KT-2A retube question

lcr
Senior Member

Posts: 802

KT-2A retube question Feb 23, 2019 12:19:44 GMT -6 via mobile

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Post by lcr on Feb 23, 2019 12:19:44 GMT -6

I understand the tubes are :

2x 12AX7, 1x 12BH7, 1x EL84

I read online that one 12ax7 is for the make up gain, the other drives into the opto cell responsible for the gain reduction meter. My question is, If one were to retube the KT-2A, is it neccessary to upgrade the tube feeding the meter? If it is, could one use a cheaper tube for this? Also, what is the location of the two (so I know which one is what). Any help would be greatly appreciated.

ragan RGO Senior Member Posts: 6,474	KT-2A retube question Feb 23, 2019 12:47:15 GMT -6 via mobile kcatthedog, lcr, and 3 more like this Quote Select Post Deselect Post Link to Post Back to Top Post by ragan on Feb 23, 2019 12:47:15 GMT -6 bowie

ericn Temp Balance Engineer Posts: 14,938	KT-2A retube question Feb 23, 2019 15:36:14 GMT -6 via mobile kcatthedog, lcr, and 1 more like this Quote Select Post Deselect Post Link to Post Back to Top Post by ericn on Feb 23, 2019 15:36:14 GMT -6 Feb 23, 2019 12:47:15 GMT -6 ragan said: bowie Beat me to it!
	“Right now I need a Telecaster through a Vibrolux turned up to 10” Memphis in the meantime by John Hiatt

bowie
Senior Member

Posts: 229

KT-2A retube question Feb 23, 2019 18:07:31 GMT -6 kcatthedog and ericn like this

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Post by bowie on Feb 23, 2019 18:07:31 GMT -6

In the traditional LA2A circuit, one 12AX7 is in the amplifier section and the other in the compression circuit. For sonic improvement in a new unit, the amplifier 12AX7 and the 12BH7 are the ones to upgrade. The other two can wait until they start to wear.
As far as placement goes, I've not helped anyone with the KT-2A (didn't even know it was a thing until now) but I've figured out other gear by looking at the internals.

ericn
Temp

Balance Engineer

Posts: 14,938

KT-2A retube question Feb 23, 2019 19:16:30 GMT -6 via mobile bowie likes this

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Post by ericn on Feb 23, 2019 19:16:30 GMT -6

Feb 23, 2019 18:07:31 GMT -6 bowie said:

In the traditional LA2A circuit, one 12AX7 is in the amplifier section and the other in the compression circuit. For sonic improvement in a new unit, the amplifier 12AX7 and the 12BH7 are the ones to upgrade. The other two can wait until they start to wear.
As far as placement goes, I've not helped anyone with the KT-2A (didn't even know it was a thing until now) but I've figured out other gear by looking at the internals.

Somebody send the man a KT2A!

“Right now I need a Telecaster through a Vibrolux turned up to 10”
Memphis in the meantime by John Hiatt

Post by lcr on Feb 23, 2019 12:19:44 GMT -6

Post by ragan on Feb 23, 2019 12:47:15 GMT -6

Post by ericn on Feb 23, 2019 15:36:14 GMT -6

Post by bowie on Feb 23, 2019 18:07:31 GMT -6

Post by ericn on Feb 23, 2019 19:16:30 GMT -6