Once you get the idea, it will all make sense. It is all about seeing it first, then teh letters and numbers will all make sense as you put the peices together. No math here, just theory.

@ Okay, so it’s mostly a matter of developing a frame of reference? Do you have any other resources you could direct me to go along with this? I have dreams of building and a design that lives in my brain and I want to make it happen.

@@DylanWOWilliams Well, my channel is one place, another is to read everything you can find on TDPRI.com, and ampgarage.com. Those two sources have a lot. If you can stand it, ax84.com and 18-watt.com are also a treasure trove of data. The easiest way is to understand the terms used, and to learn to read a schematic. If you can do that, the rest is pretty easy.

Thank you! Cheers!

It is for straightening the leads.

I pushed off that segment because it is a mixed bag. There are so many types, brands, and levels of quality, that you can't really quantify it. That is why I go with the " just choose one " mantra. Ceramics do suck, but they also do have a place. Same goes for Silver Mica caps, very good at some things, but they are prone to failure. I may do a video that is more indepth about why you would choose X over Y, but for now, I want to keep it simple for everyone.

SS amps work a little different. There is no output transformer, and there is never a tube rectifier. As for the power transformer, it is a different type of PT seconday conversion. Instead of high voltage with low current, you go with low voltage, high current. SS amps are fixed voltage amps, Tube amps are fixed current amps. With SS you have to know what voltage you want to supply the transistors, and the current supply of the low voltage secondary HT rail will determine what actual wattage you can push into X load.

In theory, if you were to add the voltages on each half of the center tap, you would have double the voltage. So a 700VCT. PT. would have a 350-0-350 rating and so on. Assuming a center tap was present. I think most vendors go with the VCT. # as opposed to X-0-X because not all transformers have a center tap. You are not obligated to use the center tap either. So it is easier to rate a PT with VCT. It is also very easy to look at that number, divide it by 2, and then multiply it by 1.4.

I'm going to try some 6v6 in it eventually

It could be red plating on the 8-ohm tap because of oscillation, that may be out of the audible hearing range. You often need a scope to sus that out. But if you are biased cold, and using the appropriate tap for the given load, you should not red plate. That is what leads me to believe you may have oscillation. Good catch on realizing what this build is based on too :) This will be an Express / Luke amp hybrid. I start with the bones, and build from there. Obviously the circuit side of things will be different. I am also using a tube rectifier, which an express does not. For me the choice on output transformer is based more on finding an OT that works in several of my amp designs. I have three amps currently that use the 6.6k OT. All very different in nature. It is my way of simplifying my inventory.

@atech9020 ok thanks for the insight. That's very interesting . I'm definitely getting some oscilations from the brite switch. I have a scope but haven't really gotten into using it yet. Yes, I need to probe around with it for sure. The express is famously 'unstable', so I'm not surprised that there's some bugs to work out. It's one hell of an amazing sounding amp, so I should get to fine-tune it. I noticed that the hammond 1750 ORF ot is an inexpensive 6.6k (100 canadian) I used the new red series pacific iron for my build and it was decently priced.

Thank you! I will take the font into consideration :) And I will be doing more of these types of videos and more Building Basics as well.

The first tube stage is a 12ax7 that is ran in parallel. Thank you for the interest and support.

@@atech9020 Ah, that helps explain the wiring. Thanks for the info.

Cliff brand jacks are one, and there are other versions as well. There are also plastic insulators that you can buy to use on metal jacks. I get my jacks from Antique Electronics Supply. Tube Depot has them as well.

⁠@@atech9020this is exactly what I was wondering too. I hate the plastic jacks and love the metal ones. Im going to have to look into those plastic insulators as that would be the solution for me!! Thanks brotha

I did not make that schematic, and it is incorrect in that orientation, so good catch. This is why I warn several times in my videos to NOT just grab any schematic on the web. If you do get one from the web, be sure to do some proofing, and checking of other schematics to ensure things are good.

I run it underneath. I find things look cleaner that way.

I am not a fan of it. I never quite understood the reasoning for it other than it would be easier to solder to than the steel chassis.

The Dale Vishay resistors can be found at Digikey, or at Tube Depot. I get them from Tube Depot. They are rated for 1 watt below a certain temperature, and are advertised as 1/2 watt though. 1/2 watt is more than enough for 90% of the amp though. The only reason to go up in wattage for most parts of the amp is to lower the noise floor. In the case of metal film, the noise floor is considerably lower than carbon film, and extremely low compared to carbon composition.

I am not a fan of CC resistors and therfore do not use them. As I mention in a few video's, there are those that swear on their grandmother's grave that they are god's gift to tone. I have no argument to that belief, and encourage builders to just use what they want to use. Beauty is in the eye of the beholder.

This particular amp is cathode biased, so the grid leak is not exactly part of the bias circuit per-se, such as a fixed bias amp would be. The grid leak is a required part of any tube circuit regardless of function. It serves as the reference for the grid to ground, and acts more or less as a volume control and as a load to the preceeding stage. A voltage is formed around this resistor, and one could call it bias, as it does serve this function to a degree. In the case of a fixed bias stage, the grid leak really only provides a reference point, controls current flow and keeps the bias under control. It cannot be too large, or the bias will " run away " within the tube, and it cannot be too small, or the tube will shut off and no longer conduct. In a cathode biased stage, the difference between ground for the cathode and the grid is what creates the bias. This is in relation to the plate voltage of course. Change the plate voltage, and the bias will shift along with the operating point of the tube. It si all about creating a " window ". There is an area, where this window works best, given the plate voltage you are working with.

Keep in mind the reasoning. It is a hard sell to place a radial, where an axial works best, and to a buyer that wants contemporary parts in their boutique build. I leave you with the knowing that there is a better option, not that you MUST use F&T. I'm not selling anything, so you can use what you please. You take the keys and do as you will.

Thank you!! Far from the best data source here, but it gets your feet wet enough to feel like you can do this. Getting in there and doing it is the important part. The math and other technical stuff comes later, when you are literally trying to split a hair.

There are a LOT of weird rules in the code books. I am not sure the application of that particular code would apply to guitar amps however. It is conceivable, based on what you say, that every Fender, Hiwatt, VOX, and Marshall ( among MANY other brands ) from the beginning of time, to even recently, are illegal to operate and resale. Most all used sub 20awg wire for many parts of the amp. Just based on the context of that last sentance, wire smaller than 20awg could not be sold. Practical application of a code is one thing, but applying it to the letter is another. Thank you for providing a commentary though. I would like to see the references to this code you speak of. Perhaps I am misunderstanding what you meant? I'm open to discussion about it. I just don't see how anything could adhere to this code however. It is easy to imagine an electrical device that has minimal current demand of a wire that is 22awg or smaller, has more than 6" of wire length, and the wire is routed in the chassis in such a way it may as well be part of it.