KT88/KT77/EL34 Discussion

[Life Eats Life]

Big fan of old Siemens 34s

I KNEW my comment would your attention.
I bet you can relate to the our ears gravitating towards the tones we were really listening to
before we picked up a musical instrument over the years/decades.

For me Ed, speakers are the biggest influence on the familiarities in my ears.

 

[likitlikeyoulikeit]

Another response from Laney in regards to bias.....

"there is a bias monitoring header on the output pcb, we set 6L6 and EL34 to 30mV which equates to 30mA per valve. this is the cathode voltage across a 1 ohm resistor.

if the amp is pre 2018 it will have a 3 way header, measure on pin 1+2 then pin 2+3 (HD2) on 9500 pcb

adjust TR1 on the main pcb to 60mV, this is set per side and not per valve.

if its the newer model with DI out it will have a 5 way header, pin 3 is common and measure 1+3,2+3,4+3,5+3 and set to 30mV, you are looking at a maximum +-5mV difference between the valve.


hope this helps.

regards Dave"

Good to know finally.

 

[TSJMajesty]

Got a response from Laney, which doesn't sound confident...I'm gonna keep pressing for info....due to my lack of understanding in how these amps are biased ....I need to know!!!


"thanks for the enquiry,

we do only advise using 6L6 or EL34 in these amps, i think using KT88 would cause issues with the power TX, it is rated at 7.5A and i seem to remember the KT88 alone draw 1.6A each so thats 7.6A with the preamp valves also.

regards Dave"

When support uses words like, "I think", it doesn't instill confidence in the answer ...I'll keep pressing on.

Maybe a transformer change would help the process......this seems a bit disappointing.

"I think"???

 

[likitlikeyoulikeit]

"I think"???

Exactly......there is anecdotal evidence that it's been done and fine .....but his current draw seems a little high ....but I lack that exact experience.