Mr. Lion's DIY Thread

[OctavianH]

In fact, the EL86 is pretty good as well. Although, I listen at reasonable levels and mainly small acoustic ensembles or solo instruments, so rarely need big loud boom boom power.

Next step for you in OTL is 12E1 in dual adapter to 6AS7. I bet it would be fun.

Judging by the prices and availability of 5998 or 421A I quess if the ensemble is small enough, hiring it to sing at your window might be a cheaper alternative.

 

[LobalWarming]

Next step for you in OTL is 12E1 in dual adapter to 6AS7. I bet it would be fun.

Judging by the prices and availability of 5998 or 421A I quess if the ensemble is small enough, hiring it to sing at your window might be a cheaper alternative.

12E1 x2 is over my current comfort zone. Over 3As for a tube that probably doesn't sound as good as pair of thrifty current-sipping EL86s. Which I've read on a special thread on the internet are among the very best output tubes.

 

[OctavianH]

Which I've read on a special thread on the internet are among the very best output tubes.

That guy on that thread is crazy, we all know the best output tubes are 300B. He buys tubes with 5 EUR / piece and tells us are better, we all know it is impossible.

 

[LobalWarming]

That guy on that thread is crazy, we all know the best output tubes are 300B. He buys tubes with 5 EUR / piece and tells us are better, we all know it is impossible.

Crazy... like a fox.

 

[g0ldl10n]

Today I was looking for my soldering tips and saw a box tucked away to the back of the top shelf of my storage rack, and not knowing what was in it I grabbed it and inside were 6 Soviet Teflon FT-3 capacitors I ordered back in September that I totally forgot about

Well, now that the SuperPly prototype/test circuit is more or less completed, guess there is no time like the present to give them a try while I make the finishing touches to the chassis before building the circuit within it.

These will be used/tested as the coupling caps from input->output .. placed them about 15 minutes ago and upon first impressions I hear nothing offensive, so that is a good start, and certainly IMHO the same can't be said of the more common Soviet PIO K40Y-9 capacitors, which I am no fan of.

They have taken the place of the Jupiter copper foils, so once I get many more hours on these comparisons will be made between those and the FT-3. Unsure how many hours these need to burn in, but id say 50+ before I can make any definitive statements on them.

@OctavianH the vent holes you mentioned, well, getting those as perfectly symmetrical as possible manually is quite the task - that is what is taking the longest to get drawn out just as I want them.

 

[OctavianH]

@OctavianH the vent holes you mentioned, well, getting those as perfectly symmetrical as possible manually is quite the task - that is what is taking the longest to get drawn out just as I want them.

I think you can order cases which have some default venting holes already made. My Galaxy case is one of them. Unfortunately this case is not recommened, small screws which block in time, I have problems opening my amp. So I would not use it, but I expect other models have this as well.

 

[g0ldl10n]

Alright - last night I found the time to drill the vent holes + terminal strip holes in the top plate as well as grind away the anodized coating on each panel so that I have full continuity between them all for ground/safety purposes - every major component is placed now.

Game plan from this point is mount the terminal strips and get to work on the circuit - there may be another hole or two I will need to make in the top plate, but if so this can be done with a hand drill.

Here is its current state - the vent holes is what took the most time, mostly drawing them out by hand with a protractor on masking tape and getting them just right was a minor task all in itself - not easy to do by hand I tell ya.

Here is a shot of the internals - the toroidal transformers you see on the side panels are the OPTs - there is still one last A/B comparison test I want to perform with them prior to solidifying exactly how their primaries and secondaries will be wired, but this is how they will be mounted.

 

[g0ldl10n]

Here is a shot of the internals - the toroidal transformers you see on the side panels are the OPTs - there is still one last A/B comparison test I want to perform with them prior to solidifying exactly how their primaries and secondaries will be wired, but this is how they will be mounted.

Alright, testing/measurements completed with how I am going to wire the OPTs.

I was confident I already had this figured out for my circuit, but ended up doing a lot of reading/research again on this subject over the weekend and thought, "man, I am doing this wrong - could I get better results wiring them this way?" .. answer is unequivocally, no - not even close.

I have done quite a bit of reading online, mostly on diyaudio in regards to using Toroidal PTs repurposed as OPTs, and I am just gonna say that a LOT of the information I have encountered is likely very dependent on if you are building a lower power HP amp, and or parallel feed or PP amp using them.

However, the vast majority of recommendations from people (whether they've used them like this or not, I do not know for sure) is that you want to wire the dual primaries and seconaries in series, which provides more voltage headroom - possibly when dealing with more powerful speaker amps rather than headphone amps. For me though, the frequency response I am getting from wiring both pri/sec in series is way worse than what I get when wiring both in parallel (or any combination between).

So, at least in my experience, in case anyone is wondering, small power HP parallel feed amps using small toroidal PTs as OPTs it would be my recommendation to wire both dual pri/sec in parallel and not series - the results are extraordinarily better.

 

[g0ldl10n]

I keep going back and forth whether I want to load the inputs with gyrators (constant plate voltage) or CCS (constant plate current) due to the compromises between each.

Gyrator loaded inputs sound great and give us the ability to roll about as much as one would ever want to between different tube variants.

CCS pigeonholes us to specific tubes since we are setting the current instead, but the benefit here IME is SQ jumps nicely - specially in regards to the finer details, separation and mind blowing imaging. But I love tube rolling, so what is one to do?

Option 1: Variable plate loads - increases complexity of the circuit a bit (nothing too crazy to do though, but something I try to avoid)

Option 2: Use CCS loads for the twin 6J5 sockets but use Gyrator plate loads for the 6SN7/6SL7 wired socket - I am leaning towards this option - doesn't really add complexity to the circuit since there will already be selectable inputs between the two - I am realizing I have to include CCS input loads, as I am listening to it now, actually some songs I haven't listened to in forever, such as Piano Man, and I am just awe struck how amazing this sounds.

Option 2 I think - this gives us tube rolling in our twin triode socket, while providing us insane SQ on the 6J5 sockets.

I am realizing how underrated Parallel Feed topology is - granted it took me thousands of dollars and countless hours to get this specific circuit dialed in, but my god was it worth it.

 

[triod750]

What about option 3? That one has to be amazing!

 

[LobalWarming]

I keep going back and forth whether I want to load the inputs with gyrators (constant plate voltage) or CCS (constant plate current) due to the compromises between each.

Gyrator loaded inputs sound great and give us the ability to roll about as much as one would ever want to between different tube variants.

CCS pigeonholes us to specific tubes since we are setting the current instead, but the benefit here IME is SQ jumps nicely - specially in regards to the finer details, separation and mind blowing imaging. But I love tube rolling, so what is one to do?

Option 1: Variable plate loads - increases complexity of the circuit a bit (nothing too crazy to do though, but something I try to avoid)

Option 2: Use CCS loads for the twin 6J5 sockets but use Gyrator plate loads for the 6SN7/6SL7 wired socket - I am leaning towards this option - doesn't really add complexity to the circuit since there will already be selectable inputs between the two - I am realizing I have to include CCS input loads, as I am listening to it now, actually some songs I haven't listened to in forever, such as Piano Man, and I am just awe struck how amazing this sounds.

Option 2 I think - this gives us tube rolling in our twin triode socket, while providing us insane SQ on the 6J5 sockets.

I am realizing how underrated Parallel Feed topology is - granted it took me thousands of dollars and countless hours to get this specific circuit dialed in, but my god was it worth it.

Great work!!!

Agree with T-75 tho. Need an option 3, where the CCS/Gyrator biasing is selectable. Sure, it's over double the work, thrice the confusion, but no amp maker offers that option. Because it's so difficult and crazy, but that's what DIY is all about, right?

And if you go that far, might as well add resistor biasing too. Cover all the biasing options, cognitive or otherwise. Your desktop version might be better for the full and complete biasing methodology. Isn't limited by the hard spatial constraints of a metal chassis.

 

[triod750]

How about AI bias? That would be a first, really! No other options neccessary, ever.

 

[LobalWarming]

How about AI bias? That would be a first, really! No other options neccessary, ever.

Hallucinated audio! Perfect. No need to purchase another piece of music, just enjoy the scraped-up stylings from billions of low-fi tracks no one wanted to hear.

 

[triod750]

Hallucinated audio! Perfect. No need to purchase another piece of music, just enjoy the scraped-up stylings from billions of low-fi tracks no one wanted to hear.

Now you're talking. Is this evolution or revolution? But I don't like that you are speaking of music, this is about sound. Music is something else.

We will soon be banned and rightly so.

 

[g0ldl10n]

Great work!!!

Agree with T-75 tho. Need an option 3, where the CCS/Gyrator biasing is selectable. Sure, it's over double the work, thrice the confusion, but no amp maker offers that option. Because it's so difficult and crazy, but that's what DIY is all about, right?

And if you go that far, might as well add resistor biasing too. Cover all the biasing options, cognitive or otherwise. Your desktop version might be better for the full and complete biasing methodology. Isn't limited by the hard spatial constraints of a metal chassis.

Yes, this has been considered and you're right, if I went this far then it's only logical to include resistor load as well. You guys are bad influences on me, although, what's the worst that can happen - something breaks and I have to fix it?

Fine, option 3 then