I wanted to come back to this thread because I saw some remarks about quality issues and about the build quality of the Helios. Just to make it clear: In general you can say that the amp is very well built from a mechanical POV and the components are really high in quality, no doubt about it.
Anyway, for me the Bogner stuff is lacking in the electrical engineering department.While I think that Reinhold has the best pair of ears in the business (he really knows what an amp has to sound like) I think he never really dug deep into theory beyond anything tube amps.
Thats why I think it was a wise decision to stop using their own FX loop in the Helios. Their own FX loop designs never worked for me.
Thats on the positive side.On the other hand I don't get why none of the connections to V1 are properly shielded. It is sort of textbook 101 stuff here. But the one thing I really don't like in this is amp is the preamp tubes being connected via rigid metal rails. While the sockets are top quality and very tight fitting it means you need to use a lot more force to get the tubes out in case you are testing different tube brands or simply replacing a broken one. Many people will automatically start wiggling them out if they are that tight. This is not a big deal if the pins are connected using wires as the wires will prevent mechanical interaction by their elastic nature. With the fixed rail connection the mechanical stress gets down to the sockets pins and is then transmitted via the rails to all the connected rigid solder joints. As commercially sold product need to use the ROHS solder and because of that solder type being less elastic compared to the lead based one, there is a high probability in this setup that any flaw in the soldering causes a connection to break under that mechanical stress overt time. Most likely right at the pins where the forces are applied but thanks to the rail connection the other joints are always connected/affected, too. I guess it is a time saver when building the amp to use the rails but not a good design.
Don't get me wrong. This is sort of big time whining but playing tube amps for nearly 30 years I have seen better designs than Bogners for less money. Reinhold is really I wise and smart marketing guy as he turned that particular weakness into his strength by serving the sound purist with Cro-Mag technology while everyone else goes crazy for digital modeling amps. Fine with me and I hope he will be in business for a long time as I do like old technology. Anyway, time marches on and amps got more refined in general such that to me it starts to sounds more like a fig leaf for covering a bit of the shallowness in the technical department. In contrast when I bought my Diezel VH4s in 2001 it already had full Midi implementation, really noiseless switching, a parallel/serial FX loop that would handle anything you would throw at it, individual channel inserts and it was a stereo capable head.
I had the Ecstasy 100A, Shiva, Goldfinger45, and now the Helios and they all had their "issues". For example the 100A would make loud pops when switching from Green to Blue, the Shivas FX loop wasn't really of any use while I found the Goldfinger having a very basic problem with the dynamic balance of Clean and Gain channel etc. Soundwise I was always a happy camper with Bogner but it were those technical issues that made me sell them in the end.
And here I am again. I really do love to play the Helios as it is the best sounding rock amp I had over the years but I will never sell the Diezel VH4 and that should tell you something. So far the amp works and I think I will keep it but not without some modding.