Suggestions for making a Fender HRD III Quieter for Practice (or Alternatives!!)

Emp_Fab

ICBM said:

earwighoney said:

I've done something to my Fender Blues Deluxe which has tamed the volume a bit, still mighty loud though.

I changed the preamp valves to the following
V1- 12AY7
V2 - 12AXY 
V3 - 12AT7 (Phase Inverter) 

A 12AY7 to the standard 12AX7 in V1 will bring the gain down and make the cleans more manageable. 

That's the best set in my opinion. The 12AY7 is a bit 'sweeter' sounding than the 12AT7 in V1, to me - the AT can be a bit 'cold'. The 12AT7 is cheaper and easier to get though - and is always worth trying first, since if you find the difference worthwhile you can then move it to V3 and put a 12AY in V1 .

@ICBM I've been struggling to control my 2002 HRD's clean channel (I don't use the drive, it's horrible!).  I recently replaced the volume pot for a 500k log (up from the factory 250k log) and it's helped, but not enough.  It's still got a huge jump in volume at the beginning.   What I'm hoping for is to get more control over it at lower volumes without sacrificing the max gig-level volume.

I'm assuming installing the AT7 and AY7 as per your and earwighoney's posts above will reduce the volume across the board? (i.e. I'll have an amp that doesn't go to 11 anymore but only 7!).

ICBM

It will help a bit - I find it improves clarity and reduces drive rather than really fixes the volume pot taper. The most effective solution is always to run a volume box in the FX loop though.

I'm actually surprised raising the pot value made much difference at all, unless you also went for a lower-percentage Log at the same time - stock is 15%, so a 10% would have helped. If anything going up to 500K should have increased the maximum volume available, since it's fed via a 220K resistor so you've increased the available signal from roughly 1/2 to roughly 2/3 of the level at the previous valve stage.

CarpeDiem

I have tried a Boss GE-7 in the loop of my HRD. It has a level control, which served the same function as the volume control solution, and adjusting the EQ improved the sound of the drive channel. However, I only use the clean channel and use pedals for a dirty sound. As @ICBM said, if you're careful, it's possible to adjust the controls to make the amp volume low enough for home use.

Telejester

Is there a risk that using a volume box in the loop and using the clean channel could result in a thin, undynamic and solid state like kind of tone if you wanted to use a hrd in the bedroom  ?

CarpeDiem

Telejester said:

Is there a risk that using a volume box in the loop and using the clean channel could result in a thin, undynamic and solid state like kind of tone if you wanted to use a hrd in the bedroom  ?

I've not experienced this issue. Conversely, the sound of the drive channel improved as I was able to drive the preamp more and used the volume (of the Boss GE-7) to reduce the output level.

Emp_Fab

@ICBM Increasing the pot value increases the volume ?  How's that work then?  I thought that at lower volumes, the signal would now be going through a greater resistance and therefore be lower.

ICBM

Emp_Fab said:

@ICBM Increasing the pot value increases the volume ?  How's that work then?  I thought that at lower volumes, the signal would now be going through a greater resistance and therefore be lower.

No, it's a potential divider not just a variable resistance. The resulting signal is the original signal multiplied by the resistance below the pot wiper divided by the resistance of the whole pot.

Adding an extra resistor in series with the pot on the input side effectively adds more of the potential divider that now can't be reached - if the resistor is the same value as the pot, then you now can't turn up the signal above halfway.

So increasing the value of the pot with the same resistor means that you can now access slightly more of the total range.

Does that make sense?

In fact, reducing the value of the pot should have been more effective.

This is also why the taper of an 'audio taper' pot is important - the quoted figure is the ratio when the pot is at the halfway point. (Strictly speaking, Log means a 10% pot, but the two terms are often interchanged.)

But none of these changes will be anything like as effective as the volume box - then you effectively have two potential dividers in series (even though they're at different places in the circuit), so the result of the first is multiplied by the second. If you have both pots turned down to the 10% point, then the result will be 1% of the original signal.

Emp_Fab

Thanks for that.  I think I need to read your explanation several times with a very concentratey expression before it'll sink in.  What I'll do then is put the original pot back in and stick my unused Dano Fish 'n Chips EQ in the fx loop.

-NFM-

ICBM said: ...

But none of these changes will be anything like as effective as the volume box - then you effectively have two potential dividers in series (even though they're at different places in the circuit), so the result of the first is multiplied by the second. If you have both pots turned down to the 10% point, then the result will be 1% of the original signal.

Actually this was why I eventually decided to go volume box for this very reason.... lots of room to dial it in. Happy to post a gut shot of the home made volume box if anyone would like to see the layout to build one!

(Full disclosure though - I can’t do any demos of it as I’m not currently using an amp; just my desktop interface, a few pedals and my laptop. I’m back studying a postgrad so space is at a premium and so my amps and a couple guitars are in storage at my parents place!  I know a couple of studios nearby with practice spaces though so hopefully rent some time there soon!) 

sm55onl

A relevant page from the website quoted on the Wampler video (earlier in this thread):

http://stinkfoot.se/archives/2159