[JLovvorn]

Completely lucked into these amazing Stax Lambda Pros.
Anyone have tips on a product to restore the leather? It's pretty dry.

 

[CJG888]

Replacement pads are available from Stax.

 

[DarkDEV28]

It's technically not an electrostat, but an electret - dynamic hybrid.
Electrets, unlike electrostatic headphones run off normal headphones amps or AV-receiver headphone outputs.

AKG never made a true electrostatic headphone.

That news, because the only electret headphone I was familiar with is the STAX SR-40 with it 5 pin plug that required the adapter to hook into the speaker output of the amp.

 

[GREQ]

That news, because the only electret headphone I was familiar with is the STAX SR-40 with it 5 pin plug that required the adapter to hook into the speaker output of the amp.

I think you're confusing electret and electrostatic.
While they operate using the same principles, electrostatics require an external source to build up a static charge like the Stax.
The SR-40 (like most Stax) has an external energizer that it requires to build up the static charge needed in order to make sound.
After use, the headphone needs to be discharged, or will discharge naturally over time until the next use.

Electrets like the one present in the K340 have a 'permanent' static charge.
They don't require an energizer, simply plug and play into any headphone-out on a receiver or amp.
Toshiba/Aurex produced quite a few electrets.

 

[CJG888]

Mitchell & Johnson were a more recent exponent of this technology (a hybrid system, like those old AKGs).

 

[DarkDEV28]

I think you're confusing electret and electrostatic.
While they operate using the same principles, electrostatics require an external source to build up a static charge like the Stax.
The SR-40 (like most Stax) has an external energizer that it requires to build up the static charge needed in order to make sound.
After use, the headphone needs to be discharged, or will discharge naturally over time until the next use.

Electrets like the one present in the K340 have a 'permanent' static charge.
They don't require an energizer, simply plug and play into any headphone-out on a receiver or amp.
Toshiba/Aurex produced quite a few electrets.

That is a bit confusing, because most modern Stax Energizer I know of require a wall outlet. Where my SRD-4 adapter for the SR-40 just require to be hooked up to a speaker out on a amplifier, so I don't believe that the SR-40 to be engerized by the adapter.

 

[DarkDEV28]

Here is my Beyerdynamic DT220 with Sony XB950BT pads, that I believe are 400ohm
https://imgur.com/Qf257yf

 

[GREQ]

That is a bit confusing, because most modern Stax Energizer I know of require a wall outlet. Where my SRD-4 adapter for the SR-40 just require to be hooked up to a speaker out on a amplifier, so I don't believe that the SR-40 to be engerized by the adapter.

It's not about believing it or not.
The fact is: an energizer powered from a wall outlet, or by speaker taps will do the same thing - build up a static charge on the electrostatic membrane.

An electret has a 'permanent' static charge... of course it will get weaker and weaker over the years until it eventually 'dies'.

 

[nick n]

Even the small electret drivers inside the AKG / Intuit ( Mitchell and Johnsons OEM source )etc etc hybrid headphones still all have transformers in the cups to run them by significantly stepping up the signal.
This also serves to separate any possible frying from a crappy source IIRC.

This is really unclear what you mean exactly:

"That is a bit confusing, because most modern Stax Energizer I know of require a wall outlet. Where my SRD-4 adapter for the SR-40 just require to be hooked up to a speaker out on a amplifier, so I don't believe that the SR-40 to be engerized by the adapter."

I'm just going to throw this out here for all , since it gets asked from time to time anyhow.

FOR FULL BIAS STAXEN
The powered adapters take the power from the wall, a bit easier.
The non-powered SB "SELF BIAS" take the power from the speakers outputs.
Both end up with same result.
A signal that is stepped up.
One may be better than the other since it does not fluctuate.
BUT THIS ABOVE PARAGRAPH IS ONLY RELEVANT TO FULL BIAS STATS
= WALL POWER IS IRRELEVANT FOR ELECTRETS unless the unit needs wall power for powering on for functionality like newer Stax AMP units or some adapters.
The power turns the entire unit on in other words.
Whether the bias is used or not they need power to even work / function.



Electret do not need a bias applied to them from a 5th pin connection , they only use 4 wires to send signal since they already have the embedded permanent charge.
That signal is supplied through the speaker terminals through the adapter obviously.
The 5th pin on a Stax electret cable is a dummy pin connected to nothing at all.
Only 4 of the 5 pins connect.
You can plug in Stax electrets into full-bias amp units ( pro or normal bias ) or even full bias adapters as the 5th pin does nothing so will never connect to the 5th pin bias charge that regualr estats need.
Eg :
SRD-6 normal bias adapter with SR-40 is fine.
SRD-7PRO pro bias adapter with SR-40 is fine.

Feel free to try running off an amp directly somehow, but the amp will still have to step the signal up by at least 26 + db . ( good luck )
Which is what the transformers so within the adapter units.
Without transformers you also risk applying a crappy charge ( DC offset etc ) to their diaphragms off the speaker terminals due to direct coupling.
Transformers also isolate that signal also from amp outputs
This parasitic charge or over-voltage situation applied to electrets from overdriving them is the cause of many electret failures ( permanent damage that cannot be reversed ).
Sony had a design that slowly bled some of that off IIRC (?) but that is another topic.
If one side is lower volume / now decreased sensitivity from this, it is screwed for good.
No regenerating an electret.

I have bought electrets terminated with a TRS for some crazy reason ( not the ones designed like that but ones needing an adapter ), but only bought them for parts ( headband assembly etc ) since when I see that goofy mess there's no guarantee they are not screwed from someone trying to power them cranked on some poor stereo.

Anyhow I am sure others can add more info.

 

[tascamtascam]

Pioneer SE-300 -- Piezoelectric Stereo Headphones (1972-78)

Power hungry, good bass, nice full-body vocal.
Neutral, balance & clean.
Pretty good!!

 

[fractus2]

 

[tascamtascam]

Sennheiser HD580

 

[jerg]

These sounded so damn good after some invasive modding (new earpads with added perforations, internal cup damping, converting to open-backs), decided to nab a second pair!

Pair #1 started with an A- tonality (that's what piqued my interest initially) but some nasty upper midrange ringing/glare, and now its tonal balance is as good as I've heard in any headphones, plus the midrange glare is under control.

Next modding project: work on the much more mint-condition pair #2, to keep the closed-back configuration for the cups and try to get internal damping up to snuff so I don't have to go medieval on cutting it up.

 

[GREQ]

These sounded so damn good after some invasive modding (new earpads with added perforations, internal cup damping, converting to open-backs), decided to nab a second pair!

Pair #1 started with an A- tonality (that's what piqued my interest initially) but some nasty upper midrange ringing/glare, and now its tonal balance is as good as I've heard in any headphones, plus the midrange glare is under control.

Next modding project: work on the much more mint-condition pair #2, to keep the closed-back configuration for the cups and try to get internal damping up to snuff so I don't have to go medieval on cutting it up.

I think most people give up on paper-cone dynamics the first time they hear them.
It's actually sounds like a pretty fun challenge to make one sound good.
Are those aftermarket beyer pads?
That suspension headband also looks familiar

 

[jerg]

I think most people give up on paper-cone dynamics the first time they hear them.
It's actually sounds like a pretty fun challenge to make one sound good.
Are those aftermarket beyer pads?
That suspension headband also looks familiar

Woah! I commissioned this headband from you back in 2013 (Just dug up my DMs). It's been 8 years, totally forgot haha.

It worked well for the Hifiman HE-500s I had back then, but was in cold storage until my recent venture into these headphones.

Did you make any more of these since summer 2013?

----

Re: giving up on papercone dynamics - I did buy a few other 70s Japanese pairs of other brands/makes out of hope that they'd also be diamonds in the rough, but they all sounded unrecoverable. So I wouldn't be surprised if that's the case most of the time. These have been an outlier in my limited venture thus far.

Re: pads - they are generic 105 mm velour earpads I found on amzn/ebay; padrolled a bit and these stood out in terms of correctly tuning these particular headphones.