Amp Layout?

[Crowbar]

Hello, I have gotten most of the parts for my Tiny Terror build, and started to figure out how to place the different parts in the chassis.

I came up with this layout, preamp tubes to the right, EL84:s to the left. Input on the right end of the tag board, then from right to left preamp - PI - power amp - power supply.

This layout seems to give the shortest and straightest run for the various cables to different places

Does it make sense or am I doing something obviously stupid here?

Thanks in advance

[Crabman]

There are a number of ways to approach the layout. If I was in your shoes I would take a look at the 18 Watt Superlite TMB layout and associated schematic from the download section. It has SS rectification and similar compliment of preamp + power tubes to the tiny terror. You will have to change the layout for pots to suite the tiny terror schematic. What I like about this layout is that the grounding scheme is where it needs to be ... E-caps positioned properly to serve the stage that is being filtered. The preamp grounds go to the input jack and power amp ground over to the PT. This should go a long way to help avoid ground loops.

[Crowbar]

There are a number of ways to approach the layout. If I was in your shoes I would take a look at the 18 Watt Superlite TMB layout and associated schematic from the download section. It has SS rectification and similar compliment of preamp + power tubes to the tiny terror. You will have to change the layout for pots to suite the tiny terror schematic. What I like about this layout is that the grounding scheme is where it needs to be ... E-caps positioned properly to serve the stage that is being filtered. The preamp grounds go to the input jack and power amp ground over to the PT. This should go a long way to help avoid ground loops.

Thanks, thats good information, and the layout for the Superlite was also enlightening.

I was planning to have all power supply filter caps in the same spot, close to the power transformer. Are there any drawbacks doing so compared to putting them close to each stage like the Superlite?

[Crabman]

I have never done it that way, but there are examples, especially in vintage designs that group all the filter capacitors together at one end of the chassis near the power supply.

If you go to Merlins website (ValveWizard) and scroll down to Grounding and Grounding Schemes, you can download the grounding section from his latest book there. Go to page 308 (11/16 in the doc) and look at the second paragraph regarding signal currents. He describes what to do if you group all the capacitors “vintage style” like what you are proposing. In that case, he suggests running a single ground wire from each stage to the appropriate filter capacitor. This will help to isolate signal currents flowing around each of the stages.

[Crowbar]

I have never done it that way, but there are examples, especially in vintage designs that group all the filter capacitors together at one end of the chassis near the power supply.

If you go to Merlins website (ValveWizard) and scroll down to Grounding and Grounding Schemes, you can download the grounding section from his latest book there. Go to page 308 (11/16 in the doc) and look at the second paragraph regarding signal currents. He describes what to do if you group all the capacitors “vintage style” like what you are proposing. In that case, he suggests running a single ground wire from each stage to the appropriate filter capacitor. This will help to isolate signal currents flowing around each of the stages.

Thanks a lot, this is very helpful