12BH7A valve. Impressions? Insights?

[Jimbo]

the Mega Micro's line stage was updated (among other things) in 2015. I don't actually know what was in there before, I had the seller ship it straight to Glenn Croft. I suspect the 12BH7As came with the overhaul (I sank £500 into it). He says it is now better than a 25R -- some of which presumably has to do with the 12 valves in the power supply unit & the four-way HT regulation... . though given the different topologies etc any comparisons with later models evoke apples & oranges.

Can you kindly post some pics of the mega micro internals?

[eksiil]

having just got the hang of Photobucket I might as well replace this post with proper pics of the insides of the two Mega Micro II boxes.

the preamp:


the PSU:


some of the PSU valves slantwise:

[pankon]

having just got the hang of Photobucket I might as well replace this post with proper pics of the insides of the two Mega Micro II boxes.

the preamp:


the PSU:


some of the PSU valves slantwise:

Wow, so many valves in the PSU box!

I wonder whether you've ever considered asking Glenn to move the transformers to a separate box, like he does with the Micro25RS... I do not know whether that would yield a worthwhile improvement, at least one that would justify the cost.

[eksiil]

Wow, so many valves in the PSU box!

I wonder whether you've ever considered asking Glenn to move the transformers to a separate box, like he does with the Micro25RS... I do not know whether that would yield a worthwhile improvement, at least one that would justify the cost.

the transformers are in a separate box. box no. 1 contains the 5 preamp valves. box no. 2 has the 12 regulator valves in the PSU. or do you mean a 3rd box?

[pankon]

the transformers are in a separate box. box no. 1 contains the 5 preamp valves. box no. 2 has the 12 regulator valves in the PSU. or do you mean a 3rd box?

Yes, Ahto, as a matter of fact, I was referring to a third box, which would completely isolate the transformers. It seems that you're not far from a no-compromise solution, so I am suggesting of some (theoretical?) further improvements, irrespective of cost. And perhaps you could also consider changing the Trigon ECC83 with something better (again theoretically...).

Just my two pence -)

[eksiil]

I don't think Croft has ever gone as far as three boxes. would it make practical sense? I must profess utter cluelessness here. it's an interesting thought though, thanks.

the Trigons remain as much an affectation (Indian Mullards, after all) as an imposition till I can justify the cost of something better.

Yes, Ahto, as a matter of fact, I was referring to a third box, which would completely isolate the transformers. It seems that you're not far from a no-compromise solution, so I am suggesting of some (theoretical?) further improvements, irrespective of cost. And perhaps you could also consider changing the Trigon ECC83 with something better (again theoretically...).

Just my two pence -)