Tube Amp Class at the new BH headquarters?

[Natural Sound]

Just wondering if there are any tube amp classes on the horizon. I regret missing all the classes in San Fran. Plus I'm looking for an excuse to prowl around the Seattle area again. My vote goes to building a Stereomour kit.

If the answer is yes I hope we get plenty of advance notice. I need to put in my vacation scheduled days off a few months in advance. The best airfare can be had when booking early as well.

 

[debk]

Are you talking about a class to build a kit as a group or a class in actual design and theory?
I would consider flying into Seattle for a class in design and theory.

Debra

[Natural Sound]

Are you talking about a class to build a kit as a group or a class in actual design and theory?
I would consider flying into Seattle for a class in design and theory.

Debra

The last sessions that were offered were a combination of both. There were lectures on theory and you built your own amp to take home with you.

[debk]

Sound interesting.  Depending on when I may be interested

Deb

[Paul Joppa]

It's been a struggle to "place" the theory part, which I taught the first time (in San Francisco) and - in shortened form - at the last VSAC. Basic design theory is well documented in college textbooks of 50-60 years ago, but not everybody has a degree in obsolete engineering methods (!) so there is a need to cover those basics, at least the part that applies to amplifiers and power supplies. The first time I skimmed over that part too fast, and it was too much too fast. On the other hand, the DIY community has learned a lot that was never in those old textbooks, so we do want to cover some of that.

Any thoughts about what would make a good curriculum, and how much time to devote to it, would be welcome. In particular, what prior knowledge might potential attendees have, that we could count on?

[RayP]

Did you ever consider making a video and selling it as a DVD or a download? I realize it wouldn't be easy, but you would reach an audience that can't make it to Seattle.

Perhaps you could approach your local Olympic College that appears to have an Integrated Multimedia program. Talk to the faculty for that program about having the students work on your video as an innovative assignment and they may jump at the idea. You might even get the students interested in great sound and buying / building amplifier kits.

Having worked for a community college for years, I know that educational links with local businesses are very important and it really helps at accreditation time if the college can show examples of such links.

ray

[Doc B.]

I think all of these ideas get discussed pretty much on a yearly basis. Here's my take on it:

The most practical application of this kind of class is hands on, to teach assembly skills. This may seem like the more mundane aspect of DIY to many, but it is where most problems occur. IME it would be an area where I could offer the greatest contribution. You can't teach it effectively by video. I need to be able to take the pliers out of your hand and show you how you need to apply just this much more twist on a lead, keep the iron on this exact spot a little bit longer, or hook up your particular meter this way.

Teaching theory sounds great - in theory. In practice everyone is at a different level, and it becomes difficult to put together a class with enough students of the same knowledge level. I think the theory classes would be most effective if limited to very narrow aspects of design. This makes them perhaps the ideal subject for a series of videos. My business side says I would never make enough money off of them to justify an investment in hiring a crew, but perhaps as a college project it could be done.

I like the idea of a Stereomour construction class. Based upon previous classes I think the best approach would be three days, with 5-6 hours devoted to construction and maybe an hour of theory focused on the Stereomour design each day. For free I would throw in lessons on pulling a good shot on a lever espresso machine and how to make your own infused gin.

The other issue that always comes up is timing. It would be very helpful if those who are interested in attending could offer up what time of year would be most convenient. Figure a Thursday thru Saturday or Friday thru Sunday kind of thing. I think we would need a minimum of 6 students to make this happen and we could probably accommodate a dozen. Not sure about pricing, I will take a look at our overhead and crunch some numbers.

[Natural Sound]

Excellent ideas folks. Here is something else to chew on. Assign a prerequisite textbook reading on certain topics that apply to bottlehead products. If there are certain areas that need further clarification those questions will be submitted to Doc B in advance of the training. Then Doc, PJ or whoever can go over the material in question. I have been monkeying around with electronics since the seventies but I have some questions that I'd love to be answered by someone who knows. Textbooks are great but nothing beats having an instructor to bounce questions off of. For example, tube operating points are a complete mystery to me. Power supply design and component selection is another one of my week areas. Why are constant current loads better than other loading methods such as resistors or chokes? What is shunt regulation and why do we need it? Etc. 

Amp construction would be fun although I would get a little less out of that. But thats only because I'm more experienced at kit building, repair and DIY. I'm sure there will be others that will get a lot out of it. I'd even be willing to help others out with construction if Doc gets busy.

If we do a little more than one hour per day on theory and Q&A, three days probably wouldn't be enough. Four would be better. That would be my preference. My questions alone will take half a day.... just kidding. ;-)

As far as timing, any day works for me as long as I get enough time to submit my vacation request, get approval and find backfill for when I'm gone. Other than that I'm very flexible time-wise.

[debk]

I agree with Natural Sound, and understand where Doc B, and Paul are coming from.
Personally, I would not get much from a building class, for I have been building kits since I was a teenager in the 70's.  Though I would enjoy helping other build their kits.
I am more interested in learning how to design an amp from the bottom up.  I am trying to slowly work up to that now.  I never had any instruction on valves when I was an undergraduate EE major. My degree dates back to 1980, and I never really worked as an engineer.  Ideally I would like to take a  2- 4 day course which includes theory, design and "homework problems" to do .  I know it is not practical especially with the vast differences in potential attendees backgrounds.  But it sure would be a treat to learn from Doc B and Paul.
I have already learned a great deal from studying the schematics, and documentation of the kits I have built.

Deb

[Grainger49]

The course could be laid out as a lab course.  The basics need covering on the first day.  That would include Ohm's law, the formulas for power, conversions to find power, current, voltage and resistance for elements.

Then there are the AC and DC analysis of the circuit.  With a capacitor bypass of the cathode resistor the cathode is grounded for the AC analysis of the circuit but the cathode is not grounded for the DC analysis of the circuit.

There would need to be an explanation of reactance in AC circuits.

On the first afternoon once these things have been discussed in the lab measurements can show how they interact.  Or the students can consume home made Gin, but not both.

The second two days would get into the actual design parameters for triodes and maybe pentodes.  Again an afternoon lab can show varying resistances results on triodes.  Visually things can sink in.

Some of Bottleheads more sophisticated design features that bring out the best of the kits could be discussed on the third day.  The SR boards, the C4S boards designs can be discussed.  Then add biasing a heater, grid and plate stoppers and transformer specifications could be covered.  The lab could show the results of changing the set resistor on a C4S board and/or SR board.

[Yoder]

It appears that people are coming in from all directions with different needs and experiences. Why not have a 3-day Level I course with some theory and a lab, and then a Level II and maybe a Level III course where more advanced theory with labs could be taught? Personally, I would love some heavy theory as well as a lab to apply what was taught.

It would make a great vacation to fly in for some training during the summer. For those of us out-of-towners, a Level I course F, S, Sn  or S, Sn, M the first week and then the Level II course Th, F, S or F, S, Sn the following week would be economically feasible. Have Iron, Will Travel!

@Joppa: Here are some of the 50-60 year old text books on vacuum tubes that you mentioned. This is the definitive site for downloading old text book--all books are free. http://www.pmillett.com/tubebooks/technical_books_online.htm

[Doc B.]

I do agree that we are probably talking about two or perhaps three different levels. And I imagine that the more introductory classes would be the ones for the most hands on soldering, the most advanced class having perhaps the least. For example a most basic class might be where one builds a Quickie in a couple/three hours and then spends maybe a couple hours on ohm's law, making measurements, basic tube theory, etc. Maybe in the most advanced class we just have a demo amp that is modified in class by the group, based upon a design developed in a few theory sessions that cover load lines, power supply design, layout considerations, etc., etc. The amp could be compared against a second version that follows "one mod behind it" as each modification is installed, to demonstrate what the modification does to the sonics. Between those two extremes might be an intermediate class along the lines of what we started talking about, building a Stereomour and discussing the specific design aspects of that circuit.

Please offer up any thoughts as I really want to tailor these classes to the student's perceived needs.

[Yoder]

Assuming we go with 3 classes and using what you suggested:

BH I: DIY Fundamentals
Obj: To provide the noob with the fundamental skills needed to construct a BH kit, and give experienced builders an overview of the BH build philosophy.

Content: safety fundamentals to include cap discharge, proper handling of components (ie, IC's), soldering, wire fundamentals and braiding, proper grounding of shielded cables (?), resistance, Ohm's Law, diodes, transistors, and beginning schematics. Lab

BH II: Tube Theory and Circuit Design
Obj: Provide the experienced builder with the theory behind vacuum tubes and the creation of audio circuits.
Content: types of tubes and their properties (power vs output, why choose this vs that), loads, power supplies, transformers, layouts, diodes, capacitor theory (how determine what caps you can use in an existing circuit), and intermediate schematics. Lab

BH III: Advanced Tube Theory and Circuit Design
Obj: Learn the fundamentals of audio tube circuit design, so that the experienced builder can both modify existing and/or create unique audio circuits.
Lab: should be able to propose/design a simple problem/desired effect, identify components, should be able to ask what tubes will do what and/or what caps will do what in the circuit, and go from design to product. (Obviously, this is out of my area of expertise and am at a loss for terms/ideas.) Lab.

An idea for the BH III Lab is to take the existing "Noisy Cricket" guitar audio amp and convert it to a tube amp. Here is the diagram for the NC http://beavisaudio.com/projects/NoisyCricket/MarkII/NoisyCricketMarkII_RadioShack_Rev2.pdf Here is a tube version of NC http://www.olcircuits.com/olc_tubecricket.html Or do something similar.


 

[fullheadofnothing]

Sorry for the major bump from the past. Has there been any more talk about classes that I've missed? My wife wants to visit some of her family in Poulsbo this summer and I'm hoping to at least get a swing by of BH-HQ, but a class would be super amazing. We haven't nailed down dates yet. Any chance anyone else is on a similar page?

-Josh