They don't have to be airtight but Stax have moved towards airtight drivers after the great design initiative which resulted in the SR-Omega. The enclosed air damps the main diaphragm but has minimal negative effects if the dustcover isn't as tight as the main diaphragm (i.e. it won't ring). You have remember that electrostatic drivers don't push and pull the air like dynamic drivers but rather make it vibrate and the lighter then air membranes let all the sound through. The pocket of air trapped next to the driver helps to minimize the effect of the inherent resonant frequency which all diaphragms have.
Most electrostatic headphones do use some form of a woven dustcover (usually on the back stator) but this can cause problems as so many owners of HE60's and Jades can attest to.
I listened 4 months ago to a 4040 setup at a local dealer and was so impressed, it was unbelievable. But well it was sooo far away being so extremely expensive (1400€ or more).
I then went straight HD650 + Beresford but Stax was still there...
Weeks ago I got a SR-404 with new earpads for 275€ and now the SRM-1/MK-2 PP for 230+50€ customs.
Originally Posted by kintsaki /img/forum/go_quote.gif I have a few questions:
1)I can adjust the bias to my custom made srd7 to 600V. Could I try the Omega2 or Omicron at that higher bias or I run the risk to damage the phones.
Yes. Any pro bias Stax is safe at 600v. That's less than a 5% increase. That kind of difference can be reached by a stock unit if all the part tolerances fall in the right direction. The sound quality will not change but the level will increase a tad. Now 700V would be too much. The second phone output on the SRM-T1W has an adjustable bias. Stax states in the manual that this can be used as a volume control to match the level to the phone in the other output.
Question... What kind of meter are you using to measure the voltage? To get a accurate reading you need an extremely high input impedence voltmeter or your reading will be way low.
Originally Posted by audiod /img/forum/go_quote.gif Yes. Any pro bias Stax is safe at 600v. That's less than a 5% increase. That kind of difference can be reached by a stock unit if all the part tolerances fall in the right direction. The sound quality will not change but the level will increase a tad. Now 700V would be too much. The second phone output on the SRM-T1W has an adjustable bias. Stax states in the manual that this can be used as a volume control to match the level to the phone in the other output.
Question... What kind of meter are you using to measure the voltage? To get a accurate reading you need an extremely high input impedence voltmeter or your reading will be way low.
So from what I know, the SRM-T1W is exactly the same as the SRM-T1 except for the inputs. I want to go up to 600V on one of my pro outputs for the ESP950. 620V is probably dangerous to the Lambdas. Can you post any info from the manual?
Originally Posted by gjkphd /img/forum/go_quote.gif I decided to explore the world of electro statics a few months ago to compliment my grado/ATH--Yammie set up. I started with the Koss ESP-950 and paired it with a Stax 717 SS amp. This combo did not do it for me. The Koss sounded dead (vs. lively) with little punch and very weak bass. So before I give up on the electrostatics could you recommend a Stax phone to try, esp one that mates well with the 717, which I have held on to. (I listen to mostly classic rock and jazz)
thanks
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Originally Posted by gjkphd /img/forum/go_quote.gif Yes, it could be that my preference is for a dynamic system over stats. I'm sure there was nothing wrong with the set up. My source is a Lector tube CD through a VAC tube preamp and I use the same brand of IC's throughout the system. I still want to satisfy my curiosity by trying another electrostatic phone. Is the 02 a very old model, it wasn't listed in the Wikipedia list of stax phones. Is it 0 like zero or is that an O as in Omega model?
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Originally Posted by audiod /img/forum/go_quote.gif I find the 950/717 a great combo for classic rock and jazz. The Lambda series has more bite in the upper midrange that you may like. The Lambda Nova Signature and Lambda Signature are good choices. The O2mk1 is my top choice for any type of music and is a good mate with the 717. The O2 is so refined that some people don’t give them a chance find them dark and heavy sounding. The O2 also demands the best source and cables. Because the 950/717 is such a great rock and jazz setup and you are not happy with them I think that electrostatics may not be for you. Many classic rock recordings are so compressed and poorly produced that a punchy less resolving dynamic may be the better choice.
I was just listening to my Koss 950 driven by the Stax 717 and it seemed pretty punchy but lacking a certain amount of deep bass compared to the Stax 007A and even the Stax 404.
Now while the 404 has more deep bass that the 950, the 950's still had more of the finger snapping quality. I can't say for sure but I doubt that you will be satisfied with any of the Lambdas .
I suspect that unless your 950 adapter is faulty you may be missing some deep bass. The 007a will give you that although at a considerable cost and you also may need to tweak this phone. There has been quite some controversy about the Stax flagship Omega line of phones as to whether the revisions of this model have helped the sound. I personally find nothing wrong with the last revision, the 007a but I prefer it with some mods. I flatten the spring in the earcup as Spritzer has suggested and position the earcups opposite to what most here seem to do, i.e. I place the circular part behind the ear.
I have discussed the need to tweak this phone here.
Originally Posted by audiod /img/forum/go_quote.gif Yes. Any pro bias Stax is safe at 600v. That's less than a 5% increase. That kind of difference can be reached by a stock unit if all the part tolerances fall in the right direction. The sound quality will not change but the level will increase a tad. Now 700V would be too much. The second phone output on the SRM-T1W has an adjustable bias. Stax states in the manual that this can be used as a volume control to match the level to the phone in the other output.
Nahh, I've run my Omegas at 700v and they didn't complain one bit.
I'm not going to recommend it though. One thing that that we should all remeber, the electrostatic force drops with the square of the distance so a 100v change at 600v is much less of an issue then at 200v. The D/S gaps are 0.3mm on normal bias phones (230v), 0.5mm on Pro bias (0.5mm) and Stax are said to have researched 0.7mm gap for the SR-Omega which had a 1100v bias.
Quote:
Originally Posted by audiod /img/forum/go_quote.gif Question... What kind of meter are you using to measure the voltage? To get a accurate reading you need an extremely high input impedence voltmeter or your reading will be way low.
Ditto. If the input impedance is too low then you are loading the very high-impedance PSU and all readings will be off. It you try to measure after the ballast resistor then the low impedance causes it to drop the voltage.
Originally Posted by manaox2 /img/forum/go_quote.gif So from what I know, the SRM-T1W is exactly the same as the SRM-T1 except for the inputs. I want to go up to 600V on one of my pro outputs for the ESP950. 620V is probably dangerous to the Lambdas. Can you post any info from the manual?
I use a Fluke 12 MM.
As far as I know all Fluke meters have a standard 10 meg ohm input impedance which is too low for measuring the bias supply. You should look into a High Voltage probe that will work into the standard 10 meg ohm Fluke load. Fluke makes 2 models. The 40KV model would be my choice because it has the highest input impedance. There are also other makes of probes, do a Google search. Just make sure that they are for a 10 meg ohm load meter. There are also a number of models that are self contained with their own meter. If you use your Fluke 12 and set the bias voltage to 600v you will actually be setting to a higher voltage when you disconnect the meter from the circuit.
The T1W is the same circuit as the T1S. I will find the manual and quote the section on variable bias.
I'm not sure all this fuss is worth it. The small variance in voltage that you are talking about is too small to make any sonic differences. The only thing you will hear is a little gain in volume. Years ago I tried over 1000 volts on a set of Lambda Pro’s and it started to sound like frying eggs in the background. I think that if I left it this way it would eventually fry off the conductive coating on the diaphragm and ruin the drivers.
Originally Posted by audiod /img/forum/go_quote.gif Yes. Any pro bias Stax is safe at 600v. That's less than a 5% increase. That kind of difference can be reached by a stock unit if all the part tolerances fall in the right direction. The sound quality will not change but the level will increase a tad. Now 700V would be too much. The second phone output on the SRM-T1W has an adjustable bias. Stax states in the manual that this can be used as a volume control to match the level to the phone in the other output.
Question... What kind of meter are you using to measure the voltage? To get a accurate reading you need an extremely high input impedance voltmeter or your reading will be way low.
I have commissioned "yanni" to build a custom transformer srd7 pro for me and based on your and spritzer's answer I will ask him to build a 600V bias instead of 580V so I can be as close to spec as possible for both the Koss and Stax given that 580<600<620.
I will ask him how he will measure voltage.
Originally Posted by audiod /img/forum/go_quote.gif As far as I know all Fluke meters have a standard 10 meg ohm input impedance which is too low for measuring the bias supply. You should look into a High Voltage probe that will work into the standard 10 meg ohm Fluke load. Fluke makes 2 models. The 40KV model would be my choice because it has the highest input impedance. There are also other makes of probes, do a Google search. Just make sure that they are for a 10 meg ohm load meter. There are also a number of models that are self contained with their own meter. If you use your Fluke 12 and set the bias voltage to 600v you will actually be setting to a higher voltage when you disconnect the meter from the circuit.
The T1W is the same circuit as the T1S. I will find the manual and quote the section on variable bias.
I'm not sure all this fuss is worth it. The small variance in voltage that you are talking about is too small to make any sonic differences. The only thing you will hear is a little gain in volume. Years ago I tried over 1000 volts on a set of Lambda Pro’s and it started to sound like frying eggs in the background. I think that if I left it this way it would eventually fry off the conductive coating on the diaphragm and ruin the drivers.
Thanks for the tips and searching the info, I'll look into getting those probes (seems they sell for $100-150!).
I'm not sure either about raising the bias for the ESP950. I have heard that the bias only effects volume and I have heard that it also effects sound quality. I'm curious myself, but this is the only way I could think to test it. It couldn't hurt too much at 620 volts bias it seems for the Lambdas and Koss, which is good news to me as well. I rarely get to a four though on the T1 with the volume, mostly stick between 3 and 3.5 out of 10.
I wanted to try out a good tube preamp to pair up with some future ss amp to run my Onix Ref 1’s in BEM that I recently did a master ninja crossover upgrade. I am currently using a Onix SP3 to play the ref’s but using some strong separates on them had my interest. While I was researching tube preamps an EC HD300 came up for sale and I jumped on it. Hey it’s the first EC HP amp and will look good next to the ZDT I have preordered. I was strictly going to use this as a preamp…but I did have to try out its HP use, which was good and on the warm side as has been noted on a search I did of this head-amp. I am still waiting for the right ss amp to show up….so I have been busy collecting some tubes to roll.
Now what does all have to do with Stax?…well I have read about preamping into the srm717 with some positive results. I have actually tried this out using a Lavry DA10 as the source, from a squeezebox running apple lossless. I tried out my Parasound Halo P3 preamp…BUT I did not think there was a major change…not enough to use up the P3 on this system. I was hoping to get some added forwardness to the SR007’s…the preamp experiment was done and forgotten.
But then I had the HD 300 really just sitting around…so I set it up as a preamp to the SRM717 as before. And to my surprise I think I am hearing a positive change to the SR007’s. Deeper bass and some increased detail and forwardness to the mids and somewhat to the trebles. Now I had previously added signalcable silver IC’s over the holidays and liked what I heard…seemed overall a touch clearer thru the mids and lower trebles. This tube preamp tho added some much needed slam to the bass.
Maybe it the new toy placebo effects but I think it warranted some tube rolling experiments.
I initially had the Svetlana 6H13C/6AS7G power tube in with a tung sol 6sn7...but it was too warm and the treble rolled off…but the bass seemed deeper and had a sense of power than just using the Lavry straight into the 717. I also have a Tung Sol gray plate 6as7G and a sylvannia 6as7g…these two tubes really brought out some good bass/slam out of the 007’s…it is very close to what I am getting out of the srd 7mk2 + dared clone hybrid amp…but the overall sound is still on the warm side… the upper mids and treble do not seem significantly affected by this change in power tube. I have a Tung Sol 5998 tube coming soon. And I have yet to try a RCA VT231 or the other 6sn7 driver tubes that I have.
The TS 6as7g and the TS 6sn7GT tubes make my son's hd 600 sound very good....
Anyone try a tube preamp with their 717?
I just wonder if anyone has tried comparing the beta22+srd7mk2 with the 717 or KGSS, feeding the O2? Does the powerful b22 bring enough power to waken up the o2?
Originally Posted by manaox2 /img/forum/go_quote.gif Thanks for the tips and searching the info, I'll look into getting those probes (seems they sell for $100-150!).
I'm not sure either about raising the bias for the ESP950. I have heard that the bias only effects volume and I have heard that it also effects sound quality. I'm curious myself, but this is the only way I could think to test it. It couldn't hurt too much at 620 volts bias it seems for the Lambdas and Koss, which is good news to me as well. I rarely get to a four though on the T1 with the volume, mostly stick between 3 and 3.5 out of 10.
Bias affects the potential of the drivers and thus only the volume indirectly. A stronger magnet in a ribbon driver will perhaps give you a bit more volume but it also provides much better control over the diaphragm. It's the same deal with electrostatics.
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Originally Posted by Lil' Knight /img/forum/go_quote.gif I just wonder if anyone has tried comparing the beta22+srd7mk2 with the 717 or KGSS, feeding the O2? Does the powerful b22 bring enough power to waken up the o2?
You can put a 1kW amp on the SRD-7 Mk2 and it still won't be enough since the size of the transformers is the limiting factor.
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