Discuss the stuff that makes your ears bleed.

Moderators: Slowy, Capt. Black

#805406
The guy obviously knows his stuff. He has used all the right components and his build and wiring is excellent. Great attention to detail.
Better than an original IMHO.
User avatar
BY Bg
#805407
Yeah Mikes a good guy, dealt with a few times over the years. Used to be a member here.
#805408
Looks like a great build, I’ve seen a number of ‘quality’ amps that are messier than that. Obviously knows his stuff, no idea on whether that’s a good price or not but probably is considering how long it would have taken him to build.
#805418
The build quality looks great but I have one issue- the addition of a standby switch between the rectifier and first filter cap is not a good idea. Once the rectifier is warmed up, throwing the standby 'on' results in a large inrush current to 'fill' that 1st cap, which (worst case scenario) could cause the rectifier tube to short out. The simplest solution is to always leave the standby on (at least during initial warm-up).

There's a heap of interesting background on standby switches (including why they're almost never necessary) here: http://www.valvewizard.co.uk/standby.html
User avatar
BY Conway
#805420
RectifiedAmps wrote:The build quality looks great but I have one issue- the addition of a standby switch between the rectifier and first filter cap is not a good idea. Once the rectifier is warmed up, throwing the standby 'on' results in a large inrush current to 'fill' that 1st cap, which (worst case scenario) could cause the rectifier tube to short out. The simplest solution is to always leave the standby on (at least during initial warm-up).

There's a heap of interesting background on standby switches (including why they're almost never necessary) here: http://www.valvewizard.co.uk/standby.html

Cheers. So basically, ignore the standby switch and just use the on/off, like the original?
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BY Molly
#805422
RectifiedAmps wrote:
Conway wrote:Cheers. So basically, ignore the standby switch and just use the on/off, like the original?


Yes, exactly. Maybe that's the reason Fender didn't have one in the original design?


Interesting. And here's me always following a strict sequence. So, so long as I still wait a minute or two to use the amp I'm OK to just ignore the standby?

Conway, I don't see the harm in running an 8 ohm output into a 16 ohm speaker. It's a safe mismatch. Don't know how perceptible any tonal difference would be compared to an 8 ohm speaker.
#805423
Molly wrote:Interesting. And here's me always following a strict sequence. So, so long as I still wait a minute or two to use the amp I'm OK to just ignore the standby?


Pretty much. If the amp makes noise, it's ready to use. Even if you hammer away before it's sufficiently warmed up to pass a signal, it won't hurt anything. Some amps seem to sound better after they've heated up for a bit (maybe thermal drift causing hotter output tube bias), but that's not to say it's unsafe to use them immediately.
#805426
Trower used to run his 8ohm amps into 16ohm cabs, said it gave it a smoother tone as well as slight attenuation.
#805437
Hi all and thanks for the feedback. Yes, many many hours to build but it's so much fun for certain types! For what is worth I was very careful and both this and #1 operated on first power up. Interestingly, this one was quieter than #1 which could be as a result of the experience gained from the first build. And to my ear, there are no perceivable tonal differences between the two. For Conway, I think the main advantages of careful building with eyelet boards, hand wiring and chassis mounted valves are reliability and ease of modification or repair. IMO this is as close as you'll get to a vintage BFPR at a reasonable cost (my aim), but with the advantages of all new components and some circuit improvements. P.S. The Fender AA1164 circuit schematic is easily obtained via the interweb but I will provide the purchaser a copy and details of the improvements done.