[keiron99]

I've had my Stax Lambda Signature Pros and SRDX Pro energiser for longer than I care to remember! I've always thought that if there was a weak part of the system, it was probably the energiser. To that end I'm thinking of "upgrading", but to do that it'd have to make a worthwhile improvement. I've seen one or two SRM-3 energisers around, but as with all things Stax it's difficult to get any reliable information.

Does anyone have any knpwledge of this, and whether indeed it would be a suitable upgrade for me? Thanks.

 

[cosmopragma]

There are lots of options nowadays.Stax amps (you could save a lot by directly importing them from Japan via Eifl), the Rudistor amps from Italy, the Gilmore designs KGSS and Blue Hawaii, the relatively affordable McAllister tube amp, and there's always the option to purchase an used amp.
What's your budget?

 

[keiron99]

Thanks. I wasn't aware that other manufacturers made energisers, I'd assumed it had to be Stax.

I was thinking of buying second hand and didn't really want to spend more than £200 (I'm in the UK).

 

[Tachikoma]

would you sell your current energizer if you upgraded? >_>

 

[keiron99]

Quote:

Originally Posted by Tachikoma would you sell your current energizer if you upgraded? >_>

Absolutely. No need for two energisers!

 

[Jahn]

if you want to stick with something you know, try the SRD-7 Pro. I've seen a few fly by eBay for 50 bucks, so keep an eye out!

If you want to move on to integrated energizers, the SRM-313 and the SRM-1/MKII are the solid state options folks like, and the tube options would be the SRM-006t and 007t. Far pricier but if you don't have a beefy power amp to hook the SRD-7 Pro into, try the standalone units instead! Also google "Simple Stax" they have a nice history of everything Stax ever put out, with recent used prices too.

 

[keiron99]

I today took receipt of an SRM-3 for my Lambda Pro Sigs. Excellent sound quality, but one significant problem. Most noticeable on piano pieces, there is clear breaking up of sound in both channels, a bit like a "static" noise. I have tried all sorts - different power supplies, different interconnects, different sources (sacd, pc, variable and fixed outputs etc etc) but with no joy. Does anyone have any ideas?

Thanks

 

[hozo]

What you describe might be insufficient bias voltage. I know with my very leaky diy electrostats, anything below 300V cause a similar symptom. The low mids sound fine. However, when it hits the highs (such as violins and female vocals) the sound breaks up almost as if it’s clipping. I’m not sure if bias voltage is the root cause or just covering up the symptoms.

 

[rickcr42]

Couple of points.

1-an energiser if I understand your meaning is not an amp but is in fact a high voltage bias supply combined with matching transformers and hooks up the the loudspeaker terminals of a power amp.A true electrostat headphone amp is all self contained and operates from a line level input.
There are upgrade transformers available for the true energiser to make it a bit better and i use mine straight off a Class-A 20WPC amp.I also have a Gilmore "All triode Headphone Amp" that is again modified and upgraded.both sound fine and I would be hard pressed to pick a favorite.

2-There are both "high bias" and "low bias" Stax cans and you must be sure to match up the cans to the proper amp output jack or your results will not be the best.

3-Electrostats do not like to be in an unbiased state for long periods so running the HV supply through them coninuously (possible with the Energizer,not so possible with an amp though can be done with modifications) a real and audible plus.If the cans went unused for a long period just let them acclimate and it may be fine.

for the definitive answers though ask Kevin Gilmore our resident Mr.Electrostatic Headhones Expert in a PM then post the answer here for others to read

 

[trbl]

Quote:

Originally Posted by keiron99 I today took receipt of an SRM-3 for my Lambda Pro Sigs. Excellent sound quality, but one significant problem. Most noticeable on piano pieces, there is clear breaking up of sound in both channels, a bit like a "static" noise.Thanks

This is the driver amplifier clipping. The maximum output voltage (and current, which is most relevant at higher frequencies) of the various driver amps is something that people often overlook. I'd recommend trying a Stax SRM-1 Mk 2 driver amp. They've been around for over 20 years, sound good, and actually have a somewhat maximum output voltage than most newer model Stax amplifiers like the SRM-313 and SRM-006t. Since the newer model Stax Lambdas are also a bit less sensitive than the original model Lambda Pros, the result can be clipping such as you heard. I had problems with excessive clipping when listening to some favorite choral recordings (Choir of King's College, Cambridge) with a new SR-404 and SRM-006t system. My 20 year old Lambda Pros with SRM-1 Mk 2 had no such problem with the same recordings.

 

[surfboardz26]

I would go for the gilmore kgss amp. Infact that is what i went for. I bought it new from him. It takes a month to build so order one now if you want one. Kevin gilmore just finished building mine yesterday so it should reach me by wedsday. Ill let you know how it sounds. If im correct this amp should liven things up a bit and give that extra sparkle you might be looking for.

 

[keiron99]

Quote:

Originally Posted by trbl Since the newer model Stax Lambdas are also a bit less sensitive than the original model Lambda Pros, the result can be clipping such as you heard. I had problems with excessive clipping when listening to some favorite choral recordings (Choir of King's College, Cambridge) with a new SR-404 and SRM-006t system. My 20 year old Lambda Pros with SRM-1 Mk 2 had no such problem with the same recordings.

Thanks. However, the earspeakers I'm using are the original Lambda Pro Signatures, like yours by the sound of it. From my knowledge of Stax gear, the amp and those Lambdas were produced around the same time and should be compatible. I do not have any of these problems with my (DC powered) SRDX Pro energiser.

 

[Jahn]

Quote:

Originally Posted by trbl I had problems with excessive clipping when listening to some favorite choral recordings (Choir of King's College, Cambridge) with a new SR-404 and SRM-006t system. My 20 year old Lambda Pros with SRM-1 Mk 2 had no such problem with the same recordings.

I know i shouldn't be such a git, but when I read that it made me feel warm and fuzzy about my new rig *hugs ol' Lambda Pros/SRM-1 MKII*

 

[trbl]

Quote:

Originally Posted by keiron99 Thanks. However, the earspeakers I'm using are the original Lambda Pro Signatures, like yours by the sound of it. From my knowledge of Stax gear, the amp and those Lambdas were produced around the same time and should be compatible. I do not have any of these problems with my (DC powered) SRDX Pro energiser.

Your old energizer used transformers to drive the headphones from your power amp. It could well be this combination never clipped at high signal levels. That would depend on your power amp.

The various amplifiers for Stax all have maximum output voltages beyond which the amp will clip and you'll hear a sound exactly like you describe. You can test this by turning the volume down significantly, which should eliminate the clipping or at least reduce its frequency. FYI, the SRM-1 Mk 2 is rated as capable of 370 Vrms maximum, while the newer SRM-313 is rated at 350 Vrms and the SRM-006t is only rated at 300 Vrms. The smaller Stax amplifiers probably have even lower clipping points, but I don't have any information on them. For completeness, SRM-007t is rated at 340 Vrms and the SRM-717 is rated at 450 Vrms maximum. The published numbers I've seen on the KGSS and Blue Hawaii seem to vary a bit according to where you look, but I think they're good for about 420 and 530 Vrms respectively.

Finally, I think your Signatures are the later, somewhat lower sensitivity version. The original Lambda Pros with the old style (fragile)headband and thicker (but still pretty thin) diaphragms are what I have from back around 1984.

I hope uou can find a good solution to your problem.

 

[keiron99]

Quote:

Originally Posted by trbl Your old energizer used transformers to drive the headphones from your power amp. It could well be this combination never clipped at high signal levels. That would depend on your power amp.

Thanks, but actually, my old SRDX Pro is not driven by the power amp, it is line level. I have it connected to the line out of a DAC.

Quote:

Originally Posted by trbl Finally, I think your Signatures are the later, somewhat lower sensitivity version. The original Lambda Pros with the old style (fragile)headband and thicker (but still pretty thin) diaphragms are what I have from back around 1984.

Actually I think I do have the earlier ones, given your description (they certainly do have the thinner plastic headband). I'm informed by the UK's very own "Stax guru" at Simply Stax that in his opinion, they are second only to the new Omegas. I guess it's all about opinion though!

Quote:

Originally Posted by trbl I hope uou can find a good solution to your problem.

You know, I think I have found the solution, after hours of plugging, unplugging etc. Quite simply, I think I was listening to them too loud! The output from my DAC is apparently quite high, and so too it would appear to be from my SACD player.

Just to satisfy myself this was the case, I got out my never before used sound pressure meter, and frightened the pants off myself when I was recording outputs of over 90db. (A search on this forum suggests others listen at around 70 - 80). A salutory lesson that could save my hearing in the long term!

It's interesting though, that the supposedly inferior SRDX Pro can drive the Lambdas to ear bleed levels without any clipping. Also, despite many hours listening, I'm not sure there is a huge difference between the SRDX and the SRM-3 (which our man at Simply Stax describes as significantly better than the current 313, and not far behind the 717), despite obvious fundamental design differences (the SRDX operates off batteries or DC). Maybe I have done my ears long term damage!

I do wonder, just how much of an improvement I would gain from the top of the range SRM-717. I wouldn't spend that kind of money unless it was a night and day improvement. Could anyone possibly comment?

Thanks for everyone's help, by the way!