I use a Grant lumley desgn point to point wired ST70 reference Stereo Power Amp currently I'm using Gold Lion Quad KT88; 2x RCA JAN NOS ECC83 & 2x Gold Lion ECC82.
In this design ECC82 (12AU7) tubes are used as a preamplifier or driver tubs. They are a lower gain compared to the ECC83, making it suitable for applications where a moderate amplification factor is needed.
The 2x ECC83 (12AX7) tubes are used as a high-gain preamplifier tubes providing the a higher amplification factor, making it ideal for initial signal amplification
In the Lumley ST70, these tubes are used in the input and phase splitter stages to ensure proper signal amplification and phase splitting before driving the output tubes.
I can use this amp easily in ultra linear and Triode mode by simply switching them when placng the amp in stand by mode briefly.
Ultimately it depends on my mood and our source material as to my preference but very simply put the amp sounds more incisive and dynamic in ultra linear and just a bit sweeter and holographic in triode mode.
I have completely recapped the amp using Mundorf Mcap Supreme Silver Gold OIL 1200VDC film capacitors for coupling along with top end Nichicon and Audionote elsewhere. Topping off with massive Nichicon reservoirs/ Filter caps. The amp has huge hand wound inputvand output transformers and can now be set to output into 4 ohms or 8 ohms via Rhodium binding posts.
I will never sell it its such a thing of beauty and sounds as good as it looks. I think fir me as long as the KT88's are as good quality as I can afford the major sound changes come via sourcing top quality ECC82 & ECC83 and experimenting although I am so satisfied with how this ampmperforms hooked up to a Tim De Pavaracini designed all tube EAR 912 pre. I just dont feel the need to tinker, its powerful enough to drive my Proac Carbon Pro speakers down low with ease its very holographic and sounds dynamic even at late night listening levels.
I love my tube based system but I don't dicriminate on source I have a much modified LP12 decent digital source streamer about to be made even better by a Chord TT2 & M Scaler a vintage Sony CD player & Tube based CD player too. I'm not too much of an Audiophile niw that I am listening to music much more than the system. It must beca sign that I'm close to where I want to be gear wise. I just cant see me being without valves in my system.