[Hirsch]

I've been digging through past threads here and at Headwize, and have been unable to come up with an answer. The pictures of the HPA-2 on KR's Headphone Lust page are identical to the HPA-1, but I can't find anything indicating what the differences, if any, are between the two amps. Anyone know?

 

[bootman]

I got this from an old KR post.

Quote:

Grado is getting ready to release a portable headphone amplifier (tentatively called the RA-1), which will debut at the CES in January 1999 and ship shortly thereafter. Based on the design of the HPA-2 amplifier (now discontinued), it is housed in a case machined from a single block of mahogany, measures 5" x 5.5" x 1" and runs on two 9V batteries. The front of the box has a volume control, headphone jack and an LED power indicator. The back has RCA inputs and a power switch. The MSRP is $350.

So it looks like the HPA-2 has the same design as the current RA-1?

 

[Beagle]

Quote:

Originally posted by bootman I got this from an old KR post. So it looks like the HPA-2 has the same design as the current RA-1?

Similar design, but the HPA-2 uses better component parts.

 

[Hirsch]

Quote:

Originally posted by Beagle Similar design, but the HPA-2 uses better component parts.

Do you know any details? The HPA-1 manual references custom capacitors and wiring specifically made for the amp. What changed between the 1 and the 2?

 

[acidtripwow]

I currently own the HPA-2 and I think it sounds better than the RA-1. Go here for some pics.

 

[Beagle]

Quote:

Originally posted by Hirsch Do you know any details? The HPA-1 manual references custom capacitors and wiring specifically made for the amp. What changed between the 1 and the 2?

No, I meant that the HPA-2 has better parts than the RA-1.

acidtripwow, those are great pics. The design sure looks similar to the RA-1, except the op-amps are not covered in epoxy..

 

[Hirsch]

Any visible differences from HPA-2?

Incidentally, in the HPA-1 manual, the design is credited to Sidney Stockton Smith, who designed the classic Marantz pieces. Final parts selection for sound was done by Joe Grado, who did all mechanical assembly of the amps. All electrical work was done by Tom Cadawas, who was responsible for trouble shooting and quality control on the original Marantz production line.