[roos]

ive been using my rs1's with my nad receiver, and recently a friend let me her ra1. it is a amazing improvement, but from what ive read the ra1 itself is pretty cheap inside and nothing special. so i thouht id investigate a diy amp before i buy the ra1. are there any recommened designs to match with the rs1s?

 

[skippy]

i don't have the rs-1, but i like grados with the szekeres amp. i haven't heard it, but kevin gilmore's dynamic amp has been getting good press.

 

[andrzejpw]

I have also heard good things about the szkeres/grado combo. Haven't heard the gilmore. . .

 

[erix]

Why not just build yer own RA-1?

It's *really* simple.

ok,
erix

 

[Budgie]

Skeres gets my vote. I love mine.

 

[antness]

Just about any of the popular DIY amps will be a huge improvement over the NAD receiver, and a good improvement over the RA-1. The RA-1 is basically a no-frills cmoy amp (see www.headwize.com project library) with extremely cheap components.

If you've never built your own amp, you should probably either build a cmoy or a META42. both are relatively inexpensive. The Gilmore amp is excellent with Grados, Kevin Gilmore designed this amp for his Grados, but it's not a good choice for your first build.

 

[Tomo]

Hello,

I would like to give my vote to Szkeres amp as well. RS-1 does not require much voltage gain, but sucks up lots of current. Szkeres amp can offer pretty high current. (Note it is not suited for headphones requiring high voltage swing due to inherent non-linearity.) I recommend primarily because it offers rare "single-ended" sound.

Note opamp-based amps are wonderful also, but you will need to decrease the voltage gain to 2~5 and add a buffer. Very simple, ... (too simple. It's boring for audio electronics fanatics like me.)

KG amp should be able to drive Grado headphones according to my recollection. You should contact him directly to confirm.

Tomo

P.S. I use opamp-based amp because I need a big voltage swing for my headphones. Yeah. The design specifications change with headphone impedances.

 

[roos]

thx for all the reply's

time do to some research

 

[The Quality Guru]

Quote:

Originally posted by antness Just about any of the popular DIY amps will be a huge improvement over the NAD receiver, and a good improvement over the RA-1. The RA-1 is basically a no-frills cmoy amp (see www.headwize.com project library) with extremely cheap components.

With my experience, I find this untrue. The CHA-47 is regarded as being better than the Cmoy, and when I compared my CHA-47 (with premium components) I thought the RA-1 was a significant improvement and was noticeably more transparent. So, with my experience, the RA-1 is far better than "a no-frills cmoy amp with really cheap components." It does have cheap components, but somehow manages to be of very good value because of its transparency and neutrality. IMO, the cmoy and RA-1 are not really in the same league. In fact, another Head-Fier, Zanth, believed that the RA-1 was more neutral than the $750+ Sugden Headmaster. Just a thought.

 

[Budgie]

And you could build one for about 10 bucks, minus the wood block they put it in.

 

[roos]

has anyone replicated the ra1 with better quality parts and compared that to a ra1? did grado use these cheap parts because of the sonics they end up creating or was it just a matter of cost. also, is there a recommended parts list for building a better ra1? thx

 

[Wodgy]

My theory is that Grado used those parts because they were all available at Radio Shack (except the Solen capacitors). In fact, the only source I know of (in the US) for the particular potentiometer Grado uses is Radio Shack. Radio Shack also sells the op-amp they chose, as well as resistors with the specific values they chose. Even the cheap 9v battery snaps are sold at Radio Shack.

There is no recommended "better RA-1" parts list because the amp is so simple. I would suggest the following though (remaining true to the spirit of the RA-1 design):
1) replace the two Solen capacitors with four Black Gates with the same rating
2) replace the potentiometer with an ALPS Blue
3) use Vishay/Dale or Holco resistors
4) consider replacing the op-amp with something else; changing it would alter the RA-1 "sound" though.

Incidentally, these changes still wouldn't raise the parts cost above $70.

 

[Budgie]

You could most likely just remove the input coupling cap from the circuit, if your source does not have dc on the line out (most don't). It is just there as a safety feature.( Unless you like the sound of caps in the signal path.) That would most likely be a huge improvement.

(disclaimer- don't do this unless you know how to check for dc voltage in the source, or the ouput of the amp.)

Build it with a socket so you can try another opamp in the circuit.

 

[eric343]

I'd build it with the original components first, then try upgrading/tweaking it.

And Kevin designed his amp to work with Grados...

 

[Dreamslacker]

Quote:

Originally posted by Budgie You could most likely just remove the input coupling cap from the circuit, if your source does not have dc on the line out (most don't). It is just there as a safety feature.( Unless you like the sound of caps in the signal path.) That would most likely be a huge improvement. (disclaimer- don't do this unless you know how to check for dc voltage in the source, or the ouput of the amp.) Build it with a socket so you can try another opamp in the circuit.

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