RA-1: Two minor glitches
Apr 25, 2004 at 4:40 AM Thread Starter Post #1 of 11

mhudes

New Head-Fier
Joined
Feb 4, 2004
Posts
1
Likes
0
I noticed two glitches with my RA-1:

1. Relatively loud pop in headphones when turning it on.
2. At extremely low volume, one channel has lower output level than the other one. In fact, when bringing up volume from off, one channel starts playing before the other.

Is this normal?

My RA-1 is used, but in pretty good shape. Looks like it is a few years old. I use it with RS-1's.

Thanks,
Matthew
 
Apr 25, 2004 at 5:02 AM Post #3 of 11
Joined
Jun 22, 2001
Posts
9,534
Likes
27
Quote:

1. Relatively loud pop in headphones when turning it on.
2. At extremely low volume, one channel has lower output level than the other one. In fact, when bringing up volume from off, one channel starts playing before the other.

Is this normal?



The loud pop is suppose to be there.

The unbalanced issue is a problem, contact Grado Labs about having it fixed. I had a RA-1 for many years and never had that happen. I also listen to many RA-1 and never heard of such things.
 
Apr 25, 2004 at 8:11 AM Post #4 of 11

Rameish

100+ Head-Fier
Joined
Jun 22, 2001
Posts
434
Likes
10
Hmm,

My experience with 4 different RA-1 differs from KR.

The loud pop when switching on and slightly softer pop when switching it off is normal - it's even stated on the "manual" sheet.

The channel invalance at very low volumes is normal as well IMO. Yes one channel does play music first (this is true of even an Alps Blue). Im talking about audiable but way below normal isntening levels here.

But if it's still slighly inbalanced at slightly below normal levels then you should change the pot. I don't know if sending the amp back to grado is such a good idea bec you'll still get the same inexpensive pot.

If you are like me and listen to lower than normal listening volumes then a very good pot to get is the TKD pot (they make a mini version) that costs about $30 (S$50). The value should be 100K. The Alps Blue wont fit in there unless you wish to do some woodwork.

The TKD pots are very good - better than an Alps Blue about the same as an Alps Black Beauty in the "how evenly balanced" are the 2 channels balanced stakes. LOL

TKD pots are usually used in high end audio equipment of japanese origin.
 
Apr 25, 2004 at 8:31 AM Post #7 of 11

Wodgy

Headphoneus Supremus
Joined
Feb 24, 2002
Posts
4,657
Likes
12
This is not unusual behavior for the RA-1. It has nothing to do with the headphones. It's the channel imbalance at low volumes caused by the potentiometer they use. Every potentiometer has a channel imbalance at low volumes to some degree, but the cheap pot Grado uses is particularly prone to this. This is the main reason most of the other amp manufacturers spend $10 on the Alps Blue or even $3 on the Panasonic potentiometers, rather than 99 cents for the cheap potentiometer Grado uses.

If it's bothersome, send it to Grado and ask for a replacement, but don't kid yourself that the new one won't have this problem. It will just have this problem to a lesser degree. I doubt you'll find one with better than 3dB channel matching at low volumes.
 
Apr 25, 2004 at 12:19 PM Post #8 of 11

Harty

100+ Head-Fier
Joined
Aug 2, 2003
Posts
267
Likes
24
I bought my RA-1 about 3 years ago here in the UK before I knew anything about headphone amps, if I knew then, that I know now, I certainly wouldn't have bought the RA-1 for £400.00 UK Pounds.
eek.gif


Best wishes,

Paul.
 
Apr 25, 2004 at 12:35 PM Post #9 of 11

tortie

Headphoneus Supremus
Joined
Aug 12, 2003
Posts
2,812
Likes
14
Quote:

Originally Posted by mhudes
I noticed two glitches with my RA-1:

1. Relatively loud pop in headphones when turning it on.
2. At extremely low volume, one channel has lower output level than the other one. In fact, when bringing up volume from off, one channel starts playing before the other.

Is this normal?

My RA-1 is used, but in pretty good shape. Looks like it is a few years old. I use it with RS-1's.

Thanks,
Matthew



Hi. Welcome to head-fi.
biggrin.gif
The loud pop in headphones is normal but the great volume imbalance in both channels is not. I suggest you send it to Grado to have them check it.
 
Apr 27, 2004 at 2:31 AM Post #10 of 11

mikeg

Headphoneus Supremus
Joined
May 4, 2002
Posts
3,171
Likes
11
Pop is normal, but sound imbalance is not. I just set my RA-1 to an extremely low volume, and the sound level from each side of the headphone continued to match.
 
Apr 27, 2004 at 2:50 AM Post #11 of 11

Sovkiller

Proved that despite its huge size the CD3000 can be shoved down one's throat.
Joined
Jul 31, 2002
Posts
12,902
Likes
26
Even while most pots, specially cheap ones have unbalance between channels, that does not mean that this should be there, in your shoes, and given they charge 350.00 for the amp, this should not happen under any circumstances, I would contact them for a pot replacement until the problem is solved....BTW I don't know which Alps have you tried, Rameish, but any of mine has unbalance in the channels....
 

Users who are viewing this thread

Top