I am thinking about the P8 as well but the version with the aluminium casing! Could you care to elaborate on sound impressions, would be greatly appreciated.
if you are considering this unit w/o mods, then I would encourage you to consider the hybrid units offered by garage1217.com instead.
& if you are willing to mod, then I don't recommend the cased unit since it will obviously hinder the modding exercise.
stock, the unit is smooth throughout the midrange but with some lower end roll-off and some very mild upper mid to high grit.
a friend has devised a range of mods to eliminate all the issues that concern me, but I cannot post w/o his permission.
with these mods, I cannot think of a better all-tube amp for under $400 usd.
if you are seriously interested in this route, I will seek permission to relay the mods. if you are not into soldering, then I would urge you not to bother (with this amp).
Cool deal. Under-spec'd components is the main concern with these "mystery-amps". I'd keep a close eye on those carbon resistors, the solder flux residue there and at the 6as7 tube socket is starting to discolor and turn brown. Hardly a worthy indication of anything... other than that area of the PCBA is getting some heat build-up. Might want to relocate those to the tube-side of the PCBA, at least up there the heat can better dissipate.
Those blue bypass caps did those come with the amp?... or did you add those?
There are two versions of this amp one with a torroid another with a traditional laminated core transformer what is the difference and is one better?
EDIT... strange all the aluminum chassis models have been not been replaced on the bay. There were at least a couple dozen of them a week ago, for around $150-170 free shipping. Theres only one left now at $199 + $45 S/H. At that price you're better off with a DV/LF 336.
1. I have closely examined the white tube socket in question --- just some excess flux. the socket appears to be ceramic & is in perfect condition. there is, as you say, excess flux residue & I have just been too lazy to clean it up. I don't notice any real signs of degradation on any of the components themselves.
2. I chose the upside down pcb because I feel it is the better configuration for modding.
3. the 'blue beauties' were added by me - although, frankly speaking, the ones on the power caps are a tad undervalued.
4. at the time that (we) purchased from ebay, there was only the toroid. as to which is better ... hmmm ... you DO know that this is somewhat of a loaded question. in theory, with all things equal, e-i is usually selected for low-level applications (like dacs) while toroid for, say, higher powered amps. but this is not a hard & fast rule by any means and there are numerous arguments either way. at any rate, we (my friends & I) have no experience with the E-I unit offered on the little bear, but the toroid meets requirements and is not mechanically noisy.
5. knowing what I do now, I would order the pcb version w/o standoffs or acrylic plates for $35 and the separate xfmr for $33 and build/mod an open structure like my buddy did in the pic below.
6. the bear powers my akg k7xx mighty fine & has no probs with senn hd650 according to my friend -- sounds wonderful. note: it will not power the he-560 properly.
7. I previously mentioned the issues I had with a cracked ac module and some standoffs that were not properly threaded. going over some notes from last year, here are the other issues:
a) a couple of caps were not soldered absolutely flush to the pcb - this caused them to hit the acrylic plate which prevented a couple of standoffs from mating properly. since I was intending to mod using much larger caps, this issue was rendered moot when I changed ALL the standoffs for much longer ones.
b) the 6.3v supply from the xfmr measured 7.1v ... a fair bit of discussion with the dealer and with my engineering buddies ensued -- not a critical issue
c) there was channel imbalance on my unit (& my unit only) ... after much trial & error, it was determined to be a tube issue. the stock tubes were crap, esp. the drivers - the output tube is okay. you need closely matched (sections) tubes here - ge 5670w to the rescue.
8. I have only done the 1st level of modding (adding the bypass caps) & have yet to do the following:
d) replace coupling caps with audyn true copper
e) replace electrolytic output caps with larger 'lytics bypassed with film/Teflon or replace with larger film/foil.
f) add resistors to increase bias currents.
hth,