Level Differences on Mesa Dual or Triple Rectifier Solo channel settings

[nevetslab]

I have a client's Mesa Dual Rectifier Solo Amp head here, with the complaint that the Ch 1 Clean Channel level is way too low. I know that channel in general is lower gain than the Ch 2 and Ch 3 output levels, if all settings were identical. Mesa doesn't publish any useful gain or level differences to guide you, other than stating there's significant difference between them. This being the holiday schedule at CenterStaging, there wasn't anyone over at our warehouse where all the rental gear is, but I might be able to get there tomorrow and borrow one of our Dual or Triple Rectifier Solo heads for comparison.

So, I sat myself in front of my shop test speaker, set all the channel controls at 12 o'clock (Gain, Master, Bass, Mid, Treble & Presence), started with the lowest switch settings (Clean for Ch 1, RAW for Ch's 2 & 3), and adjusted the Output level for 65dB SPL A-wtd with burst pink noise feeding the amp. I was parked at 1 meter from my test speaker (an Ampeg SVT 115HLF bass cabinet). This is what I found between the three channels and the switch settings:

Ch 1: CLEAN: 65dB SPL PUSHED: 75dB SPL

Ch 2: RAW: 85dB SPL VINTAGE: 101dB SPL MODERN: 111dB SPL

Ch 3: RAW: 85dB SPL VINTAGE: 101dB SPL MODERN: 111dB SPL

Does this seem typical of a Mesa Dual or Triple Rectifier Solo amp? I had swapped out V1 and V2 tubes without that making any difference. Internally, Mesa uses Relays to change between the channels and the switch tone circuit settings.

Dual & Triple Rectifier Solo OM.pdf

boogie_dualrectifier_3ch_solo_head.pdf

[Enzo]

Well, just my opinion, but I think people somehow expect all channels to equate at the same knob settings. And how do we even compare a normal channel with its single volume knob to a dirt channel with pre and post controls? I mean someone will always rationalize it somehow. But what should be the standard. To me the idea all my channels need to match volume to knob numbers is unrealistic.

[The Dude]

...... and, that's precisely why they give you controls.

[g1]

The owners manual gives sample settings (pg.16 of attached). I would guess they are supposed to give ballpark similar stage volume.
For clean, they have master at 12 o'clock (gain about 11 o'clock). For all other type sounds they have master set at 10 or 11 o'clock.

So to me that says at equal master settings, clean would be lower output. If the owner said 'way low' it's hard to know exactly what they mean. I would want to know if this was something that just changed all of a sudden.

[nevetslab]

This morning I stopped off at our warehouse on the way in, and picked up one of our Mesa Dual Rectifier Solo heads for comparison. Slightly different on the rear panel, but allowed common set-up as on AuntieM's amp. Again, fed burst Pink Noise into the input, starting with Ch 1 in CLEAN mode. Preset all of the front panel controls the same as on the other amp (all at 12 o'clock position), and adjusted the Output control for 65dB SPL A-wtd, @ 1 meter as before: Here's the SPL readings on this amp:

Ch 1: CLEAN: 65dB SPL PUSHED: 74dB SPL

Ch 2: RAW: 83dB SPL VINTAGE: 98dB SPL MODERN: 107dB SPL

Ch 3: RAW: 83dB SPL VINTAGE: 98dB SPL MODERN: 107dB SPL

Similar readings, enough that I see no reason to go digging for something that is not there to be found. I sent the SPL readings I got yesterday, and will send those from this amp from our inventory. Saves me the headache of having to go dig into the innards of a Mesa amp, at any rate.

[Mick Bailey]

I had a runaround this year with the same thing - owner complained that the clean green channel was much lower in volume than the orange or red on his Mesa amp. It drove me nuts trying to rationalize this with him. Also the reverb controls were set at different knob positions for the same degree of reverb - the orange and red channels had less reverb than the green with the knobs at 12 O'clock. Aaargh............