[KaiSc]

Well, I got really excited about this theory as it seemed entirely plausible and ran to test it out! Unfortunately, that seems not to be the case. I had to set the EQ to cut everything sharply below 750 Hz before dropouts started to diminish in frequency, but they were not gone entirely. In fact, the limit of -11db where dropouts never occur on the A70 remained there even regardless of that brickwall EQ - i. e. with or without that EQ going past -11db is guaranteed to give me dropouts on a certain song.

It looks like the "HP DC abnormal" that only appears very rarely may be related to those subsonic frequencies, but overall the issue lies elsewhere.

If you really used a cut-, not a shelf filter EQ - with no success, then it‘s the other type of DC problem:
Topping A70 must have a DC offset on the output and goes crazy when trying to push lots of DC current through Ti1a/b.

If you (or a friend, …) has a Volt meter the DC can be measured.
In this case a blocking cap between Topping and Ti1 would help.


Or maybe it’s just a general, load-impedance related, amp-instability past volume position -11 dB, - such things exist.
You might try to stay below this mark, and drive Topping’s input hotter to achieve more volume.

 

[Buckie]

If you really used a cut-, not a shelf filter EQ - with no success, then it‘s the other type of DC problem:
Topping A70 must have a DC offset on the output and goes crazy when trying to push lots of DC current through Ti1a/b.

If you (or a friend, …) has a Volt meter the DC can be measured.
In this case a blocking cap between Topping and Ti1 would help.


Or maybe it’s just a general, load-impedance related, amp-instability past volume position -11 dB, - such things exist.
You might try to stay below this mark, and drive Topping’s input hotter to achieve more volume.

Hmm. I do have a moderately sophisticated voltmeter. What do I need to measure?
As for driving it hotter, well, I tried to use the 16 ohms input on the TI instead of the 32 ohms input and it simply brought the -11db limit lower. I'll see if I can find a more powerful line out source lying around.

I'm also wary of using caps because I think that exposed unshielded pieces of electronics hanging on the wire like that may degrade signal.

 

[KaiSc]

Hmm. I do have a moderately sophisticated voltmeter. What do I need to measure?

The DC Voltage at Topping A70’s headphone output when idle.
If it’s more than a few Millivolts we caught the thieve.

As for driving it hotter, well, I tried to use the 16 ohms input on the TI instead of the 32 ohms input and it simply brought the -11db limit lower.

That’s in line with the assumption that T1’s load is taxing Topping A70 too much.
As Ti1‘s impedance is specifically low at very low frequencies and almost zero at DC, that’s the range that provokes the error.

I'll see if I can find a more powerful line out source lying around.

It’s just a try, with no guarantees it helps.

I'm also wary of using caps because I think that exposed unshielded pieces of electronics hanging on the wire like that may degrade signal.

No need to worry, a power amp / headphone output can’t catch any stray signals for multiple reasons.
Most headphones cables e.g. are unshielded because of this fact.

A 500 uF cap would prevent the Ti1 to go below 32 Ohm impedance below 20 Hz and thus make it an easier load.
For Ti1’s 16 Ohm input a 1000 uF cap would be the fitting value, but 16 Ohm isn’t needed with Toppings power.

 

[Buckie]

The DC Voltage at Topping A70’s headphone output when idle.
If it’s more than a few Millivolts we caught the thieve.

That’s in line with the assumption that T1’s load is taxing Topping A70 too much.
As Ti1‘s impedance is specifically low at very low frequencies and almost zero at DC, that’s the range that provokes the error.

It’s just a try, with no guarantees it helps.

No need to worry, a power amp / headphone output can’t catch any stray signals for multiple reasons.
Most headphones cables e.g. are unshielded because of this fact.

A 500 uF cap would prevent the Ti1 to go below 32 Ohm impedance below 20 Hz and thus make it an easier load.
For Ti1’s 16 Ohm input a 1000 uF cap would be the fitting value, but 16 Ohm isn’t needed with Toppings power.

So the voltage is zero. Guess it's something else.
While fumbling with DACs I discovered an interesting behavior, perhaps I should inform Topping about it: A70 mutes outputs even without any load present, fully disconnected from any consumers. I know that because I hear it clicking. The volume threshold is higher than with a TI connected but it still disconnects. What would that mean?

A couple of other findings: another more powerful DAC's line out simply moved that -11db limit lower, no surprises there.
I somehow managed to get the "HP DC abnormal" message to get stuck on the screen for a long time, but I cannot remember exactly what I did, it was either the powerful DAC and A70 without load, or that DAC alone, or maybe I was playing with brickwall EQ too. Before that the message only appeared for a very short time.

 

[KaiSc]

So the voltage is zero. Guess it's something else.
While fumbling with DACs I discovered an interesting behavior, perhaps I should inform Topping about it: A70 mutes outputs even without any load present, fully disconnected from any consumers. I know that because I hear it clicking. The volume threshold is higher than with a TI connected but it still disconnects. What would that mean?

It‘s broken.

A couple of other findings: another more powerful DAC's line out simply moved that -11db limit lower, no surprises there.
I somehow managed to get the "HP DC abnormal" message to get stuck on the screen for a long time, but I cannot remember exactly what I did, it was either the powerful DAC and A70 without load, or that DAC alone, or maybe I was playing with brickwall EQ too. Before that the message only appeared for a very short time.

Same, if the behavior changed some time, it‘s broken.

EDIT:
But it seems this had only worsened an existing problem.

 

[Strayngs]

Is there any issue using a standard XLR to 1/4 adapter to plug the interface into my se amp (ampsandsound Bigger Ben Rev 2). I should not have to buy the Raal adapter cable should I?

 

[technobear]

Is there any issue using a standard XLR to 1/4 adapter to plug the interface into my se amp (ampsandsound Bigger Ben Rev 2). I should not have to buy the Raal adapter cable should I?

If you wish to make your own, the pinout is the regular Headphone Balanced 4-pin XLR pinout:

Pin1: L+, Pin2: L-, Pin3: R+, Pin4: R-.

The cable between the amp and the TI-1b is not critical. You can use whatever you like.

The cable between the TI-1b and the headphone is critical and you should only use those supplied by Raal-Requisite unless you understand the electrical requirements and can make a cable to the specific specification.

 

[Reputator]

I've had about a week with my new (open box) CA-1a. Running it off of a close-out Jotunheim A and Moon Audio Black Dragon cable, because that was the cheapest way to get into this headphone, and as it breaks in and as I adjust to it, I'm really impressed with the clarity and detail. It's definitely a level up from my other headphones in that regard. The bass dynamics are also pretty good, and I found I prefer the coffee bean pads but with the bass boost on the Jot A switched on. Closed pads (even without the bass boost) have a touch too much bleed on the low-end for some genres.

It's really good with a number of genres, particularly jazz, but it doesn't quite have the overall dynamics of some of my other headphones for those more visceral, energetic genres. That's fine by me, I don't need it to do everything, but what it does do well is very impressive.

Spoiler

And if you're wondering "Well why don't you use this >$1k cable and this $200 software filter and this crazy $3k discontinued amp, well..... Again, I had to find the cheapest way to enter the world of RAAL headphones, so here we are.

 

[FiGuY1017]

I've had about a week with my new (open box) CA-1a. Running it off of a close-out Jotunheim A and Moon Audio Black Dragon cable, because that was the cheapest way to get into this headphone, and as it breaks in and as I adjust to it, I'm really impressed with the clarity and detail. It's definitely a level up from my other headphones in that regard. The bass dynamics are also pretty good, and I found I prefer the coffee bean pads but with the bass boost on the Jot A switched on. Closed pads (even without the bass boost) have a touch too much bleed on the low-end for some genres.

It's really good with a number of genres, particularly jazz, but it doesn't quite have the overall dynamics of some of my other headphones for those more visceral, energetic genres. That's fine by me, I don't need it to do everything, but what it does do well is very impressive.

Spoiler

And if you're wondering "Well why don't you use this >$1k cable and this $200 software filter and this crazy $3k discontinued amp, well..... Again, I had to find the cheapest way to enter the world of RAAL headphones, so here we are.

I'd highly recommend reading up on recommended amps for CA-1A as it's worth building around and you will find the dynamics can be outstanding with the right set up. I was very close to trading mine actually then listened to them and came back to my senses. They are sades smooth and depending on the amp I highly recommend Mitch's accurate sound filters.

 

[Reputator]

I'd highly recommend reading up on recommended amps for CA-1A as it's worth building around and you will find the dynamics can be outstanding with the right set up. I was very close to trading mine actually then listened to them and came back to my senses. They are sades smooth and depending on the amp I highly recommend Mitch's accurate sound filters.

I anticipated a response like this which is why I added that spoiler tag note. I don't have a summit-fi budget (see my other decidedly not summit-fi gear in my sig) so certain things will be outside my grasp. But I still enjoy what I can get out of it with my available resources.

 

[FiGuY1017]

I anticipated a response like this which is why I added that spoiler tag note. I don't have a summit-fi budget (see my other decidedly not summit-fi gear in my sig) so certain things will be outside my grasp. But I still enjoy what I can get out of it with my available resources.

Meh you don't need a summit level amp to enjoy those benefits, my Kinki studio thr1 does the trick just fine. You need power and synergy imo

 

[Reputator]

Meh you don't need a summit level amp to enjoy those benefits, my Kinki studio thr1 does the trick just fine. You need power and synergy imo

I should also note my open-box CA-1a came without the TA-1a. I assume your amp suggestion requires it.

 

[FiGuY1017]

Yes mine came with T1-1b and it's not direct drive so it does require it. Worth buying imo though as it's acoustically transparent and makes the Ca1a much more versatile

 

[Reputator]

Yes mine came with T1-1b and it's not direct drive so it does require it. Worth buying imo though as it's acoustically transparent and makes the Ca1a much more versatile

T1-1b, that's it. Yeah I don't have that, and it doesn't appear to be sold separately. But I'll live.

 

[FiGuY1017]

T1-1b, that's it. Yeah I don't have that, and it doesn't appear to be sold separately. But I'll live.

I bet they do just shoot them a email, great guys and easy to work with