Overdriving a Model T

[elvis_bucklehorse]

At my last band practice, (following "Guest's" suggestion) I ran my guitar into my Model T's Bright input, then patched the Bright Out into the Normal In.  With the Bright channel cranked (8 or 9) and the Normal at around 4, I got a really mean-but-musical distortion out of the amp, the likes of which I hadn't been able to achieve before.  This sounded way better to me than using the bridged input--which just seems to combine both channels transparently and doesn't really add much substance to the tone at all.  With this setup, the tone was meatier, and the distortion was much more responsive and easier to control in general.  Anyhow, my band mates were impressed--as were most people within a 5 block radius of the garage, I'm sure.  

Now, I'm using an old set of KT-88s and I have a feeling they're getting pretty tired.  I bring this up because after about 90 minutes of balls-out shit-kicking, I noticed the sound was a bit muddier than it was at first--a little murkier.  I've never actually blown tubes before--for the record, all four tubes were still glowing a consistent dull orange at the end of the practice.  Is muddiness a symptom of overworked/failing tubes?  Moreover, do you think looping the cranked Bright signal back into the Normal channel is overworking the tubes, or burning them up faster?  They certainly were sounding more pleasantly saturated than they have in the past...  Anyway, I'm asking 'cause I'd rather settle for a decent OD pedal for my rig than blow $100 on tubes every two months.

Thanks for reading,

Ted

[Anonymous]

Ted... my suggestion about the brite and normal channel looping involved an overdrive or distortion pedal between the brite out and normal in.  If you just looped these inputs with a guitar cable, you achieved the exact same thing that the both-in jack does only using more "wire" to do it.

You are not looping a cranked brite signal back into the normal channel, only the output of your guitar.

If this was the way you set up the amp... and it sounded way better, then I'm willing to bet the muddiness you heard after practice is a symptom of overworked/failing EARS.

Cranking the channel volumes will not overdrive your output tubes unless you increase their drive via the master volume.

[elvis_bucklehorse]

Hmmm...

Well I certainly wouldn't rule out the possibility of my failing ears contributing to the muddiness of the sound.  It is, at times, a comically loud band.  So I'll let the muddiness be for now.  

As for the other stuff though, I can definitely say the gain that I seemed to be getting from the Brite channel sounded meatier than the breakup I get when I just crank the Brite channel using the bridged input.  Furthermore, I was drowning out the drum kit with my Master Volume on 3.5, where I typically kept it up around 5-6 using the bridged input.  So I'm fairly confident SOMETHING is happening with this configuration...  I don't know if this is the case with yours, but when I use the bridged input on my Model T, it sounds like I'm hearing two distinct channels (Brite, Normal) superimposed, as opposed to one "blended" channel--in other words, the two channels sound completely independent of one another and don't affect each other at all.  In this case, the Normal channel volume seemed to have an effect on the volume of the Brite channel as well.

Guess I'll tinker with this thing a little more in the next couple of days and try to be a little more scientific about it.  I'll fill you in on my findings.  Thanks for the feedback.

T.

[Kid Klash]

I'd guess that the "dullness" is caused by your ears, which were overexposed to high SPL.  High frequencies are the first to go, but should return the next day (unless your hearing is permanently damaged).  That's why it's never a good idea to mix a record right after you've ridden in a car... even though the noise level inside of a car is (usually) fairly low, there's enough low level noise to affect your hearing.  Exposing your ears to a cranked up fire-breathing dragon like your model T will take out just about everything above 5Khz after about 10 minutes of exposure...  be careful...  

[elvis_bucklehorse]

That's a fair assessment.  I was practicing without ear plugs, which is totally foolish, I know...  I'd like to think this isn't the first time a "Protect Your Ears" advisory has been posted on a Sunn discussion forum!

[Anonymous]

Ted... try this "test", one channel at a time.  Keep the master volume at a suitable level (around 1 1/2 to 2 maybe), and don't change it or the tone controls when you switch channels.

Plug your guitar into one channel's input jack, nothing into the other channel - do not use the both-in jack, you want to have zero input going into the other channel.  Turn the other channel's volume control to zero.  On the channel you are plugged into, turn the volume all the way up to 10.

Play a sustained chord... something like an A Major... and while it is still ringing, turn the volume control on the channel that has no input.

Do this with each channel... a couple of times.  What you will notice is that the channel volume control with no input has an effect on the overall sound.  You will find a "sweet spot" on each... probably between 4 and 8 on the knob where the clarity of the sound seems to open up.

What this will demonstrate to you, is the interactive nature of the channel volume controls... they are not as independent as you may believe.

Now... when you try comparing the looping of inputs versus the both-in jack, make sure you do not change the position of any controls.  You should get the exact same sound in both cases.  

If you don't, it could mean that the both-in input jack has been "over-used"... meaning it may not be making good contact or has some crud on the terminals that has build up over the years.

Have fun!!