The Amp Garage

Looking at the power supply in Aaron's schematic. I notice several of the Bassman models do have the extra filter cap. I am curious where he came up with the dropping resistors. CW Hi Charlie, Sorry to all for not reposting a revised schematic with the 475k resistors. As Dustin said at the start, i...

Aaron, Do you have any other photos of the Bandmaster? Front or side? Would love to make a project of it! Unfortunately not. Only this pic, I remember looking at it and thinking there’s a fair few parts that HAD used in the 70’s, notably in the Winterland #003. And cause of the snakeskin tolex I th...

Was organising the computer and found this picture I had saved from somewhere. Looks like it could have been modded by Dumble in the mid 70's? There's a lot of parts and where they are used that looks like it might have been.
I don't think the added reverb is his work though.

Thanks,
Aaron

redshark wrote: ↑Sun Jul 05, 2020 9:53 pm Yes. I remember that amp. I did a recap on it. Those blue Spragues is the serviced I did. The original orange Sprague filter caps had bubbles. I have a file full of the pictures of that amp.

I’d be keen for some voltage readings.

Thanks,
Aaron

Hi Rootz,

I didn't describe it very well. In the pic you posted, its the earth lug between the tube socket and rectifier board. Must be all good if its working
I have a set of these transformers as well. But my power transformer looks bigger what's the part number on yours?

Thanks,
Aaron

Nice build!

Looks like there's a black wire not soldered between the power supply board and output tube socket?

Thanks,
Aaron

dreric wrote: ↑Fri Jun 05, 2020 2:44 am I got my boards this week! Very nice quality. Well done!

Thinking about making a beast with a transformer set from a 1970's Fender PS 160 (2 - 6550s)

Hi Dreric,

I built an amp with that set. It sounds as much as it weighs!

Thanks,
Aaron

The sketch says OD-150W, s/n: #012. Is that a typo in your post? I think the "Dumble OD-150W, s/n:#012" was written by someone else for their own records. The letters are different to the ones in the block diagram. I'm no CSI so don't quote me. They might have left it out accidentally? It's from th...

Hi Aaron Sound wise- What are your thoughts?? Loud yes- but to my ears pretty musical sounding OT? Markus Im a big fan of the Hammond Transformers. They're nice and big and have a lot of weight in them. I use them in most of my builds. My VOX is the Treble model, so cuts through great and has that ...

This is the block diagram for ODS #121 which might be of some use to you.

Aaron

Hi Steve and Marcus, Just so happened that I installed a Hammond replacement yesterday. And its back! I'd forgotten how loud it was. It wasn't as direct a replacement as they claim, in mine the original lays on the side and the mounting bolts are in the middle. And the cover plate bolts that attach ...

So,update. User error it was inverted. It’s a push pull switch and a lead must have got caught and pulled it out. The Marshall I worked on earlier scoped fine.

Sad news though, thanks to Beasley helping me to diagnose it, output transformer had gone bad.

Aaron

I bought my Vox about 20 years ago and it sounded great, plenty of volume. But after a while it sounded like it was getting quieter. Wasn't noticeable but then it got to the point where I was cranking the volume 3/4's. So it sat in my room for about 15 years, rarely played. Fast forward to 2020 lock...

Funny thing, when I was typing it I originally wrote overdrives! And agree with Fuzz Faces, always sounded raspy. To me anyway.
Although, the Pentode amp is AB2 and it sounds great!

Aaron

I should note, my builds have been slightly modded. The only way they resemble the circuit is the PI/Driver section. :D Both amps have the Tone Filter circuit. "Odyssey" inspired build is running a pair of KT88's with 700 volts on the plates and UL output transformer. And reverb. "Winterland" inspir...