2nd Amp arrived, stripped, cleaned & tested...
Received the 2nd Amp a few days ago so used a few hours today to see what they were all about.
This 2nd Amp suffered even more damage in transit than the first. The case is alloy but the chassis is heavy steel however the transformers are so heavy that they bent it like a banana even though there was no obvious signs of damage to the box or packing, see first pic. The Preamp PCB spans this bend however it wasn't broken. I did discover a broken output Tube though and have requested a used replacement from the seller as he has been very understanding and obliging throughout the entire process.
Before I could attempt to repair the damage I had to strip off the outer case so decided to do this to both Amps as I plan to recase them anyway. The case unscrewed from the chassis without any problems and I was left with two naked Amps after only about 45 minutes. Another hour of gentle persuasion of the Russian steel chassis and I managed to get both Amp chassis pretty much as straight as they should be (see pics 2 & 3).
Spent another couple of hours cleaning & detailing both Amps as best I could (they're not exactly pretty afterall) then decided to fire them both up for a proper test. Populated one with tubes and applied power. All worked OK however there was some pretty serious scratching & static sounds being produced. I initially thought it was due to some dodgy carbon resistors and that would've been fine however after tapping around I found the 2N2P tube (ECC83/12AX7 equivalent) to be microphonic... my first
I powered it all down, swapped the tube with the one from the other Amp and powered it all back up. Bingo, it was the tube all along because after the swap there's no static, no crackling and this tube isn't microphonic! I've ordered a handful of replacement 2N2Ps and 6F5Ps (ECL85 equivalent) to keep in stock once I've got these Amps in service so all good there.
Once I had one Amp working properly I took some time to have a play with it, see last pic. I then loaded this same set of good working tubes into the other Amp and had a long play with it too just to make sure they were both working about the same to the ear. Thankfully they do! Running them from the Pre-out of a little NAD Integrated I played a few different tracks to see how they sounded. The results were again pretty encouraging, smooth, mellow & delicate down low on tracks that deserved it yet when the volume was turned up a bit for other tracks these Amps sound like they have no limit... like a Russian freight train at full speed! I look forward to receiving my new tubes in a few weeks so I can connect both Amps to larger speakers in my Lounge room.
Next step is to re-case these into something more appropriate for the Lounge room but that will be several weeks away yet as I've only just ordered the new cases from the UK. I'll post more here when I've progressed...
The cases I plan to put them in are just very plain, boring black metal enclosures but they'll have perforated panels front & back for air flow so yes there will be a visible glow-fest at the front while in use.
