Hi Dogbox,
               Arrh obviously you're an aussie? :tu:
Yes the big pineapple is down the road from me.
Sadly the tourist trade has suffered in recent years and it's now all sold an no longer running as a resort.

Re the the tone box;
In a word no on both counts.

These Valve type tone controls are *High impedence* circuits which suck the life out of any voltage gain and with no Active component to recoup the loss,, it's a dead end street.

A 1 Volt signal in can be reduced to about 300 mV,, that's on a good day.
The loss can be worse if it's not looking into a very high impedence.
You can lose heaps of Bass this way and you end up with tone controls that only sorta kinda work.

My tone box was designed with the idea of just delivering Real tone control that is lacking in a lot of Amps. (yes even some Valve ones)

Re running the PhAbbTone direct into LM3886;

Having just returned from the shed after testing the PhAbbTone circuit straight into my little LM3886 sub woofer,,, You will likely need another stage.

Check my preamp circuit for LM3886 I brewed,, you will likely have to turn down the gain if you desire super clean or just add a trim pot for gain adjustment.
(look at how the volume/gain/trim pot is used on the PhAbb circuit for ideas)


Re Your idea of Clean;

Be very aware that everyones idea of clean can be quite different.
Some folks would be quite supprised to learn that Hank Marvin's Sound had some distortion happening to the signal,, even though you might consider that sound pure clean tone,, It's Not.

Some rattlin adds a certain about of body/depth to the sonic signature which is why a lot of early SS Guitar amp where a flop because they just refused to breakup at all.
Ultra HiFi Clean can be very unimpressive and boring to play.
That said I'm sure some like it.

Anyway keep reading and suck up as much as you can.
A bread board and some components will soon get you in some understanding of how it all comes together.
Have fun,, Phil.

Hi ,, I just posted some circuits here;
http://www.ssguitar.com/index.php?topic=1672.msg11002;topicseen#new

Might give some ideas to work with.
Phil.

Hi JMF,
         Well for the moment it works great for whatever reason.


I've read more than once where the LM3886 chip will clip hard and is apparently to be avoided but this just sounds gloreous when it distorts/compresses. (Ideal sound for the blues freaks)

My simulations tell me the signal from the preamp I built is bigger than needed but that is controlled via the Volume pot anyway. The harder you drive the volume the more it compresses, not as good as a tube amp but still very touch responsive,, ver-rhy Nice.

I wanted to be able to use it as a stand alone amp hence the simple 2 knob circuit.
Makes for a convenint little rig to pick up and go Jam.

The 150mm (or 6 inch,,, for you yankies, wink) speaker is not great in the SPL department but somehow this works well for my needs.
Remember it's the tone you want not so much the raw power.
Raw power is easy to get but IMHO a lot of them lack any real tone mojo.

Anyway I've added an extention spk socket to drive an external Spk box when needed and then it really starts to get LOUD.

I've got at my disposal;
2x 12" Eminance Legands in one box (loud but harsh).
A single 12" Fane in another (killer tone, just a little sharp)
Then 2 x 12" Peavey Black widows in an other box (about the loudest SPL on the planet, but useless for guitar)

And my trusty 15" in a sealed box (Devine tone, well balanced)
This one is a cheap Dia-achi (never can remember how to spell it but made in the SE Asia)

Anyway enough talk here are the schematics.
In time I will retrace the pwr chip (Again to be sure) and all the surrounding components then post my findings for better minds that maybe able to establish why it works so well.

The PreAmp schematic is very quite but
***don't delete the 1k R after the first stage as it will go crazy and squeal with to much treble.***

The tone pot should be 250k *Linier* and the Volume Pot 50k *Log* for best results.

The overall sound (using the internal 150mm driver) is just a touch bassy so I tested it in another box with no back and it lost something,,,
so sealed back is the better option.
Bare in mind I have no idea as to what is ideal here because this speaker has no name and it's one of those half baked designs that is not quite sure whether it's a woofer of a full range driver.

The local Muso's club metting tomorrow so next week I'll pull it apart (Again) and take some gut shots as I know you are into speakers and you may be able to shed some light.

I will try to get some film of this working but as I've never done the Utube thing it's all new to me and I don't know if the sound on my cheap camera is going to pick up a decent sound.
And understandably I don't wish to make a complete goose of myself doing these things.

Otherwise I'll become known as the Phatt U Goose.
Thanks for the interest.
Cheers, Phil.

Thanks for the input Joe Cool,

Well all very interesting, but rather frustrating for me.
I hate it when something works great but you have no clue as to WHY!
Drives you crazy :duh

I will soon post the preamp and my scratchings of how the Pwr chip is wired up.

I hotwired a Trademark 60 a while back and that uses the LM3886.
It was clean and loud but crap distortion.
I assumed all the comp/dist/OD effect was in the preamp.
(and you can't access the Pre circuitit as it's one big blob of black plastic)
Cheers, Phil.
                 

No that is *only a visual inspection* :trouble
You need a DMM on the Hsink and the other end to CT of PSU
Phil.

Quote from: balaboo on July 06, 2010, 09:50:29 AM
No need to worry - the chip IS bolted directly to the heatsink, which is left UNCONNECTED to any wiring traces on the pcb. I just use regular white lithium grease - works great.

Have you verifyed that the Hsink is indeed *ground isolated* with a Continuity test?
Phil.

Hi mgcasella,
                You may need to clarify the 150Watts? (Headscratch)
If that's what you expect to get from an LM3886T ,,then I have bad news as the best is about 50W @8R.

That said it is a stunning little chip and well suited for guitar in my recent findings.

I'm Having an absolute ball working with this little throw away.

See here:
http://www.ssguitar.com/index.php?topic=1672.0

Contains an LM3886T running from 36-0-36 VDC Rails.

I have not updated the progress as there has been a distinct lack of replies but if you wish I'll post the schematic of PowerAmp circuit and little Preamp I hooked up.

I only wanted to utilise a 2 knob preamp as all my fancy stuff is done via outboard preamps so I only need simple control over the poweramp chip section.

The wacky thing is it does a wonderful compression job of guitar signals  and I'm still looking into why that may be so but for the moment I'm having so much fun playing it I don't wish to pull it apart.

From what I've found so far;
If you want all clean power at 50Watts then don't bother with the LM3886 as it distorts when driven.  which is exactly what I wanted. A cheap little amp that breaks up nice,,,
I'm chuffed. <3)
Cheers Phil.
Edit: I should add it's friggin loud when you plug into a 15 speaker

Hi Skynyrd,
               Re the tone tweaking;
Think long and hard before changing much in the circuit because by the time you find the magic R and C for that tone circuit the tracks will have been destroyed from so much reheating.
No matter how you tweak it that tone circuit is rather mundane no matter how much you wish to change the surrounding values.

What is often missed in the pursuit of greater tone is that the only part that *Cannot be replaced* is the PCB itself.
(parts are easy to find,,Boards are NOT)

You would be far better served by using an outboard circuit for tone.
Tweak a new circuit on a bread board until you are happy, That way no harm comes to the Amp.
A quick simulation tells me what I already knew, that being about 10~14 Db of difference at any freq of interest. (i.e. from 100hZ to 4kHz,,, guitar response worth boosting or cutting)

Read my post for a simple off board tone control that can deliver a 35Db cut at 400hZ.
You will be pleasantly supprised.
http://www.ssguitar.com/index.php?topic=1136.0

I've added my findings of your circuit at full boost and full cut.
My *PhAbbTone* (at full boost) is added for ref.

Mace Trace1 B=0, M=10, T=0  (Green)
Mace trace2 B=10, M=0, T=10  (Yellow)
PhAbbTone   B=10, M=0, T=10  (violet)

Note,
       Passive Tone circuits like these can only actually cut
(no real boosting)
So the only way to make them effective is create the biggest possible cut/difference, especially in the mid bands.

Big shallow dips tend to pull too much out and hence you are always fighting against something,,Tone/verses Signal loss.

You will find that pulling a deep notch in the mid band delivers the best possible result.
Delivers a more defined tone alteration with minumal signal loss. 

Having played with gear for many years it eventually dawns on you that you are far better to work *outside of amps,, not in them*.

Unless there is something major wrong it's easier to work with external circuits.
you can still use the onboard Tone to do some extra tweaking. :tu:
Have fun,,, Phil.

Hi,
   Maybe Read up on *Log and Linear* pots and learn how they can alter the percieved power.

If both amplifiers can deliver the same wattage then it may simply be a different pot used for Volume control and I doubt there is anything wrong.
This is a common quirk with different gear.
Phil.

Hi Enzo,
          Yep I see that,, Until I see that the *Spk Neg* terminates at the Switching terminal *Inside the HP socket*,
**Not directly to R34**.
That is why the head scratch.
Consider What's going to happen if that sw inside HP socket goes open???

The wire obviously goes to a Sw inside the socket (although it may not be mechanically used as a switch).
Those terminals inside those cheap plastic sockets are dodgy to say the least,,, I'm sure you are familiar with the questionable reliability of them?

In my understanding if the FB is lost (open cir) then
Bang = dead chip.
Phil.

Hi CharlieF,
               I'd say zobel is; R 32,38,39,40 and C25.
But I doubt that is the issue.
My guess is something strange as *JS3* (Headphone socket) lifts the defined imp (R34) *out of circuit*
Also looks like it lifts R31 from loop?
And that does not look right to me. (headscratch?)

Especially since you noted that trouble happens when HP is used
(or not used).
I would be looking into that part at least.

If R34 gets bridged then the current will rise in the power chip.
The HP jack might be at fault.
Sorry I can't be of more help.
Phil.

Hello trialabc,
                   Yep Reverb not as easy as it my seem, especially for the novice.
You may want to consider a seperate unit before onboard units.
Try the "Belton unit" Though I've not heard one in the flesh, I've read good reports.

BYOC make a whole kit based on the Belton digital rev unit.
all the DA stuff is done inside the black box the rest is simple analog circuitry. :tu:

Still not quite as cool as the real spring tank it maybe your best option.
Phil.

Hi Enzo,
           Me not having the benifit of experience like some of you chaps,, I don't see enough gear to make a well considered comment but having repaired a few SS fenders from this era, (as I stated) some seem to have no issue while others are just a few degrees away from self destruction.
IMHO,, it may have been more inteligent (and cost effective) to impliment a second winding for the preamp circuitry.

And yes you do have to have enough talent to know how to connect the secondary otherwise you are just playing with fire.

It's honerable to try and help a friend but plain silly to attempt things you don't fully understand.
I turn away quite a few kids with exotic Amps cause I know darn well that if I make a booboo I have to cough up the repair bill.

The above Performer 1000 was fixed on the understanding that if it went poof my mate was prepaired to loose the amp,, as he did not like it that much anyway.
Cheers Phil.

Quote from: bry melvin on June 25, 2010, 12:39:15 PM

QuoteNo other passive tone circuit I know of can pull the mid notch like HiWatt.

Curious  if that included the on guitar circuit board and tbx  (Eric Clapton signature strat)

I build (or have built) all of my strat type guitars with that circuit

I've never used a HiWatt.

Yes I know that's an "active" guitar setup...just curious of the comparison if someone has tried.

The post about TBX circuit was here,,, you may wish to read it.
http://www.ssguitar.com/index.php?topic=1416.msg8896

I doubt the test pics are still there but if it helps a good friend owned a *Strat Elite* but eventually sold it and went back to stock units.
The only useful trick active circuits can do is the Volume acts as a gain knob which is a nice touch as it allows more distortion control over the passive Volume knob setup.
But then a good pedal may work out more user friendly.
Depends on your style of playing and how you wish to work with the gear you have.

Same chap now uses a stock guitar and a little tone box I invented I very much doubt he would go back to onboard ideas now.:tu:
Phil.

Hi ,
   If we are talking same or similar circuit then This little snip might be helpful?
FWIW I was trying to understand a *Pro 1000* Fender a while back. (Similar circuit)
            (& Edit whoops,,,make that *Performer 1000*) 
The heat stress on these R's and the two following Zeners was just insane.
The Zeners where a first degree burn on the old temp/bias probe digit sensor,,, my Finger.  
Those big R's are only 1mm off the board and the Zeners make contact to the PCB. The wisdom of the design is beyond me. :duh
I notice that some of these circuits use very similar ideas but obviously some don't have problems yet others are just a fire hazard.

From memory I paralelled 2x 470 R 10Watt to replace each 270 R.
(you might have to trial and error a couple of values)

Mounted them off the board on a metal bracket to chassis.
This dropped the heat from both the R's and the Zeners now are only just warm.
The Amp will now at least last a lot longer than it would have.

The Amp BTW was for a friend Who I jam with every couple of weeks so my backyard fix is obviously working. cross my burnt finger and hope it stays that way.
Cheers Phil.