Stax SRD 6/7 - opinions?

[John Buchanan]

OK - putting the neck on the chopping block here!

I have the SRD-7 with the Spritzer Professional bias board, so, in effect, an SRD-7 Pro. Love the sound with the Sigma/404 and driven by a Studer A68. The bottom end is nicely in control (as Birgir has said happens with upscale amplification ala Blue Hawaii SE or that ilk), and there is more of the power that these earspeakers have in spades. They seem to convey the "oomph" of the performance much better than any other Stax I've heard. Although the Lambda Nova Signature/SRM-Monitor is probably more technically neutral, this combination seems to get a natural sound out of most recordings, just as Naotake Hayashi mentioned. Piano and vocals through this set just sounds real - IMHO not even the SR-007 Mk 1 could do that as nicely - without any midrange stridency or upper midrange cymbal emphasis. Someone mentioned the distortion in the SRD 7 - not sure what he/she is talking about. Can't hear any problems there. Measurements may prove me wrong however, but that's fine.

Currently listening to Jacques Loussier's "Baroque Favourites" - piano sounding live and the drum kit is reproduced well with no unnatural cymbal emphasis and with great speed also. I'd love to hear a super deluxe version of the SRD-7!

[deepak]

I have a spritzer modded SRD7 turned pro as well. Fun little box and better than the regular SRD7-pro (without the dreadful stock Stax speaker wires), but doesn't even compare to the Blue Hawaii. This is with a SR-007 MK1.

There is some pleasant distortion going on with the pro box, but the BH lays it flat out like it is.

[John Buchanan]

Interesting view - I have found that the SRM-717 wasn't a patch on the SRD-7/Studer combination. It sounded OK in isolation, however. I'm not so sure about pleasant distortion either. But, I haven't heard a BHSE either.

[deepak]

It has been some time since I've heard a 717, but I believe Birgir has said it was intended by Stax to have a pleasant sonic signature. The distortion I'm referring to with the pro box might be the transformers running out of steam and applying some "compression" (not sure if this is the correct word?) to make things sound more punchy. This is the way I perceive it and I'm quite sensitive to compression applied in music. The Blue Hawaii doesn't do this and can sound more plain in comparison.

[spritzer]

There isn't a whole lot of distortion in the SRD-7 but it will naturally only add to what the amp is doing. The 1:25 ratio isn't that bad but I do prefer lower ratio's as unlike 1971 when the SRD-7 was introduced, we have power to spare. Higher ratio can only mean more distortion.

Transformers do have merit and I'm getting good results from the massive Lundahl irons. Not cheap by any means and about 5 times larger then the SRD-7 trafo's but this is team overkill after all. Even the small LL1630 was very nice upgrade over the WEE at CanJam even if it was struggling a bit with the lower ratio. Add a small diecast box, one of my bias boards and it's also cheaper than the WEE, at least for people who don't have to pay silly import fees. I did one WEE owner claim that it was as good as it gets which just shows how clueless people really are.

The 717 was indeed changed but whetther they did it to save money or just that the neutral sound of the KGSS wasn't their cup of tea. Neutral it isn't and the 727 (after mods) is a better amp just because of that.

[luvdunhill]

Soon enough I'll be able to measure the distortion, working on getting the data into a computer at the moment. I think it will be a lot more than people think.

I'd guess around .05%-.1% at full power at 1kHz.

[spritzer]

That's about what Stax said back in the day. Compared to the Exstata then it isn't anything to complain about.

[luvdunhill]

That's about what Stax said back in the day. Compared to the Exstata then it isn't anything to complain about.

The question I have is would there be less distortion in using a low ratio transformer and lots of gain / power behind it, or vise versa? I have a feeling, but nothing to back it up (yet).

I think that's plenty to complain about though

Edited November 19, 2010 by luvdunhill

[spritzer]

You are always so cranky... A SS amp with 2+% distortion is just facepalm material.

The problem we have is that we are stuck with 1960's mentality and transformers optimized for that age. Most amps you can use today can easily driver a 1:15 to 1:20 transformer so why use a higher ratio?

[luvdunhill]

I am cranky

The reason is that as power goes up the distortion will go up. Same with ratio. The question is which goes up less and where is the sweet spot.

[spritzer]

Indeed that is the question and it isn't simple to answer. I was just reading the measurements for the Pass INT30 and with something that well designed we could find the sweet spot but amps such as these are all too rare...

[Smeggy]

well I don't have the souped up transfos in my srd 7 mk2 but I've always been partial to the transfo boxes. They do things my ears like, whether it's getting the flavor of my amps or a good dose of distortion. Whatever it is, I seem to like the way they sound. Gives the sataxes some well needed bite.

[graben]

In regards to Omega 2 and the Sigma I prefer the SRD7 Pro Mk2 to any Stax made amp that isn't a 717/727. For Lambdas or SRX though I prefer a Stax amp over the SRD7.

[Beefy]

That's about what Stax said back in the day. Compared to the Exstata then it isn't anything to complain about.

I still maintain that the Exstata sounds considerably better with my SR-Lambda than the SRD7-SB fed from either my M3 or a t-amp. Would the transformer box improve with a better speaker amp behind it? Absolutely. Would it make up the difference in sound quality? I'm pretty skeptical; the difference it quite large to my ears.

[spritzer]

It really depends on what the difference is to you ears. My biggest issue with the Exstata is just how bloody unlinear it is, the bass is wooly and undefined and the top end is edgy even with the SR-007. Even the most basic Stax amp can't be accused of doing that nor the transformers.

Now before somebody claims the Exstata can't drive the SR-007, that is just not correct and I use all of my amps with the Omegas. The SRM-300 or SRM-Xs can drive them just fine but not the Exstata? Sure it isn't up to the BH levels but a SRM-1 Mk2 works just fine.