The Amp Garage

M Fowler wrote: ↑Wed Mar 13, 2019 5:03 pm Glad to here your loving it.

I was just at my local Guitar and amp show last Sunday and we rocked out all day.

Mark,

How did the local respond to your wall of doom?

Are people requesting to buy those at the show?

The Hot Rod 50 is complete with all of the features working correctly.

What a fun amp to play!!

Thanks Mark

M Fowler wrote: ↑Sun Mar 03, 2019 2:11 am I would just reflow the solder joints for V6 and see if that helps.

Mark,

I'll try that and do the same to the components in line.

I would think I should be getting the same voltage as the other leg of the PI.

Cool amp, thanks for the puzzle

What kind of meter? Try another meter. Cycling from OL to low mV is not a characteristic of an amp that is stable and sounds good unless you are Neil or Eddie. My meter is a newer Klein, I'll try another meter and make a video. Thank you Here is a quick video mstsMP-mrMw Mod Edit: Fixed youtube link

sluckey wrote: ↑Sat Mar 02, 2019 10:57 pm What kind of meter? Try another meter. Cycling from OL to low mV is not a characteristic of an amp that is stable and sounds good unless you are Neil or Eddie.

My meter is a newer Klein, I'll try another meter and make a video. Thank you

Which schematic are you working from? Is V4 a LTP PI? If so, does pin 6 settle down if you disconnect the NFB loop? I disconnected the NFB and re-measured the voltage at V4-6 and it is still jumping around. It cycles from OL to a low mV value to a low voltage value. The amp is stable and sounds goo...

Yes for Switchcraft type jack it's wired together (12A) type. See 2nd attachment below. Here is the preamp schematic, power amp schematic is normal 2204 or 2203 Marshall. Mark Darkbluemurder high gain amp.gif DBM #39 layout W loop.jpg Thanks for the Switchcraft layout advice. I ended up doing that ...

Update I switched out the FX Jacks to 12A's. I tied the shunt to the tip and then connected the tips together to complete the circuit. Wowza!! Hello Kitty. It's getting really good now. I also found a bad ground connection on the MV pot going to the buss, got that connected and the MV works great. ...

Start Up Notes and Question I am up and running without an event, if you know what I mean. The amp is playing ok but it is thin and the MV is not working. Question 1 : On Marks layout he is showing the FX loop Send and Receive jack tied together with a positive leg and also the ground. I am using S...

sluckey wrote: ↑Thu Feb 28, 2019 5:30 am You would be OK even with a 15V cap. There's only a couple volts on that cathode cap.

Thanks Steve! Stay tuned for the Dual 50 project

I have a bag of 250 blue metalized polyester film caps .68uf/250v and I also buy smaller yellow .68uf/100v caps that look like those large Sozo caps. Can't remember where I got those smaller yellow .68uf caps from. Left me know if you need some of those blue film caps. Mark Question : Why would I b...

Does anyone have a better source for .68 Caps? The smallest ones that I found were big. I think I bought them from Antique Electronics. Hoffman has a small one... .68uf/250v 684 250 volt Panasonic Polyester film capacitor - cathode bypass cap 16.8mm wide x 5.39mm tall x 5.3mm thick Price each = $1....

Progress Update Starting to look like an amplifier! I need to study the guidelines for polarity so I can get my Sozo caps aligned correctly. Missing a few parts but it is coming together well. Does anyone have a better source for .68 Caps? The smallest ones that I found were big. I think I bought t...

There are a lot of new caps out there that are physically much smaller with same value. I flat out bothched my first board by being lazy. I laid out anothe board properly with all of the correct filter caps and the board came to 17", I haven't pulled the trigger on that board yet. I am using a JTM ...

I botched my board by freehanding the layout without having the Filter caps in hand. I am having a new board built by Hoffman and I am taking off the 3-20 uF and 47 uF/500 Caps and replacing them with an interior mounted multi cap. I'll have to do my own Visio drawing to make sure I wire it correctl...