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So yesterday I posted that the top plate was complete. Today I can say that the new spud amplifier is totally complete and ready for testing.

The wiring on the top plate for the 6EM7 “Bloodwood” Amplifier is essentially complete.

After several false starts, and a couple of minor reshufflings, The power supply side of the new amp is complete. Now it’s time to finish up the actual amp stages and get the top plate on the chassis.

There are a thousand small decisions we make when building a project. Some matter more than others. But anyone who’s built several projects knows that sinking feeling one gets when either you don’t have, or can’t get, a specific component called for by a design.

I was looking at the new power transformer from Edcor for the latest project today. This is the one I talked about in my posts Failings of Memory and Weirdness with Edcor Order. I noticed a change in the new transformer. However this change I consider an upgrade.

I took my time and was very patient. And it paid off in a finish that while not exceptional, is acceptable. I am talking about the top plate for the new amplifier, of course.

I’ve been doing some straightening and rearranging in my office and I’ve decided to thin the heard a little. I have a Superior Instruments TV-11 emission type tube tester that I haven’t looked at in over a decade. Anybody interested?

I took the time to finish the chassis wiring on the spud so that I could focus on the top plate. Now comes the tough part.

I managed to get some time to perform the bulk of the chassis work on the new amp.

Just a quick note on the new project. Ten days ago I posted about how much trouble the wood gave me because of warps and twists in my plank of Bloodwood. Well, today I can say that it was well worth the effort.

Would you be surprised to learn that there is a real difference between volume controls and level controls? Unfortunately today, controls which are really “level” controls routinely get tagged with the label “Volume”. But what’s the difference?

I know that I said I wasn’t going to do a lot of posting about my new project, but this morning’s session is worthy of a quick note.

Those paying attention to my post from May 9th already know I have a new project coming. This one is nothing new or Earth shaking. Just a slight performance upgrade to the 6EM7 Vertical Amp in a more traditional chassis.

Or… maybe not.

The project page for the 6V6 Curly Maple Amplifier is now up and viewable. Take a look and let me know what you think.

As always, questions and comments are welcome.

There was one thing about my Edcor delivery today which surprised me a bit.

Do you ever do a bunch of work on something and then completely forget about it? And it’s only when something else happens that you then remember what you were doing? Well, that’s what happened to me today.

In my last post I discussed what it means to make an amplifier go to 11. But in spite of the issues involved, many amp builders simply can’t help themselves. Even before the first connection is made they start craving more power. However, the truth of the mater is that increasing amplifier power is almost always a fool’s errand. And even the rated power outputs of most commercial amplifiers have nothing to do with listening, and everything to do with marketing.

The year was 1984. The spoof “rockumentary” titled “This Is Spinal Tap” was just released to theaters and it was then that this immortal phrase entered the modern lexicon. I’m referring, of course, to that classic line “These go to 11”.

In the intervening 40 plus years, a million and one jokes have been made about things that go to 11; including amplifiers. As amp builders we would like to know what it takes to make our amp projects go to 11. Unfortunately, the answer is more complicated than you might think.

The TAD 6V6GT-STR “Redbase” Premium tubes showed up and I got them installed in the 6V6 Curly Maple amplifier. I took new voltages and have been listening to the tubes with a variety of music. These tubes are very detailed and musical. They produce a stronger bass than the 6V6Gs and a very even tonality in the ultra linear topology. I would consider these a nice upgrade for any 6V6 amplifier.

Today marks five weeks since I hurt my ankle. And this morning I managed to do my full mile plus morning walk without any issues. My dog was happy about this as well. At 18 years old the definition of “walking it off” after such an injury meant maybe a day. I guess now over 40 years later “walking it off” means five weeks. Who knew?

But I’ve also made a slight deviation with the 6V6 Curly Maple amp.

So I’ve been laying low for the last couple of months and not entirely by my own volition. I finished up the Curly Maple amp on the first of June and have not yet gotten the project page posted. But rest assured, the entire write up on the new amplifier is coming soon.

I haven’t gotten the time to complete the testing on the Curly Maple yet, but I did receive a couple of tubes for which I’ve been waiting so I can try them in the new amp.

While working in my office today I suddenly realized that the music had stopped. Looking at the Source Selector Preamp showed that the output levels were not moving. A little investigating revealed the culprit.

The resistors for which I’ve been waiting to finish the amp showed up in the mail yesterday. Today I got the final resistor installed and did a full check on the amplifier.

I took some time yesterday to finish up the 6V6 Curly Maple assembly. Everything is complete and in place except for the main dropping resistor, Rd.

I had a good bit of time to work this morning and I completed the top plate wiring. The next step is to get it affixed to the chassis.

I carved out some more time to work on the amp today. I managed to get the entire power supply section wired in.

In spite of some other things commanding my time, I’ve finally managed to get started on the wiring for the new amplifier.

Something has come up a couple of times recently and I’d like to quickly address it once and for all.

I took some time this morning, now that the paint is dry on the top plate, to install the mechanical aspects of the amp. The top plate is now fully populated.

While dealing with my other spring chores, I’ve been working to get the finish applied to the amplifier’s top plate. While not perfect, I believe it is acceptable enough for me to proceed.

I keep referring to the new amplifier as the 6V6 “Curly Maple” Amplifier. But is it really?

The chassis has all its coats of oil finish and things started coming together today.

I managed to steal a little time over Easter to do a some work in the shop. The chassis for the new 6V6 “Curly Maple” Amplifier is coming along nicely.

After some delay I have managed to finish all the metal work for the Marblewood Upgrade Amplifier. Hereafter referred to as the 6V6 Curly Maple Amplifier.

Having performed the investigations I wanted on the gain stage on which I was working, I then moved on to another part of the project. And the chaos from a couple of days ago was nothing compared to yesterday.

It seems I’m nothing if not predictable. I’m just really getting going on the assembly of the Marblewood upgrade amplifier and I’m already doing design work for another project. This is in addition to the two other amplifiers which are already in the queue.

I had an opportunity to spend some time on the Marblewood upgrade amplifier. The mechanicals for this project are all coming together nicely.

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After getting some chores out of the way this weekend, I got an opportunity to do some chassis work. The project is proceeding well.

There are some projects which are not big or flashy. Simple little things which are easy to build and fill a tiny but important niche in our audio setups. I call these “popcorn” projects.

We got some unseasonably nice weather here today. Clear blue skies and about 72° outside. This meant I got some time in my shop to move projects forward.

For the last couple of days I’ve been revisiting an idea for a “tone control” preamp. I had originally decided to go one way with the design, but then something happened to change my mind. My ears got involved.

I haven’t talked about the new amp in a while so I thought I’d share current progress.

Yesterday I auditioned some new reissue Tung-Sol 6L6GC STR tubes in the 6L6 “Spalted Alder” amp. I was quite surprised at the results.

I seriously despise cheap interconnects. And I don’t mean inexpensive, I mean cheap.

In my last post I threw in a comment at the end pointing out that lowering plate load resistance will play a part in how the cathode bypass capacitor behaves. Someone asked, so I thought an example of how this affects things might be in order.

There seems to be a little confusion concerning the true effects of cathode bypass on low frequency amplifier performance. The truth is, gain benefits from cathode bypass are limited. And not by capacitor size, but by the basic design of the amplifier stage.

Remember when I said that you can’t always get what you want? Well, it turns out you can. At least in this case. Especially if you are willing to shift some priorities.