The Amp Garage

Thanks for the awesome, detailed build and analysis thread. I'm currently doing research for my own tweed deluxe build. I've looked and the Mojotone, Weber, and Stew Mac kits. There are a few others I'm also considering. Boothill Amps, https://boothillamps.com/5e3-kit. I'd have to get the transforme...

Is anyone familiar with Tube Town? This looks very interesting, https://www.tube-town.net/ttstore/tt-ki ... anguage=en

Is anyone familiar with the Weber kit? https://www.tedweber.com/5e3-c-kt/

What would be the best tweed deluxe kit? I've seen a lot of recommendations about the Mojotone kit, but I see there are many others to choose from.

I've read that Matchless addressed the bass issue with the Cobra, King Cobra and Phoenix. I wonder if schematics are available for them?

Any suggestions for upping the gain a bit on the Ef86 channel? I have zero experience with the EF86, but from the Mullard Data sheet it looks possible to increase the gain by increasing the plate current. Need to plot some load lines. The tricky part is setting the screen Voltage. Link: http://www....

I changed the PI input caps to 0.0047uF. I'm still not feeling it. There's still this woofiness about it that just isn't vibing with me. Maybe it's my guitars or cabs? Even when I turn down the gain (volume) on either channel, as it cleans up, it seems bland to me. No chime or sparkle. Here's what I...

LOUDthud wrote: ↑Fri Oct 07, 2022 5:40 pm

Ledvedder5150 wrote: ↑Fri Oct 07, 2022 12:32 pm Do you mean the 220k and 100k at point D?

Yes.

Any suggestions for upping the gain a bit on the Ef86 channel?

To up the gain on Ch-1 there are a couple of things you could do. Try one or both. There is a 10dB attenuator just before the Effects Loop. It is the 220K and 100K resistors to ground connected to point F. Remove the 100K (or change to 1Meg) and short across the 220K. This will increase the signal ...

Increasing the resistance between the OT CT and screen grid HT supply nodes will reduce screen grid voltage and hence anode current. So anode dissipation should come down. So I would put the resistor where I've marked up this drawing? The OT CT comes into point R. Screenshot_20221004_234200_Gallery...

I measured my bias today. Looks like I'm getting 46.5mA, which is 126% dissipation.

Reduce the two caps from the PI to the Master Volume dual pot from 0.1uF to 0.047uF or 0.022uF. On the VTB channel, reduce the cap from "F" to PI pin 7 from 0.047uF to 0.022uF or 0.010uF. F to PI pin 7 is already 0.01uF. The two cap from the PI to the MV were 0.047uf. I reduced them to 0.022uF. It ...

pdf64 wrote: ↑Sun Oct 02, 2022 9:55 pm There you go, try adding a resistor in series with the choke. 330ohm or 470ohm, probably needs to be at least 5W.

Does it matter which side of the choke?

There’s some pretty severe high pass filtering available in both channels. Maybe the issue is you just don’t get on with open loop power amps? Yeah, I'm almost wondering since I've been playing Marshall type amps for so long, that it'll just take a while to get used to this type of circuit. I'm try...

pdf64 wrote: ↑Sun Oct 02, 2022 4:12 pm

Ledvedder5150 wrote: ↑Sun Oct 02, 2022 3:35 pm …
How can I confirm that? …

With a meter set to measure resistance.
One probe at one choke terminal, the other at the other.
Amp deenergised and isolated from the mains.

I'm getting about 160r.