[Dramlin]

I've spent the last few weeks testing to see if the Sparkos SS2590's are an upgrade in the Conductor 3 Reference (C3R). So this entire post will be about my opinions on how the SS2590's compare to other op amps. This will be a bit long winded but to those that actually care about the specifics of how the SS2590 sounds then all information may be useful to you. To those that just want to know the outcome of the testing, here is my recommended setup in the Conductor 3 Reference:

*Singles (LP stage) = Sparkos SS2590 (35mm Burson Extension Leads Required)
*Duals (I/V stage) = Sonic Imagery Labs 994Enh

*Edited as my recommendation has changed. See a few posts down.

C3R Digital Filter = LP FAST

The digital filter is important. I typically use AP Fast but going to LP Fast was critical to getting the right sound with this op amp combo. How I came to this conclusion is below for those that are interested.

Background:
Up to this point I've tried close to 60 different op amps, and for the last year or so I've been using the SIL 992Enh & 994ENh's in the Conductor 3 Reference. The 992/994's offer a crystal clear sound with a surround speaker like sound stage. In previous testing I found the 992/994's were a a few technical levels above the next best discretes. I was quite happy using the 992/994's, but a few weeks back I was listening to a lower quality amp and was enjoying some bass heavy music. In that time I started to wonder why my C3R didn't put out the same quality & quantity of bass as a less refined amp, and that put me down the rabbit hole again of trying op amps to get more out of the C3R.

First I tried all of the other great discretes in combination with a 992 or 994: V6 Vivid, V6 Classic, Sparkos 3601/3602, and Staccatos. Some of the op amps like the V6 Vivid gave me that added richness & bass I was looking for, but all were such a significant drop in detail and sound stage that the overall sound was a downgrade to the 992+994 setup. In looking around about the only other op amp I could find that may be able to compete with the 992+994's is the Sparkos SS2590's. I decided to start with the Single 2590's to see how they were, and then when I heard the singles I immediately got the dual 2590's to try as well. Here's the testing starting with my original setup:

Op Amp Testing:
Sonic Imagery Labs 992Enh (Single) and 994Enh (Dual)
Sounds like a 5 speaker surround setup minus the subwoofer. Exceptionally clear and detailed, but also on a bit on the thin side. Lacks fullness and deep bass. Performs Technically better than every other op amp I've tried except for the SS2590's (more on that below..). In the pursuit of more bass & fullness, more op amp testing was needed.

Sparkos SS2590 (Single) and SIL 994's (Dual)
The surround speaker like sound stage of the 992/994's is gone (boo..), but the sound stage is still correct. It's just more stereo now instead of surround. Detail is significantly improved, textures are improved, the sound is fuller, bass is improved in both quantity and quality. Overall the sound is improved in a noticeable and impactful way. It's obvious that the Sparkos SS2590 performs better technically than the 992/994's. Hearing how much of an improvement there is, I immediately got the Dual SS2590's as I expected to get another big jump in sound quality by going full Sparkos. As is, this setup sounds excellent though.

Sparkos SS2590 (Single) and SS2590 (Dual)
I had some trouble installing the duals here. I tried using right angle dip8 adapters to install the duals flat in a "bull horn" setup and I was successful, but the adapters had a major impact on the sound quality. In the end I used Burson 35mm extensions to install the duals sideways by carefully bending the extensions using soft tip tweezers. As for the sound, going Sparkos was indeed another big jump in detail, richness, texture, and in the width of the sound stage. Sounds didn't have any hint of compression in them, they just extend as far as they are supposed to. Violins, piano, and other instruments sound more life-like than ever. Bass, specifically the sub-bass, hits harder and cleaner than any other amp I've ever tried. Very very satisfying. I immediately thought that this was the optimal setup in the C3R, however over the course of a week I started to notice I wasn't enjoying listening to TV, Games, or Music as much as my previous setup. In the end I concluded there's 3 problems with going full Sparkos:

1) The overall tone is lower than neutral. Voices sound deeper and lower than they should, not just by a little bit either.
2) While the sound stage extends well horizontally, it lacks depth compared to the 992/994's. This makes the sound 'flatter' than you would expect.
3) Treble is lacking. Without enough treble to make a a contrast between the lows & highs, there's less sound engagement even when there's more detail and richness. Or in other words, the sound is boring :/

Given how rich and detailed these op amps are, I tried to make this setup work. Silver headphone cables, rhodium extension cables, different filters. Nothing worked to correct the tone. As great as this setup is technically, it's just not right. So, more op amp rolling was needed to somehow get the detail, bass, fullness, and stage width of the SS2590's, but with a more neutral tone and more treble.

At this point I tested around 15 different combinations of Sparkos SS2590's and other op amps in various configurations. Important to note with all op amp testing is that the sound stage largely comes from the DUAL (I/V) stage, whereas the overall tone and the general sound comes from the SINGLE op amps (LP stage). There's a little give and take across all areas though. In testing I concluded that the only way to get a very high quality sound was to use a combination of the SS2590's and the SIL 992/994's. I did also quite enjoy using the V6 Vivid singles with the Sparkos SS2590 duals, but compared to having a 992/994 in the mix the detail loss was too great. So really the only options were to use the SIL 992+SS2590's or SS2590+994's. Back to testing...

SIL 992 (Singles) and Sparkos SS2590 (Duals)
This takes most of the sound stage of the Sparkos with the overall tone of the SIL 992's. So you get a full wide sound and great detail. This is a clear improvement over the 992+994 setup, basically sounding mostly the same with an extended sound stage and additional detail. The only downside is that since most of the sound comes from the 992's the sound still lacks some fullness, and can be perceived as a bit thin. Depending on your preference and headphones this may be the ideal sound setup for you, but it lacks the fullness I'm looking for in my setup.

Sparkos SS2590 (Singles) and SIL 994 (Duals) ... again
Back to just about where we started. Without the SS2590's in the dual slots the sound stage width is reduced a bit, but goes out further in depth. You end up with a kind of sound bubble that you know could extend further if only the SS2590's were in the dual slots, but it's still satisfying. The overall tone is completely neutral, with the fullness & bass being as they should thanks to the SS2590's in the single slots. This is also a clear improvement over the 992+994 setup. The only thing I missed was the extra richness of the full Sparkos setup, and so after trying several more op amp combinations I came back to this one and ended up playing with the digital filters. Going from AP Fast to LP fast did the trick. There was a shift which gave most of the rich detail of the full Sparkos setup and made the entire sound more robust.

So in conclusion the SS2590+994's is the clear winner to me. (Edited, see a few posts below for a better recommendation..)


If anyone finds any other op amps that can potentially compete with the SIL 992/994 or Sparkos SS2590's in the future, let me know.

 

[Slim1970]

I've spent the last few weeks testing to see if the Sparkos SS2590's are an upgrade in the Conductor 3 Reference (C3R). So this entire post will be about my opinions on how the SS2590's compare to other op amps. This will be a bit long winded but to those that actually care about the specifics of how the SS2590 sounds then all information may be useful to you. To those that just want to know the outcome of the testing, here is my recommended setup in the Conductor 3 Reference:

Singles (LP stage) = Sparkos SS2590 (35mm Burson Extension Leads Required)
Duals (I/V stage) = Sonic Imagery Labs 994Enh
C3R Digital Filter = LP FAST

The digital filter is important. I typically use AP Fast but going to LP Fast was critical to getting the right sound with this op amp combo. How I came to this conclusion is below for those that are interested.

Background:
Up to this point I've tried close to 60 different op amps, and for the last year or so I've been using the SIL 992Enh & 994ENh's in the Conductor 3 Reference. The 992/994's offer a crystal clear sound with a surround speaker like sound stage. In previous testing I found the 992/994's were a a few technical levels above the next best discretes. I was quite happy using the 992/994's, but a few weeks back I was listening to a lower quality amp and was enjoying some bass heavy music. In that time I started to wonder why my C3R didn't put out the same quality & quantity of bass as a less refined amp, and that put me down the rabbit hole again of trying op amps to get more out of the C3R.

First I tried all of the other great discretes in combination with a 992 or 994: V6 Vivid, V6 Classic, Sparkos 3601/3602, and Staccatos. Some of the op amps like the V6 Vivid gave me that added richness & bass I was looking for, but all were such a significant drop in detail and sound stage that the overall sound was a downgrade to the 992+994 setup. In looking around about the only other op amp I could find that may be able to compete with the 992+994's is the Sparkos SS2590's. I decided to start with the Single 2590's to see how they were, and then when I heard the singles I immediately got the dual 2590's to try as well. Here's the testing starting with my original setup:

Op Amp Testing:
Sonic Imagery Labs 992Enh (Single) and 994Enh (Dual)
Sounds like a 5 speaker surround setup minus the subwoofer. Exceptionally clear and detailed, but also on a bit on the thin side. Lacks fullness and deep bass. Performs Technically better than every other op amp I've tried except for the SS2590's (more on that below..). In the pursuit of more bass & fullness, more op amp testing was needed.

Sparkos SS2590 (Single) and SIL 994's (Dual)
The surround speaker like sound stage of the 992/994's is gone (boo..), but the sound stage is still correct. It's just more stereo now instead of surround. Detail is significantly improved, textures are improved, the sound is fuller, bass is improved in both quantity and quality. Overall the sound is improved in a noticeable and impactful way. It's obvious that the Sparkos SS2590 performs better technically than the 992/994's. Hearing how much of an improvement there is, I immediately got the Dual SS2590's as I expected to get another big jump in sound quality by going full Sparkos. As is, this setup sounds excellent though.

Sparkos SS2590 (Single) and SS2590 (Dual)
I had some trouble installing the duals here. I tried using right angle dip8 adapters to install the duals flat in a "bull horn" setup and I was successful, but the adapters had a major impact on the sound quality. In the end I used Burson 35mm extensions to install the duals sideways by carefully bending the extensions using soft tip tweezers. As for the sound, going Sparkos was indeed another big jump in detail, richness, texture, and in the width of the sound stage. Sounds didn't have any hint of compression in them, they just extend as far as they are supposed to. Violins, piano, and other instruments sound more life-like than ever. Bass, specifically the sub-bass, hits harder and cleaner than any other amp I've ever tried. Very very satisfying. I immediately thought that this was the optimal setup in the C3R, however over the course of a week I started to notice I wasn't enjoying listening to TV, Games, or Music as much as my previous setup. In the end I concluded there's 3 problems with going full Sparkos:

1) The overall tone is lower than neutral. Voices sound deeper and lower than they should, not just by a little bit either.
2) While the sound stage extends well horizontally, it lacks depth compared to the 992/994's. This makes the sound 'flatter' than you would expect.
3) Treble is lacking. Without enough treble to make a a contrast between the lows & highs, there's less sound engagement even when there's more detail and richness. Or in other words, the sound is boring :/

Given how rich and detailed these op amps are, I tried to make this setup work. Silver headphone cables, rhodium extension cables, different filters. Nothing worked to correct the tone. As great as this setup is technically, it's just not right. So, more op amp rolling was needed to somehow get the detail, bass, fullness, and stage width of the SS2590's, but with a more neutral tone and more treble.

At this point I tested around 15 different combinations of Sparkos SS2590's and other op amps in various configurations. Important to note with all op amp testing is that the sound stage largely comes from the DUAL (I/V) stage, whereas the overall tone and the general sound comes from the SINGLE op amps (LP stage). There's a little give and take across all areas though. In testing I concluded that the only way to get a very high quality sound was to use a combination of the SS2590's and the SIL 992/994's. I did also quite enjoy using the V6 Vivid singles with the Sparkos SS2590 duals, but compared to having a 992/994 in the mix the detail loss was too great. So really the only options were to use the SIL 992+SS2590's or SS2590+994's. Back to testing...

SIL 992 (Singles) and Sparkos SS2590 (Duals)
This takes most of the sound stage of the Sparkos with the overall tone of the SIL 992's. So you get a full wide sound and great detail. This is a clear improvement over the 992+994 setup, basically sounding mostly the same with an extended sound stage and additional detail. The only downside is that since most of the sound comes from the 992's the sound still lacks some fullness, and can be perceived as a bit thin. Depending on your preference and headphones this may be the ideal sound setup for you, but it lacks the fullness I'm looking for in my setup.

Sparkos SS2590 (Singles) and SIL 994 (Duals) ... again
Back to just about where we started. Without the SS2590's in the dual slots the sound stage width is reduced a bit, but goes out further in depth. You end up with a kind of sound bubble that you know could extend further if only the SS2590's were in the dual slots, but it's still satisfying. The overall tone is completely neutral, with the fullness & bass being as they should thanks to the SS2590's in the single slots. This is also a clear improvement over the 992+994 setup. The only thing I missed was the extra richness of the full Sparkos setup, and so after trying several more op amp combinations I came back to this one and ended up playing with the digital filters. Going from AP Fast to LP fast did the trick. There was a shift which gave most of the rich detail of the full Sparkos setup and made the entire sound more robust.

So in conclusion the SS2590+994's This is the clear winner to me. If anyone finds any other op amps that can potentially compete with the SIL 992/994 or Sparkos SS2590's in the future, let me know.

Great write up!

 

[EternalChampion]

3) Treble is lacking. Without enough treble to make a a contrast between the lows & highs, there's less sound engagement even when there's more detail and richness. Or in other words, the sound is boring :/

You shook my head. , thank you! I forgot to mention in my review that the SS2590 treble at the very top is more bright than on SIL and that it could be perceived as piercing by some depending on the setup and ear sensitivity. This becomes very accentuated when all 4 op-amps are in place and it feels much smoother when the 992s take their spot.

But yeah, the treble in lower registers is definitely lacking. The so called "bite" and "substance" I was talking about. No wonder the pitch with the 992/994 feels more correct and natural.

So the SS2590 makes a contrast, but the wrong one: warm sound with very energized high treble.

I wish I had the means to sit at a lab bench, fix its minor flaws and inject a bit more soul into it. That would be the first op-amp to obtain the "godlike" status by me.

Its slam, clarity and overall presentation though is very addictive.

So in conclusion the SS2590+994's This is the clear winner to me.

I spent the whole night trying combos and filters. 4 x SS2590 + MP_SLOW is better but still meh....Also, your chosen configuration with the 994s in I/V, thus eliminating four SS2590 boards from the mix will produce a very serious compromise to my ears.

2 x Sparkos Dual + 2 x 992 on default AP_FAST is as good as it gets with the HE6se. Nice tonal balance with the least compromises.

 

[Dramlin]

Very nice! Yes, so we've got two differing but similar opinions now, both correct for us, and both of which are a mix of SS2590 & 992/994 just with different orders and filters. As far as I know we may be the only two people that have ever done a written comparison on the 992/994 and SS2590's, so more people need to join in on the fun here

One thing I neglected to write earlier is that this improved sound is really only possible because the C3R allows us to switch the op amps. The C3R is truly an amazing headphone amp, especially when you hear how much of a difference changing the op amps can make. Also worthy of mention is the Burson 35MM extensions, as without those being available these larger op amps couldn't be attempted. I mentioned briefly that I was able to install the SS2590's using right angle adapters, but the sound quality took a major dive. It's nice having some op amp extensions on the market that don't degrade the sound quality. Now we just need Burson to come out with the V7's to compete with the 992/994/SS2590's.....

 

[Dramlin]

In the spirit of (hopefully) helping others I'm going to freely admit... I was wrong. I previously posted my impressions on the SS2590. All of the info in that post is correct and still stands, except for my end conclusion.

Quickly summarizing the issue, I did a bunch of testing and found that the best sound in my setup is a combination of using the SS2590 & SIL 992/994 op amps. Using any other op amps is a significant downgrade in multiple areas. When I tested using 992 singles with SS2590 duals the sound stage is perfect with excellent detail, but the treble is sharp, the sound is a little thin, and there is a lack of dynamics. For that reason I disregarded that setup and went with SS2590 singles with 994 duals. Using 994 duals the sound stage decreases but there's improvement in the fullness of the sound and any harsh treble is fixed. it's not perfect, but the SS2590+994 was the better compromise, or so I thought.

After about two weeks of using the SS2590+994 setup I began to really miss the extended sound stage of the SS2590 duals. I'm a sucker for sound stage with proper placement, and sound stage is largely dictated by the I/V stage (dual slots). There is no op amp I've ever tried that performs better in the I/V stage than the SS2590, so I started testing again to see if I could somehow get the SS2590's to work in the dual slots. Eventually I went back to the 992+SS2590 setup and once again it was thin, sharp, and lacking dynamics. I changed the digital filter from AP Fast to LP Fast and WOW. That did it! It's THE sound. Full sound stage, accurate placement, no compression, all thinness is removed, richness increases, correct tone, bass increases in quality and quantity. The sound transformed from excellent but flawed, to absolutely brilliant just with that digital filter change. It seems I neglected to try out different filters when I originally tried this setup

So, my updated and final recommendation (for the current op amps on the market) is:

Singles (LP stage) = Sonic Imagery Labs 992Enh (35mm Burson Extension Leads Required)
Duals (I/V stage) = Sparkos SS2590 (35mm Burson Extension Leads Required)
C3R Digital Filter = LP FAST

Respect to @EternalChampion for spotting this op amp combo a lot faster than I did, and getting it right the first time . With that, both of us now have the same opinion on the ideal op amps to use in the C3R. We differ only on which digital filter to use, which likely comes down to our different headphones and gain settings. I haven't tested this yet, but I suspect that LP Fast may be ideal for low gain while AP Fast may be ideal for high gain.

 

[EternalChampion]

Respect to @EternalChampion for spotting this op amp combo a lot faster than I did, and getting it right the first time . With that, both of us now have the same opinion on the ideal op amps to use in the C3R. We differ only on which digital filter to use, which likely comes down to our different headphones and gain settings. I haven't tested this yet, but I suspect that LP Fast may be ideal for low gain while AP Fast may be ideal for high gain.

Three years since I got this device and until this day I've been switching between multiple filters all the time depending on the headphones and tracks. It just so happens that 70% goes with default AP_FAST because of its superior technicalities, the excellent extension in all directions and the most "3D" soundstage out of the bunch.

LP_FAST sends a very sweet, low distortion signal to my ears and shares most of the remaining time along with MP_SLOW which I like a lot due to its slightly more closed-in stage presentation that is so much needed at times.

Conductor V2+: Being in a situation like that, like I was previously, right know that is a total nightmare! No swappable op-amps to play with sound signatures and take advantage of the superior discretes, no digital filters...yikes! My entire mindset has changed.

 

[Metron]

In the spirit of (hopefully) helping others I'm going to freely admit... I was wrong. I previously posted my impressions on the SS2590. All of the info in that post is correct and still stands, except for my end conclusion.

Quickly summarizing the issue, I did a bunch of testing and found that the best sound in my setup is a combination of using the SS2590 & SIL 992/994 op amps. Using any other op amps is a significant downgrade in multiple areas. When I tested using 992 singles with SS2590 duals the sound stage is perfect with excellent detail, but the treble is sharp, the sound is a little thin, and there is a lack of dynamics. For that reason I disregarded that setup and went with SS2590 singles with 994 duals. Using 994 duals the sound stage decreases but there's improvement in the fullness of the sound and any harsh treble is fixed. it's not perfect, but the SS2590+994 was the better compromise, or so I thought.

After about two weeks of using the SS2590+994 setup I began to really miss the extended sound stage of the SS2590 duals. I'm a sucker for sound stage with proper placement, and sound stage is largely dictated by the I/V stage (dual slots). There is no op amp I've ever tried that performs better in the I/V stage than the SS2590, so I started testing again to see if I could somehow get the SS2590's to work in the dual slots. Eventually I went back to the 992+SS2590 setup and once again it was thin, sharp, and lacking dynamics. I changed the digital filter from AP Fast to LP Fast and WOW. That did it! It's THE sound. Full sound stage, accurate placement, no compression, all thinness is removed, richness increases, correct tone, bass increases in quality and quantity. The sound transformed from excellent but flawed, to absolutely brilliant just with that digital filter change. It seems I neglected to try out different filters when I originally tried this setup

So, my updated and final recommendation (for the current op amps on the market) is:

Singles (LP stage) = Sonic Imagery Labs 992Enh (35mm Burson Extension Leads Required)
Duals (I/V stage) = Sparkos SS2590 (35mm Burson Extension Leads Required)
C3R Digital Filter = LP FAST

Respect to @EternalChampion for spotting this op amp combo a lot faster than I did, and getting it right the first time . With that, both of us now have the same opinion on the ideal op amps to use in the C3R. We differ only on which digital filter to use, which likely comes down to our different headphones and gain settings. I haven't tested this yet, but I suspect that LP Fast may be ideal for low gain while AP Fast may be ideal for high gain.

This is very valuable! Big thank you for posting your extended testing results!

 

[Dramlin]

I don't think I ever posted any pictures of my setup with the Sparkos SS2590 Duals and SI 992 singles. EternalChampion posted some pictures previously, but my install differed by just a little bit. Both install types work fine:

Also, it's been a few months since I went to the configuration above. I haven't ever had a single thought that there is anything wrong with any aspect of the sound. There's always the chance that there is something better out there, but this sounds about as pure as I can want. I hope Burson takes note of this configuration so they can design the V7's to deliver this type of quality from a stock configuration in the Conductor 4 Reference. They've got the amp design down wonderfully, just need to refine their V6's to match the above op amp combo.

 

[EternalChampion]

I don't think I ever posted any pictures of my setup with the Sparkos SS2590 Duals and SI 992 singles. EternalChampion posted some pictures previously, but my install differed by just a little bit.

Now it differs by a little bit more.

The available information on this board related to the new single-ended Burson flagship and its op-amp situation in general (there's not even a manual yet!) is essentially non-existent. I'm not going to derail this thread with off-topic content....I just want to assure whoever might be considering upgrading from C3R to the C3 GT that the op-amps are identical, 2 x dual + 2 x single, and that despite having the Noctua blocking the way in the middle it remains flexible enough to accommodate all kinds of op-amp configurations including the most challenging one with four SS2590s, with the help of some dip-8 sockets and lead wires.

About the Burson lead wires: It is always a good idea to run the signal without'em if you can in order to cancel the very small, yet perceivable amount of noise that they introduce. They will also shift the sound profile by a little bit, so better use two of these for the single sockets or none to avoid the slight channel variation.

Enjoy your gear

 

[Dramlin]

That's awesome, congrats! Invaluable info on the op amps too. Hope you are enjoying the upgrade. I can't even imagine the C3R sounding better, so the GT must be something truly special.

 

[EternalChampion]

That's awesome, congrats! Invaluable info on the op amps too. Hope you are enjoying the upgrade. I can't even imagine the C3R sounding better, so the GT must be something truly special.

I have an entirely new audio chain on burn-in (cable, GT/V6, SC 5A) minus the headphone. It will be done in about a week.

I tried the op-amps to see what's going on with the installation but did not listen that much. It wouldn't make any sense afterall.

As cold as it is out of the box, it feels to be a significant step ahead of C3R even more so when I turn the volume knob all the way up to 93% (3000mW vs 6000mW into 50 ohms at that volume approx.), holy smoke! The 6se will dive into the music just like that. The vocals on this headphone are nothing less than spectacular.

And...surprise surprise, in spite of that, the drivers don't seem to be stressed at all.... The definition of "insatiable" I guess.

My early impressions suggest less dependency on the Supercharger as well. It's way too early to assess anything though. We'll see after burn-in.

 

[Onik]

Where can I sell my C3 ref?

 

[SCBob]

Go to Classifieds -> Source Components -> DAC/Amps -> Add Listing -> GLWS!

 

[jjazzy]

Probably a long shot, has anyone compared the Conductor with the Violectric V590 or the SPL Phonitor XE, as all in one solution?

I compared the Conductor 3rx reference connected balanced with the Violectric v590 (With burned in Arya Stealth) Both detailed, but to me listening to the Burson and then the Violectric, to me it sounded like with the Violectric they took the headphones, and put some sheepswool into it. The details where there yes, but it was like bring focus the lowend and put the treble more backwords. The Burson Conductor 3rx reference had a sparcle, sounded way more balanced to me. Clean put still leaning to the slightly warm sound.

Before I started listening I expected to prefer the Burson, most sabre builds I hate, but with the Conductor reference it was different (I listened for say one and half hour, comparing back and forth).

I do have to mention though, I loved the Burson conductor 3xr reference, but did not like the models lower I did not like at all, it was like removing the air and stage around everything. So the composer for example, I did not like at all.

 

[jjazzy]

Did anybody had the change to compare the following?

Soloist & Composer 3XP
VS
Conductor 3X Reference

I liked the sound of the 3xr Reference a lot balanced, but I never tried the 'Soloist & Composer 3XP' so would like to know if it sounds better or not.

They are both around the same price, try to figure out which is the nicer pick, soundwise that is. Also read the soloist 3 has a better volume control chip?

(I heared the conductor 3xp, and did not like it compared to the Conductor 3x reference, the reference had a better stage, more are around the instruments, but that's lower model)

So how does the combo compare to the conductor 3rx reference?