The Amp Garage

Thanks for your reply Ian. The amp seems in many respects to be a forerunner for #183. Very intriguing! Yes, the Dumble had an interesting power supply and pot tapers. They were very similar to a bluesmaster. The PS dropping string is 6K=>15K=>10K and the pot tapers were all 10%. I'm guessing the a...

Dr d wrote: ↑Mon Apr 01, 2024 7:35 am Hi Ian, so i've picked up on the el34s. I'm guessing this might have a high B+. Don't worry if you don't want to answer this one.

Hey Andy,

The B+ is around 460V with the bias at 60% for the HP skyline and the Dumble. Same for the #0183

Dr d wrote: ↑Sun Mar 31, 2024 5:35 pm Thats useful to know, thank you. So where does the 3rd gen build figure?!

If I were to cover the most ground I would take the HP Skyline and 3rd Gen. Totally different amps but do their own thing really well. The 3rd Gen is great for strat cleans and does great ZZ Top with the LP.

Hi Ian, out of curiosity I reversed the choke leads to see what would happen. The amp sounded lifeless after the change with little sustain etc etc. Changed the leads back to the way they were and the amp sounded clearer and the sustain returned. It would seem that by luck I had connected the choke...

Hi again Ian, Yes, I think he probably silk screened the panels. I'm trying to guess what else he might have had available to him other than, say, letraset. So, are the front and back panels essentially preformed (cast?) U section aluminium bought to length? Also, I know you are convince that this ...

Hi Ian, what a fantastic build! You really know what you are doing! I am really impressed by your chassis build. I think the vinyl lettering works really well with this chassis. I take it that HAD silk screened his lettering .....or are you going to tell me that he used a vinyl cutter!!!! Would you...

For a first time build, your best chance of success: - select an amp to build (you chose #0124.. great choice) - Study the layout and schematic until you are pretty familiar with it - Try and find pictures of the amp you are building ( http://www.amparchives.com/folder/2493/ ) - stay as close as pos...

How important is that tatalum cap on the preamp board, I have a 1uf, 25v cap as shown on the "low plate classic" picture? And what is the rating on the Tantalum cap. 25V is more than fine. I think it sees 0.7V If the two wires from the 10K Bias pot go to the board in the 3rd picture what wire goes ...

I would try and stick closer to what HAD used in #0124 regarding part selection. I mentioned previously that he used 6PS and not 716 orange drops. I would strongly suggest you swap them out and use 6PS. I would also change out those 2watt metal oxide power tube grids for 1/2watt carbon film resistor...

All the transformer leads are way long, I can trim the ones I’m not using though right. There are literally hundreds of pics of builds on this site as well as pics of actual Dumbles that show lead dress and trimmed transformer leads. All you need to do is a little work to find them. I'm not trying ...

Let's take a walk around the inside, wires, wires, and more wires...... I have 470R 3 watts coming for the 6L6 tubes, See I do take your advice, I also need to look at the schematics better... Question, can I cut the transformer wires to a more suitable length or leave them, they're like 9" long. D...

That looks amazing!

dbharris wrote: ↑Wed Mar 13, 2024 12:09 pm What wattage are those screen resistors? You may also want to situate them more in front of the socket than over it for a little less heat convection.

I was also looking at those screens too and they look like 1/2W 470R. You definitely want to get something bigger like a 3W or 5W...

Very nice!

ynor wrote: ↑Mon Mar 11, 2024 2:27 pm Is there any significant differences between the two menioned above (TT 1uF 100V or Mallory 1uF 63V)?

That is difficult to answer and the only way to know would be to try both and see which one you like.