"same amp" but seemingly different???

[guiltless]

I am not a design guru, but I definitely know how to follow a schematic and a layout.

Both of these are a 36 watt version of the marshall 18 watt, but there are some definite differences and I can't tell by looking what those differences will do.

Design 1: Ceriatone http://www.ceriatone.com/images/layo...wCeriatone.jpg

Design 2: Richie Hall design from turret boards .com http://www.turretboards.com/layouts_...6_watt_new.bmp

Aside from the half power switch (which I like) I also see differences in components and layout all over the place.

Does anyone know the difference between these two and what they amount to?

Thanks!

[Tone_Terrific]

Can you post schematics, too?

[guiltless]

Unfortunately no. I am sure they could be had off 18watt.com but I am waiting for my membership to activate.

[elkym]

Just my .02--

I assume some of what you're noticing is differing cap values and resistor values.
A) Some of these values aren't super critical
B) The tonal changes made by said value differences may be tailored for the major differences-- A.K.A with a longer signal path, the points at which treble and bass are dropped or filtered out may be adjusted for by cap and resistor values to retain more of your original signal.
Make sense? (This is mostly a guess based on basic principles)

[Keyser Soze]

What Elkym said.

Just a quick glance, but the most obvious changes are the cathode resistors and cathode bypass caps.

Lower R's tend to produce more gain, while larger C's also can produce more gain but also tend to increase bass content.

But you'll note that one has higher Rs, but also higher Cs, while the other has lower Rs and lower Cs.

The 1.5k/25 uF combo is more typical of Fender amps and the 820/1 uF (actually 0.68 uF) are more typical of Marshalls, but that is not a hard and fast rule.

[andrekp]

As a general rule with 36 watters upgraded from 18 watters, the only necessary differences are bigger trannies, two more tubes, and an extra cathode circuit in the power section. Everything else is just to taste, or maybe to accomodate something.

Additionally, the schematics at 18watt have been tweaked a bit over time. And remember, there was no original 36 watt that this evolved from, so layouts evolved from ideas of how it should be, not variations of what was.

So without looking at all this any deeper, I'd say the differences are just differences in opinion. You might look at the respective 18 watt schematics and see if you note the same differences.

If you are building from scratch, go with the latest info at 18watt.com. But if you are planning to order a Ceriatone, I wouldn't sweat the differences. There are certain layouts that get dissed a little on occassion, but I don't recall seeing Nik's get any grief. And if you are upgrading your 18 watt, just leave everything where it is now and put in the new stuff where it is now.