...if there is only a single speaker, what is it out of phase with?
I remember reading that article(s) in Vintage Guitar mag years ago when it/they came out, I had a subscription, and it caught my attention.
This is the way I understand it, I may be wrong.
He, (GW) is talking about the speakers 'throw'. Which way the speaker moves 1st. A speaker can move forward 1st or backwards 1st.
You can have an amp (whether, SS or tube) where it's said to be 'in phase with itself', ie, non-inverting, from input to output.
Meaning that if a sine wave is sent into the amp with the positive 1/2 (top 1/2) of the sine wave 1st, then at it's output the same positive 1/2 (top 1/2) appears, then the amp, as a whole, from input to output
is not inverting the signal (sine wave) then it's in phase with itself
or non-inverting. Remember every gain stage inverts the signal 180 degrees. (CF are not a gain stage and do not invert the signal.)
(There's a Marshall amp that is wired with a Hi gain jack
and a Lo gain jack, that adds a 12AX7 triode for the Hi gain, which makes the 2 different input jacks inverted from each other at the output, same with a # of Fender BF reverb amps.)
If you take such an amp, non-inverting, and hook up the positive speaker lead to the positive OT lead, then the speaker will 'throw' forward 1st.
There's
another part of the article where he (GW) starts out talking about flip/flopping the speaker leads, positive/ground, on an amp they were blind testing with a harp player and he said that each time the speaker was wired reverse polarity (his term) or backward throw 1st, the harp player liked it much better. He said it was 'softer' sounding (not volume, aggressiveness) something like that.
So, I believe there's more to it and he (GW) was tying to try 4 points together (some of which, SG hasn't posted) when he say's, "Here's the other part of the accident."
1. Reverse throw of the speaker, for a softer sound, less presence.
2. He put in a pot to dial in the PI's bias.
3. Found they liked the sound of an unbalanced PI.
4. They say it lessened feed back which allowed the harp player to turn up louder.
Now whether anyone
can hear if a speaker is wired forward or backwards throw 1st?
Or if it makes a difference with an adjustable PI balance control with the speaker wired reverse 'throw', you'd have to try it for yourself.
I think he worded what he (GW) said when he wrote the article in a confusing way and could have been much clearer, but at the time he
was making that amp for harp players to buy, so........
Also I think what GW calls a 'waveform symmetry control' is the same thing as in Kevin O'Connor's TUT books, as a PP to SE control?
Doug has GW's 5th book that has a chapter on harp amps that may have more clear info on it, for sale in his web store.
Brad
Topic: Built a Harp/Guitar combo (Read 10290 times)