Hi All
A few weeks ago I bought a Quad 405 Mk 1 for peanuts and to add to my other Quad dinosaurs, or so I thought... It has been in storage elsewhere for at least 10 years and over the weekend, I decided to find out what gives, after all the negatives I read about it.
I took off the top plate and saw a virgin amp with everything clean, just like Huntingdon made it. I have a couple of restored 33 pre's but decided to use my workhorse Kenwood Ci Basic as a pre-amp, after making up an interconnect with rca phonos at one end and a 4-pin din at the other.
I don't know if my expectations were too low but I was actually pleasantly surprised - no crackles of pops, just surprisingly dynamic in sound - not bad for the 5 tenners (UK) I paid. And it packs a nice wallop too.
Later, I will try another pre or Quad's 33 to see what's up.
bulgin
A few weeks ago I bought a Quad 405 Mk 1 for peanuts and to add to my other Quad dinosaurs, or so I thought... It has been in storage elsewhere for at least 10 years and over the weekend, I decided to find out what gives, after all the negatives I read about it.
I took off the top plate and saw a virgin amp with everything clean, just like Huntingdon made it. I have a couple of restored 33 pre's but decided to use my workhorse Kenwood Ci Basic as a pre-amp, after making up an interconnect with rca phonos at one end and a 4-pin din at the other.
I don't know if my expectations were too low but I was actually pleasantly surprised - no crackles of pops, just surprisingly dynamic in sound - not bad for the 5 tenners (UK) I paid. And it packs a nice wallop too.
Later, I will try another pre or Quad's 33 to see what's up.
bulgin
Hi,
an amp that has aluminium electrolytic capacitors in it may need a bit of tender care before switching it on after long storage.
Apparently the oxide insulator degrades with time when insufficient voltage is across the terminals.
To recover the caps a process called reforming is advised. this builds up the insulator between the plates to ensure that excessive leakage does not damage the cap at switch on.
an amp that has aluminium electrolytic capacitors in it may need a bit of tender care before switching it on after long storage.
Apparently the oxide insulator degrades with time when insufficient voltage is across the terminals.
To recover the caps a process called reforming is advised. this builds up the insulator between the plates to ensure that excessive leakage does not damage the cap at switch on.
Quad 405
Hi Zombie, AndrewT
I know all about that (the caps) vulnerability at startup after storage and took a reckless chance (which I shouldn't have!), not knowing how to feed regulated ac to the amp. Fortunately, all is well by the looks of things.
Would you have any idea on how to go about this, please?
bulgin
Hi Zombie, AndrewT
I know all about that (the caps) vulnerability at startup after storage and took a reckless chance (which I shouldn't have!), not knowing how to feed regulated ac to the amp. Fortunately, all is well by the looks of things.
Would you have any idea on how to go about this, please?
bulgin
/sreten.Modifying?
Some of the kits at net-audio replace old elcos with new and better ones...why not change the opamp for a better one while at it?
The double PSU kit is not a mod, just an upgrade to the 306 and 606 level.
Would replacing the original PSU caps with 15000uF+ be a mod or an upgrade?
Would changing the 120p ceramic to a silver mica be a mod? Or make the upgrades Quad itself did to the 405-1?
Nope.
But I would consider the Snook and Ludwig suggestions to be "mods"...
Happy solstice
Thomas
Some of the kits at net-audio replace old elcos with new and better ones...why not change the opamp for a better one while at it?
The double PSU kit is not a mod, just an upgrade to the 306 and 606 level.
Would replacing the original PSU caps with 15000uF+ be a mod or an upgrade?
Would changing the 120p ceramic to a silver mica be a mod? Or make the upgrades Quad itself did to the 405-1?
Nope.
But I would consider the Snook and Ludwig suggestions to be "mods"...
Happy solstice
Thomas
Hi Bulgin,
you need to remove the electrical connection from at least one terminal of each electrolytic to allow connections from very high source impedance and DC voltage supply. And then monitor leakage and charge rate over a few hours. Quite a time consuming process and you must be careful to NOT accidentally short a charged capacitor risking internal damage and to yourself.
you need to remove the electrical connection from at least one terminal of each electrolytic to allow connections from very high source impedance and DC voltage supply. And then monitor leakage and charge rate over a few hours. Quite a time consuming process and you must be careful to NOT accidentally short a charged capacitor risking internal damage and to yourself.
Quad 405
Thanks Guys!!
I know about those dangers. My local expert sage for years on old timer amps has unfortunately moved away and 'gone fishin'. Time to read more electronics books and do the jobs myself, I guess. Replacing caps and changing stuff to make these old amps better and more convenient to use, I've done before.
Regards to all
bulgin
Thanks Guys!!
I know about those dangers. My local expert sage for years on old timer amps has unfortunately moved away and 'gone fishin'. Time to read more electronics books and do the jobs myself, I guess. Replacing caps and changing stuff to make these old amps better and more convenient to use, I've done before.
Regards to all
bulgin
Quad 405
Hello All & Current Dumper
My congratulations (and amusement!) at your original choice for a 'rack mount handle' here at diyaudio.com -clap, clap and a hearty Heheeheee!
If you could find the time, I would appreciate very much a posting of this schematic as the Quad impressed me until now and I'm trying to find a little space to fit it somewhere to be permanently hooked up.
I visited a friend today and found a little orange and gold tuner tuned to some jazz this afternoon. Anyway, he told me about another 405/44 setup for sale locally (Cape Town) for the equivalent of UKP450.- , far too much.
At the moment, I'm running it with a Kenwood Basic CI pre, which is my little workhorse (also using it with my Leak Stereo 20) and this partnership sounds really good.
Thanks for your kind offer.
Nice weekend to all
bulgin
Hello All & Current Dumper
My congratulations (and amusement!) at your original choice for a 'rack mount handle' here at diyaudio.com -clap, clap and a hearty Heheeheee!
If you could find the time, I would appreciate very much a posting of this schematic as the Quad impressed me until now and I'm trying to find a little space to fit it somewhere to be permanently hooked up.
I visited a friend today and found a little orange and gold tuner tuned to some jazz this afternoon. Anyway, he told me about another 405/44 setup for sale locally (Cape Town) for the equivalent of UKP450.- , far too much.
At the moment, I'm running it with a Kenwood Basic CI pre, which is my little workhorse (also using it with my Leak Stereo 20) and this partnership sounds really good.
Thanks for your kind offer.
Nice weekend to all
bulgin
Quad 405 MK 1 - MAINS AC ON/OFF
Hi Wise Men
I've hooked-up the Quad on my overpopulated equipment rack which is parked against a wall. It had to go in sideways, next to my Leak Stereo 20 and the mains lead goes to an ac 220V socket extender, where all my other things are also plugged-in. This extender powers whatever amp I'm using, plus the pre-amp, and is also hidden in an inaccessible place.
The ac socket extender will never be overloaded as only two items are drawing current at a time and there is enough space between the equipment for dissipating heat.
It is however inconvenient to reach the ac extender to switch off the Quad although I know many prefer to leave amps powered-up permanently.
I am however a bit uneasy about this (leaving it on) and am thinking about fitting a suitable rocker/toggle switch to the Quad's back panel so I can turn off the mains.
I can work carefully and electrically safe. Does anyone have any opinions re this, please?
Other ideas are that I could possibly fit an ac inline switch to the powercord or does anyone know if a switched IEC terminated powercord is made?
Cheers
bulgin
Hi Wise Men
I've hooked-up the Quad on my overpopulated equipment rack which is parked against a wall. It had to go in sideways, next to my Leak Stereo 20 and the mains lead goes to an ac 220V socket extender, where all my other things are also plugged-in. This extender powers whatever amp I'm using, plus the pre-amp, and is also hidden in an inaccessible place.
The ac socket extender will never be overloaded as only two items are drawing current at a time and there is enough space between the equipment for dissipating heat.
It is however inconvenient to reach the ac extender to switch off the Quad although I know many prefer to leave amps powered-up permanently.
I am however a bit uneasy about this (leaving it on) and am thinking about fitting a suitable rocker/toggle switch to the Quad's back panel so I can turn off the mains.
I can work carefully and electrically safe. Does anyone have any opinions re this, please?
Other ideas are that I could possibly fit an ac inline switch to the powercord or does anyone know if a switched IEC terminated powercord is made?
Cheers
bulgin
Quad 405 MK 1 - MAINS AC ON/OFF
Thanks Andrew
I'll check it out tomorrow at an electrical wholesaler but I'll think twice if the cutout will have be made bigger.
I have fitted these IEC sockets to many things like my pre's and quite a few tt's as they are so convenient and allow better quality powercords but I usually avoid hacking stuff unless the end result looks like 'the factory made it so'.
Regards
bulgin
Thanks Andrew
I'll check it out tomorrow at an electrical wholesaler but I'll think twice if the cutout will have be made bigger.
I have fitted these IEC sockets to many things like my pre's and quite a few tt's as they are so convenient and allow better quality powercords but I usually avoid hacking stuff unless the end result looks like 'the factory made it so'.
Regards
bulgin
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