The Stax Thread III
Jun 21, 2018 at 4:56 PM Post #15,391 of 25,558
True, it is more similar to the ES-1/2 I was confused because my friend had built the DIY version way, way back, and I remember that he told me that he had used a Stax circuit.

Found it (in low-res), maybe I think this was the one. Kind of fun to see it dating back almost 10 years.
 
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Jun 21, 2018 at 5:22 PM Post #15,392 of 25,558
This is the original SRX circuit:
Figure 1.jpg


The [Singlepower] ES-1/2 was a rip-off of the original SRX. It was botched because unlike the original, it used a common filament supply for both input and output tubes (notice that there are two filament supplies in the original circuit, seen at the bottom to left of center). Since the input tube cathode voltages are close to zero or positive, and the output cathode voltages sit near B-, the output tube filament to cathode voltages far exceeded their rated limits, resulting in early failure of the output tubes.

And this is the simplified SRX Plus circuit:
Figure 2.jpg


The double circles represent the constant current sources/loads.
 
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Jun 21, 2018 at 5:33 PM Post #15,393 of 25,558
Apologies if this not allowed, I have a Mojolnir KGSSHV Carbon and 009 combo for sale, just over 18 months old. Please PM me if of interest, will have to restrict this to UK only, sorry.
And once again if I've tripped up protocol on Head Fi apologies.
 
Jun 21, 2018 at 5:44 PM Post #15,396 of 25,558
Is your new shunt supply 100% ready yet? Can't find boards for the grhv, and it looks complicated

Yes, it is. Schematic here:

Figure 3.jpg




The GRHV board files are posted on another web site, do a search for stax mafia circuit boards. The GRHV is more complicated than my shunt supply, but it has much lower output impedance and probably lower noise.
 
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Jun 22, 2018 at 8:40 AM Post #15,397 of 25,558
Any of the older amps (i.e. SRM-1, SRA-3S, SRM-T1 series) which were all pre-1995 should really have all the electrolytic capacitors replaced as those are well past their design lifespan. The newer amps post-2000 lack a normal bias output socket for your SRX MkIII. The 313 was the last amp to have a normal bias socket, but it was released in 1995 so the oldest samples either need or will soon need electrolytic cap replacement.
I guess the most basic question (and believe me my knowledge on the subject is as basic as it gets) is 'Would the 313 be expected to be an upgrade in SQ or at least as good as the SRD-7/N22 combination?" I thank you for your patience.
 
Jun 22, 2018 at 11:32 AM Post #15,398 of 25,558
I guess the most basic question (and believe me my knowledge on the subject is as basic as it gets) is 'Would the 313 be expected to be an upgrade in SQ or at least as good as the SRD-7/N22 combination?" I thank you for your patience.
Generally, when you use a transformer, you add a slight veiling to the sound. So the SRM-313 should have less distortion and better detail although it may sound brighter. But there are many speaker amp-based setups that sound great with a Stax adapter as well.
This is the graveyard thread about it using the SR-X Mk3 and the SR-404 with both an SRD-7 and speaker amps and a Stax SRM-006t as well.
 
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Jun 23, 2018 at 4:57 AM Post #15,399 of 25,558
009 vs L700 on KGST amp. Which one would sound better? I am thinking of getting a used 009 instead of the L700. I already picked up a KGST.
 
Jun 23, 2018 at 5:03 AM Post #15,400 of 25,558
009 vs L700 on KGST amp. Which one would sound better? I am thinking of getting a used 009 instead of the L700. I already picked up a KGST.
Taken from a comparative review: "SR-009 has slightly better technicalities overall (in resolution and especially in sound texture more real), but both has their specificities. The L700 has warmer mids, more impact in the bass department, and less trebles (with a little bit more plastic feeling you usually get with electrostats). The SR009 has a little bit colder mids, more trebles energy and quality, more refined bass with more linearity. The soundstage is quite different, SR009 has a bigger soundstage and a slightly more laidback approach. L700 has a more intimate and more frontal presentation of the music which is more engaging (and personally like a lot) and keep the out of the head feeling. As a conclusion, while the SR009 is the better headphone, I can imagine people preferring the approach of the L700 over the SR009 and for the pricing of the L700 it's one of the greatest value in this price range"

If you can get the SR-009 for a good price, it is probably worth it for that amp.
 
Jun 23, 2018 at 5:37 AM Post #15,402 of 25,558
Also, that particular amp which I think you picked has a normal bias output, so might as well consider picking one of those as well, if you like to listen to old recordings sometimes.
They are a nice contrast to the hyper-detailed presentation of the new ones, they are excellent at playing music without taking too much on technicalities.
 
Jun 23, 2018 at 9:09 AM Post #15,403 of 25,558
Generally, when you use a transformer, you add a slight veiling to the sound. So the SRM-313 should have less distortion and better detail although it may sound brighter. But there are many speaker amp-based setups that sound great with a Stax adapter as well.
This is the graveyard thread about it using the SR-X Mk3 and the SR-404 with both an SRD-7 and speaker amps and a Stax SRM-006t as well.
Thanks! You are a prince.
 
Jun 23, 2018 at 2:11 PM Post #15,404 of 25,558
Just realized Spritzer has a new Electrostatic amp on his Electrostatic amplifiers page (since the 14th of June)... the Octave III.

Simple electrostatic amp in the vein of an SRD-7 with no volume control on unit. It's an Octave V2 with balanced input only for use with a preamp.

DSC_0310-2-1024x604.jpg

DSC_0311-2-1024x630.jpg


Small unit with what looks to be the same form factor as his modded SRD-7.
 
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