levels. It didn't cut off, however. Which is interesting because now I wonder if Topping A70 may start to distort before cutting the signal off. I haven't definitely heard it, but it's a possibility still.

 

[nfandi]

Well, it's exactly the lack of standard that is the culprit here. 17 watts measured what way, exactly? If I would pry, Topping could answer with a similarly nonsensical value for sustained power which in the end would tell me nothing. Perhaps if I could measure the power at my end somehow, playing a specific tune, but even then that would not help me make an informed decision on what amplifier to buy instead, given that their specs are so misleading.

It's also interesting that I drove VM1-a's Ultra-Linear past its rated 15 watts – I knew because audible distortion appeared at very loud levels. It didn't cut off, however. Which is interesting because now I wonder if Topping A70 may start to distort before cutting the signal off. I haven't definitely heard it, but it's a possibility still.

Try talking to SageM (that’s Danny from Raal-Requisite) he’s a very knowledgeable guy and helpful at the same time.

 

[nfandi]

Try talking to SageM (that’s Danny from Raal-Requisite) he’s a very knowledgeable guy and helpful at the same time.

On the other hand I just read a review of the CA-1a that I found on the Home Screen, posted 1st Feb. He cites the A70 as one of the amplifiers he used that could drive the CA to over 100dB with no problems. Maybe you do have a fault with yours.

 

[ra990]

The A70 does run out of steam on some of my music with the CA-1a. It was fine for a lot of the louder tracks, but lacked the volume I needed on some others. I got a Benchmark AHB2 for them and it was like having unlimited headroom with the CA-1a.

 

[nfandi]

The A70 does run out of steam on some of my music with the CA-1a. It was fine for a lot of the louder tracks, but lacked the volume I needed on some others. I got a Benchmark AHB2 for them and it was like having unlimited headroom with the CA-1a.

In my early days with the SR1b and CA1a I also found that the problem is not just the amplifier but the DAC and Amplifier combination. I had a cable made so that I could use my SP2K Dap in line-out mode into the HSA-1b direct drive amplifier; the DAP acting as a DAC in this situation. There was no problem with volume but the sound was very ‘thin’; almost no bass. The spec says the SP2K outputs a 6Vrms signal which should be more than enough, BUT, the important thing is in brackets after the 6Vrms; it says (no load). What happened was after a few minutes the DAP became very hot and couldn’t sustain the output demanded by the phones. Aleks said it was the output stage that was overheating. I now use a Holo May which outputs 5.8Vrms via XLR which on paper is less than the SP2K, but the Holo can sustain this all day and is in fact too ‘hot’ for my Nutopia. I just ordered some RCA cables to see what difference this makes when the Holo output is 2.9Vrms. So, it’s not just the amplifier, look at the DAC as well.

 

[Buckie]

The A70 does run out of steam on some of my music with the CA-1a. It was fine for a lot of the louder tracks, but lacked the volume I needed on some others. I got a Benchmark AHB2 for them and it was like having unlimited headroom with the CA-1a.

So it does confirm A70 is underpowered. AHB2 seems to be a power amplifier. I've read briefly that people do connect their CAs directly to such amplifiers, but what's the bottom line? Is that a working solution that's replacing headphone amplifier+TI combo?

 

[nfandi]

So it does confirm A70 is underpowered. AHB2 seems to be a power amplifier. I've read briefly that people do connect their CAs directly to such amplifiers, but what's the bottom line? Is that a working solution that's replacing headphone amplifier+TI combo?

No, all amplifiers need the TI combo except the 2 direct drive amps the HSA-1 and VM1. In the early days of the SR1a you needed amplifiers with at least 100W output and the interface was a resistor box. This box was then replaced by the 1b version which is a transformer box instead and allows the use of higher output Headphone Amps.