[Mzisman4]

I just got my Stax gear (SR-Lambda Pro, SRM 1-MK2, SR-30).  I excitedly plugged in the lambdas but to my disappointment there is static on any bass note.  It's especially bad in the left ear.  The SR-Lambdas are professional but there is no label on the amp.  I'm assuming this means it is normal bias.  Gut tells me no but is the mismatch with the amp the cause of the static?  The SR-30s sound clear.  Another concern is that the volume is fairly low  I have never had a stax setup but it seemed strange that I had to crank the knob all the way up to get a normal listening volume (on both sets).
 
Just a little background, I got these fairly cheap but it was a blind CL buy from across the state.  I had a buddy of mine visiting so he picked them up for me before trekking here.  The seller knew next to nothing about the equipment but seemed reasonable.  I think she was selling a family members stuff.  If these can't be repaired, I can talk to her about getting a refund for all/some of the equipment.  
 
The pics of the Lambdas were a little misleading.  They need new pads--the leather is cracked and the inner foam is about 90% gone.  There are some small bumps on the inner grill but nothing really major.  Anything I should look for?
 
I really appreciate the help. All info is greatly appreciated as I need to act fairly quickly.  
 
If pics will help, I can post them.  Just let me know what you need to see.

 

[Mzisman4]

Any Stax gurus?  I hate to press so hard but my buddy is leaving on sunday so I need to make a decision quickly

 

[deadlylover]

It sounds like there might be some dust inside the drivers, that's not good.
 
If the jacks on the amp have 6 pins, then it's normal bias, using the Lambda Pro will result in much less volume, and I don't believe it will cause the strange static on the bass notes, but I could be wrong.
 
Leave them plugged in on the amp (just turned on, nothing needs to be playing) for a while (could be a couple of hours or even overnight), and see if anything improves.
 
Personally, I'd pass on them. The caps in the amp must be dying as well from old age, and would need to be replaced too.

 

[Mzisman4]

Deadlylover - Thanks for the tip.  I plugged them in this morning and left it on all day. The sound is significantly improved now.  It now sounds more like distortion, specifically at high volumes.  It's still mostly with bassy tracks.  Is this due to the pro/normal mismatch?

 

[vinyllp33]

You say you have an SRM1-MK2 but there are no markings on the amp?

There are two headphone outputs on this amp: The left should be labeled "Pro Only" and the right "Normal".

Do you have Lambda Pro plugged into the left jack? If it is plugged into the normal bias (right) then you will definitely have drive/volume issues as it has only 230V bias voltage as compared to 580 volts on the Pro.

 

[Mzisman4]

What I meant was that the google search kicked back an image that said "professional" on the top for the pro bias model.  This one doesn't say professional and both plugs are just labeled "Earspeakers".  
 
It seems like this may be the source of some of the problem.

 

[vinyllp33]

What you have is a normal-bias only SRM1-MK2, as it stands this will never properly drive the Lambda Pro's, it is only providing 230V, not the 580V required.

As I recall some of these amps had the ability to be modified to provide a Pro-Bias output but I do not know the cost of the parts and labor involved.

Good Luck!

 

[Mzisman4]

Update: I let them sit for a while longer and the sound has improved again in general.  Still getting vibration out of the left side.  If it is dust, can I somehow clean it out? (compressed air or something?).  There is also a channel imbalance.  Will correcting it with the volume knob be good enough?  
 
Volume is a little better but there is still distortion at higher volumes. I searched and found this conversion: http://www.headfonia.com/stax-srm-1mk2-bias-modification/
Would this be something to consider doing?  I'm decent with a soldering iron but I may need to get help from some friends in EECS. 
 
I've noticed that the wiring on the left side is weak.  Tilting my head to the left causes audio to cut in and out.  If I wiggle the plastic connector where the wire meets the left can, I also get audio cut out.  Is the issue maybe a wiring problem?  Can these be recabled?

 

[Mzisman4]

No reply form the seller so I'm assuming that means no return option.  I am fairly sure the amp is good which is a relief because I can sell it a recoup most of my investment.  Is there anyone that does repairs on the headsets?  I emailed Yama's but based on the reviews here, I'm not holding my breathe.

 

[pkshan]

Plugged a pro version headphone in to a normal bias amp,
& turning the volume too high,  will damage the headphone,
it was mentioned on stax manual

 

[Mzisman4]

Yama's replied but as I expected, not much can be done for such and old set of headphones.
 
What can I expect to get for the lambdas as parts?  They right driver is still good.
 
Can the srm 1-mk2 power newer sets (sr-207 up to sr-407)?  

 

[NamelessPFG]

What can you expect for a "parts" Lambda? Tough to say, but I wouldn't expect much over $150. It doesn't help that Yama's/STAX USA can't even help with drivers as recent as those in the SR-303, as it seems that driver repairs can only be done for the current generation offerings.
 
On the other hand, now I'm curious as to how much of the issue is with the cable and how much is with the driver itself. You can probably recable them with ease if you have a replacement cable, but given the proprietary nature of Stax cables, I don't expect them to be easy to source short of buying another "parts" headphone.
 
All those newer sets are still Pro bias (pretty much everything made after the original 1979 SR-Lambda is Pro bias), so you'd still have to modify the amp for Pro bias. Whether it'll be good enough for those newer sets once modded, I can't say for sure, but I don't see what the problem would be if you're not attempting to drive anything nearly as demanding as the SR-007.