I am not an EE minded person, but share time with Audio Enthusiasts that are adept at EE and build/modify Audio Devices.
In many cases I am able to audition equipment in a HiFi System I am familiar with, which helps when being asked to attend a home, with a purpose to take part in a Device Audition, and offer a assessment.
I have supplied ears for assessments and listened to SS Stereo and Monoblock Power Amps that have been built, as well as,
modified Versions of builds and Branded Amps, where changes are being made, with the intent to improve on such builds.
From my limited experiences, any perceived sound changes with SS,
are to me, being perceived as quite limited, even though a change to the SQ and Performance can be noticed.
I have heard SS Power Amps that I have been impressed by, any one of these could very easily be accepted to be trialled to be used in my system.
I am a Valve Power Amp Owner for many years, starting with Stereo and today Monoblocks are in use.
I have again had the opportunities to assess Valve amp Builds and Branded Valve Amp's as well as a few other Devices modified to work with Valves.
The range of Valve Amp's I am familiar with are:
Phonostage > Pre Amp > Power Amp's, Valve Modified CDP's and DAC's.
Apart from being familiar with adept EE minded Audio Enthusiasts,
another Plus Point is that a Friend can be described as having a specialist knowledge of Valves through their life experience, and is in possession of a Two Generation Collection of Valves, which has a vast catalogue.
This friend has always expressed generosity and been willing to aid others with allowing for Tube Rolling to be undertaken with a variety of very closely matched Valves.
Again my experiences are limited but have been revelatory.
One thing I feel very sure of, is that a Valve Device can undergo perceived changes in the SQ and Performance that can be seen as a exceptional improvement over a previous guise, as a result of
exchanging Valves, if a opportunity to Tube Roll was undertaken,
this can make the observation even more apparent, as to how a selection of Valve will interface with a Device, the marriage will be for better or worse.
I have also auditioned Valve Amp's, where Components have been exchanged in the circuit.
In one case a particular component (Copper Foil Cap's) was Rolled,
using different Brands, and at one stage a selected component was perceived as a noticeable improvement over other respected Brands.
When this selected Cap' was in the circuit and Z Foils were introduced to the circuit, the perceived changes were phenomenal.
My limited knowledge would not be able to comprehend why their were such perceptions of improvement.
After such a impression, this device was taken to my friends to undergo
Tube Rolling.
The Builder of the Device was present and was quite sure, prior to Tube Rolling, his selected Valves were not to be improved upon.
Well he got a shock on two accounts when the Input/ Output Valves were
rolled, the Device found a new level with a Permutation that was used.
Then followed a few swaps of Rectifier Tubes and another level of performance materialised.
As for Valves vs SS,
If one discovers a exceptional performing SS Device, that is what it will be.
I feel fortunate to have been able to hear SS Devices that have made such a positive impression.
In my limited experience, If the chosen SS Device is modified, the perceptions of improvement on offer are with limitations, and opinions will vary on how noticeable they are.
These modifications will also be best carried out by a very adept EE minded person.
There is no doubt in my mind that others who have more experience than mine can dispute the above.
If one discovers a Valve Device that is offering a very satisfying performance, in my limited experience that will be a Device that can potentially offer much more.
The chances are that if a investigation is undertaken,
that is limited to Tube Rolling only, a opportunity will be arising, that can potentially offer a perception of improved performance, beyond a persons expectation.
When a Valve is perceived as offering a improvement, there is usually a unanimous agreement, what would be more of a discussion is how much the cost will be as a result of the valves availability.
To achieve such a perception, is only a case of exchanging a single Valve or a Selection of Valves, depending on a Device, and generally does not require a EE minded person to achieve this is Valve Sockets are used as the connections.
To the person considering Tube Rolling, if a single Valve Exchange is
a option, in most cases this would be the most cost effective, and would be a good place to start, i.e, a rectifier.
Note: Tube Rolling can be costly, so learning in advance of how a particular Valve might interface and offer a improvement would be time well spent.