Hot Rod Deluxe clean sound way too thick and unpleasing at high level... Ideas?

[freefrog]

Hi,

I've here a 2d hand Fender HRD "White Ligtning" with the following mods (done by the humble me):

-V1= a better 12AX7.
-PI= a 12AT7.
-Bright cap added on the volume pot (clean channel).
-"Blackfaced" mid pot (two lugs soldered together> no sound when all tone controls on zero).
-Removed resistor (don't remember its number right now) for a fuller reverb.
-Volume box with a 100k pot in the FX loop.
-Jensen C12N instead of the (IMHO awful) Celestion Century Vintage.

I always use the "low" level input and keep the channel volume pot below 4.

The amp sounds bright, crisp, clear at low levels. But once the added "master" set at gig levels (beyond 5/10), the clean sound becomes thick/middy/muddy/bassy and just awful.

Why? Has it to do with the (stock) 6L6's?

Solutions?

Thx in advance!

Footnotes:

-I don't forget the "psycho-acoustic" dimension, Fletcher-Munson law and so on. BUT what bugs me is the contrast between the HRD and my Vox AC15, which stays clear with the SAME settings and in the SAME place which make the HRD muddy (itself being not even as loud as the AC15, BTW: several of the mods that I've done lead the HRD necessarily diminish its overall output power).

-I know the HRD is a budget amp. I also know that a simple little mod is sometimes enough to clean up a tone (I've done it before with a Marshall that I still own).

[Jazz P Bass]

Hot Rod Deluxe amps generally are at full power with the volume at 4.
Anything above that & the amp is well into clipping the output.
Is this the sound (clipped) that you are after.
Or do you want it clean?
Remember, the tone controls have a huge effect on the preamp voltage going into the phase inverter.
Try turning down the bass & mid controls.

[freefrog]

Hot Rod Deluxe amps generally are at full power with the volume at 4.
Anything above that & the amp is well into clipping the output.
Is this the sound (clipped) that you are after.
Or do you want it clean?
Remember, the tone controls have a huge effect on the preamp voltage going into the phase inverter.
Try turning down the bass & mid controls.

1) I thk you for your answer.

2) I've understood that the "taper" of pots is not progressive at all on such amps. That's precisely why I've added a "volume box" in the loop of my HRD.

3) I know the HRD has waaay too much gain in its stock version. That's why I've put a 12AT7 as a PI and have modified the mid control in such a way that it cuts much more frequencies (mid control that I set between 0 and 4). That's also why I plug in the "low" input...

4) With all my mods, I don't think that the preamp of my HRD drives "hard" its power amp: actually, my stock Vox AC15 always sounds louder now than my "watered down" 40W Fender...

What I'm talking about is not power tube distorsion to my ears: the sound of my HRD remains clean at high level. No grit, no dirt.

What bugs me is the tendency of this clean tone to become unpleasantly "midrangey" once my added master volume is beyond 5/10, despite of all the things that I've done to brighten the tone...

[jmaf]

What JPB said, the HRD uses linear volume pots, at volume 3 you think the ceiling is gonna fall if you go louder, but if you crank it to 10 you'll only hear more boomy distortion. It's standard behavior, the highs are the fist ones to go down upon clipping.

Other than that, depending on what reverb resistor you changed it may also affect tone.

[freefrog]

What JPB said, the HRD uses linear volume pots, at volume 3 you think the ceiling is gonna fall if you go louder, but if you crank it to 10 you'll only hear more boomy distortion. It's standard behavior, the highs are the fist ones to go down upon clipping.

Other than that, depending on what reverb resistor you changed it may also affect tone.

Thank you too!

The reverb mod that I've done is this one: http://www.justinholton.com/hotrod/reverb.html

I've just cut a leg of R103... But the reverb was not used when I've noticed the middy clean thing.

[g1]

Firstly, what did it sound like before the mods? If you don't have a benchmark to compare it to, you're in for a tough time. Compare it to another stock HRD. Completely forget about any comparisons with the Vox. If you can find out if this is normal or not for a stock unit, you will have a much easier time of it.

[jmaf]

Thank you too!

The reverb mod that I've done is this one: The Unofficial Fender Hot Rod Deluxe Owner's Guide! | Reverb Mods & Info

I've just cut a leg of R103... But the reverb was not used when I've noticed the middy clean thing.

I see. That mod won't be the cause of your mushy sound.

Did you by any means change anything on the output impedance? If you hooked up the 8 ohm speakers to the 4 ohm tap that'd also cause less high end and a more boomy sound.

[freefrog]

Firstly, what did it sound like before the mods? If you don't have a benchmark to compare it to, you're in for a tough time. Compare it to another stock HRD. Completely forget about any comparisons with the Vox. If you can find out if this is normal or not for a stock unit, you will have a much easier time of it.

It sounded awfully middy / muddy and that's the reason why I've done the mods listed above. These mods work really well at low volume... and their effect seems to disappear once the amp at gig levels, at various degrees...

I see. That mod won't be the cause of your mushy sound.

Did you by any means change anything on the output impedance? If you hooked up the 8 ohm speakers to the 4 ohm tap that'd also cause less high end and a more boomy sound.

No, the loudspeaker is plugged in the right (I mean the "proper") output.


Thx again for your answers, anyway.

I'll try to use an amp stand and a sonic reflector behind the open back, in order to see if it solves anything... And maybe I'll change the power tubes at least one time. If it doesn't work and if I discover that this HRD is inherently middy, I'll simply get rid of it (since this mid clean mentioned above is totally unable to cut the mix with my bands, unlike my 3 other amps).

[jmaf]

It sounded awfully middy / muddy and that's the reason why I've done the mods listed above. These mods work really well at low volume... and their effect seems to disappear once the amp at gig levels, at various degrees...

Well you mentioned a clue on your first post: maybe you got old 6L6's. They go boomy and mushy. JJ's are costing almost the same as Chinese lately, why not try a pair? Easier and cheaper than undoing all your mods.

[freefrog]

Well you mentioned a clue on your first post: maybe you got old 6L6's. They go boomy and mushy. JJ's are costing almost the same as Chinese lately, why not try a pair? Easier and cheaper than undoing all your mods.

Yep, I'll try that first. Thx!