mwl168

...wearing your pajama.

Thanks! I posted about this "universal" PSU in the Carbon thread I think. It's a GRHV tuned for 400VDC rails and a GRLV tuned for 18VDC rails. It also has 2 sets of 6.3vac/4A secondaries from the Antek AS3T325 transformer (300VA, 325v/450mA x 2 and 6.3v/4A x 2). I put a switch and thermistors on the 325v secondaries to function as a manual B+ delay. I originally had one resistor in series with each of the two 6.3vac secondaries to lower the filament supply to the EL34 but have removed them a few weeks ago when I realized I was already losing a few 10th of volts between the tranny and the amp board. I bought a 7-pin female chassis socket I intend to replace the male one I am using now but have not gotten around to do it. I don't have small children in the house to worry about but I have been known to do stupid things that only 5 years old would do (according to my wife).

A few more pics of the Grounded Grid with the top cover on, including a side-by-side with the Blue Hawaii built using the same chassis. Got a set of tube socket rings coming. Will decide if to use them when I have them in hand. Drilled a few more holes on both the top and bottom plate of the Blue Hawaii to help ventilation inside the chassis and hope it'll run cooler. Will likely do the same for the GG.

Not familiar with the circuit and the board you are using. But if it's like other KG ES amps, you need to disable the offset servo when you adjust the offset trim pot then enable the servo afterwards.

Thanks! the chassis is BZ3608A I purchased from TaoBao. Also available on eBay. It should fit the Megatron fine except you don't need heatsinks for the Megatron.

Another Grounded Grid lives. Have been listening to it for about a week. Powered by the same GRHV/GRLV PSU I use to power my KGSSHV, Carbon and Blue Hawaii. 400VDC rails and 20mA plate current. Using EH 6CA7 - the true beam tetrode not pentode. Runs much cooler than the Blue Hawaii. A tough job remains to drill the holes on the top plate. This is one fine sounding amp!

Very neatly done modification. I had to look up the original T1 photos to spot the modification

All international-destined packages have been sent too. I'll PM each with the postage. Happy building!

You would want your trafo to be capable of delivering more than 120mA current per rail. I would personally spec at least 250mA per rail for Megatron use. I am sure there are others that would prefer going much higher. Also, base on my own experience, 20V drop across the regulator may not be sufficient for 450V regulated output under load.

All packages with US shipping address have been posted to USPS Priority Mail. Please PayPal me $7.2 US for the postage. Overseas packages will be posted next week. I'll PM each with the postage as it will be based on destination and weight.

If the valves are lit but do not heat up, I wonder if the filament supply is on but not the high voltage supply? I am not familiar with the BHSE, does it have separate fuse for the high voltage supply?

What's the small board with the terminal blocks for?

On my builds, the Blue Hawaii draws just over 80mA on the positive rail but close to 150mA on the negative rail. The Caron draws around 100mA on both rails. I use the same PSU for Carbon, KGSSHV and Blue Hawaii and will be for the GG as well. The 5.1R current limiter is good for about 120mA and works fine for the Carbon but not for the negative rail of the Blue Hawaii. I paralleled a 15R with the 5.1R on the negative rail to get about 3.8R to support the Blue Hawaii. I have not completed my GG build so don't know what the current draw is. Maybe someone will chime in.

The GRHV boards arrived today. The boards look good! As promised, here is a quick photo. Will be packing and start shipping next week.

The amp boards were delivered tonight. Too late for me to take photos but the board is nice and heavy as can be expected given the 4oz copper. The GRHV boards are supposed to arrive tomorrow. Will take some photos if I get home in time. By the way, please PM me your shipping address if you did not include it in PM or PayPal note to me. Thanks!