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As Ive stated before,I own a used 2000e and was considering replacing the tubes,I was able to locate a pair of J.J. ECC 81 12AT7s(new).
Im getting ready to lay vocal tracks,
1. Is there anything I should look out for as far as replacing the
the tubes
2. How many hrs of use on the Seb before they brk in?

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Sebatron Wed, 06/01/2005 - 10:37

1. Is there anything I should look out for as far as replacing the
the tubes

The boogey man..... Elvis Presley ......
No seriously... ,, look out for microphony ..... tap the tube with your fingernail and listen to the sound. Does it ring?
If so , it may be microphonic.
Avoid Sovtek by all means.

2. How many hrs of use on the Seb before they brk in?

4 hours minimum.
10 hours is good for NOS.
20+ hours should settle them in well if they are brand new.

8)

anonymous Wed, 06/01/2005 - 14:11

Sebatron wrote:

1. Is there anything I should look out for as far as replacing the
the tubes

The boogey man..... Elvis Presley ......
No seriously... ,, look out for microphony ..... tap the tube with your fingernail and listen to the sound. Does it ring?
If so , it may be microphonic.
Avoid Sovtek by all means.

2. How many hrs of use on the Seb before they brk in?

4 hours minimum.
10 hours is good for NOS.
20+ hours should settle them in well if they are brand new.

8)

If you wouldnt mind,please explain the term "microphony"---is it some source of unwanted tone?

Sebatron Fri, 06/03/2005 - 11:52

If you wouldnt mind,please explain the term "microphony"---is it some source of unwanted tone?

Well,
sometimes valves ( due to variances in construction) exhibit a tendancy to be sensitive to sounds and vibration.Sometimes it's so bad they can feedback on themselves during high gain demands.
Tapping the valve is one way to check for microphony.
Usually the J.J valves don't have many problems.

8)