Burning Amp BA-3

[Melon Head]

Is this the trimmer Nelson uses?
3386F-1-501LF Bourns Inc. | 3386F-501LF-ND | DigiKey

 

[buzzforb]

I might try the FR caps. Probably just an update to the FC. Can't imagine them making huge difference. As for the pots, Nelson uses single turn it seems, but i have always like multi turn better, as it feels like you have a little more precise control. The 3299 series is popular i believe because it has mulitple wipres vs just a single one on the 3296 series. Thats all i got. Hope it helps.

 

[Melon Head]

Yeah I like the multi-turn too but I hate the small screwdriver and steady hand that is required to make the adjustment.
I wish they made the pot in a multi-turn

 

[Melon Head]

I might try the FR caps. Probably just an update to the FC. Can't imagine them making huge difference.

Just put an order in for the FR caps.

 

[buzzforb]

Yeah I like the multi-turn too but I hate the small screwdriver and steady hand that is required to make the adjustment.
I wish they made the pot in a multi-turn

They do, but they run about $6. THey are only 5 turn vs 26. Murata, I think

 

[jacco vermeulen]

.

 

[Zen Mod]

knowing you , you have stash of one plus dozen

 

[jacco vermeulen]

knowing me, i have even more handier ones, that look like knob.

(plus regular ones by the NOS box, cause they was too cheap to leave lying. sometimes i try to write with a screwdriver)

 

[Melon Head]

Nice bit of kit that.
Can I have one?

 

[jacco vermeulen]

Any parts store sells those plastic ones for two bucks if it's Bourns, or cheaper homey brands.

Nicer one is a Belzer 5550, costs ten times as much though (or get a bit socket for trimpots)

 

[Melon Head]

I want my amp burning but not vaporizing. Would it be considered reasonably safe running 2sk2013/j313 at 8W assuming one was to mount them on an adequate heatsink (ie bad @ss)?

 

[buzzforb]

IN Juma's f5, I think they are biased at .5A with 24V rails BIG heatsink. At least mine were. Sounded very nice IMO.

 

[Melon Head]

sounds good. Ok I will bias them at 300ma

 

[Melon Head]

Nelson you did not talk much about R13. Quite a bit of gain is lost through this resistor, I like that but not sure what other effects it has on the amp.

 

[Zen Mod]

sleepin' on class , again ........

read comments : Burning Amplifier BA-3 - diyAudio

 

[Melon Head]

yeah. I'll have to get off my @rse and start reading the thread from the beginning.

 

[Melon Head]

This is confusing the hell out of me Nelson.

"This was taken with a 600 ohm source. It gets a little better with a 25
ohm source, but that's not to say it sounds better."

Are you talking about source resistors R10 and R11?

 

[buzzforb]

He is talking about source that the input sees, or the Zo of whats driving it. I believe he has a switch on his AP rig that allows this to be selected.

 

[Melon Head]

Yeah that is what I initially assumed, but then I thought what has that got to do with the performance of the amp?
That is an indication of the performance of the preamp.
Besides it would be very easy to increase the input impedance of the BA3 to 100k.
I don't understand the point he is making

 

[buzzforb]

600ohm could suggest a transformer input/output. ZM talks in M2 threead about interesting fun with transfomers in differential mode