Hi,
trying to recreate the voxac15 pentode chanel.
Up til now, it sounds like any other valve, no highs, no chime, nothing special.
It breaks a little when cranked, but in low to mid range, dont like it.
Started to believe that they cheat in the demo and use some processor.
(vox ac15 heritage)
PT after rectifier, uder load - 294v
Voltage at plate, ef86 - 204v
Voltage at g2 - 34v
So, I suspect it is pretty low voltage, so the gain is not enough
(but the hum is already comming..)
What's the normal plate voltage for these? Pretty new, cant calculate it yet.
I followed this scheme>
View image: ef86 part
trying to recreate the voxac15 pentode chanel.
Up til now, it sounds like any other valve, no highs, no chime, nothing special.
It breaks a little when cranked, but in low to mid range, dont like it.
Started to believe that they cheat in the demo and use some processor.
(vox ac15 heritage)
PT after rectifier, uder load - 294v
Voltage at plate, ef86 - 204v
Voltage at g2 - 34v
So, I suspect it is pretty low voltage, so the gain is not enough
(but the hum is already comming..)
What's the normal plate voltage for these? Pretty new, cant calculate it yet.
I followed this scheme>
View image: ef86 part
Last edited:
After all
more distortion at lower current through the valve?
I noted, when I fire up the machine (no stand by switch), it sounds more distorted before heating is fully on.
The supply voltage is higher, but the current through the valve is lower
I think the effect you are hearing is more due to lower emission than lower current.
Cheers
Ian
Hi,
trying to recreate the voxac15 pentode chanel.
Up til now, it sounds like any other valve, no highs, no chime, nothing special.
It breaks a little when cranked, but in low to mid range, dont like it.
Started to believe that they cheat in the demo and use some processor.
(vox ac15 heritage)
PT after rectifier, uder load - 294v
Voltage at plate, ef86 - 204v
Voltage at g2 - 34v
So, I suspect it is pretty low voltage, so the gain is not enough
(but the hum is already comming..)
What's the normal plate voltage for these? Pretty new, cant calculate it yet.
I followed this scheme>
View image: ef86 part
Mr ValveWizard
http://www.freewebs.com/valvewizard/pentode.html
has a few things to say why this is so, i9n his book. Basically, Vox runs the EF86 at a very high gain and high loading, which makes it sound "HiFi" and without character.
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