I fixed the freak-a-zoid boost my PAB was making, and more.

[LPSGME]

I read some old posts about an email from NIK concerning adding a resistor to a Bluesmaster in order to tame the extreme level change that the PAB introduces (which many people including myself have complained of).

So I decided to look at my PAB circuit.

As I started to follow the wiring, I couldn't match it to the schematic - although it seemed to match the 'layout'. I thought, perhaps, my mind was not up to the task of deciphering what I was seeing - even though several things didn't look right to me.

However, I was also seeing parts connected to the DEEP switch [that should then go elsewhere] wired back to the unused terminals on the switch - as if someone thought they could do that [being the terminals were not used] without altering the function. Duh!

So I tore the all parts off the switches and relay board and wired it from the schematic.

Guess what? Now the PAB creates a slight boost instead of the freak-a-zoid boost it had before!!!

I also changed the position of the Master volume, as the HRM's [1Meg] 'Master' is wired so that it only controls the clean channel, while the [1 Meg] 'Level' or 'Ratio' pot controls the OD - without there being any single control means to change the level of their mix.

After re-positioning the Master, to be like the non-HRM, I detected a decided improvement in the OD tone - but I don't know why. I know it changed because I could see it on the scope when I injected a signal.

As the non-HRM Level or Ratio pot is much lower yet @ 100k - I'm wondering if I should replace the Level pot (now 1Meg) with a 100K

[talbany]

Could the change in load from 1Meg to 500K have done that?

Yes.. with the lower value pot there the OD will yield a brighter tone with less body (in non HRM) and less gain

As the non-HRM Level or Ratio pot is much lower yet @ 100k - I'm wondering if I should replace the Level pot (now 1Meg) with a 100K

If it's an HRM you should keep it a 1 meg..in theory..However if you like the tone it gives you and the amp still stays balanced volume wise (which I seriously doubt) w/ 100K knock yourself out..

Hope this helps!!

Tony

[LPSGME]

Thanks Tony,

With the HRM bypassed, it's now basically the 101 non-HRM.

I still see the same kind of waveform distortion as before (which I believe is correct) but the symmetry is now much better.

I ordered this Heyboer Fender output transformer hoping it will add a bit more body to the tone.

I think the real test will be how it sounds when recorded, as that always seems to exposes any tone problems.

[Structo]

Is your amp 50 watt?

[LPSGME]

Is your amp 50 watt?

Yes it was the 50 watt OTS HRM.

After looking at the 101 non HRM schematic that you previously pointed me to (thanks), besides removing the HRM, I also removed the ROCK/JAZZ switch (as shown) - leading me to discover I could get the same sounds by simply turning the tone controls.

The switch now changes V2a resistors between 220/150 and 180/150. The 180/150 being a bit brighter, more rubbery and less spongy than the 220/150.

Some other added toggles shift the PS voltage ratios and alter the Master Vol bright cap.

A pull pot also switches the V2b snubber; and another drops a cap (to ground) on the V2a output (as a treble bleed).

An added relay also lowers the slope from 150 to 100 in OD; and the pre OD trim resistor is low (100K) as well as the OD pre ratio pot resistor (100k or lower).

The tones are presently as good as I have ever gotten, except that it doesn't seem to bloom or feedback - not even with an ES-335 or with all the controls I have available.

I got the new Heyboer Fender transformer today and will try to install it tonight.

[JD0x0]

IMO bloom is 45% amp, 55% player. (the guitar has an influence as well but the players touch is more important IMO)

Try a light touch. My amp always seems more bloomy and feedbacky with a light touch. When i dig in i loose that and the tone is more "rock" sounding

Im not just talking pick attack either. It seems when my fretting hand is more relaxed and just barely resting the string on the fret i get more bloom and sustain than if im a little on edge and i fret just a little harder

[LPSGME]

IMO bloom is 45% amp, 55% player. (the guitar has an influence as well but the players touch is more important IMO)

Try a light touch. My amp always seems more bloomy and feedbacky with a light touch. When i dig in i loose that and the tone is more "rock" sounding

Im not just talking pick attack either. It seems when my fretting hand is more relaxed and just barely resting the string on the fret i get more bloom and sustain than if im a little on edge and i fret just a little harder

Re; Light touch for bloom;
I noticed what you said about how just resting your finger on the string (almost like you hit it muted and then press down) helps and, also, picking lightly helps.

But I only get the most minimal response (hardly none at all) and no where near what I hear on many of the audio posts.

I'm puzzled, as the tone is 100% there; and I have the PI difference of 6v - although I was previously able to vary it externally and noticed little difference.

I can shift my voltages to combinations of:
----- PI ----------- V2 ------------ V1
313/307 ------- 204 ------------194
300/294 ------- 198 ----------- 188
188 179

There was brief time when I could get even my Les Paul to feedback a bit but, then, the voltages were way higher: PI/345; V2/225; V1/215 but the tone was no where near as good as now.

I do get good compression and a nice syrupy rubber quality, and interesting intermodulations - just no bloom or feedback.

I'm using a old RCA (I have many) in V1 and JJ's everywhere else.

[JD0x0]

hmm i'd try some different tubes. All amps are different but i hated my amp with JJ's I had an old used RCA an V2 and like the results but currently use an old GE out of a Princeton. New production Tungsols in V1 and V3, i tried a JJ803s (original tubes were all JJ 12ax7's) I was expecting the JJ to sound better in the PI since it's a long plate but i completely lost my bloom and those swirling harmonics. The amp just didnt seem to want to "sing" anymore so i went back to the tungsol.

IMO tungsols have the best all around tube currently in production. JJ's are now my "test tubes" in amps because of their ruggedness, and I hate their tone so i dont mind risking them in new builds

[Tonegeek]

+1 for trying some other tubes. You can try different trimmer settings on the OD entrance too. Also have you tried a reverse wired speaker cable? Don't laugh, it can help. (There are threads going into deep discussion about this). Layout and wiring may play a part in feedback as well. Look at pix of real Dumbles and route your wiring like that, especially tube wiring. Set your PI trimmer by ear. There is a thread on how to do that. It all adds up.

[LPSGME]

I give some other tubes and a change in the speaker polarity (saw those posts too) a try - and let you know of any change. Thanks.

[LPSGME]

+1 for trying some other tubes. You can try different trimmer settings on the OD entrance too. Also have you tried a reverse wired speaker cable? Don't laugh, it can help. (There are threads going into deep discussion about this). Layout and wiring may play a part in feedback as well. Look at pix of real Dumbles and route your wiring like that, especially tube wiring. Set your PI trimmer by ear. There is a thread on how to do that. It all adds up.

Guess what... reversing the speaker wire polarity worked. I didn't get a lot of feedback, but definitely got some.

To make sure, I swapped the wire several times. Each time the reversed wire always produced some feedback whereas the other was just dead.

I also changed the OT replacing the Ceriatone with Mojotone's stock Fender made by Heyboer.

As expected it added body. Now the lower strings had a more solid tone as did the highs. While the lows were much better, I think I preferred the highs from the Ceriatone OT as they were not so 'in your face' sounding.

[greiswig]

There's a thread about OT polarity. Is the amp you're working with a combo, or a head sitting right on the speaker cabinet? Just curious about whether it makes a difference switching polarity if the amp is not acoustically connected to the speaker cabinet.

+1 for trying some other tubes. You can try different trimmer settings on the OD entrance too. Also have you tried a reverse wired speaker cable? Don't laugh, it can help. (There are threads going into deep discussion about this). Layout and wiring may play a part in feedback as well. Look at pix of real Dumbles and route your wiring like that, especially tube wiring. Set your PI trimmer by ear. There is a thread on how to do that. It all adds up.

Guess what... reversing the speaker wire polarity worked. I didn't get a lot of feedback, but definitely got some.

To make sure, I swapped the wire several times. Each time the reversed wire always produced some feedback whereas the other was just dead.

I also changed the OT replacing the Ceriatone with Mojotone's stock Fender made by Heyboer.

As expected it added body. Now the lower strings had a more solid tone as did the highs. While the lows were much better, I think I preferred the highs from the Ceriatone OT as they were not so 'in your face' sounding.

[Structo]

LPSGME

Are you using a Dumbleator with your amp?

I think we agreed that when using the D'lator it reverses the phase of the signal due to the unequal number of stages in amp and loop.
The final stage of the D'lator reverses the phase when compared to an amp without the loop.

So reversing the speaker wires supposedly corrects this phasing issue.

I reversed the speaker wires on my cab and noticed a difference too.

[LPSGME]

LPSGME

Are you using a Dumbleator with your amp?

I think we agreed that when using the D'lator it reverses the phase of the signal due to the unequal number of stages in amp and loop.
The final stage of the D'lator reverses the phase when compared to an amp without the loop.

So reversing the speaker wires supposedly corrects this phasing issue.

I reversed the speaker wires on my cab and noticed a difference too.

I forgot about that.
I'm actually using the parallel/serial mod with a bypass switch.

I don't recall getting any feedback when bypassed, and don't see how the bypass was achieved on any schematic at hand - but I guess however done it would leave the bypass signal non-inverted and opposite the d'lator signal.

[LPSGME]

There's a thread about OT polarity. Is the amp you're working with a combo, or a head sitting right on the speaker cabinet? Just curious about whether it makes a difference switching polarity if the amp is not acoustically connected to the speaker cabinet.

Guess what... reversing the speaker wire polarity worked. I didn't get a lot of feedback, but definitely got some.

To make sure, I swapped the wire several times. Each time the reversed wire always produced some feedback whereas the other was just dead.

The amp is a head and doesn't ever sit on the speaker cab.