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I completed two identical builds using the Marshall JTM45 1986 circuit design. This is the same as the regular JTM451987 except #1 the V1 A/B has a shared cathode cap and resistor like the original Bassman and #2 the coupling caps between the inverter and the power stage are .022uf instead of .1uf and #3 input 2 has a 500pf cap. These builds use NOS Classic Tone Transformers, OT is a bassman 2/4/8ohm, the PT is a Marshall 100, Hammond choke, Nichicon power caps, Tungsol AX7s, orange drop coupling caps in one and vishay in the other, one has tunsol EL34, the other is mullard EL34. I am amazed how low the noise floor is on these amps. I believe the grounding scheme was the key. I recommend that you do not wire the volume pots to the PCB ground plane. And make sure there is only one jumper or wire from the pre-amp ground plane to the common ground. Please note my Classic Tone PT requires a full wave bridge rectifier. See the earlier post I made pointing out the correct eyelet for the full wave. Also note the PT has a 50V winding for the grid bias. I used it and changed R29 to 33k to get my grid bias to range -20 to -45V. Both amps are biased to 18W per tube a litter under -30V on the grids. Blue Box Vishay Orange Drops

Train Express 6V6 completed. This build uses Vishay coupling caps, Nichicon power caps, Hamond 372DX PT, Hamond 1760H OT, DIY drilling on a blank JTM chassis. I have the tubes biased for 8.5 Watts. One change on the AAE layout is grid bias uses 50V tab, so R30/R31/P1 changed to 39k/30k/10k. I am still waiting for the second coupling cap on V2 (C5 2200pf), but fired up an playing anyway. Grounding is good and there is no hum. However as I turn it up I am getting a sound like the shower is on - basically white noise and static. No noise with the volume all the way down, so either in V1 A/B or the tone stack. It occurs with or without the input connected. I have checked the pots, by replacing the volume and disconnecting the tone stack ground. I am suspicious of the unused V2B, should I ground the cathode or remove the heater on 5? One other weird thing is when I change my volume on the guitar it is supper scrachy, and changing pickups makes a loud pop. This happened for two different guitars on this amp, and both guitars are fine through other amps. Any idea what this would be? Train Express Completed adsf

Was reading up on some of the discussion on other forums like EL34world on doing BOTH the DC heaters as well as Elevated AC Heaters. It sounds like if you're running both that C41/C42 should be changed to from 4700uF/16V, to 100nF/100V. Copying from there: "Hence, I can think of three options (chime in if you see more): - skip C41 and C42 altogether - (to provide extra filtering) keep C41 and C42, keep the reference to ground, but change values to 100nF @100V - (to provide extra filtering) skip the reference to ground and connect a single axial cap between the positive pad of C41 and the negative pad of C42. Anything in the range of 1000-4700uF@16V should be fine." That's a huge jump down capacitance wise so wanted to verify those numbers are accurate and see if at that point we're still talking Electrolytic Caps or just Film caps since the only 100nF electrolytics i've been able to find are 50V? Would love to keep extra filtering for a smooth a DC voltage as possible, but looking at mouser i'd have to go to 0.47uF /100V as the closest option in 100V electrolytic - would those work? Otherwise it sounds like one of the other options might be preferable? Thanks! Steve