Technical specifications

QUAD 22
• Stereophonic preamplifier
• Tubes: Mullard ECC83 (x2) and Mullard EF86 (x2)
• Inputs: Tuner, tape, phono, etc
• Year: Aprox. 1957

QUAD II
• Push-Pull monophonic power amplifier
• Power output: 15 watts
• Class: A
• Power tubes: GEC KT-66 tetrodes (x2)
• Driver tubes: Mullard EF86 (x2)
• Rectification tube: Mullard GZ32 double diode
• Year: Aprox. 1955

Al least! One of my favourite tube desings. I have been waiting for a Quad combo so many years... I have just received the units from the UK, thanks to Nick T. Besley, owner of the The Emporium. All the units look great. The first thing that has impressed me is the quality of construction of the units, specally the circuit of the preamp. I haven't heard them yet. But I hope I will do it next week-end. Keep tuned on this pages to see how things are going.

April 18th, 2000. The information available on the net about these wonderful units is massive. I would like to highligth one site. It is called Quad World. There you will find everything you need: schematics, tweaks, history, a lot of images, etc.
Of course, you can contact Quad Hi-Fi, the manufacturer of Quad products. Quad has a legendary technical service and there you will find everything. They can also repair 22s an IIs. I have ordered the original manuals of the units (10 pounds). That's what I call a good technical service!.

I have just started to plan the upgrades to do to my units. As I said before the trio is in excellent condition. So all the the work I will do will only be changing some components. Upgrades will include:

• Substitution of all the componenets out of tolerances. To do this I have selected the changes proposed by The Parts Connections in their web site. This will de done with the help of Jorge Bueno of Amptek.
  
  
• In order to connect a CD player to the 22 preamplifier it is necessary to do some changes in the unit. There're several ways to do it and you could find them at Quad World. I have chosen the "cleanest" option but to do it I have to began relations with the antipodes. Mike Coatham, from New Zealand, builds a connector that fits in the TAPE socket of the 22 and allows a CD to be connected. The price of the connector is 15 pounds (all included).
  
  

May 8th, 2000. I have just received the CD adaptor made by Mike Coatham, from New Zealand. It is perfectly build and it also works perfectly on the 22. If you want to connect a CD to the 22 preamp, this adaptor is what you need and Mike is your man.
But now I want to talk about the sound of the Quad 22/II partnered with the Quad ESL57.You can not imagine how I have enjoyed during this listening sessions. If the sound of the ESL57 + Dynaco ST 70 was good, now the sound is superb. The Quad preamp-amps are still in original condition (as you have read before I'm planning a component upgrade) but I couldn't resist and after cleaning the units I connect them to the Quad panels. The sound emerging from the panels is excellent. The clarity and definition is greater than before. The musical presence is also greater. The mid and low frequencies are better. Seeing this, I wonder why hi-fi world and hi-fi components are now worst than before. If Peter Walker built this wonderful components in the 50s, why we, with our greater technical development, can't have better gear at modest prices?I know the answer to my question. But I can't belive it.
But, let's talk about the sound.....As i said before mid and low frequencies are now better. I wonder if one of the reasons of this improvement is the fact that the Quad II are operating at an impedance of 15 ohms. I asked about this question at audioasylum and somebody, I can't remenber who, explain the reason why this happens. I will try more impedance combinations with the ST70. That's all. Keep tuned to know more.

May 29th, 2000.At least I have had time to take some photographs of my Quad units. Enjoy them!

• The Quad 22 and Quad II/II combo and a detail of the Quad 22 preamplifier.




• The Quad 22 from the back side and the Tape, CD (made by Mike Coatham from New Zealand) and Phono adaptors.




• The upper side of the Quad II circuit and the lower side of the same circuit.




• The Quad II power amplifiers and a detail of one of them.




• The another Quad II power amplifier and the quad plate where you can see the serial number of this unit: 52147.




• The another quad plate with serial number 56199 and a detail of the tubes used in Quad II. First, two Mullard EF 86 and on the back the GEC KT 66.




• Two images of the Quad II circuit.

Next episode: Modifying the Quad combo with images and explanations.

August 14, 2000. After intensive listening sessions during my holidays of the Quad 22/II combo partened with the ESL57 speakers and after receiving many emails about modifying these units, I have decided to leave them without changes. Changes will only be made when a componenet is out of tolerance. The sound from the Quad is so good that I think that It couldn't be improved changing components. Also, it seems that there's some kind of synergy between the components in the units that were chosen looking for their behavior in the whole context of the amplifier. So.. things will remain the same..