[runeight]

Are you interested in a tube amp?? If so, look at:

Morgan Jones Headphone Amp

I think the feedback version is the better project. Reports from DIYers are very, very good.

 

[puppyslugg]

Dreamslacker,
Quote:

How do you check for DC voltage in the source. I do have a simple digital multimeter.

Connect one lead to the body (ground) of the rca jack, the other lead to the center conductor of the jack. If meter is not 'auto ranging', set for 'mv' range.

 

[Gariver]

I completely disagree with The Quality Guro on the Grado RA-1! The Grado RA-1 uses extremely cheap components combined with very poor power supply. Results? It's the biggest ripoff in audio! They sell it for $350, which is ridiculous!

Over at Headwize.com, Rubin opened up his Grado RA-1 to check out the components in it. Everything in the RA-1 is ultra-cheap! Read Rubin's RA-1 thread below...

http://headwize2.powerpill.org/ubb/s...=0&srch=rubin;

The Szekeres Amp...
This amp works very, very well with Grado headphones

 

[Hirsch]

Quote:

Originally posted by Gariver I completely disagree with The Quality Guro on the Grado RA-1! The Grado RA-1 uses extremely cheap components combined with very poor power supply. Results? It's the biggest ripoff in audio! They sell it for $350, which is ridiculous!

Just out of curiousity, how do you disagree with someone's opinion about what he hears? It would appear that the only person with any first hand knowledge about what a person hears is that person. If you look at the parts, and forget to listen to the music, you've lost sight of the goal.

 

[Gariver]

Hirsch:

Before The Quality Guru came out favoring the RA-1, other posters mentioned the Szekeres Amp and Kevin Gilmore's Dynamic Amp. In essence, he is saying the Grado RA-1 is the best choice for Grado RS-1 Headphones. My opinion? I disagree! I've heard the RA-1, and I don't think it is the best amp in that group. I believe the Szekeres and KG's Dynamic are better choices.

To reinforce his argument, he says: "In fact, another Head-Fier, Zanth, believed that the RA-1 was more neutral than the $750+ Sugden Headmaster. Just a thought." Wow! That's a stretch! Well, I disagree with that statement. Sure, these Head-Fiers are entitled to their opinions. However, I am entitled to my opinion also. I simply disagree with these RA-1 reviews! I just don't think the RA-1 is the hottest amp around!

Figure it out yourself: The RA-1 uses the cheapest possible opamps ($0.29 each), and it forgoes a PS unit. Imagine that: There's no electrolytic caps in it all! It's an amp worth about $10.00. That's the reason why Grado sealed those components with glue inside a mahogany box. They didn't want anybody to see their cheap component choices. I must say this, though, Grado made the right choice in selecting a sexy mahogany box for the RA-1. It sure is seductive...maybe too seductive!

In my case, the seductive appeal of mahogany (caoba) does not work. Mahogany is too abundant here in Puerto Rico. As a matter of fact, one of my relatives has a farm with hundreds of mahogany trees. So I am not swayed by the RA-1's wood at all.

Once again: I pick The Szekeres Amp and KG's Dynamic Amp for the Grado RS-1 headphones. These two amps beat the RA-1 in sound quality! That's my opinion!

--------------------------------------------------------------------------------
RA-1's opamp and schematic.

NJM4556 or JR4645...
The RA-1 uses this opamp. Japan Radio now makes the NJM4556 opamp, and they have renamed it JR4645. Why do they keep changing the name of this opamp? Easy! This opamp is not too hot! By changing the opamp's name, they are trying to clean up its past history.

http://www.njr.co.jp/pdf/ae/ae04051

RA-1 Schematic...
Here's the schematic of the RA-1. Notice the lack of a power supply unit. That's amazing in a $350 amp! Click on the schematic done by Thomas (of Toronto, Canada). At Rubin's site, you must click on 5 to get the schematic.

http://www.geocities.com/rubin_jpk/rubin/page_4.html

 

[Budgie]

Yah, but isn't that cool chunk-o-wood box worth about $349.00?? And don't forget that cool knob too!

 

[Tomo]

Hello,

I will have to agree with Gariver about how RA-1 has outrageous price for very very simplistic design using very very mediocre parts. I could build on for less than 20 USD! (And wood is gimmick and PSU is practically worth 1 dollar.)

However, Hirsch is right about other people's opinions. It is difficult to set what is better and worse.

On the other hand, Hirsch, I believe Gariver is "hot" about cost quality ratio than overall quality. I think, Gariver, you should tone down when you "trash" RA-1 like we all wanna do.

Note RA-1 does sound good. However, with 300 USD, you could get Grado RS-2 headphones which should be a hellova cost-effective upgrade.

Tomo

 

[Dreamslacker]

Quote:

Originally posted by puppyslugg Dreamslacker, Connect one lead to the body (ground) of the rca jack, the other lead to the center conductor of the jack. If meter is not 'auto ranging', set for 'mv' range.

Alright, I seem to be getting values like +/- 0.0 - 0.4 millivolts when I do that. It's within the margin of error on my DMM.

Would that be considered DC voltage?

If not, I'm plucking the capacitors out of my amp. because I don't have decent pieces to use.

 

[puppyslugg]

Dreamslacker,

Yes, those dc readings. Those are good numbers. Actually, great numbers. There shouldn't be any problems.

Way to go!

 

[Dreamslacker]

Quote:

Originally posted by puppyslugg Dreamslacker, Yes, those dc readings. Those are good numbers. Actually, great numbers. There shouldn't be any problems. Way to go!

So I can pluck the caps out of my amplifier right?

Thanks for the great help!

 

[puppyslugg]

Dreamslacker,

If those readings were correct, then you can remove the caps. Just remember, when hooking up other sources, recheck the output for offset because....

YOU DON'T WANT TO FRY YOUR PHONES!

 

[Dreamslacker]

Quote:

Originally posted by puppyslugg Dreamslacker, If those readings were correct, then you can remove the caps. Just remember, when hooking up other sources, recheck the output for offset because.... YOU DON'T WANT TO FRY YOUR PHONES!

Don't worry about that. I'll be having 2 inputs on my amp. One with and one w/o caps in the line. When hooking up unknown sources, I'll just use the input with caps.

Now, I just need to find a nice metal tin to put everything nicely in.

Thanks for the help once more..