I must confess that I’m not really into all this “boutique” market . Always the same boring fender-like or Marshall-like clones. this all thing can be resume to : who make the best reissue or “clone” ? I don’t understand why people always want what the neighbor has . Being a sheep must be cool I guess.
Anyway, one exception exists , sort of , 65 amps . I’ve been obsseded with 65 amps for few years now without having the chance to try one . I think they achieved great distinct look and original desing (as Boul claims it). Their vintage oriented vibe is really attractive . They aren’t the cheapest products and therefore they’re pretty rare , espcially in here. And when one hazardously land , it’s hard to convince the owner to let a stranger make an autopsy of his 2000euros amp .
Also, I used to watch the dan boul’s show on ustream , really interesting although a bit redundant over the weeks.
I’ve tried , as a respected geek, to trace the schematic of several of those amps based on pictures. Even if the global topology is clearly known , nothing Hi-tech in here , I though knowing the detail could be nice.
As few new interesting pictures came out recently I give a try on the lil elvis.
I haven’t traced the tremolo part and the output stage yet. The tremolo is a standard phase-shift oscillator modulating the grid bias of the EL84s. Note the poorly designed effect loop , beurk….
The couple C15/R23 is another guess , there’s a veroboard circuit in the amp which obviously hides the solder tracks underneath. Older versions have a simple keystone solder lug but apparently they can’t use those solder tag any longer (law stuff) . As the amp isn’t really gainny in spite of the 4 stages I assume this couple forms a simple voltage divider with treble bypassed. Otherwise , C15 could placed in parrallel with the anode’s resistor (to tame highs).
As expected, nothing “clone” in it (as far I can tell) ! This amp has been co-designed with a former engeneer of Vox amp , Derek Underdown, based on a non commercialized amp . “too gainy” they said. You’ll get more imformations about that in Dan Boul’s videos (he talks about a particular output transformer). He explained the whole story in one of them but I don’t remember which one.
11/15 : I’m actually a bit wrong with the schematic. I was watching one of the latest Dan Boul’s show with the lil elvis and it appeared that the circuit uses a “radar circuit” designed by Underdown back in the WWII to fatten up the radar signal during German bombing (I wasn’t expecting talking about war in this blog , brrrr….) . I don’t expect a special magic circuit or voodoo electron though. I think this particular circuit is the one built on the veroboard. So , unless I can see the solder tracks it’ll stay unknown for me . Boul talked also about a “cathode follower” which can make sense regarding the fact that the amp isn’t that gainy , 4 gain stages is certainly not right.
So Keep in mind this is just a pure guess and assumptions on what the amp could be! Nevertheless the preamp as traced could be intereseting on its own ! Maybe I’ll give it a try later…