Tweaking Order and call for Sugestions?

[heisthl]

Ok say your amp project is completed and now the final tweaking begins.
Here's what I do, but I'm open to better suggestions
Before tweaking make sure you are using an appropriate guitar and speaker combination. i.e. don't tweak with a Jensen if you amp will have a Celeston.
1. Do the voltage changes first - i.e. dropping string adjustments (don't forget to re-bias after each change). Lower = smoother
2. Coupling caps next - if you make a change and like it but think you lost something try changing the bypass value accordingly on the stage ahead of the coupler. i.e. if you gained highs but lost lows increse the bypass cap
3. Bypass caps next - in addition to tone these caps affect gain too, so you can add or take away "character" as the tone changes. i.e. changing to a 10uf (from a 05uf) will add bass and gain, if you like the gain but think it's too bassy try reducing the coupling cap to the next stage.
4. RP and RK values - I've learned not to mess with the ratio of these much, changing the ratio more than a few % hurts the "linearity" for lack of a better word. 220/3k3 180/2k7 150/2k2 120/1k8 100/1k5 pairs can be tried in any location. Sometimes replacing both pairs in the OD section is just what an amps needs i.e. V2 180/2k7 and 120/1k8 changes to 220/3k3 and 150/2k2 or vice versa.
5. Bleeders and filters - you can place a cap and resistor in series to gound anywhere in the signal path to bleed off highs or do a resistor/cap parallel pair to increase highs i.e. a .001 - 330k series from OD2 CC output to ground gets rid of "OD fizz" or i.e.2 lowering the 500p in the 220k/500p filter on the input to CL2 for less mids.
6.PI and output tweaks - I saved the best for last - you can really make or break an amp in this section. For max headroom try and use the smallest PI entrance cap you can (a lot of Fenders used .001!) and larger output tube grid resistors (I like 5k1s better than 3k3s) Screens on 6L6s sound better to me at 500 rather than 1k. If you have a trim pot to balance the plates make sure you can adjust them to within 5 volts of each other if not change one RP until you can, start at 5 volt difference and then very slowly increase as you strum a chord through the amp - you are trying to get maximum overtones - you'll know it when you find it.
.The NFB area is especially fun - max the presence control and cliplead in various values of caps and the FB feed resistor to taylor the gain and NFB cut off frequency.

Now the dilemma - How do you know whether a tweak is good or not? Short of testing it in a live situation I'm not sure. I have learned that in my case the sound on the bench is not to be trusted until I hear it live.

[tele_player]

This is a MOST EXCELLENT+++ guideline!

[mat]

This is a MOST EXCELLENT+++ guideline!

Yes, it really is Just what I needed.

Thanks heisthl

[tonelab2]

Thanks heisthl brilliant, I really needed this post