Headphone Heights

Welcome to Headphone Heights, the place for all your ear bud discussion

Use this form to submit comments directly to the Asylum moderators for this forum. We're particularly interested in truly outstanding posts that might be added to our FAQs.
You may also use this form to provide feedback or to call attention to messages that may be in violation of our content rules.

You must login to use this feature.

Inmate Login

By default, logging in will set a session cookie that disappears when you close your browser. Clicking on the 'Remember my Moniker & Password' below will cause a permanent 'Login Cookie' to be set.

Moniker/Username: The Name that you picked or by default, your email. Forgot Moniker?	Examples "Rapper", "Bob W", "joe@aol.com".
Password:	Forgot Password?
	Remember my Moniker & Password ( What's this?)

If you don't have an Asylum Account, you can create one by clicking Here.

Our privacy policy can be reviewed by clicking Here.

Inmate Comments

From:
Your Email:
Subject:

Message Comments

Original Message

Talking about Grado

Posted by neolith on May 6, 2016 at 09:21:39:
I had static one channel of my RA1 amp. Yesterday, I opened the box and melted the glue that covers the circuit board with a heat gun. I then was able to determine that one of the input caps was bad. Unfortunately while removing the glue, I obliterated the markings on the caps. I did measure 5 uF on the good cap but I decided to contact Grado for confirmation.
My email was answered within 2 minutes and the 5 uF value was confirmed. They also sent me a schematic of the circuit (basically a Cmoy with gain using JR4556 opamps). I replaced both caps with 2 uF Solens which I had on hand and all is well again.
Kudos to Grado for incredibly rapid response. OTOH the circuit is about as simple as you can get and the circuit could not cost more than $15.00 plus perhaps another $30 for the pot, audio jacks and power jack. I paid about $300 T 10 years ago. So the very nice wood box cost me about $250 - a very nice profit. The RA-1 works very well with the SR-60's which is all I need for occasional headphone listening.
Here's the schematic: