P.S. I should also add that if anyone is interested in buying a Bottlehead Crack w/ speedball upgrade and upgraded capacitors (10uF bypass caps) I am selling mine for only $480 CAD (with stock RCA 12AU7 input tube and stock GE 6080 power tube). Stock tubes give a very linear and very clear sound, with just a very slight amount of tube smoothness that makes the sound a bit more organic sounding, but with loads of air that opens up the sound and reduces the "veil" found on certain headphones.
I also have these tubes available for cheap:
Input tubes:
- (2X) Sylvania 12BH7A - Used, but test as new - $15 each
-- Good linearity, slightly smooth & recessed upper mids/lower treble, good sub-bass extension
- (2X) (Rogers labelled) Mullard 12AU7A (were NOS, I've put ~100-150 hours on one of them) - $30 each
-- Warm, smooth sounding, but with some amazing high end treble sparkle - Very euphonic - One of the highest rated 12AU7 variants
- (2X) Ei Yugoslavian 12BH7A (were NOS, I've put ~50-100 hours on one of them) - $10 each
-- Neutral tube, with slight mid range emphasis, good linearity, good extension. Adds a bit of emphasis and weight to male and female vocals.
Power tubes:
- RCA 6AS7G grey plate top-getter - was NOS, has less than 50 hours on it - $20 - Has very very faint background hum that can't be heard when music is playing - this is normal for all RCA 6AS7G tubes
-- Warm, smooth upper treble, good extension, slight midbass boost; very slightly more neutral sounding than black plate version bellow
- RCA 6AS7G black plates top-getter (not currently shown in pictures) - Used, but tests like new - $15 - Has very very faint background hum that can't be heard when music is playing - this is normal for all RCA 6AS7G tubes
-- Warm sounding, smooth upper treble, good extension, slight midbass boost; very slightly darker sounding than grey plate above
- Sovtek 6AS7G - new manufacture, has only ~100-150 hours on it - $15
-- Warm sounding, with smooth upper treble