[OctavianH]

I will let Mischa answer this one... Just to make sure I am not providing a wrong answer here.

Do not worry, just tell your story. For output stage is clear with 300B but for input, seeing you have 6 sockets I was thinking "why?". Because you could have 3 and adapters and just adjust the bias for the tube type. This is how I do, I have one double triode socket and 2 single triode sockets wired for 6SN7 and 6J5. With adjustable bias I can put whatever there as long as I have an adapter towards 6SN7 or 6J5. Most probably you have an input selector and select 6J5 / 12AU7 / 6922 and do not care about the bias. But I was also wrong saying that "both are novals" because they are but have different pinout so you cannot put them in the same noval socket, you need adapter. Anyway another thing which bothers me is how you use 2 x dual triodes (6922 and 12AU7) or 2 x single triode (6J5) and you do not need a quad of these.

 

[Zachik]

Do not worry, just tell your story. For output stage is clear with 300B but for input, seeing you have 6 sockets I was thinking "why?". Because you could have 3 and adapters and just adjust the bias for the tube type. This is how I do, I have one double triode socket and 2 single triode sockets wired for 6SN7 and 6J5. With adjustable bias I can put whatever there as long as I have an adapter towards 6SN7 or 6J5. Most probably you have an input selector and select 6J5 / 12AU7 / 6922 and do not care about the bias. But I was also wrong saying that "both are novals" because they are but have different pinout so you cannot put them in the same noval socket, you need adapter. Anyway another thing which bothers me is how you use 2 x dual triodes (6922 and 12AU7) or 2 x single triode (6J5) and you do not need a quad of these.

Actually, there is no switch for input tubes.
I will defer to @A2029 to answer these questions, and will continue my story on the other details that are not yet revealed

 

[cdanguyen08]

Today's chapter might be named "Mischa's next strategic mistake"...
After agreeing to 2 topologies (SET / Parafeed) and 2 loads (CCS / Resistor) - Mischa wanted to know which driver tubes do I want to use for driving the 300B power tubes.
"What are my options?" I asked.
So, Mischa told me I could go with 6SN7 (or 2 x 6J5), 2 x 6922, or 2 x 12AU7.
"Why was it a mistake?" you may ask...
I think that would answer your question:



So far, I only tested it with 12AU7 and 6922 drivers. The super busy life of working in a startup........

As implied by the "INPUT" switch - Solar Flare has 2 (RCA) inputs.

What else? hmmm.....
Power tubes! OK, we all know the internet is a fascinating and dangerous place. Case in point: I was searching around to learn more about 300B amps, and came across a couple amps that support both 300B as well as 2A3 tubes. Pinout is the same, but bias and operating points are different. Mischa told me that in order to support both - neither would likely work in its optimal point. Also, Mischa told me 300B tubes can be driven HARD and produce a lot of power (and distortion), or driven gently and produce less power but also less distortion. In fact, according to Mischa, they could sound quite differently depending on how they're driven / biased.
Hmmm........ Challenge or opportunity?
And while we are at it, what other tubes types are pin-compatible? You know... Asking for a friend...
The result:


Say what??? 2A3 tubes and 300B tubes (at 2 different operating points), and 45 tubes??? and 71A as well?
Yes, yes, yes, yes and yes!!!
Each tube type operates at the right bias and operating voltages, so no compromises here.

There is still more to come. I know it is already A LOT, but we are not done yet. More surprises on the front panel AND the back panel to come

This looks familiar hopefully my build is right around the corner.

 

[maxpudding]

This is an amp on steroids.

When can we see what the whole amp looks like? I bet it's a monster. A beautiful monster. Bride of Frankenstein. Bright and hot, like a Solar Flare.

 

[whirlwind]

Today's chapter might be named "Mischa's next strategic mistake"...
After agreeing to 2 topologies (SET / Parafeed) and 2 loads (CCS / Resistor) - Mischa wanted to know which driver tubes do I want to use for driving the 300B power tubes.
"What are my options?" I asked.
So, Mischa told me I could go with 6SN7 (or 2 x 6J5), 2 x 6922, or 2 x 12AU7.
"Why was it a mistake?" you may ask...
I think that would answer your question:



So far, I only tested it with 12AU7 and 6922 drivers. The super busy life of working in a startup........

As implied by the "INPUT" switch - Solar Flare has 2 (RCA) inputs.

What else? hmmm.....
Power tubes! OK, we all know the internet is a fascinating and dangerous place. Case in point: I was searching around to learn more about 300B amps, and came across a couple amps that support both 300B as well as 2A3 tubes. Pinout is the same, but bias and operating points are different. Mischa told me that in order to support both - neither would likely work in its optimal point. Also, Mischa told me 300B tubes can be driven HARD and produce a lot of power (and distortion), or driven gently and produce less power but also less distortion. In fact, according to Mischa, they could sound quite differently depending on how they're driven / biased.
Hmmm........ Challenge or opportunity?
And while we are at it, what other tubes types are pin-compatible? You know... Asking for a friend...
The result:


Say what??? 2A3 tubes and 300B tubes (at 2 different operating points), and 45 tubes??? and 71A as well?
Yes, yes, yes, yes and yes!!!
Each tube type operates at the right bias and operating voltages, so no compromises here.

There is still more to come. I know it is already A LOT, but we are not done yet. More surprises on the front panel AND the back panel to come

Ha....this amp in insane, LOL.

Great idea making it a mono design!

 

[triod750]

The architect wanted this and the engineer built it.

Mischa...?

 

[Zachik]

This is an amp on steroids.

When can we see what the whole amp looks like? I bet it's a monster. A beautiful monster. Bride of Frankenstein. Bright and hot, like a Solar Flare.

Soon! Just a few more surprises left, and then I will share photos of the entire amp. Promise

 

[OctavianH]

Soon! Just a few more surprises left, and then I will share photos of the entire amp. Promise

You work for HBO right? "Just 8 seasons to tell you what happened with the Night King"

 

[Zachik]

You work for HBO right? "Just 8 seasons to tell you what happened with the Night King"

At least I do not kill everyone at the series finale...

 

[Xcalibur255]

One of the most original amplifiers I ever saw. Incredible. But it has manual fixed bias right? Otherwise you would be able to use 12A*7 and 6922 in the same sockets but with an adapter. Both are noval but bias differently. Right?

12AU7, 6922 and 6J5 are all quite close to each other electrically and could comfortable share the same operating point from my understanding even with resistor bias. I'm very interested in the output stage implementation myself. There are two different filament voltages, three different plate voltages and four different bias current requirements here. I thought what Mischa did with my amp, having two bias modes that changed both voltage and current (it's far more common for amps to only change the current and keep the voltage fixed when they have a feature like this), but this is another level of capability here altogether. Especially since we're dealing with DHT and the headaches they bring.

 

[Xcalibur255]

Say what??? 2A3 tubes and 300B tubes (at 2 different operating points), and 45 tubes??? and 71A as well?
Yes, yes, yes, yes and yes!!!
Each tube type operates at the right bias and operating voltages, so no compromises here.

There is still more to come. I know it is already A LOT, but we are not done yet. More surprises on the front panel AND the back panel to come

Including the 71a is pretty rad. I've never heard one and would love to someday. Enjoy this amazing new amp.

 

[Zachik]

Today's episode is all about switches. Kind of...
While designing this amp, at some point Mischa told me this amp is going to look like a cockpit:

So let me shed light on a couple more switches...

This is your typical low/high gain switch. Nothing exciting really.

Did I mention already the amp has preamp output? Well, it does! and you can turn it on/off so you can leave powered speakers connected if you wish:

Now this is more exciting... The ability to bypass the driver tubes and use ONLY output tubes as a 1-stage amp:

At this point, no more secrets or surprises left on the top panel. So here is the top at its full glory

 

[bcowen]

Today's episode is all about switches. Kind of...
While designing this amp, at some point Mischa told me this amp is going to look like a cockpit:

So let me shed light on a couple more switches...

This is your typical low/high gain switch. Nothing exciting really.

Did I mention already the amp has preamp output? Well, it does! and you can turn it on/off so you can leave powered speakers connected if you wish:


Now this is more exciting... The ability to bypass the driver tubes and use ONLY output tubes as a 1-stage amp:


At this point, no more secrets or surprises left on the top panel. So here is the top at its full glory

You're gonna need 6 months of training before you can turn it on the first time.

Note that is intended as a compliment. @UntilThen would need a year.

 

[UntilThen]

You're gonna need 6 months of training before you can turn it on the first time.

Note that is intended as a compliment. @UntilThen would need a year.

Now where do I start?

Shall I take out the fuse first?

 

[bcowen]

Now where do I start?

Shall I take out the fuse first?

Yes, take out the fuse and replace it with a QSA Gold. I think the shipping is free, so obviously a no-brainer.