Very nice work PW.It looks very well planned as well as executed. You must be a fellow woodworker, yes? I like the use of the dovetail mitre locks. Is that purpleheart I see? I used solid maple, from a tree that I cut down and planked, and used some slivers of purpleheart to lock my mitres also. No time to dovetail this one I'm afraid. Great job.
Thanks Rumad
To get real good wood for carpentry, I usually pick up trown away furniture
No wood today is as good as an 100 years old chair, or an office chest
It´s free, and real good quality.
I usually use ash and wallnut, but it depend of what the trash station has to offer
This is a simplier box, using old pine and wallnut
Grgds
Pix
Sweden
personally, I think simplicity is the only way to go. Good design, originality and execution bring it all together. Simple looking with fairly complicated, or at least different, joinery executed perfectly is key. I hear ya on picking up furniture or whatever you can get too. Before I was injured I worked at a big cabinet/woodworking shop. I was a "working" supervisor so I got pick of the litter of leftovers. Still have a good stash of some very nice hardwoods. SO, on top of making my own boards, I made out fairly well with wood such as walnut, curly maple and many others. My injury severely limits what I can do now, that's one reason my cabs are TOO simple. But also, as the saying goes and it's VERY true, it's always the mechanic who's car is least taken care of. In other words, when I had a project for a client, it was much more thought thru, more complicated and more time was dedicated to it. I'm nnot sure why but it's true. My projects for ME always end up rushed or less amazing than if it were for someone else.
Oh well! Sorry for straying off topic. Best to all, and KEEP BUILDING!!!
Oh well! Sorry for straying off topic. Best to all, and KEEP BUILDING!!!
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Dead Parrot preamp (Norwegian Blue)
Dead Parrot preamp:
The main goals for this preamp were low distortion, low noise and capacity to drive power stages with medium low input impedance (2Vrms into 10k load). Max gain should be about 10-12dB.
Topology:
Gain stage is a triode strapped pentode (EF86/6267) with degenerative local feedback. This reduces the gain to ~4x and should ensure low distortion.
The driver stage is a cathode follower (triode section) with active load (pentode section). The pentode section is basically a constant current source, but a small fraction of the input signal is fed into g1 to make the pentode track the output signal from the cathode follower.
To keep hum away the power supply is separate. Both B+ and heater voltage is dc.
Quick measurements:
Freq resp: <10Hz - 50kHz +0/-1dB (1Vrms out, 33k load, Attn at 12 o'clock)
S/N: ~50µV, ~90dB below "line level" (2V)
Max output: 23Vrms into 5k (1% THD)
Dynamic range: 113dB
Max Gain: 11.5dB.
Distortion:
HD: 0.03% (2Vrms out, 33k load)
HD: 0.07% (2Vrms out, 5k load)
HD: 1% (23Vrms out, 5k load)
2nd and 3rd harmonic dominant, falling distortion pattern
Output impedance (1kHz): 220 ohm
The preamp is quiet as a dead parrot and passes on the music the way it should sound.
Jan E Veiset
Dead Parrot preamp:
The main goals for this preamp were low distortion, low noise and capacity to drive power stages with medium low input impedance (2Vrms into 10k load). Max gain should be about 10-12dB.
Topology:
Gain stage is a triode strapped pentode (EF86/6267) with degenerative local feedback. This reduces the gain to ~4x and should ensure low distortion.
The driver stage is a cathode follower (triode section) with active load (pentode section). The pentode section is basically a constant current source, but a small fraction of the input signal is fed into g1 to make the pentode track the output signal from the cathode follower.
An externally hosted image should be here but it was not working when we last tested it.
To keep hum away the power supply is separate. Both B+ and heater voltage is dc.
Quick measurements:
Freq resp: <10Hz - 50kHz +0/-1dB (1Vrms out, 33k load, Attn at 12 o'clock)
S/N: ~50µV, ~90dB below "line level" (2V)
Max output: 23Vrms into 5k (1% THD)
Dynamic range: 113dB
Max Gain: 11.5dB.
Distortion:
HD: 0.03% (2Vrms out, 33k load)
HD: 0.07% (2Vrms out, 5k load)
HD: 1% (23Vrms out, 5k load)
2nd and 3rd harmonic dominant, falling distortion pattern
Output impedance (1kHz): 220 ohm
An externally hosted image should be here but it was not working when we last tested it.
The preamp is quiet as a dead parrot and passes on the music the way it should sound.
Jan E Veiset
Speaking of tube dampers... Why not to use something like this?
An externally hosted image should be here but it was not working when we last tested it.
I can see it now, boom mic stands all over the place . . . turn out the room lights and you'll be among the stars. Lead length gets a little out of hand though.
B65+nc16+300b
My second amp 300B with interstage NC16
My second amp 300B with interstage NC16
An externally hosted image should be here but it was not working when we last tested it.
