New Mesa Studio Caliber Owner

[Patton1970]

High every one! Picked up my very first Mesa not long ago. It's a Studio Caliber DC-2B built in 93'.

It seems to be very dark sounding from both channels. The lead channel in particular. Even with the presence and treble maxed out.

If I run a Boss GE7 in the loop and bring the 3khz band up a ways, and the 1Khz band a just a bit, it sounds so much better.

I put new Groove Tunes in it just to see if that made a difference, and it made none.

Are these amps typically on the very dark side of sound?

 

[D2dark]

It's a dark sounding amp but not as much as you describe here.

What's the speakers in it ?
Can you make it sound loud ?
Are the output tube ok ?
What guitar do you use ?
What pedal do you use in it ?

 

[Patton1970]

Well, I found the problem...

First, I ran the recording port to a separate amp to see if the pre-amp section sounded Ok, and it did. Not dark at all, with plenty of high frequency response. So looking at the schematic, it could be anything beyond the pre-amp stage.

Next, I ran the slave port out to a separate amp and it wasn't dark sounding either. So that left only the power amp section, supply voltages, output transformer and speaker.

The speaker is a brand new Eminence Wizard, so I pretty much ruled that out.

The EL84's I tried were the original Mesa tubes, and also a new set of Groove Tubes. Nether set of tubes made a difference.

It turned out NOT to be the power supply nor the output transformer.

Speaker is an Eminence Wizard - New.
Is it Loud - Very!
EL84's - Old and New - No difference in sound.
Guitar: I have two Les Pauls - P90's, 490R & 498T
Pedals: When troubleshooting - none

Anyone care to take a shot at what it was?

 

[jpdennis]

Just a thought. Change out the phase inverter tube. If that does the trick - done. If not, use the eminence with another amp. Then, if the speaker checks out ( I know it is new but ... ) run another preamp into the power side of the DC and see how it sounds.

Dennis

 

[jimmyplant]

...speaker wired wrong ?.....

 

[Patton1970]

The Phase Inverted tube was a good answer. However, I forgot to mention earlier that I had swapped it out with no effect either.

The problem ended up being the two .047uf Orange Drop coupling capacitors between the Phase Inverter plates, and each EL84 grid. I suspect they had simply changed in value over the past 19 years. Anyway, replaced those and now I have plenty HF response. Great sounding amp...

 

[D2dark]

Thx to share the info