well, the 150s might be a solution!
soundermn
given you said a ??? set of KT 120s had an issue in the mids another set of ??? EL 34 did not demonstrate, have you been able to experiment with more than one brand of 120’s or 34s? and, or, different Eras of either?
different brands and or eras of tubes will definitely yield different results and or sonics, some quite noticeable, some more subtely. Even in a self biasing amp.
I only read a couple online reviews of the PL Dialog HP INt but liked what I read. Mostly. It has a large tube compliment on board which if one is prone to experiment with the wicked and magical world of tube rolling, can become quite expensive.
Six inputs and eight outputs? Hmmm.
When you left the 34s for the 120s, did you as well replace the 6SN7s, or before the switch of output tubes?
A note I saw in the reviews I read mentioned the longevity of tubes with a caveat: “provided the matching of the amp to speakers was optimal or close to it, tubes would last for years.” If not an optimal speaker & amp arrangement, the implication was tubes would have a quite shorter life span.
Sourcing tubes as NOS or current, especially given all the various subs and iterations of the same tube values can become quite involved. CED, Mullard, Jj, etc. And, ‘ ‘spensive. The output tubes aren’t the only ones which will alter the sonics either, merely the out put power.
I’ve owned several tube power amps and preamps. A couple had more tubes than the PL mentioned here. Self biased and manually biased. Stereo and mono blocks.
I’ve always gotten the impression, after a lot of tube rolling, makers deliver their products with what they feel is the best for a specific application, or range of speakers. As audio nuts we try to expand that range, or simply ignore it and attempt to feed speakers which are in fact not the best fit, but what we have an investment in already on hand.
I truly get it. Been there and done that too.
Having owned several BW models, all of them enjoyed more than double digit watts to perform well across the entire bandwidth. All were of the nautilus variety and below it.
Sometimes this ‘make it work’ with in house speakers theme isn’t always the best path, or we did not get the right or better, or even the best power amp for them…. Despite the notion we can up the out put power of the amp with altering the output tubes later on. It becomes still harder a thing to do, if the amp does not have different transformer taps, 2, 4, 6, or 8ohm for various speaker configs. Sometimes, even if it does have various output taps, getting it hooked to the speaker with an amenable or amp friendly impedance graph can be daunting.
Its always about the proposed speaker’s ‘impedance curves’ more than the speakers sensitivity the amp will see and have to deal with that provides the chance for an optimum amp to speaker connection, in bandwidth reproduction, control, and volume.
With a pair of Dodd 120wpc monos (running ultralinear) & Silverline Sonata IIIs a supposed 93db 8ohm speaker which did not dip below 4 ohms, I initially hooked it onto the 4 ohm taps to be safe. The sound was velvety smooth. 300B-ish sounding. Changing onto the 8 ohm tamps, was night and day different. Immensely better control and bass reproduction and slam. Better across the board sonically. Far more musically detailed.
To a point, in the volume levels. In a 14ft W x 21ft L arched ceiling fully enclosed room. It would play loudly for sure with a little ZZ, AC/DC, etc! As the volume escalated the bottom end thinned out though. A sub search was in order and done thereafter. Issue resolved.
The PL HP as I read it has an output for a sub. That might solve the lower range desire without more tube rolling and expense therein. Especially in an ‘opened’ non enclosed room… and if acquiring or trading out speakers is not an option.
Personally, I liked very much the accounts of the reviews on the PL D HP I read, and may well get one for my office next year, as I have some very amp friendly speakers on hand already which could be quite happy with less than 40wpc. We’ll see.
If the fun knob is not turned up, tons of amps work with tons of speakers in many rooms. Twisting the fun button up, and everything begins to show what’s up with the pairing. Every time.
Hopefully these experiences and insights can be helpful. Good luck.
