AD200MK1/MK3 sound and settings comparison

[garci]

hi all,

I have been searching the web but didn't find any proper answer to my question.
I baught my Mk3 around 2004/5 (love it) and got a mk1 today.
I just tried the mk1 and got very surprised by the very different voicing but also by this impression of lack of power.
I was so surprised that i used a sound meter to mesure both amps and i gave me the same result of 90 db !
So it apparently as to do with their different voicing, mk1 staying cleanner and brighter.

To be able to approach the same sound i had to set the amp i an opposite way :

- 6 on master and 3 on gain for the mk3
- full master and 6 on gain for the mk1

Is that a normal setting for the mk1 ? (maybe as to see with a strange power tube selection, having two 6550 and two kt88, wich i plan to change for 4 6550) or do you think there is a problem with tubes or caps ?



Excuse me for my poor english as i have not practice for a long time,


Garci (garcimore but lost my password )

[bclaire]

Could be tubes - I'd start with a fresh set of output tubes and then see....

[garci]

thanks,

i still have the original set of 6550 i had in the mk3, do you think i can give it a quick try without risk ?

[Les Paul Lover]

thanks,

i still have the original set of 6550 i had in the mk3, do you think i can give it a quick try without risk ?

I believe your amp needs biasing with a new set of power valves.

[garci]

i went for a try, i had to know
i swapped the quad for 6550 and changed the preamp tubes.
same result.
What surprises me is that i have to set the master to 3/4 to get a decent volume level when, with the mk3 at the third it's really already very loud.

[bclaire]

Well, there were definitely changes made between MK I, II, and III and you may be hearing some of that.

However - with a new high-powered amp like this that has been bought used should really get a fresh start with new output tubes so you can hear what the amp is supposed to sound like....

[garci]

I agree, change for a new set and tech check up is already planed.
As said, this quad wasn t worn out and were the orginal set that came with
my ad mk3, so it s hopfully balanced. It works well with the mk1 and give the same result than the former tubes may be a bit better .
so i think it has to do with the amp s conception .
it s not a bad amp but totally different, i would say it s more linear ans subtil less overdrived bass oriented.
I gone a give myself more time and try it with a different cab (6x10 70 s ampeg)

[bassdrop]

You can't assume that just because the tubes were matched as a set and biased properly in your MkIII that they would be running optimally biased in your MkI. So have your tech bias that set of tubes in your MkIII to get the optimal output. As well, you may want to check your preamp tube as well. There's only one preamp tube in the MkI and I believe it has less gain so you should expect to have to set the gain higher to get the same gain as your MkIII, but if that preamp tube is wearing out then you may not be able to get as much gain as you would otherwise so swapping a known good spare in V1 is probably not a bad idea.