audio-talk

This would be another way without SMPS. It's safe against mains fluctuations (unless dramatic) as the DC/cap buffers it. It would need the perfect transformer or some extra power resistors to get to the exact voltage. But it works.

I will start a new thread about this amp soon, Steve. Even if nobody on this forum will build it because the ratio of power demand vs output power is even worse than with typical SE OTLs -and from many comments I got the impression that OTLs are anyway not highly coveted here -it will be at least en...

I think this is a very good compilation from R.Coleman in diyaudio on the topic of "anode stopper, grid stopper, ferrit beads": "Oscillations in a triode (or MOSFET), at high frequency occur though unintentional feedback paths, especially from anode circuit to grid circuit. The 180 de...

If this is directed at me I need to ask.....What defense mechanisms? This wasn't directed at you, Steve. It was fun to follow this thread and how you approached each step. Obviously it needs more background information for someone who is not part the "inner circle" of this forum in order ...

A lot of angry reactions and defense mechanisms showing just because I was making some suggestions based on my own experience with single output tube OTLs. The case in point was:"Well, a week down the line and I’m no nearer, finding anything, although it’s been great fun reacquainting myself wi...

For testing those OTLs I can recommend the following CDs, all real music (no plinkty plonk) and very revealing of what the amps (and front end) can deliver. This selection doesn’t demand acoustically treated rooms or a lot of amp power. John Zorn: Masada guitars (especially the songs played by Marc ...

I think this amp has some potential as low power output OTL for 16R drivers with zero NFB. Four 6AS7 or EL509 could be enough per channel and for $20/$40 each this is a very good deal compared to the 300B OTLs. I have no idea how such an amp could sound in comparison to typical OTLs but there are so...

I am really tempted in the meantime to try something with this 13E1 (NOS from the 1960 or later ?) myself. Just starting with one tube for experimenting. The biggest limitation with the 6C33 was the 60W max which was easily reached with 470mA/130V and the necessary min peak output power even for 15R...

The best part of using the 6H30 is that it ca be easily replaced by a 6H6p or 6H1p and more. My guess is, from listening to all 3 tubes in my sound systems (AR, SE OTL ), that a 6H30 might sound too sterile in a single output tube OTL. The 6H6p might sound warmer with more bass, the 6H1p a little mo...

It’s really about protecting the output tubes in OTLs from extreme stress every time the amp is turned on. It also depends on the amp type. In case of PP OTLs a soft start is recommended to protect some of the tubes from conducting initially a lot more current than for what they have been set up in ...

I noticed that the resistor for setting the current with the TL783 is not at the output where it should be. Just a typo? The 0.1uFcap between the 2 triodes of the input stage was part of the phase problem with the feedback loop in the original 300B OTL DC which caused the motorboating/bass driver pr...

To cut a long story short, the feedback resistor is now 3K3 as opposed to the 4K2 it had been. The result of the increased feedback is excellent and has both evened out, and tightened the bass up very nicely. I decided to use ears rather than scope and sig gen to fine tune the feedback to my own ta...

What are your concerns with the voltage doubler and what will you use instead in this position? What kind of psu do you use now for the 13E1? This might be also interesting for using the 13E1: I finally added a socket/made the necessary connections for testing the 6C33 with my TS tube analyzer. It's...

I cannot see at the moment how we could integrate the hall sensor for monitoring the current. But maybe there is a way? The digital output could trigger a SSR. I use CMOS Hex inverters for this in my circuit.... so it would go in the same direction. A very simple but not very precise/practical solut...

That’s why Steve’s experience with the blown cap/arcing tube was a wake- up call for me. Add to it that these kind of amps really respond very accurately to whatever is done to them no matter where -and you don’t want to ruin the SQ! - and you find yourself very quickly stuck between a rock and a ha...