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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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Thread Tools |
3rd Aug 2021, 10:04 am | #1 |
Diode
Join Date: May 2020
Location: Oeiras, Portugal
Posts: 5
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QUAD 303 protection diodes
I am repairing a Quad 303 and visited some sites and posts about it.
It came to my attention that some 'improved' driver boards use 3 diodes instead of just one for MR104 and MR105, to protect the driver transistors. Does anyone knows the reason for this change ? Best regards, Pedro Oliveira |
3rd Aug 2021, 12:11 pm | #2 |
Octode
Join Date: Aug 2006
Location: Stoke-on-Trent, Staffordshire, UK.
Posts: 1,082
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Re: QUAD 303 protection diodes
this will enable the amplifier to drive lower impedance loads
The 303 standard circuit peaks into an 8 ohm but current limits into 4 ohm you have to be careful though as the output transistors can overheat or overcurrent Trev |