18wt tmb build with no tone controls working

[Curranproducer]

I did post this on the 18 watt forum as well.

OK! Built,powered up and played through my little 18wt TMB. input one is seemingly fine, decent plexi tone(if a little dull), the TMB input has a flat thuddy dull sound overall. the tone controls so not work on the TMB and when I turn down the volume and master volume the sound begins to brighten up. when I 1st fired it up and played though it I had the cathode resistor/cap set reversed with the TMB channel. The tone at that point on the non tone stack input was very nice JCM crunchy crunchy. BUT I switched it to fit the schematic/layout, and i have proofed the wiring twice now, I cannot find out why the tone stack is non-responsive/doing nothing. Could there be a ground I am missing that will snap the tone stack into function? I have a ground bus line going from the pots to the turret board then to the power cap, THEN to master ground. I only have one ground point in the entire amp. could this be my problem?

[Curranproducer]

PIX!

[Curranproducer]

PIX II

[Curranproducer]

PIX III

[Curranproducer]

PIX IV

[Curranproducer]

So I tried a switch on the input jack for klicking between the two pre-amp stages form the input jack. I do not like multiple input jacks, I just wanted a switch. It did not work so that is why the switch magically disappears from the amp pix as it progresses. You will also notice i loaded the turret board backwards and flipped the input from right to left(being a lefty I tent to do these things) anyway I hope some one can see the goof in here since i am not finding it yet

[Littlewyan]

Is the left leg of your middle pot grounded? Can't see very well in the pictures.

[Curranproducer]

yes it is, and I checked for continuity just now as well.

[Littlewyan]

Im struggling to follow your signal path in the pics. I suggest you follow the signal path from start to finish for the TMB channel. Also check voltages on all valves.

[menger66]

You must have drew up your own layout for this, Is there a layout that you used for some guidance? being everthing is backwards it's pretty tough to figure out the signals path, you may want to consider turning everthing around as this layout is making ever wire run way longer than need be, as far a one ground point i see plenty of kits groundng everthing at one point on a powertransformer bolt. myself and most builder don't advise this, is the amp humming? everthing from the PI and PA including there filter caps and pots and inputs should be grounded over by the inputs, the power amp gets grounded back by the PT along with the PT centertaps, I don't know how much help you'll get with this one because the backwards layout ill give it a good looking over though mark

[M Fowler]

Next time you want to build an amp please contact me or post on TAG so we can get you the layout and schematic.

I think this is the second time you built an amp with backwards board.