Kaldas Research

[Jonny]

An the sound with 007-pads is even better?

[JoaMat]

Well, I’m back with the original pads and nothing wrong with them. Besides, I don’t like to comment on sonically differences on things I change or modify. On the other hand I like to tell (to much) all here what I’m doing.

[PolloLoco]

On 2/10/2020 at 2:53 PM, JoaMat said:

The bolt was OK, the wire though was broken. Maybe the bolt damage the wire when it was tightened.

Anyhow I got the opportunity to see how the RR 1 is built. I also disassembled the driver unit. Spacers seem to be about 1.3 mm thick and the sound when knocking the diaphragm it sounded about right. And yes, everything is easily accessible, except the pads maybe.

Bottom line: I like the design.

P.S.
As the original pads were removed I took a pair of 007 pads

JoaMat, 

Can you provide more detail about how you disassembled the Conquest to get to that terminal block?  And how difficult it was to remove the pads?

I'm tempted to pad roll based on your response.

[Leonardo Drummond]

On 2/10/2020 at 3:14 PM, Aumkar Chandan said:

Interesting, not sure how the bolt would come loose.

Stators are now laser-cut Brass, you can directly solder onto them if you like. The front Stator connection might be challenging due to packaging reasons but it is workable if you want to solder it and not use our bolt method.

Furthermore, every part of the Driver is serviceable because it’s all bolted and no glue is used. Spacer is Aluminium though. 

Aumkar, I'm late to the party but, from a fellow entrepreneur (although the headphones my startup makes are definitely not on the same level as yours and exclusive to Brazil for now), I just want to congratulate you for what can only be described as some truly inspiring work, on every level.

And, as a product designer, I have to say that the way you've turned the internal wires, which could be an aesthetic challenge, into a beautiful and distinctive detail was pure genius!

Edited May 26, 2020 by Leonardo Drummond

[JoaMat]

On 5/26/2020 at 7:35 PM, PolloLoco said:

Can you provide more detail about how you disassembled the Conquest to get to that terminal block?  And how difficult it was to remove the pads?

It’s some time since I disassembled the headphone and my memory isn’t the best, anyhow. Remove earpad fixed by double sided tape and remove the two screws now exposed. Gently remove the now loose inner ring one none ear side and all inner parts are accessible. It’s easy to detach earcup from headband, one screw only, and cable – then you have the earcup completely free.

I believe it’s fairly easy to work on the headphone, but as always be careful. Personally I think Kaldas is an overall nice design.

Good luck.

[PolloLoco]

I bought a pair of Kaldas RR1 cups/drivers/pads from the previous owner about 2 months ago.  They squealed, Aumkar had generously replaced the headphones for him - and didn't require shipping back the original bespoke hardware.  These were among the first RR1 produced.  I've been totally stir crazy due to the lockdown.  Though the most I'd played with electrostats was removing rotted foam from a set of lambdas, I figured this might be a fun project to tear down, and if I'm lucky restore.

I modded an old Hifiman headband, and bought a cable from Mjolnir audio.  I immediately heard the electric squeal, but it would periodically go away.  I had a full 2 hour stretch of silence where I realized these were awesome headphones.  Though I was biased towards my Koss ESP95X - after a head to head listening session, I had to admit I liked the Kaldas more for everything but treble.  Unfortunately, the squeal and/or buzzing from the left earcup grew to become practically continuous. 

So I used Joamat's instructions to investigate and completely disassemble the left earcup.  They were fairly easy to disassemble, except for one bolt that sits right behind the mini XLR connection.  The mini XLR pins being so small, and me being TERRIBLE at soldering - I tried to avoid undoing the solder joint, but broke one of the wires.  If you do this, be careful to undo the wired connections last, there are tiny M2 nuts that will fall out if you're not careful.  After that, I found basically the same issue that Joamat found, the Bias wire was broken, and there were strands inside the female thread of the housing.  It's possible that one strand got into the driver and caused the whine and buzzing.  I liked the bolted assembly, and wanted to keep the headphones easy to disassemble, so I soldered in M2 terminal connections as shown.

I had to use longer heat shrink tubing because I had wiring exposed at the mini XLR connection.  I used a grinder on a dremel tool to make a larger hole in the cover - I found when I assembled initially, that I caused a short and lost volume out of the left earcup.  To fix it - I ended up resoldering two of the wires at the mini XLR connection.  Then I blew compressed air across the driver and stators, being careful to expose the driver for the most minimal time possible.  Then I reassembled as shown including the two dust covers.

Eager to test my work, I reassembled the headphones and connected to my Stax SRM 717.  The left earcup was completely silent - success!  Funny thing - the right earcup started squealing even louder!  So I repeated the process of soldering terminal connections.  When I reassembled, the right earcup still squealed.  I was super frustrated, but went back and did the step I skipped, I blew compressed air across driver and stators.  And that seems to have solved the final issue.

I've now listened for about 10 hours with almost complete silence.  To be honest there's been a handful of times, totaling maybe 30 seconds where I heard a slight buzzing, and thought "Oh no!  Not again!"  But shifting the earcup slightly cleared it immediately.  My ears touch the dust covers, so I suspect it's a different issue entirely.  Perhaps with a shift, my ear presses against the stator.  The final picture is of my Frankenstein Kaldas RR1 conquests.

I contacted Aumkar, not for help - but to suggest a few manufacturing improvements based on my findings.  Aumkar was very kind, suggested that I solder directly to the bolts - and then informed me that he'd already incorporated all of the manufacturing improvements I suggested.  So if you order a Kaldas RR1 conquest now - it will be more robust than the initial versions.

Overall - I think this is a great product, and Aumkar has been a pleasure to chat with.  If you're willing to buy an energizer separately, these sound better than the Koss, and far better than the L300/L500 I used to own.  I hope Kaldas will produce a sequel.  I like these headphones so much I'm having Vesper Audio quote out slightly thicker pads so my ears don't touch - and I ordered touch up paint to fix a couple spots I scratched or gouged during my project.

[Pirx]

So quiet ... Does this project live, any new happy owners, new reviews? Maybe some improvements from makers?

[Aumkar Chandan]

There is an active HF thread if you're interested. 

I try to limit my postage here on Head-Case as I understand most people here are happy with what they have and are not interested in further marketing posts which nobody cares about. 

[Voltron]

I think Head-Casers want to hear news about your e-stats even if it is marketing. I had the same question as to what was going on with your cans out of curiosity.

[Aumkar Chandan]

Yes, in that case we have been in production since last year and have crossed over a hundred units in the production mark. It's not a lot but, this is passion not a business. 

In terms of refinement, refinement to minor fixes have been done. As @JoaMat had pointed out last year regarding the connections, now it is a fully soldered connection from the earlier screw down one. This solved majority of the issues we had in the early units. 

Then upon Spritzer and Wachara's recommendations since last year, the drivers have 2-stage dust protection and go through vigorous anechoic chamber testing to detect noise/buzz/squeal. We have positively eliminated that as well. 

Lastly, the overall assembly and Manufacturing has also been refined now that we have been in production since last year. 

The RR1 is here to stay, it will not be updated as "2.0" or a "2nd Gen" as other Manufacturers do. There will be future products coming out but, that's another story as we are currently busy with other non-headphone related projects as well. 

[Pars]

40 minutes ago, Voltron said:

I think Head-Casers want to hear news about your e-stats even if it is marketing. I had the same question as to what was going on with your cans out of curiosity.

Same. And I really detest going to HF...

[Aumkar Chandan]

Here are some photos of a recent Bespoke unit we delivered - 

[Lord_Rexter]

Hmm so you have resumed taking in Bespoke orders, good news, Aumkar ✌️

[morphsci]

I am not especially fond of red headphones, but I find these really stunning. Excellent job.

[Long Way Around]

Finally have one on order - looking forward to it! the L700 has been dominating my head for a good 6 months or so, and made me gradually stop listening to my non-electrostats. Will be neat to have a different type of stat to complement the 700.