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Luxman L-309V restauratie recap 2014 Luxman L-309V amplifier 2014 and SQ507X See the 2021 one ->>

This during 2014 refurbished L309V is for sale in the Netherlands, fixed price 700 Euros, cash and Local Pickup as I do NOT ship, I only answer if you provide your phone number also, see the moving mail address on my main page. Offers are NOT appreciated.

Deze Luxman L-309V had een brandgat in een der eindversterkers, en de andere was ook stuk. Beide defecte eindversterkers zijn opnieuw opgebouwd, de voeding is rigoureus verzwaard en alle aluminium elco's zijn vernieuwd, in 2014.

This L-309V amplifier rebuilt during 2014 suffered a partly burnt-through amp mainboard and multiple failures of both main amplifiers. Both main amps were rebuilt. A rigid recap and power supply upgrade was done.

The two main smoothing capacitors are enormous 33000 uF/100volts, now. Hardly fitting in the enclosure, they were chosen on availability and diameter size.

To be able to put them in, the bleeder resistors have moved to the place where the rectifier diodes resided. As they were not suitable to survive the peak currents the big caps use after switching on the power anyway, they were replaced by a 35 amp rectifier module, which is invisible below the wiring.

Observe the hole in the pcb on the picture on the right. An earlier repair was done by putting some wire over there, apparently the main amps were both repaired before.

One of the reasons one sees a lot of failures, is probably only the obvious faulty parts are replaced.

However, there are numerous reports of "crackling sound" and "hick-ups" in old Luxman amplifiers, in general.

The cause may be (and numerous times proven) NOT the failing power stage but the other smaller transistors causing the power stage to fail.

On internet forums, the two little input transistors part numbers are on the "replace whenever you see them" list, as they are supposed to deteriorate.

Interior of the amplifier, after the work was done.

The extent of it was less than the one done in 2021, although this one took a few weeks, also.

On the left picture top right, the Bleeder resistors are visible. There was no room for them on the capacitors, obvious on the picture on the right they are bigger than the original ones. Also, they are 100 Volts types, which is quite generous.

Just to the right of those bleeder resistors, the big rectifier is mounted on the chassis.

Het gat in de print is gevuld met epoxy, zodat hij netjes bestukt kan worden zonder zwevende draden, tenslotte is het geen oude buizenversterker, waar dat wel eens gebruikelijk is. De nieuwe weerstanden zijn meest metaalfilmtypen. Sommige elco's zijn "tantaal"typen, echter wel de "dure" welke je wle eens in militaire toepassingen ziet.

The pcb hole is epoxy-filled now, I want no hanging wiring like in a tube amp. Mostly metal film resistors are used, some metal-case Tantalum capacitors too.

Het schema van de gemodificeerde Luxman L309V eindversterker module, eventuele foutjes voorbehouden. De modificatie betreft de circuits voor nulinstelling en ruststroominstelling.

Het originele schema is verwant aan dat van het type L-85V.

Apart from possible errors, this schematic is as the main amplifiers presently are. Whereas offset and bias circuits have changed, it differs a bit from the real schematic of the Luxman L-309V

Also, the schematic of a Luxman L-85V main amplifier, closely resembles the L309V main amplifier schematic.

The L-85V schematics can be found on the internet, but the one of the L-309V seems to be not there. It is good enough to use as a repair guide.

With minor differences, the L-309V contains all the electronics found in the L-85V although placed on different circuit card layouts, including having the very same transformer.

This "EIC" transitor below may be a counterfeit one, or at least some "aftermarket brand". The brand was googled, it seemed to exist, but there is not enough info found to conclude anything. It was found in one of the main amplifier modules. Shamelessly, the font of the "NEC" brand is used. As the transistor looked old already, this apparently was from a repair long ago.

SQ507X en L-309V

See my other L-309V refurbished during 2021

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