nikongod
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Posts posted by nikongod
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With the understanding that we are in speculation mode, what say ye with more expertise than I about the power of this new amp compared to the GES?
I would be that this has a bunch more power than the GES.
I would guess that there are plenty, when you look at your old gearAnd further, are there any readily-apparent sonic drawbacks here?
So Dinny when you buy one, can you host a mini meet
QFT
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My K1000 had the PCB "spontaneously removed" while recabling.
If you would like to borrow them to compare you are welcome.
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In ray's B52 mall-fi thread he posted that 2 B52's shipped, and 2 more were burning in (I assume sold) just over a month after the thread went up.
On the other hand, he first showed a cased prototype of the B52 about 6 months before his intro thread at the first national meet.
The guess that this is a rushed job does not sound so far-fetched.
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happy happy birthday
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Nope try again...
One triode of the two in the same tube is the high side, and the other is the
low side.
agreed, ray does it as you say, and wrong.
in an effort to use an SRPP circuit safely even with very high B+ this would certainly do:
both triodes in 1 bottle for the "top halves" of 2 SRPP blocks with their own floating heater supply.
both triodes in another bottle for the "bottom halves" of the 2 SRPPs sharing the heater for the gain/input tube.
Its soooo stupid the way he (ray) does things. an additional heater supply and some more wires in the umbilical to do it right costs a bit, but I doubt thats really a significant cost for an amp that many people are speculating to cost more than $5000. After that its just a mater of NOT wiring things in the stupidest way possible, which he seems unable to do.
he *could* have floated or "referenced" the heater on the craptor/B52 and been within safe limits of Vhk, but he chose to use an idiotmode switching supply and shared ground wires.
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MAJOR FAIL. The top tube violates the filament to cathode spec. Nothing can
be done about this either, as they are dual triode tubes.
there is a way to do it without violating Vhk limits, but he has never done it right before. taking the (safe) assumoption that the output stage in this amp is called on to give some gain, the cathode of the "top" triode is going to be at FAR higher voltages than in the Craptor or "2 craptors back to back" (B52). the failboat is coming into port.
Ray dosnt seem to be one to take any kind of advice or learn from the mistakes of others (even those he happily mocks himself) very well.
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posted at the other site, and probably deleted. it is a paid thread.
That sounds like that would be a good thing - no matter whether you select SE input or balanced XLR input, the preamp outputs balanced drive XLR to your amp. Is the 60's reference a knock on the A-10? I didn't understand.the 60's reference is that phase splitters to output balanced signals from single ended inputs have been available in preamps since at the latest the 60's, and probably earlier.
My point really is:
why not add a phase splitter to the B52? And really, why not build it that way from day 1?
This raises the interesting question, considering that the B52 cant be guaranteed to output a balanced signal through the XLR's (It outputs unbalanced on XLR when an unbalanced input is selected) and that the A10 uses the phase splitter when a single ended input is selected, which Im assuming is switched in and out of the signal path as needed:
What happens if a single ended signal is fed into an XLR input on the A10? Does the amp still output a balanced signal as required to drive an electrostatic headphone?
Its a question that would have me ripping out my hair.
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Isn't the A10 close, with its preamp section?
the output impedance will be pretty high (about 150 ohms at best, could easily be higher/worse if ray did the "right" things incorectly although he has experience from a similar output stage on the B52... why not use 5687 here too? ) and unless they are electrolytics, the output caps are probably too small.
it may work for 2000 ohm headphones
dont waste your time for anything else. increasing the size of the caps could make it do good things to beyers, which like higher output impedances.im curious if ray thought far enough ahead to use the preamp buffers (6sn7) to isolate the 12ax7 from the miller capacitances of the output tubes... bandwidth fail.
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Searching for maestro insides pictures now...
WCF driving high impedance cable load, even internally loaded with 150 ohms ??
got to be nasty. At least if the stealth was used that way it would be pure class A.
I think you have the 2 flip-flopped.
The original purpose of the WCF was driving cables. its performance is independent of load as long as its not too low.
SRPP on the other hand is totally load dependent. SRPP can come out of class-A without clipping audibly, and gets wrecked driving anything but its optimal load. the idea of driving a 32 or 300 ohm load off of the same SRPP output stage frightens me...
I kinda wonder why Mikhail or Ray didn't try to rig up something using a concertina/cathodyne to feed the balanced frenzy..If the ES-1 is what everyone says it is, it has a long-tail-pair input stage. the disadvantage of a LTP is you dont get as much gain, BUT you gain PSRR. A "Williamson style" concertina has more gain, but practically no PSRR... LTP can take a balanced input and claim "fully balanced", not that that really matters on head-fi as long as it has XLR in and out.
A concertina is also somewhat sensative to how the outputs are loaded. The 2 plate outs from a LTP have equal Zo, where the "plate" and "cathode" outs on a concertina are not even close. miller capacatances or a resistive load screws the balance up.
anyone who knows Ray knows there is at least 2 or 3 circuit boards made LONG before any chassis is complete.A real designer would rough his design out on paper taking a few iterations if necessary, P2P his prototype, tune 3 parts, and make 1 circuit board.
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I would say a singlepower amp with no fuse and random wallwarts in the PSU has a higher chance of causing a fire than the A-10.
way to derail a thread, I thought we left head-fi to keep clear of this shit. there are plenty of threads here and there to muckrake in.
Most wallwarts integrate the fuse into the transformer in various ways: saying "no fuse" is incorrect. what you meant to cut and paste was DR. gilmore's recommendation elsewhere that a fuse be placed in the DC rails to the actual audio stage. with alarmingly few exceptions, no wall wart is more likely than ANY manufacturered PS to cause a fire.
The safety of rail fuses in an amp with bipolar supplies and whether they would even blow predictably in a class-A circuit and in a way which would prevent further damage to the speaker and amp is very questionable. in fact, you only need to look at the raptor to see a case where the B+ fuse blows somewhat randomly, although generally at NYC meets. fortunately, its a single supply amp with cap coupled outputs... on the other hand with a dual supply (+ and - voltages) when you blow one rail, the output goes to the live rail... good luck with that across your headphones.
back to bashing RSA, its much more fun.
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What's wrong with an amp having an HE90 output and a 5-pin Stax output? I have two amps configured like this, and also requested the BHSE this way. I figure if there's anything wrong with this Justin would slap me upside the head and refuse to do it.
If you have the headphones for it, there is absolutely nothing wrong with those plugs, and the plugs are outstandingly awesome.
on the other hand, if you dont have the HE90, you paid for an expensive socket that you cant use. for these people (and I think that people who DONT have the HE90 are going to be the majority of buyers for this amp, on the assumption that people who DO have the He90 already have gear they are happy with) something else would serve their needs better.
putting the HE90 plug on is impressive because its a statement that this amp is good enough for them. sort of like running the R10 out of a portable amp....
I've never been able to find the chassis mount esp-950 connectors, if youknow of a place, i would certainly like it.
I dont have a source for chassis mount EXP-950 connectors. I was referring simply to the headphones.
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Kevin, will two 6sn7s have enough juice? Moreover, can the 6sn7s reliably handle 500 volts p-p?
the 6sn7 does not have enough juice, but the 500v is stator to stator, so its only 250v p-p per section, which the 6sn7 can do. it just cant do the current necessary for the O2 and that voltage swing at the same time.
Im a little upset (although not surprised) that ray used the connector for the HE-90, rather than the connector for the more obtainable he60 or easily obtainable koss ESP-950. he could have really gone out on a limb, and sourced 5-pin XLR's for the jades directly [sarcasm]much harder to find than the stax connectors...[/sarcasm] bummer, it was made to look pretty and impress people who have never heard anything else.
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What values do you need?
Rat-Shack has an OK selection in higher power ratings. Looking at the schematic, you should be able to get most of the resistors listed from them. The only issue is that the "part to part" matching may not be so good.
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So the adapters may be the issue?
They can make oscillations or noise worse.
It dosnt sound like the amp is running properly with 6SN7 as gain. Thats what the amp was designed around; if its not right on its best tube noting else stands a chance. I would take it into a shop.
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I kind of disagree with DR gilmore's statement that the dyna(whatevers) and some of the others mentioned are op amps. I dont think they have enough open loop gain to satisfy the condition of opampishness.
To Dr G's credit, im sure that if his only goal was to make 60dB or more of open loop gain he could have designed another gain stage into the amps only to cancel it out with more feedback later on. there are no free rides: are the more complex harmonics worth it? I'd say not.
on that note, not everything in an IC package is an opamp either.
Kevin (and anyone else), in addition to my question above, is there a specific area of improvement with a discrete design?With a discrete design you can do a couple things you CANT with an IC.
At the end of the day, it boils down to the designer having control over what goes into his (her...) product VS selecting the best part that may be made for something else.
1: You can unconditionally guarantee that EVERY transistor in the gain stage(s) runs class-A no mater what. Many IC opamps run the internal transistors class-A but who really knows how hard?
2: In the design stages you can "roll" transistors in a discrete design, where you just swap the whole IC.
3: Since all of the parts are separate, they can dissipate much more heat individually. You can safely "burn" off a couple watts in the gain/driver stages of a discrete design if thats what it takes to make the amp work well... you only get a hair over a watt TOTAL dissipation with a dip-8 package.
4: If you are designing an amplifier as opposed to an op amp, you can build to suit a specific gain. you also have access to the internal transistors, so smaller local feedback loops (around 1 stage) can be used rather than 1 big one which is typical with an op amp.
dont waste your time for anything else. increasing the size of the caps could make it do good things to beyers, which like higher output impedances.
New RSA amp...
in Headphone Amplification
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