[BassicScience]

Good catch on the typo. Meant DAC->HPA4->AHB2->iESL. Yep, the CRBN only plugs into the 5 pin pro jack (set to 580V).

Actually, it'll plug into the Normal jack as well, and sound like crap. I know cause I did it first time I listened to my Shangri-la Junior.

Does the AHB2 have a gain setting? If so, I'd suggest maxing it.

EDIT: I just looked at the AHB2 manual, and the highest gain (lowest sensitivity, in their nomenclature) setting is only intended for unbalanced inputs. If you're running XLR (as you should be) from the HPA4, the middle setting is the one they recommend. FWIW.

 

[etc6849]

Happens to the best of us! I'm using the 22dBu sensitivity setting (recommended for pro-audio levels). This is with the sensitivity switch all the way down. This is what Benchmark recommends as their DACs and HPA4 all output pro audio signal levels that run hotter than consumer gear (for XLR anyways).

Unfortunately, as you probably know, if I did change the sensitivity setting on the amp to 14dBu, it would indeed make the amp louder, but then the HPA4 volume would need to be set -8dB lower to compensate. This is because gains add and if you don't lower the volume of the HPA4, you would get clipping on the amp. Thus, this would not make the entire system louder (if the goal is to avoid clipping as it should be).

I was really hoping there was some jumper setting inside the iESL. I went and added a second AHB2 I took from my theater. By setting the amps to bridge mode and running them as monoblocks, the CRBNs are indeed loud enough. So 380 W Bridged Mono into 8 Ohm is what the AHB2 is rated as in this configuration. Just doesn't seem right that I need this much power to drive the CRBNs with the iESL?!?

Actually, it'll plug into the Normal jack as well, and sound like crap. I know cause I did it first time I listened to my Shangri-la Junior.

Does the AHB2 have a gain setting? If so, I'd suggest maxing it.

EDIT: I just looked at the AHB2 manual, and the highest gain (lowest sensitivity, in their nomenclature) setting is only intended for unbalanced inputs. If you're running XLR (as you should be) from the HPA4, the middle setting is the one they recommend. FWIW.

 

[BassicScience]

Happens to the best of us! I'm using the 22dBu sensitivity setting (recommended for pro-audio levels). This is with the sensitivity switch all the way down. This is what Benchmark recommends as their DACs and HPA4 all output pro audio signal levels that run hotter than consumer gear (for XLR anyways).

Unfortunately, as you probably know, if I did change the sensitivity setting on the amp to 14dBu, it would indeed make the amp louder, but then the HPA4 volume would need to be set -8dB lower to compensate. This is because gains add and if you don't lower the volume of the HPA4, you would get clipping on the amp. Thus, this would not make the entire system louder (if the goal is to avoid clipping as it should be).

I was really hoping there was some jumper setting inside the iESL. I went and added a second AHB2 I took from my theater. By setting the amps to bridge mode and running them as monoblocks, the CRBNs are indeed loud enough. So 380 W Bridged Mono into 8 Ohm is what the AHB2 is rated as in this configuration. Just doesn't seem right that I need this much power to drive the CRBNs with the iESL?!?

Glad to hear you could get the desired volume when bridging the AHB2s. FWIW, I have to crank up the volume a goodly amount on my preamp when driving my Shang Jr. with the iESL compared to using the same amp to drive my Susvara directly. I don't know the relative sensitivity of the CRBN vs. the Shang Jr., but my amp is rated at 185W into 8 ohms. I do set the iESL's impedance at 64 ohms because that yielded the best sound for me. Setting it to a lower impedance would bump the effective gain but likely at the cost of some linearity.

 

[etc6849]

I have heard that the CBRN is quite insensitive, but I wonder if you're saturating the transformer in this case... saturating the transformer will momentarily cause their AC impedance to go to zero, which will cause the amp to clip. There is no way you need more than one 500W amp to drive a pair of electrostatic headphones, its more likely that running in mono simply allows the amp to brute force the current demands of the transformer when it goes into saturation.

Check the amp for DC offset, ideally it should be less than 10 mV. If that's not the issue, then maybe the iESL's transformers just aren't big enough for the CBRN. If the transformers are constantly being driven to saturation, they will die eventually.

Another thing you can do is to add a high-quality 5W-10W 2 ohm resistor to the transformer's inputs (drop to 1 ohm if HF rolloff is significant). This will keep the amp from clipping at least, and it will reduce whatever effect DC offset has on the transformer. I would assume that iFi already has resistors on the inputs, but the clipping implies that the iESL has very little DC resistance.

https://www.head-fi.org/threads/stax-sr-x9000.959852/post-16722997

The above quote is from another thread; a bright member had some excellent suggestions that would have fixed my problem. I never got around to trying them as I really like having the second AHB2 amp to drive my speakers anyway, but I bet their hunch is right and the suggestion would work well.

I ended up returning the CRBN though as it had distortion with certain bass tracks. No worries though, as I have another e-stat on order (Stax SR-X9000). In the time being, I've been using the iESL to drive an HD800S with two Benchmark AHB2's, HPA4 and a DAC3; sounds fantastic!

 

[etc6849]

@Tachikoma

I actually ended up returning the CRBNs due to the very minor distortion on a few tracks, and ordered some Stax headphones (can't wait for them to show up).

In the meantime, I've done some testing of the iFi Pro iESL based on your thoughtful post. Measurements were done using two AHB2's, each in bridged/mono mode.

I do indeed measure about a 10mV DC offset if I really crank the volume to uncomfortably loud levels while using the iESL to drive some Sennheiser HD800's. For almost too loud measurements, they range from 5mV-10mV (no clipping at all from the amps though as I'm running two of them now).

Further, with or without the HD800s attached to the iESL dynamic 4 pin XLR on the front, I get similar measurements for DC offset that fluctuate based on the music between 5mV - 10mV with the HPA4. Thus, once I found this out, I decided to do some clipping testing with no headphones attached to the iESL as I didn't want to risk damaging my headphones (e.g. amps would then see only the input impedance of the iESL as I left the iESL turned on). As you suspect, clipping does occur near or above 0dB on the HPA4 (a level that would be unbearably loud with headphones on or even just my speakers).

When I measure the DC input impedance at the iESL using my multimeter (amps are unhooked from the iESL), I see 11.91 ohms for the 16 ohm setting (where I usually keep the impedance selection dial on the iESL); 25.23 ohms for 24 ohm setting; 26.22 ohm for the 64 ohm setting; and 39.55 ohms for 96 ohm setting. These measurements were without any headphones attached. If I attach headphones, and redo the input impedance measurements, the measurements are slightly smaller, ranging from 11.83 ohms (16 ohm setting) to 39.24 ohms (highest setting of 96 ohms).

That said, I assume your post meant putting a resistor in parallel with the load the amp sees (e.g. in parallel with the input impedance of the iESL). I do have some 4.5 ohm 12 watt resistors, but don't have anything of higher wattage. Assuming 4.5 ohms, this would lower the impedance the amp sees to around 3.26 ohms if I keep the iESL impedance selector on 16 ohms (4.5 ohms in parallel with 11.91 ohms).

I'm hesitant to do this, unless I ever need more volume out of the current set up (not sure what headphones this would ever be with two AHB2's). If I ever go back to only one AHB2, it definitely seems a large 4-6 ohm resistor in parallel with each speaker input on the iESL would fix the low volume issue when driving some headphones like the CRBN (one AHB2 amp is actually rated to drive a 3 ohm load at 240 watts: https://benchmarkmedia.com/products/benchmark-ahb2-power-amplifier).

I am curious on your thoughts...

I think as long as there is no clipping at loud volumes (e.g. above normal/loudness is still bearable, around -10dB on the HPA4 volume), my meter shows less than 10mV DC offset with a track playing at the loud level, and no distortion is heard, I am OK unless I go back to one amp... In the current setup, it seems the clipping lights on the AHB2's will alert me to whether the iESL sees any large DC offset.

I haven't taken the iESL apart yet, but it does seem the impedance selector's impedance would protect the iESL's transformers regardless?

Thanks!

 

[Tachikoma]

That said, I assume your post meant putting a resistor in parallel with the load the amp sees ...

No, in series. If the impedance is already 11.91 ohms there is no need for it. My own transformer solution has a DC impedance less than 1 ohm and therefore requires a little extra series resistance.

I guess the iESL transformers are simply not large enough to handle the CBRN then.

 

[eskamobob1]

Anyone here tried the iESL on either the HSA-1B, AMP-13R, or AIC-10? Curious to hear subjective impressions of any of the above pairings tbh

 

[MokhaMark]

Anyone here tried the iESL on either the HSA-1B, AMP-13R, or AIC-10? Curious to hear subjective impressions of any of the above pairings tbh

There is a respected member of another forum who did try the HSA-1b with iESL & CRBN and found it unsatisfactory in comparison to the other options being tried at the same time. He does not like to be quoted but I can link you to the comment via message if you would like.

 

[MokhaMark]

Hello all,

I think I have read most of this thread and thank you all for the helpful comments. I am a newer reader here and appreciative of the resources available for e-stats and amps.

I may have just purchased one of the last iESL out there (hoping I do not get an out of stock email later).

I have CRBN coming this week, and a used STAX 007t2. I have been subsequently informed by an expert on e-stats that the STAX amp may not be up to the challenge of the CRBN. These are my very first e-stats and I may not have researched well enough before diving in on the amp. The iESL is my hedge.

I am wondering if anyone has any experience with the Schiit Aegir or Vidar in mono configuration into the iESL? Based on some other set ups in this thread, it would appear not to be over kill. This set up could be had for about half the price of a Mjolnir Carbon for example.

I am a fanatical Raal listener and very excited to have my first e-stat listen soon.

Happy listening.

 

[eskamobob1]

There is a respected member of another forum who did try the HSA-1b with iESL & CRBN and found it unsatisfactory in comparison to the other options being tried at the same time. He does not like to be quoted but I can link you to the comment via message if you would like.

Hahaha. I think I know who it is then. I must have missed that comment in his thread. I'll check it back out

 

[MokhaMark]

Hahaha. I think I know who it is then. I must have missed that comment in his thread. I'll check it back out

It's a long thread, look in Oct 21

 

[BTD1]

Hello all,

I think I have read most of this thread and thank you all for the helpful comments. I am a newer reader here and appreciative of the resources available for e-stats and amps.

I may have just purchased one of the last iESL out there (hoping I do not get an out of stock email later).

I have CRBN coming this week, and a used STAX 007t2. I have been subsequently informed by an expert on e-stats that the STAX amp may not be up to the challenge of the CRBN. These are my very first e-stats and I may not have researched well enough before diving in on the amp. The iESL is my hedge.

I am wondering if anyone has any experience with the Schiit Aegir or Vidar in mono configuration into the iESL? Based on some other set ups in this thread, it would appear not to be over kill. This set up could be had for about half the price of a Mjolnir Carbon for example.

I am a fanatical Raal listener and very excited to have my first e-stat listen soon.

Happy listening.

I have a CRBN and I use an iESL. I have connected an iFi Pro iCan amp to the iESL via the special HDMI connector that comes with the iCAN. At the same time, I have connected a Raganrok 2 speaker amp to the speaker inputs on the iESL. I can go from one to the other simply by changing the input selector on the (different DACs) iESL. To me, the iCAN sounds better. The treble is slightly less bright, and you have 2 tube modes and xBass to fine tune the sound to your liking. There is plenty of power being delivered through the Ragnarok 2 but it doesn't sound as good as the iCAN. A benefit of the iESL is that I can use it to power my Susvaras driven from the Ragnarok 2 speaker taps. The CRBN sounds fine, with plenty of bass. However, since I don't have a dedicated Mjolnir Carbon or Blue Hawaii to compare it to, I can't say what's missing. My question: Is the missing sound quality worth $5K for a dedicated e-stat amp or is the iESL 95% of the way there. I wish I knew.

 

[MokhaMark]

I have a CRBN and I use an iESL. I have connected an iFi Pro iCan amp to the iESL via the special HDMI connector that comes with the iCAN. At the same time, I have connected a Raganrok 2 speaker amp to the speaker inputs on the iESL. I can go from one to the other simply by changing the input selector on the (different DACs) iESL. To me, the iCAN sounds better. The treble is slightly less bright, and you have 2 tube modes and xBass to fine tune the sound to your liking. There is plenty of power being delivered through the Ragnarok 2 but it doesn't sound as good as the iCAN. A benefit of the iESL is that I can use it to power my Susvaras driven from the Ragnarok 2 speaker taps. The CRBN sounds fine, with plenty of bass. However, since I don't have a dedicated Mjolnir Carbon or Blue Hawaii to compare it to, I can't say what's missing. My question: Is the missing sound quality worth $5K for a dedicated e-stat amp or is the iESL 95% of the way there. I wish I knew.

Thank you for the info and observation regarding Ragnarok. I love that amp, I have owned both versions for 2 channel, interesting that the iCAN sounds better. Your question gets to the heart of my dilemma, save up for a dedicated e-stat amp or try speaker amps. My purchase today means I'll go the speaker amp route first and hope I am done. Thank you again for the info.

 

[BassicScience]

I have a CRBN and I use an iESL. I have connected an iFi Pro iCan amp to the iESL via the special HDMI connector that comes with the iCAN. At the same time, I have connected a Raganrok 2 speaker amp to the speaker inputs on the iESL. I can go from one to the other simply by changing the input selector on the (different DACs) iESL. To me, the iCAN sounds better. The treble is slightly less bright, and you have 2 tube modes and xBass to fine tune the sound to your liking. There is plenty of power being delivered through the Ragnarok 2 but it doesn't sound as good as the iCAN. A benefit of the iESL is that I can use it to power my Susvaras driven from the Ragnarok 2 speaker taps. The CRBN sounds fine, with plenty of bass. However, since I don't have a dedicated Mjolnir Carbon or Blue Hawaii to compare it to, I can't say what's missing. My question: Is the missing sound quality worth $5K for a dedicated e-stat amp or is the iESL 95% of the way there. I wish I knew.

As a resident of NYC, it would seem you'd have options to audition the BHSE (and possibly other estat amps) at a local shop. In the best of circumstances, some retailers will allow you to bring your own gear into the shop for an A/B, or will let you borrow a piece of equipment for a home audition.

 

[DougD]

I have a CRBN and I use an iESL. I have connected an iFi Pro iCan amp to the iESL via the special HDMI connector that comes with the iCAN. At the same time, I have connected a Raganrok 2 speaker amp to the speaker inputs on the iESL. I can go from one to the other simply by changing the input selector on the (different DACs) iESL. To me, the iCAN sounds better. The treble is slightly less bright, and you have 2 tube modes and xBass to fine tune the sound to your liking. There is plenty of power being delivered through the Ragnarok 2 but it doesn't sound as good as the iCAN. A benefit of the iESL is that I can use it to power my Susvaras driven from the Ragnarok 2 speaker taps. The CRBN sounds fine, with plenty of bass.

However, since I don't have a dedicated Mjolnir Carbon or Blue Hawaii to compare it to, I can't say what's missing. My question: Is the missing sound quality worth $5K for a dedicated e-stat amp or is the iESL 95% of the way there. I wish I knew.

And that is exactly the heart of the question. It was the #1 hot issue in my internal "strategic planning for the path forward to h/p bliss", but I'm budget-constrained and iFi Audio sadly discontinued the iESL before I got to a purchasing point.

The legendary Torq (most often seen on another h/p discussion site) didn't like the iESL a lot on his first pass, with an SR-007 Mk II. But he was convinced by someone to retry it, and wrote that he liked it a lot more on the second go-around. Notably, his first shot was with the ICan, but the second try was with "proper speaker amplification," namely the Raal HSA-1b and some others. But then he also said that the exercise convinced him to get a BHSE *and* a Carbon CC to test out with the newer e-stats. (He has not been budget-constrained AFAICT.)

And then he got very tired of the chirpers and naggers, and we probably won't hear any more about what Torq finds works well, or doesn't, and how the top-$$$$ e-stat amps compare to the more-thrifty iESL.