6005w Q+introduction

[x9moto]

hi everyone im new, used to be here a year back but my email changed and i forgot my password so i have just registered a new.

i have an interesting little problem, i have a class A 6005w parallel pp Amp, that i built from a kit, and i am playing with some configurations, i have been testing with and without cut/boost tone contols, also trying 2 valve per channel and 4, here is my question when changing from parallel pp to 2 valve pp how is the impedance effected?

as i understand it im currently running 4 valves with a matched impedance of 4 ohms, so when i run 2 valves am i correct that i will then be matched to 8 ohms?

[SY]

If you remember your old account name, I can merge your new and old identities.

[x9moto]

heres some pics ......


the case was built by me, the base is mdf, the front is drawboard that was prepped and then sprayed mat black, the back was laser cut at work and the top was stolen from an old vcr and given a new lease of life, the badgework was laser ingraved at work onto sheet tin tablets.

as you can see from the pics some valves are missing from one shot and present in the other, the valves missing are the second set which were in parallel.

[x9moto]

i see, this forum is just as helpfull to new members as it was when i left, think i would have learnt the first time oh well at least i got the answer from a friend on a completely different forum that is not even for hifi.

i believe withought the 4 valves in parallel the impedance the valves as a group goes up so one would change transformer taps from 4ohm to 8ohm etc.

also the amp seems to sound far more refined and has better definition withought the extra wattage in parallel and actually seems to drive my speakers better than 4 valves pch, think this has more to do with my speakers impedance than the valves.

also discovered that running the amp withought a valve in the tone board and dissabling it by joining the audio links, i fitted a switch so i can make changes withought soldering every time, it sound so much more natural withought but just slightly lacking in bass.

last question i dont think the valves supplied with the amp were a matched quad so is this likely to cause the perculiarity with the sound when running 4 valves pch?