[tortie]

hmm bummer. Im thinking what other components your using in the ra1 that your not using in your supermini.

Well if grado says your old one was working fine and your new replaced one still hissess, theres nothing to blame now but your .......1/4 to 1/8 adaptors

But thats highly unlikely.

The RA-1's are loved my many because they are supposedly dead quiet. Its just ironic that the problem with your unit is the hiss...

 

[bcwang]

It's actually the supermini that I use and rca to mini adapter, and a 1/8th to 1/4 adapter for the headphone (RS1), the RA1 uses no adapters.

Yeah, it's too bad one of the main reasons I went with this amp was because it was supposed to be dead silent, which it unfortunately doesn't look like it is. The only possibility now is there is some RF or magnetic or some other interference in my city affecting it. I've walked around with the amp to see if it was interference but it doesn't seem like it as it hisses the same anywhere I go, even at work. Unless this intererence is constant in the whole city where I live, but doesn't exist where Grado is, that would explain it. Of course that would also be kinda freaky if it was true.

 

[archosman]

I hooked up my new Sony 3000s to my RA-1 & noticed a very slight hiss as well. I never noticed it with my 325s though. I was actually impressed with the RA-1 & my NAD 541i. I've got an Earmax Pro coming at some point but for now I'll run the Sonys thru the RA-1 for now.

 

[Ph34rful]

Quote:

Originally posted by archosman I hooked up my new Sony 3000s to my RA-1 & noticed a very slight hiss as well. I never noticed it with my 325s though. I was actually impressed with the RA-1 & my NAD 541i. I've got an Earmax Pro coming at some point but for now I'll run the Sonys thru the RA-1 for now.

Same here. I just received CD3000s and they do have slight hiss through the RA-1. Not noticable though at my listening level. However with HD600s w/Equinox there was absolutely no hiss at any listening level.

But when I disconnect my ICs it goes away.

 

[D555]

1) Use lower sensitvity headphones
2) Reduce the gain of the OPAMPS
3) Do 1 and 2 together

 

[was ist los?]

I've built a few RA-1 clones and all have hiss. It is really due to your headphones being very sensitive. The solution may be to put 47-100 ohm resistors at the output.

 

[bcwang]

How does that explain the people who have completely silent RA1s? I use an RS1 with mine which they are designed to work with, and yet still get the hiss.

 

[bcwang]

Sorry to bring up an old thread, it just brought back memories when I read it again. So I'll tell you what happened in the past 3 years.

So after giving up on 2 RA1 units because of hiss, I went and got the emmeline xp7. Guess what, that hissed too with my RS1. Yet both Todd (vinyl junkie) and Ray could not hear it. In any case, Ray replaced it with a second unit, and that one hissed just the same. At the end, I found out that I had to replace the stock AD825 opamp with AD797 and the hiss was finally gone!

What's the verdict? I must be much more sensitive to hiss, or listen in a much quieter environment than a lot of others so that I notice the hiss. 2 RA1 and 2 stock XP7 hissing is more than just coincidence.

On a side note, getting the Tomahawk was a real pleasure because that's the first amp that I can detect absolutely no hiss with my most senstive headphones, an IEMs (e4g) which show hiss in the supermini (which was silent with my other headphones). Yay!!!

 

[skitlets]

I have the same problem with my RA-1. Even with no interconnects, I can hear a slight hiss in it. Not enough to bother me but present nonetheless.

 

[feckn_eejit]

Checked mine in a very quiet environment with no interconnects. Also with a 1.5 metre pair of Cardas GR RCA IC's hanging off. Also hooked up to a CAL Icon mkII CDP with no power hooked up to it. No hiss with either my RS1s or SR325s. RA1 #6014. Plain jane Duracell copper tops.