cfcubed
1000+ Head-Fier
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- May 1, 2007
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OK, I've been trying to pawn off the starting of this thread but one can't always pass the buck
And since I've the first working proto PCB CTH (by a few days?) guess it should be me.
Surely much of what may be posted here will be based on opinion, listening tastes, headphone synergies, source attributes, etc. But some observations could/should carry across these. I'll get this rolling (ha ha) with a few bits that come to mind & that I think transcends the variables above.
Tubes
O.K. I've started this. There's a huge world of tubes for this amp... My last search of the bay yielded 600+ listings AFAIR. My gut says this design lets tubes "come into their own" by running them closer to spec, using better/lighter loading, etc. than some other designs.

And since I've the first working proto PCB CTH (by a few days?) guess it should be me.
Surely much of what may be posted here will be based on opinion, listening tastes, headphone synergies, source attributes, etc. But some observations could/should carry across these. I'll get this rolling (ha ha) with a few bits that come to mind & that I think transcends the variables above.
Tubes
- Amperex 6dj8 white label Holland - Lower end & upper ends a bit enhanced, perhaps at some expense of mids. Bugle Boy variant perhaps a bit "better" presentation of these characteristics. Is/was a personal favorite (w/BoM, Sonicap Gen II or Wima coupling caps & D2000s)
- Siemens "chrome plate" ECC82/12AU7 (1963) - Bit more refined/balanced presentation, vocals/mids performer. As many tubes do, lends an interesting personality to music... Hard to pin down but enjoyable. Not particularly a bass or top end champ - but this can be a good thing.
- Mullard Mullard 6922/E88CC Gold Pin, Sylvania 12BH7A, RCA 12au7a "clear top", Raytheon 5814a - All fine candidates that I need to come back to. My enjoyment of the above 2 or 3 has kept me from rolling these back in. BUT see below WRT coupling caps - I WILL be giving these another shot.
You certainly don't need expensive tubes in this amp for it to sound good. Tube trading amongst those w/CTHs would be a fun & inexpensive way to go.
- General - Thinking this design, like some other Cavalli designs, do not need boutique parts to sound good/great. The BoM couplers (@ 75 cents USD?) & minor Wima upgrade caps are fine in this design. Some builders prefer these to alternatives below, perhaps most will.
- Sonicap Gen IIs - These, which fit reasonably well tombstoned on PCB, I found slighly "sweeter" in the amp. But not enough to go to great lengths to acquire or install them (e.g. only as part of mini GB or other larger order).
- Mundorf Supreme Silver/Oil - These huge & expensive caps (Sonic Craft - 20% off) require larger-than-target enclosure. Have only had these in for a couple days but can say most noticeable is the bass enhancement & softening of the highs. Shift is enough that my DT-880s become a better match than the Denon D2000s I primarily use & I'll have to cycle through my tubes to ID a more "balanced" one than those Amperex 6dj8s.
If $$ is no object, you've the room, want more bass/softening of highs & want to play around you could try this. Doubt anyone could want more bass out of a tube hybrid than this design w/S+O & those Amperexs... My bet is they would want less. Edit: Take away shouldn't be that I'm disappointed w/the S+Os.. They do more to the sound than enhance bass & soften treble. They lend a different character to the amp though that I'm interpreting as less crisp/darker than before. Perhaps more like some would like from an amp w/a tube in it
O.K. I've started this. There's a huge world of tubes for this amp... My last search of the bay yielded 600+ listings AFAIR. My gut says this design lets tubes "come into their own" by running them closer to spec, using better/lighter loading, etc. than some other designs.