JDS Labs - Subjective 3

[Timbo2]

I figured I'd give my impressions of JDS Labs Subjective 3 - a three band analog EQ housed in an enclosure similar to the O2 headphone amplifier. I listen to multiple sources that don't have EQ - so having an easy way to adjust the sound seemed like it was worth a try.

The nice thing with JDS Labs is they take care with product design and provide detailed specifications. They are also accessible, I had hoped to avoid an additional power cord and wall wart. Both their O2 and the Subjective 3 use 15VAC so I hoped to use one transformer. I emailed JDS and asked if it was possible to split the power between the two. John replied within 24 hours saying he had tried that, but it resulted in a 60Hz ground loop. So two transformers it is!

For those interested the following blog posts provide more information that I could hope to. The one caveat being he didn't say what he used to measure the device.

http://melp242.blogspot.com/2018/02/jds-labs-subjective3-tone-control.html
http://melp242.blogspot.com/2018/02/jds-labs-subjective3-part-2.html

His biggest complaint would be the channel imbalance the device creates. I don't have a great way to measure this, but gave it a shot. I used multimeter and 2kHz sine wave and found about a 0.006V increase in the channel imbalance with device in line and all the tone controls in their middle position from a 2V source. Subjectively, I can't hear any change in the channel balance fortunately.

The nice thing about the device is that it uses a relay. In the off position or if the device is unplugged it defaults to full bypass. So you can leave the device inline and fully defeat the tone controls.

My biggest gripe with the device is the gain. I should have remembered this from my 1980s hifi days of inserting 10 band equalizers into tape loops. JDS labs does mention it, but it is pretty well buried in the product page. The device provides around 15dB or so of gain. On an amplifier designed like the O2 that means that with a 2Vrms source you can overload the input. Fortunately my lower gain is 1X, so no issue. But other O2 owners may not be so fortunate. This also means that depending on my source and the amount of EQ applied my high gain of 3.5X may be unusable.

Despite the channel imbalance and the gain issues I'm happy with the device. It's quite satisfying to be able to adjust the sound with something physical and easy to access instead of digging through menus and fiddling with software EQ.

 

[Deleted member 4081]

I figured I'd give my impressions of JDS Labs Subjective 3 - a three band analog EQ housed in an enclosure similar to the O2 headphone amplifier. I listen to multiple sources that don't have EQ - so having an easy way to adjust the sound seemed like it was worth a try.

The nice thing with JDS Labs is they take care with product design and provide detailed specifications. They are also accessible, I had hoped to avoid an additional power cord and wall wart. Both their O2 and the Subjective 3 use 15VAC so I hoped to use one transformer. I emailed JDS and asked if it was possible to split the power between the two. John replied within 24 hours saying he had tried that, but it resulted in a 60Hz ground loop. So two transformers it is!

For those interested the following blog posts provide more information that I could hope to. The one caveat being he didn't say what he used to measure the device.

http://melp242.blogspot.com/2018/02/jds-labs-subjective3-tone-control.html
http://melp242.blogspot.com/2018/02/jds-labs-subjective3-part-2.html

His biggest complaint would be the channel imbalance the device creates. I don't have a great way to measure this, but gave it a shot. I used multimeter and 2kHz sine wave and found about a 0.006V increase in the channel imbalance with device in line and all the tone controls in their middle position from a 2V source. Subjectively, I can't hear any change in the channel balance fortunately.

The nice thing about the device is that it uses a relay. In the off position or if the device is unplugged it defaults to full bypass. So you can leave the device inline and fully defeat the tone controls.

My biggest gripe with the device is the gain. I should have remembered this from my 1980s hifi days of inserting 10 band equalizers into tape loops. JDS labs does mention it, but it is pretty well buried in the product page. The device provides around 15dB or so of gain. On an amplifier designed like the O2 that means that with a 2Vrms source you can overload the input. Fortunately my lower gain is 1X, so no issue. But other O2 owners may not be so fortunate. This also means that depending on my source and the amount of EQ applied my high gain of 3.5X may be unusable.

Despite the channel imbalance and the gain issues I'm happy with the device. It's quite satisfying to be able to adjust the sound with something physical and easy to access instead of digging through menus and fiddling with software EQ.

I've previously tried software EQ and never seemed to have the patience to tune things to my liking. It's also not convenient to fire up the software EQ control to make small changes from track to track. Instead, I've been using a Schiit Loki 4-band EQ for a year with the MrSpeaker Aeon Flow Closed in my secondary system, with constant bass boost due to the headphone's inherent brightness and sometimes a reduction in the high frequencies for harsher recordings. Something about having physical knobs makes this a great experience!

I've sold the Aeon Flow and haven't figured out a new use for the Loki yet. I've tried inserting it into my main system but I have ground loop issues with RCA components. However, with an ADI-2 DAC incoming, I'm getting ready to get into some PEQ with knobs and buttons to tame the HD 800!

I haven't tried the Subjective 3, does only having 3 bands become a limiting factor to you?

 

[Timbo2]

I've previously tried software EQ and never seemed to have the patience to tune things to my liking. It's also not convenient to fire up the software EQ control to make small changes from track to track. Instead, I've been using a Schiit Loki 4-band EQ for a year with the MrSpeaker Aeon Flow Closed in my secondary system, with constant bass boost due to the headphone's inherent brightness and sometimes a reduction in the high frequencies for harsher recordings. Something about having physical knobs makes this a great experience!

I've sold the Aeon Flow and haven't figured out a new use for the Loki yet. I've tried inserting it into my main system but I have ground loop issues with RCA components. However, with an ADI-2 DAC incoming, I'm getting ready to get into some PEQ with knobs and buttons to tame the HD 800!

I haven't tried the Subjective 3, does only having 3 bands become a limiting factor to you?

I've mostly used the top and bottom. So the three bands haven't been a huge issue. I'm think more than four and you may as well use software given the complexity.

 

[Gabe777]

Old thread. But Hi anyway.

Looking at the JDS Labs stuff, but I really need a balance control too.

They have no plans to include one .. couldn't be difficult to add a 4th knob to the Subjective 3 ?

However, I was hoping someone could point me towards something that would work with these units.

I'm planning on Tidal from phone android app to the Atom DAC .... Subjective 3... Atom Amp 1W to AkG 702 and Shure 1540.

Is there a substitution I could make that would give me a compatible hardware Balance Control...or alternatively a completely different system with one...?

Thnx for advice.

 

[GeorgeWalk]

I have been using the Schiit Loki equalizer. I like it. It is four bands and does a good with my headphones. I have never been a fan of SW equalizers.

 

[Gabe777]

Hi.
Yes I like that.
But I am looking for a similar device that allows the volume balance to be adjusted... Left to Right due to hearing issues.

Thnx.

 

[Timbo2]

Really all you need to do is attenuate one of the channels.

So in between the DAC and the headphone amp you'd add a volume pot on just one channel. Whichever ear you have the higher level of hearing would be the one that you want to put the volume pot to reduce the volume on that ear.

Sadly, when I Googled around all I can find are cheap car stereo versions so the potentiometer is likely not of the best quality, but I'm honestly not sure how audible it will be.

https://www.ebay.com/sch/i.html?_fr...+Level+Remote+Volume+Control+Knob+US&_sacat=0

Note - they all say "bass" as they seem to be the primary use for adjusting a subwoofer amp - but I don't believe they actually have any crossover. Just make sure what you buy doesn't actually have any specific bass attenuation.

 

[Gabe777]

Hi.

Thnx for your help.

I have found a company that do amps with L and Right volume controls.

Amity.de

Unfortunately they are quite old tech wise and only go to 24/96..... So that's MQA out.

But it may be my only choice.

Don't want to sound sorry for myself, as some people are completely deaf...or...worse, but there must be a big market for people with hearing disabilities.

Both JDS Labs and Schiit do EQs.....hardware ones. How hard could it be to add an extra knob ?

It is annoying...but hey ?!

May just have to make do with software balance.

Thnx again.

 

[Slc80]

Has anyone had both the JDS Subjective3 and the Schiit Loki and can give input on which is better? I saw a Youtube comparison that said one sounded muddier and noisier but information was limited and I wanted some more opinions. Both appear to use baxandall with the bass response curve between the JDS and Schiit being almost identical. The advantage of the Schiit seems to be the extra knob but there is a lot of overlap with the other adjustments. Here are the response measurements between the two units:

JDS Subjective3:
https://blog.jdslabs.com/wp-content/uploads/2018/02/FR-Curves-Bass.png
https://blog.jdslabs.com/wp-content/uploads/2018/02/FR-Curves-Mids.png
https://blog.jdslabs.com/wp-content/uploads/2018/02/FR-Curves-Treble.png

Schiit Loki:
https://external-preview.redd.it/Yy...bp&s=5a7374ffc64ef59a203ec45488acca2c6430ac76

 

[Timbo2]

Has anyone had both the JDS Subjective3 and the Schiit Loki and can give input on which is better? I saw a Youtube comparison that said one sounded muddier and noisier but information was limited and I wanted some more opinions. Both appear to use baxandall with the bass response curve between the JDS and Schiit being almost identical. The advantage of the Schiit seems to be the extra knob but there is a lot of overlap with the other adjustments. Here are the response measurements between the two units:

JDS Subjective3:
https://blog.jdslabs.com/wp-content/uploads/2018/02/FR-Curves-Bass.png
https://blog.jdslabs.com/wp-content/uploads/2018/02/FR-Curves-Mids.png
https://blog.jdslabs.com/wp-content/uploads/2018/02/FR-Curves-Treble.png

Schiit Loki:
https://external-preview.redd.it/Yy...bp&s=5a7374ffc64ef59a203ec45488acca2c6430ac76

I don't have any experience with the Loki unfortunately. One thing that was important to me was that when the EQ is bypassed it is completely when not used. For the Subjective 3 the equalizer is mechanically switched (actually a relay I believe) by the front toggle switch in and out of the circuit. I've no idea of the Loki works that way as well.

UPDATE: Jumping over to their website suggest it also is switched by relay.

 

[Slc80]

I don't have any experience with the Loki unfortunately. One thing that was important to me was that when the EQ is bypassed it is completely when not used. For the Subjective 3 the equalizer is mechanically switched (actually a relay I believe) by the front toggle switch in and out of the circuit. I've no idea of the Loki works that way as well.

UPDATE: Jumping over to their website suggest it also is switched by relay.

So they do appear to be almost the same with the difference being the Loki having one more band. Do you feel limited by the 3 bands of the Subjective3? Are you able to add low end without muddying the sound?

 

[Timbo2]

So they do appear to be almost the same with the difference being the Loki having one more band. Do you feel limited by the 3 bands of the Subjective3? Are you able to add low end without muddying the sound?

I find with my Sen 600 and 650 I get plenty of bass enhancement with the knob at about 2 o'clock without making things like vocals sound unnatural. I normally never touch the middle band unless I'm trying to clean up vocals on a specific track. Nice thing is that it is 2/3rds the price, but it does have a bit of a home made look to it. My stack is an Atom and Topping D50s so it actually matches better than the Loki would.

 

[GeorgeWalk]

I have the Loki and use it with my D50s/A50s and Senn 599. It works great.

 

[MRC01]

I figured I'd give my impressions of JDS Labs Subjective 3 - a three band analog EQ housed in an enclosure similar to the O2 headphone amplifier. ... So you can leave the device inline and fully defeat the tone controls. ... My biggest gripe with the device is the gain. ... Despite the channel imbalance and the gain issues I'm happy with the device. It's quite satisfying to be able to adjust the sound with something physical and easy to access instead of digging through menus and fiddling with software EQ.

Thanks for posting this. You got me interested enough to build one from the kit. Here are details & measurements. My impressions are similar to yours, though with some differences.

• Channel balance is within 0.25 dB, so not an issue for me.
• Knob consistency (move them around full scale a few times, then back to the detent) is also within 0.25 dB.
• In EQ mode, THD+N are negligible (below -93 dB). But Bypass mode has THD+N around -60 dB.

The bad news is that bypass mode adds THD+N. I contacted JDS Labs in case the distortion in bypass mode was due to a mistake I made in building or measuring this device. They have excellent customer support and responded promptly, even on a weekend. They confirmed that it is known and normal, and they’re looking into ways to address this.

The good news is that EQ mode is clean enough (channel balance, consistency, THD+N) one can simply leave it on all the time.

 

[guildenstern]

Hi.
Yes I like that.
But I am looking for a similar device that allows the volume balance to be adjusted... Left to Right due to hearing issues.

Thnx.

It's been a while since you posted your note above, but like you, I confront similar issues, and after trying various low cost options with no success, I've found that the RME ADI-2 FS dac/amp helps solve a lot of audio problems for me. Granted, it does its work on the signal in the software domain, but the signal remains remarkably clean. You can control balance, stereo/mono, and use the front panel bass/treble knobs for quick adjustments, or dive deep into the weeds with the onboard EQ. Yep, it's not cheap, but for me, it does what needs doing.

 

[MRC01]

JDS revised the Subjective 3 EQ to eliminate the distortion in standby (off) mode. The revision adds another relay for better isolation when it's turned off. Since I asked them about this last year, they sent me an early pre-production version of the new kit to build and test.

Cut to the chase: they fixed the problem. I measure no difference between a loopback connector and the S3 in standby mode. The added distortion is gone, no difference in channel balance, frequency response either. In standby, it measures transparent. The rest of it is the same: knobs, center frequencies, etc.

Since this is an early pre-production kit, during construction I had to do a few extra steps with jumpers and wiring. They will sort this out, so when the revised kit is released it will be just as easy to build as the original.

Kudos to @jseaber for the customer support and followup.

 

[Moderate Dionysianism]

JDS revised the Subjective 3 EQ to eliminate the distortion in standby (off) mode. The revision adds another relay for better isolation when it's turned off. Since I asked them about this last year, they sent me an early pre-production version of the new kit to build and test.

Cut to the chase: they fixed the problem. I measure no difference between a loopback connector and the S3 in standby mode. The added distortion is gone, no difference in channel balance, frequency response either. In standby, it measures transparent. The rest of it is the same: knobs, center frequencies, etc.

Since this is an early pre-production kit, during construction I had to do a few extra steps with jumpers and wiring. They will sort this out, so when the revised kit is released it will be just as easy to build as the original.

Kudos to @jseaber for the customer support and followup.

Kudos for the review & measurements! I'm close to ordering one of these for my office setup. I'm not allowed to install any software on the work computer so software EQs are out of the question. I'm just wondering about two things:

1. Is there a reliable way to identify an assembled unit of the revised version? I'm going to order from an EU distributor, and I suspect they might have some older stock. Did JDS mention anything about this?
   
   
2. How are those potentiometers holding up in your unit? If I purchase it, it will be some 5-6 hours of use a day, 5 days a week, with probably a lot of adjusting So I'd like to know if they last long before becoming noisy. Can you comment on this based on the experience with your kit?

Thanks!

 

[Timbo2]

Kudos for the review & measurements! I'm close to ordering one of these for my office setup. I'm not allowed to install any software on the work computer so software EQs are out of the question. I'm just wondering about two things:

1. Is there a reliable way to identify an assembled unit of the revised version? I'm going to order from an EU distributor, and I suspect they might have some older stock. Did JDS mention anything about this?
   
   
2. How are those potentiometers holding up in your unit? If I purchase it, it will be some 5-6 hours of use a day, 5 days a week, with probably a lot of adjusting So I'd like to know if they last long before becoming noisy. Can you comment on this based on the experience with your kit?

Thanks!

JDS is really good about answering email. Just send them an email and you should get an answer within two business days or less.

The pots on my unit are on their 4th year or so with no issues.

 

[MRC01]

1. Is there a reliable way to identify an assembled unit of the revised version? I'm going to order from an EU distributor, and I suspect they might have some older stock. Did JDS mention anything about this?

If you open it up (which is easy), just look at the board. I've got pictures in my review. The original version has 1 orange rectangular relay behind the RCA jacks. The new one has 2 of them side by side.

2. How are those potentiometers holding up in your unit? If I purchase it, it will be some 5-6 hours of use a day, 5 days a week, with probably a lot of adjusting So I'd like to know if they last long before becoming noisy. Can you comment on this based on the experience with your kit?

As I mention in the review, all the parts are high quality. IIRC the pots are Alps RK09 which have good channel balance (within 0.5 dB) and should last a long time. They also have a nice feel with a positive center detent. Mine have been trouble-free. They have little holes/vents so you can open it up and spray some contact cleaner in there if it ever gets scratchy.

 

[Moderate Dionysianism]

If you open it up (which is easy), just look at the board. I've got pictures in my review.

Thanks! Although it would be nice to know before purchasing. A sign of transparency from the company too. Will try contacting them.