What would be the reason to replace the bolts? It is quite intrusive to replace them all, and the patina is part of the appearance of the amp, IMO.
If you do replace them, then you need to take care with the ones for the valve sockets since the head size is such that the valve base does not foul the bolt heads. Not sure if that is standard with 4BA, but my vintage metric ones are not quite correct.
One of my amps was missing the rectifier socket, and it was non trivial finding one to fit in that hole too.
If you do replace them, then you need to take care with the ones for the valve sockets since the head size is such that the valve base does not foul the bolt heads. Not sure if that is standard with 4BA, but my vintage metric ones are not quite correct.
One of my amps was missing the rectifier socket, and it was non trivial finding one to fit in that hole too.
Ah yes, my mistake. Mains transformer will be 6BA. EF86 sockets 2BA. Not sure about the Jones socket but if they're small they will be 2BA again. As far as I can remember all the rest are 4BA. I'm away from home at the moment and can't check. Anyway everything will be one of these three. Everything cheesehead except the 2BAs which I can't remember. Never seen such a diagram as you mention. There are extant suppliers for all these new, in both UK and USA.
Found them all.6BA is the small ones.so 2BA x 1/2 inch x4 for mains transformer,4BA X 1/2 inch x 4 for output transformer.
4BA X 1/2 X 2 for choke.4BA x 1/2 x 4 for output transformer.
4BA x 5/16th x 14 for nameplate,KT66,KT66,GZ32,2 prong mains input and Jones 6 pin socket.6BA x 1/2 x 4 for EF86s and
6BA x 6/16th x 2 for mains voltage selector strip.
Have 2 slightly different Qiis.One has different screws in choke and the C5 cap clamps arent the same size.
This is fun...
4BA X 1/2 X 2 for choke.4BA x 1/2 x 4 for output transformer.
4BA x 5/16th x 14 for nameplate,KT66,KT66,GZ32,2 prong mains input and Jones 6 pin socket.6BA x 1/2 x 4 for EF86s and
6BA x 6/16th x 2 for mains voltage selector strip.
Have 2 slightly different Qiis.One has different screws in choke and the C5 cap clamps arent the same size.
This is fun...
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I've gone a bit mental on my par of Quad II's (and 22 preamp). I replaced all the passives as I typically do. But I replaced the very aged filter caps with a PCB and a set of film caps. These amps will now run for another 100 years. I didn't do anything with the IO, and I never cut metal. I left the Jones plugs since I typically run these amps with the companion preamp. I did make a custom set of standoffs for my PCB that are 8-32 on the PCB side and BA4 (british association) on the amp side so I can use the original screws.
Heres a few pics of my madness:
And testing with my rebuilt 22 preamp:
The Quad II's into a rebuilt set of original Quad ESL's and a good high res source shows just how little we have advanced in 60 years in terms of sound quality and musical transparency.
Sheldon
Heres a few pics of my madness:
And testing with my rebuilt 22 preamp:
The Quad II's into a rebuilt set of original Quad ESL's and a good high res source shows just how little we have advanced in 60 years in terms of sound quality and musical transparency.
Sheldon
I think you can change the sonic character in bad ways by using good parts. My goal in restoring mine was to use good quality parts, but nothing that quad wouldn’t have used if they had had them available at the time. That was how I felt I was being true to the original sound, but giving the amps another 30 years.
You can put exotic parts in it, but the bits that matter most - the transformers, tubes, and circuit - remain the same. So I’m not really sure what you would gain?
You can put exotic parts in it, but the bits that matter most - the transformers, tubes, and circuit - remain the same. So I’m not really sure what you would gain?
I hold the same philosophy Ahankinson , if you buy a vintage amplifier with a well known audio "signature " and was/is held in high regard by many audio professionals "uprating it " usually changes that well respected signature and it becomes a "new " amplifier --personally I would not buy a World Classic that was "doctored ".
The very same applies to old tube radios replacing all the components for the latest "Flavour of the Year " components actually reduces its value to those wanting the original sound even if it isn't what is considered "perfection " in 2021.
Once you start tampering with the actual design then you don't have an original .
The very same applies to old tube radios replacing all the components for the latest "Flavour of the Year " components actually reduces its value to those wanting the original sound even if it isn't what is considered "perfection " in 2021.
Once you start tampering with the actual design then you don't have an original .
Gonna grab the F&T caps plus some 0.1ufs pio from Mother Russia.K40Y-9. Resistors as some are way off spec.I think Amtrans AMRT carbon film.Was going for the AMRGs but at £4.40 each thats a bit ott.AMRTs 70p each.Will go 2 watt as rated for 500v.Also looking at Arcol carbon composite but seems max voltage 350V
I'm no expert by a mile about valves but I am enjoying researching it all and slowly learning.If all the components where in spec id leave it alone.
I'm no expert by a mile about valves but I am enjoying researching it all and slowly learning.If all the components where in spec id leave it alone.
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Ahankinsons Quad iis have obv had a lot replaced.The input 1M5,All the resistors on the tag board.Not sure what make but R3 different as well.Plus the main power caps.Also the KT66 coupling caps and C1.
If the resistors and caps are out of spec its obv a bit difficult to get the same components Peter Walker had at his disposal in circa 1956 ish.
I have no intention of changing the circuit in any way.Merely replacing components.And think that doing all the resistors may be best.Also quite a few resistors in the 22 pre amp are out of spec as well.Ie R31 which should be 47K is 116K.Guess its to be expected given their age.In the power amps the 180Ks are reading 220K and the 680Ks are reading between 710K to 730K.The 1M5 input to ground are 1M75 and 1M68.
Smiffy
If the resistors and caps are out of spec its obv a bit difficult to get the same components Peter Walker had at his disposal in circa 1956 ish.
I have no intention of changing the circuit in any way.Merely replacing components.And think that doing all the resistors may be best.Also quite a few resistors in the 22 pre amp are out of spec as well.Ie R31 which should be 47K is 116K.Guess its to be expected given their age.In the power amps the 180Ks are reading 220K and the 680Ks are reading between 710K to 730K.The 1M5 input to ground are 1M75 and 1M68.
Smiffy
My Quads were sitting in a basement (not overly damp, but not heated) for an unknown number of years before I got them. Most of the resistors tested out of spec, and one of the can caps was actually bad. I had no idea why they were in the basement, or what condition they were in, so they received fairly extensive testing and a thorough check-over for power supply, choke, and transformer shorts prior to applying power. I decided that it wasn't worth just keeping a couple of the original resistors in place if I was replacing so many others, so I did a wholesale revamp, but with as close to original values as I could get.
I also have two preamp units: One that was quite bad that I have heavily modified, and one that I've tried to keep as close to spec as possible. They're both out of commission at the moment as the balance / volume / power control is toast -- definitely the weakest link. I've got an order in with Blore-Edwards to make new ones, but that's taking some time.
I'm a bit less precious about the pre-amps because, while they're nice to have and do contribute to the whole package historically, they're mediocre pre-amps at best.
I currently have them running with the RCA-to-Jones adapter, and a Mackie "Big Knob" for volume control from an Apple TV via an HDMI audio extractor. Speakers are a pair of Onkyo Scepter 100s. They don't really need a pre-amp from most modern digital sources.
I also have two preamp units: One that was quite bad that I have heavily modified, and one that I've tried to keep as close to spec as possible. They're both out of commission at the moment as the balance / volume / power control is toast -- definitely the weakest link. I've got an order in with Blore-Edwards to make new ones, but that's taking some time.
I'm a bit less precious about the pre-amps because, while they're nice to have and do contribute to the whole package historically, they're mediocre pre-amps at best.
I currently have them running with the RCA-to-Jones adapter, and a Mackie "Big Knob" for volume control from an Apple TV via an HDMI audio extractor. Speakers are a pair of Onkyo Scepter 100s. They don't really need a pre-amp from most modern digital sources.
