Onix OA21 Stereo Integrated Amplifier - Rare Retro Classic - Upgraded Components
Item History & Price
| Reference Number: Avaluer:20589922 | Brand: Onix |
| Audio Outputs: XLR | Audio Inputs: XLR |
| MPN: OA21 | Model: OA21 |
| Type: Integrated Amplifier | Colour: Black |
| Number of Channels: 2 | RMS Power: 60 W |
| Rack Mountable: No |
I've owned this amp longer than any piece of kit and it sounds excellent IMO.
I've been interested in diy audio for well over 15 years and must of spent a small fortune on premium parts to try in this amplifier.
This is a list of the upgraded components fitted into the amplifier:
Noble volume pot - As used In the Avondale Grad 1 preamp - NLA unfortunately.
Main smoothing capacitors - Panasonic UP series 4700uf 63v - Chosen for their high ripple current rati...ng - 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 cheap stuff used).
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 :(
I've been interested in diy audio for well over 15 years and must of spent a small fortune on premium parts to try in this amplifier.
This is a list of the upgraded components fitted into the amplifier:
Noble volume pot - As used In the Avondale Grad 1 preamp - NLA unfortunately.
Main smoothing capacitors - Panasonic UP series 4700uf 63v - Chosen for their high ripple current rati...ng - 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 cheap stuff used).
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 :(
