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[Paolo]

JM - What i meant is that i don't need so much technical detail with suggestions because i probably won't understand it; conversely, i need SOME explanation along with the suggestion of how things will work so i can picture it in my mind. People seem forget i'm an electronics novice.

Anyway, good news and bad news on the reverb front:

Before i spring for a reverb tank (yeah you got it!) i need to know it will work WELL, not just work in the manner it does already (ie badly).  As i said, i have a few other old amps (Carlsbro's) that i suspected had Accutronics tanks, and just .. maybe.. a near enough input impedence tank might be lurking in there.  So i dragged out the Carlsboro Lead 100, and sitting inside was a type 1 Accutronics which is the 2 spring smaller tank. Designed for practice amps, a step down from the 3 spring smaller tank, but still USA Accutronics, so all good.

Well, i tested the input and output impedance  and .... it's virtually IDENTICAL to the Prince amp!! This is exactly what i needed, bacause if this works, i know a 3 spring will be even better. So i hooked it up to the Prince and there is a vast 500% improvement over the original 1 spring tank.  Not super lush but pretty good at lower levels.

Now the bad news. The same undercurrent of overdrive fuzz that was present before was still there when the gain knob was also turned up. (If you are following the gain problem post, you will know that the gain knob only functions as a volume with a strange barely audible fuzz gain in the background when turned up from 8-10 or so.)

Basically, i think i will be only be able to have gain OR reverb. I suspect that the artefact of ghost fuzz in the reverb will still be there when the gain knob problem is solved.  I say this because many years ago the reverb knob on an amp i had back then basically turned into a gain knob overnight.  The guy who fixed the amp back then told me what made that happen but i can't remember what he said, but that it had been an easy fix.  So i think that will be almost a third problem with this amp!

So at least i know that a different tank can be put in this amp and make a dramatic improvement, ableit with caveats at the moment.

As always i look forward to your comments and advice!

Paolo

[phatt]

Hi Paolo,
Well you got lucky,,, now is when you quit and say job well done and don't try to get more gain from that Amplifier.

The Answer to the rest of your O/drive problems/questions is;

***They are called pedals*** winky, hint.

Cheers Phil.

[Paolo]

Hi Phil

Even with a better reverb tank there is still the ghost overdrive going on in the reverb, which increases the more you turn the reverb knob. Besides, i'm only really borrowing that reverb tank from the Carlsbro at the moment. I would need to buy a similar new one.

I call this ghost overdrive because it is only semi there and haunts the sound which should be clear.  To clarify: it sounds like the normal reverb, but it's like someone is playing along with what you play in the backgound on a overdrive pedal where the batteries are dying and it's more fuzzy.  Everyone know that sound!?  C'mon, someone must have had this issue with their reverb in an amp over the years?

Since the Gain knob problem is nearing a solution, i'd rather have gain working than reverb if i had the choice.  Lifes too short for bad reverb!!  The ghost artefact is not there when the amp is just clean.

The real problem with this amp i suspect lies with that ghost overdrive, as that is also present underneath the crunchy overdrive i'm getting now from the gain knob. As the good overdrive is fading the ghost overdive/fuzz is still there.

For now i'm going to leave the reverb problem as is, until the Gain problem is completely solved, then hopefully the ghost overdrive might disapear from the reverb/ or be a seperate issue to solve.

Thanks to everyone who has been helping and commenting.  I'll update this post when any new deveolpments occur.  Please still feel free to comment though, if you have any advice on the above.

Paolo

[phatt]

No the ghost problem will NEVER dissaper,,, read my original comment.
The circuit that drives that tank is INCAPABLE of driving the reverb clean.

Adding more gain before (which you are doing by jumping the 470 R thinking you are fixing the gain,, other thread)  Just makes the Rev result worse.

You are in a no win situation..

So Still I say,,, Quit while you are ahead!

If you want more drive then forget the reverb and use a Rev pedal.

If you want a huge Twin Reverb sound,,, Buy one.
Phil.

[Paolo]

If the ghost overdrive in the reverb depends on the gain stage, then if the gain stage problem is fixed it seems to me that the the reverb is also likely to be fixed.  It happened in another amp i had and it WAS fixed. If it doesn't, then so be it, but i'd rather look on the bright side! 

As the ghost overdrive artefact is also present under the regular overdrive, it is a problem that needs to be fixed, as the amp would not have been made to sound like that originally. It is a problem that can be fixed by someone who knows what makes the ghost overdrive happen.

I have several reverb pedals, such as the EHX Holy Grail and Boss Fender 63 reverb.  The holy grail is too dark, and the boss is a one trick pony and sucks tone while it's engaged! You can't get a Fender amp accutronics tone from either. The reverb pedal i have used for years is a cheap Behringer DR100. The 'Spring reverb' setting on it is terrible but the 'Hall' setting on low is very similar to the reverb in my Fender Princeton.  The 'Room' reverb setting is what i use most because it sounds like you are playing a fender spring reverb amp in a small room, which in the house is perfect. so you get the best of both, with no tone suck on or off. The whole pedal is only useful on a low level setting though. 

I was deliberating about the Digitech Hardwire RV-7, which has the same sort of features as the behringer but is a superior quality pedal. On demos on youtube (like from proguitarshop), the spring reverb sounded great but i wasn't sure about the room setting, which is what i'd use mainly.  I'll have to try it in real life.
At some point in the future i will probably look into building a reverb unit from your schematic Phil.

Paolo

[phatt]

OK,
    Your Amp Not mine so as you wish.
Be aware that even if the input gain issue is improved the ghosting effect maybe due to the Reverb driver setup so even if god fixes the input section the rev drive can't reproduce the signal and my guess is that part is causing the issue.
Lets hope I'm wrong. wink.

There is also the possibility the power amp section may have trouble with big signal swings.
If they are not biased well they can often produce wonky sound like you mentioned.
Small amps like yours often run very basic power amp stages and a lot struggle with big sounds.
Again the hotter you make the input gain the worse it gets.
Phil.