Last Friday I put myself together and - more or less - finished a pair of Pensils 12.2p .
Basic plywood finish, lightly varnished. To save cost & weight, I went with 3 window braces (like I found in a Bob Brines mltl design) instead of the recommended cross bracing. Around the speaker I lined the sides with 2 cm thick recycled cotton insulation, the speakers are furthermore stuffed with app. 150 gr polyfill each. Temporary 2 x 1,5 mm wire runs directly from the speakers - no terminals - to the amplifier (I plan to change this for some 2 x 4 mm wire I've still laying around).
At the moment they are connected to a Quad 33 amplifier and standing in a 3,6 x 4 m room. After app. 300 hours of playing in, they already sound very smooth and detailed. Listening mostly to classic (all epoques and genres) and some jazz.
The lowest bass notes sounds a little lumpy, which might be due to the small room and/or the Quad 33 not coping too well with the impedance in the lower bass.
Next steps:
- Use thicker speaker wire
- Try with other amps (Quad 405, Marantz 1030 & B&O 610 tube amp at hand)
- Add handles to the sides (the cuties are a bit heavy to move ... ). Would this be heresy?
- Uncouple them from the floor with rubber feet
- Add protection for the fragile drivers, but no metal grille. Any suggestions here?
Basic plywood finish, lightly varnished. To save cost & weight, I went with 3 window braces (like I found in a Bob Brines mltl design) instead of the recommended cross bracing. Around the speaker I lined the sides with 2 cm thick recycled cotton insulation, the speakers are furthermore stuffed with app. 150 gr polyfill each. Temporary 2 x 1,5 mm wire runs directly from the speakers - no terminals - to the amplifier (I plan to change this for some 2 x 4 mm wire I've still laying around).
At the moment they are connected to a Quad 33 amplifier and standing in a 3,6 x 4 m room. After app. 300 hours of playing in, they already sound very smooth and detailed. Listening mostly to classic (all epoques and genres) and some jazz.
The lowest bass notes sounds a little lumpy, which might be due to the small room and/or the Quad 33 not coping too well with the impedance in the lower bass.
Next steps:
- Use thicker speaker wire
- Try with other amps (Quad 405, Marantz 1030 & B&O 610 tube amp at hand)
- Add handles to the sides (the cuties are a bit heavy to move ... ). Would this be heresy?
- Uncouple them from the floor with rubber feet
- Add protection for the fragile drivers, but no metal grille. Any suggestions here?
How are you enjoying them?
There is a reason window braces are not used in this design. They are not recommended. 1st they are not as effective, and 2, they constrict the transmission line reducing its performance. You may need to use less damping and will suffer a bit more LF ripple
Also try skinnier wire inside. We use a pair of 24g solid wires pulled from a CAT5/6 cable.
dave
There is a reason window braces are not used in this design. They are not recommended. 1st they are not as effective, and 2, they constrict the transmission line reducing its performance. You may need to use less damping and will suffer a bit more LF ripple
Also try skinnier wire inside. We use a pair of 24g solid wires pulled from a CAT5/6 cable.
dave
They are really nice sounding, towards the clear & analitical side with a twist. Until now I've been listening mainly to good quality classical music internet radio at low and medium levels. Can't wait to test them with cd and higher definition sound files. They are a bit like assisting to a live concert. The few Jazz I listened to was even better. Probably still in need of some more break in though. Before I used to listen to some B&O S45, which are quite nice as well (be it a bit old). The Pencils sound more life-like with a better sound stage.
It's clear the recomended bracing would improve the sound (more detail too?) and stability of the cases. Maybe what I hear in the low bass/around 100 Hz could be this aditional ripple, though the Quad 33 is known to have some issues with low bass as well. (That will be my permanent flogging for deciding not to go with the best bracing)
I'll try with smaller instead of thicker wire too. Thank you for the suggestion.
And above all: thank you for this nice design!
Take care,
Wouter
It's clear the recomended bracing would improve the sound (more detail too?) and stability of the cases. Maybe what I hear in the low bass/around 100 Hz could be this aditional ripple, though the Quad 33 is known to have some issues with low bass as well. (That will be my permanent flogging for deciding not to go with the best bracing)
I'll try with smaller instead of thicker wire too. Thank you for the suggestion.
And above all: thank you for this nice design!
Take care,
Wouter
QUAD 303? Or the 33/303 pair? There are certainly a lot of better amps today.
I have owned at least a dozen 303s and a few 33s (as well as a 22 and a pai rof QUAD IIs. I gave up on them after comparing to my LM3875 AudioSector gain clone.
dave
Hi Wouter,
Nice 12p Pensils! I love mine, especially with a high impedance/low damping factor amp...tube or Firstwatt F1 or F2....and are still outstanding even with AmpCampAmp.
Mario
Nice 12p Pensils! I love mine, especially with a high impedance/low damping factor amp...tube or Firstwatt F1 or F2....and are still outstanding even with AmpCampAmp.
Mario
A Quad 303 without 33 indeed, my mistake. I did switch the speaker wires around, it's connected directly to my WAXD-10 streaming box.
With some micro full range speakers this amp works fairly well over here, but the pensil 12p speakers indicate where it could be better. I'll pair them with the tube amp I mentioned before (B&O 610).
Cheers,
Wouter
With some micro full range speakers this amp works fairly well over here, but the pensil 12p speakers indicate where it could be better. I'll pair them with the tube amp I mentioned before (B&O 610).
Cheers,
Wouter
