fatmarley
20-09-2019, 09:25
I've owned this amp longer than any piece of kit and i'm honestly in two minds about selling it. What I would Ideally like is to sell it to someone who would give me first refusal if they ever decided to sell. I'm more than happy for people to come and listen first (you wont be disappointed)
Vocals are lovely and clean, and project well. Treble is smooth and detailed, and bass is tight and deep. It sounds very similar to my modified Quad 306, so in that respect, there's no reason to keep it. I'm keeping the 306 because it's easier to work on and I can experiment with passive preamps.
Volume pot was replaced with a Noble - As used In the Avondale Grad 1 preamp - NLA unfortunately.
Main smoothing capacitors - Panasonic UP series 4700uf 63v - Chosen for their high ripple current rating - Also NLA, and also unfortunate.
Bridge rectifier replaced with LQA30T300 Q-Speed soft recovery diodes.
Relays replaced for service/longevity reasons
T0-3 Transistors heatsink thermally bonded to the case with Noctua NT-H1 thermal compound (better heat transfer than the usual stuff).
Coupling capacitors replaced with Nichicon FW (standard for audio) These are by far the best sounding coupling caps I've tried In the Onix and i've tried a lot.
Vishay Sprague Tantalex 150D are in the feedback position. Chosen because they are, or were used in the Avondale NCC200 power amplifier and sound better than anything else i've tried. In the past I tried Elna Silmic (Too smooth/soft) - Nichicon Muse KZ (thin and harsh In the upper midrange), Polypropylene (various), polyester and Russian K52-2 Silver Tantalum all gave a similar sound to Nichicon Muse KZ.
Transistors in the long-tailed-pair are matched (HFE and VBE) and thermally bonded. This lowered the DC offset from about 20 to 25mv down to about 5 to 10mv (See here for details - http://paul-kemble.tripod.com/sound7e.html)
Bias set to 18mv (as it should be)
Most of the resistors are replaced with Vishay Dale RN60 apart from the sensitive feedback loop area, where i've used standard MRS25 metal films (RN60 sound a touch soft here)
The negatives - No phono card Is fitted, and the external power supply Input socket was removed (only needed if you were planning on adding a Soap power supply). They were removed when trying out various mods but the shed leaked and they must of got thrown out with a load of electrical equipment that went rusty :(
There are a few scratches and a small dent on one side as can be seen in the pictures.
Looking for £250 plus £15 p&p
Pics to follow...
Vocals are lovely and clean, and project well. Treble is smooth and detailed, and bass is tight and deep. It sounds very similar to my modified Quad 306, so in that respect, there's no reason to keep it. I'm keeping the 306 because it's easier to work on and I can experiment with passive preamps.
Volume pot was replaced with a Noble - As used In the Avondale Grad 1 preamp - NLA unfortunately.
Main smoothing capacitors - Panasonic UP series 4700uf 63v - Chosen for their high ripple current rating - Also NLA, and also unfortunate.
Bridge rectifier replaced with LQA30T300 Q-Speed soft recovery diodes.
Relays replaced for service/longevity reasons
T0-3 Transistors heatsink thermally bonded to the case with Noctua NT-H1 thermal compound (better heat transfer than the usual stuff).
Coupling capacitors replaced with Nichicon FW (standard for audio) These are by far the best sounding coupling caps I've tried In the Onix and i've tried a lot.
Vishay Sprague Tantalex 150D are in the feedback position. Chosen because they are, or were used in the Avondale NCC200 power amplifier and sound better than anything else i've tried. In the past I tried Elna Silmic (Too smooth/soft) - Nichicon Muse KZ (thin and harsh In the upper midrange), Polypropylene (various), polyester and Russian K52-2 Silver Tantalum all gave a similar sound to Nichicon Muse KZ.
Transistors in the long-tailed-pair are matched (HFE and VBE) and thermally bonded. This lowered the DC offset from about 20 to 25mv down to about 5 to 10mv (See here for details - http://paul-kemble.tripod.com/sound7e.html)
Bias set to 18mv (as it should be)
Most of the resistors are replaced with Vishay Dale RN60 apart from the sensitive feedback loop area, where i've used standard MRS25 metal films (RN60 sound a touch soft here)
The negatives - No phono card Is fitted, and the external power supply Input socket was removed (only needed if you were planning on adding a Soap power supply). They were removed when trying out various mods but the shed leaked and they must of got thrown out with a load of electrical equipment that went rusty :(
There are a few scratches and a small dent on one side as can be seen in the pictures.
Looking for £250 plus £15 p&p
Pics to follow...