[joelongwood]

Quote:

Originally Posted by lmilhan /img/forum/go_quote.gif I will reserve judgement until I hear one paired with my RS-1s. I don't care what it's made of, or how cheap the parts are. If it synergizes with the RS-1s the way people say it does, that's all that matters to me. I care only about sound, not part quality or count. If it sounds good, it is good.

Exactly!

 

[kramer5150]

Quote:

Originally Posted by dsavitsk /img/forum/go_quote.gif Fewer parts are good, but the problem with your logic is that while an opamp looks simple on the outside, it is anything but on the inside. Here is the circuit that is actually in the RA-1 complete with transistors, resistors, caps, and diodes all in the signal path. You can be the judge of whether it is a simple circuit or not. Anyway, that said, the NJM4556 is actually not a bad opamp. My experience says that, opamp flaws aside, the sonic character of the RA-1 is determined less by the opamp, and more by the terrible input caps it uses. Remove those and replace them with a better quality cap ... or just remove them all together, and the RA-1 would be a much better amp. And, this is why the cheapness of the parts is frustrating. The opamp can hold its own against just about any other, but if grado would have spent $7 on a Sonicap instead of $3 on the SCR they use, it would have made a world of difference. -d

x2... IMHO the 4556 is not all-together a terrible sounding chip. It sounds kind of cold and flatly "accurate" in my cmoys. But its not all-together terrible. IMHO caps in the signal chain are a bad thing, if you don't need to filter DC.

If I had an RA1 I'd bypass the caps and socket the OP amp and drop in a 2107. IMHO the 2107 is warmer and easier to listen to than the 4556 in single OP amp designs. IMHO the RA1 could use better power supply caps too, something like ~470Mfd, 16-25V variety. I am using some panasonics and they sound decently good. The OPA2107 responds beautifully with the battery-RA1 power-scheme. 2x9V, virtual ground the series node between the cells. I have been using this power-circuit.. and I have never had a problem with differing cell voltages. Now, granted I don't usually run my 9V cells all the way down.

IMHO the 4556 sounds better than the OPA2227 (for example), which is a very popular chip. To my ears the 2227 has a very distant and sterile sound from ~70-4000 Hz.

 

[nickchen]

A colleague helped me to build a RA1 for my Alessandros -a portable version with 2 9V batteries- and I get into liking this little amp. It sounds better than some other cheap SS I've heared. I didn't like the 4556 -too bass heavy and somewhat midfi-ish- and exchanged it against the 2132.

But I must say, compared to my Millet, the RA1 lacks soundstaging, blackness & details.

The price for a stock RA1 never ceases to amuse me.

 

[robm321]

After all the RS-1 is just a couple of small drivers, wires.... Oh and the wood, headband.

Problem is no one can make the RA-1 DIY and have it sound as good

I've had mine for years, and enjoy it with the GS-1000.

 

[a shovel]

a wheel is pretty simple. still took awhile to develop though..

that said,

after all the research and synergy, it is still physically and technically a pos.

*runs away quickly with cot*

 

[ericj]

Quote:

Originally Posted by robm321 /img/forum/go_quote.gif After all the RS-1 is just a couple of small drivers, wires.... Oh and the wood, headband. Problem is know one can make the RS-1 DIY and have it sound as good

the difference there is that the diaphragm geometry in a microphone-style voice-coil driver is an engineering problem of such difficulty that it still has not been perfected to any lasting satisfaction, and it's manufacture requires tooling not available to the average DIYer.

 

[Forest Design]

virtually everything after like the 5th post in this thread is greek to me. i should've probably stated from the beginning, if it wasn't implicit in my first post as it is, that i was reacting merely to the aesthetics of the design rather than the actual electronics involved. i know that is a dangerous road to travel ignorant, and thus i thank kramer and ericj for shedding some light (albeit greek-light) on the more technical aspects.

slightly modding the RA-1 (when pairing them with grados, other cans may require heavier mods) seems like the way to go, but if you follow the link to that page, it seems like getting into the RA-1 is a pain in the butt...

 

[Dept_of_Alchemy]

I also suspect that the guys at Grado are not electrical engineers and that might in part explain the simplicity of the circuit. They may be great headphone builders but that doesn't mean they are automatically great amp designers as well. You don't expect a good chef to be a good farmer, do you?

 

[Dept_of_Alchemy]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif the difference there is that the diaphragm geometry in a microphone-style voice-coil driver is an engineering problem of such difficulty that it still has not been perfected to any lasting satisfaction, and it's manufacture requires tooling not available to the average DIYer.

You know that Grado does not manufacture their own drivers, right? I think your post might mislead people into thinking that Grado has all the tools to wind their own drivers and such...

 

[cotdt]

Quote:

Originally Posted by Dept_of_Alchemy /img/forum/go_quote.gif I also suspect that the guys at Grado are not electrical engineers and that might in part explain the simplicity of the circuit. They may be great headphone builders but that doesn't mean they are automatically great amp designers as well. You don't expect a good chef to be a good farmer, do you?

well there's nothing wrong at all with their design, for the money it is actually a good design. but by "for the money" i mean $20 parts (and labor) cost, perhaps less. it's nice if someone likes the sound, but why pay $350 for it is what i'm thinking. it's far from a unique product actually. a lot of portable amps use a very similar circuit, but is much cheaper. you can always replace the opamp for that RA-1 sound.

 

[nickchen]

Quote:

Originally Posted by Dept_of_Alchemy /img/forum/go_quote.gif You know that Grado does not manufacture their own drivers, right?

Who produces the drivers then? Toshiba? Halliburton? Kellogs?

 

[kramer5150]

Also.... don't knock something just because it is simple. IMHO there is a certain comfort level and peace of mind that comes with simpler amps. Some of my more complicated amps... I'm always worried about power-up/down cycles, op- amp oscillation, tube stability & bias, power supply noise, AC wall outlet fluctuations.... AAARGH!!!

The supermicro BTW is NOT an amp that i would consider to be "simple".

 

[Arainach]

Exactly. Why people think something has to be complex to be good I will never understand.

At the end of the day, all technical details are ********. Dizzy Gillespie had it right: If it sounds good, it IS good.

 

[ccontreras]

Quote:

Originally Posted by dsavitsk /img/forum/go_quote.gif Anyway, that said, the NJM4556 is actually not a bad opamp. My experience says that, opamp flaws aside, the sonic character of the RA-1 is determined less by the opamp, and more by the terrible input caps it uses. Remove those and replace them with a better quality cap ... or just remove them all together, and the RA-1 would be a much better amp. And, this is why the cheapness of the parts is frustrating. The opamp can hold its own against just about any other, but if grado would have spent $7 on a Sonicap instead of $3 on the SCR they use, it would have made a world of difference. -d

exact, I replace caps of my original RA-1 by a Auricaps 4.7, at least psychologically the sound it improved

 

[robm321]

Quote:

Originally Posted by ericj /img/forum/go_quote.gif the difference there is that the diaphragm geometry in a microphone-style voice-coil driver is an engineering problem of such difficulty that it still has not been perfected to any lasting satisfaction, and it's manufacture requires tooling not available to the average DIYer.

My typing has been hurendous. I retyped my original post to what I meant to say - you may need to edit your rebuttal