looking closer at the REV E board
Original Q8 audio driver and Q2 voltage driver MJE340 are there (NPN).
Q9 audio driver and Q1 voltage driver MJE350 PNP have been substituted with a Motorola device with 2453B marking. Having trouble determining what the 2453B devices are?
Motorola MJE350 are still available...thinking of pulling the devices marked with 2453B and replacing with MJE350.
Original Q8 audio driver and Q2 voltage driver MJE340 are there (NPN).
Q9 audio driver and Q1 voltage driver MJE350 PNP have been substituted with a Motorola device with 2453B marking. Having trouble determining what the 2453B devices are?
Motorola MJE350 are still available...thinking of pulling the devices marked with 2453B and replacing with MJE350.
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thanks Duke for letting me know that the 2453B is a house part number. BGW went to house part numbers in their amps after the 750's because discrete components were used on the front end instead of the opamp so these needed to be matched.
2453B is a MJE350 PNP with a grade of B.
that's good news that the front end components are original.
2453B is a MJE350 PNP with a grade of B.
that's good news that the front end components are original.
thanks Duke....definately worth the effort.
Both channels running at 30mV or less offset at output of opamp.
Also found one channel measuring 330V on bias tweaked to match other channel 380mV.
not sure if it's psychological but sitting in listening room wouldn't know it was the same amplifier. great amp lots of headroom, imaging galore and musical....dont believe the nay sayers...great amp for a home environment. I have all of $80 into it, some parts, some loving labor. can't judge the amp until it's been tweaked to sound as great as it can.
using an AEA 520 preamp that I acquired recently.
Both channels running at 30mV or less offset at output of opamp.
Also found one channel measuring 330V on bias tweaked to match other channel 380mV.
not sure if it's psychological but sitting in listening room wouldn't know it was the same amplifier. great amp lots of headroom, imaging galore and musical....dont believe the nay sayers...great amp for a home environment. I have all of $80 into it, some parts, some loving labor. can't judge the amp until it's been tweaked to sound as great as it can.
using an AEA 520 preamp that I acquired recently.
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thanks Duke....definately worth the effort.
Both channels running at 30mV or less offset at output of opamp.
Also found one channel measuring 330V on bias tweaked to match other channel 380mV.
Also back in 2016 during the recap effort took the time to source Wima MKS2 polyester capacitors for C1...it was a stretch getting them in but worth it.
not sure if it's psychological but sitting in listening room wouldn't know it was the same amplifier. great amp lots of headroom and musical in a home environment.
using an AEA 520 preamp that I acquired recently. Neither the seller nor I was aware what a great preamp this is.
Great to be able to speak with Ken Leonard (designer of 520) and Duke (VP engineering BGW) who both shared their passion for this industry. Legends
Both channels running at 30mV or less offset at output of opamp.
Also found one channel measuring 330V on bias tweaked to match other channel 380mV.
Also back in 2016 during the recap effort took the time to source Wima MKS2 polyester capacitors for C1...it was a stretch getting them in but worth it.
not sure if it's psychological but sitting in listening room wouldn't know it was the same amplifier. great amp lots of headroom and musical in a home environment.
using an AEA 520 preamp that I acquired recently. Neither the seller nor I was aware what a great preamp this is.
Great to be able to speak with Ken Leonard (designer of 520) and Duke (VP engineering BGW) who both shared their passion for this industry. Legends
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