[sdiy] New to sdiy but w/ some knowledge

[Tom Wiltshire]

On 27 May 2017, at 22:51, Donald Tillman <don at till.com> wrote:
> 
>> On May 27, 2017, at 9:04 AM, Tom Wiltshire <tom at electricdruid.net> wrote:
>> 
>> I had someone contact me about distortion in my digidelay pedal. It turned out the guitar was fitted with "hotrod" humbucker pickups that were able to give enough output to overdrive a 3Vpp input. Such pickups are apparently popular with metal guitarists, since they allow you to drive the front end of your guitar amp harder and produce more preamp distortion.
> 
> I just scoped my Stratocaster... for normal playing it's goes up to 500mVp-p and maybe just a little bit more.  Fingerpicking can double that.
> 
> Most guitar amps have the input directly driving the grid of a 12AX7 stage, and if you check out the curves, you'll see that it's limited to under about 4 volts p-p.  So that's a serious practical limit.

Sorry Don, but nooope!
Since when did anyone *not* overdrive the grid of their 12AX7 input stage?! Isn't that the whole point of the Dallas Rangemaster or the Tubescreamer? Didn't Brian May/Eric Clapton/SRV make a career doing basically just that?!

More seriously, yes, a Strat and the levels it produces are probably about as "standard" a guitar as you can get, and probably 4Vpp is a reasonable limit, but it won't be the absolute top end, and you still have to deal with signals as low as few tens of millivolts in some cases. Guitars are a pretty wide range to cope with on their own, and guitar amps expect (some) people to run 18V boosters into the input stage to drive it hard - they won't get a clean signal, but that's not the point.

Tom