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Using the QUAD II's without the QUAD 22

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Nemeske

Nemeske

Member
Joined 2016
#1
Dear Forum,

I am asking, what are the most important arrangements to use the amps without it's preamp?
I found these probably suitable to directly hook them up with my DAC's RCA output.
I have to buy an another set of Bulgin power plugs, and earth the chassis, too, but I could use the existing one from the 22's

I read somewhere, that there is no DC coupling cap at the signal input of the II's, that one's should think about of.

What do you think?

Is it mandatory to have a preamp, or would the DAC's output enough?

Thank you for your help in advance!
 
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#2
I use my QIIs without the 22 preamp. They each have an RCA plug, and I did add a DC blocking cap, as in Patrick Turner's minimalist modded version. Don't forget the grid resistor after the cap.

The main hassle of not having a preamp is setting the volume. I mostly use a Bluetooth Receiver, so volume is set on the source device.
 
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#4
It was just a suggestion to add the blocking cap, to protect from a potential issue from a source with DC. I think it would be too much of a squeeze to get the cap in the plug, but I suppose it does not need to be 630V, so maybe a lower voltage one would fit.


Screenshot 2022-05-30 092635.png
 
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#5
OldHector said:
J'utilise mes QII sans le préampli 22. Ils ont chacun une prise RCA, et j'ai ajouté un capuchon de blocage DC, comme dans la version modded minimaliste de Patrick Turner. N'oubliez pas la résistance de grille après le capuchon.

Le principal souci de ne pas avoir de préampli est le réglage du volume. J'utilise principalement un récepteur Bluetooth, donc le volume est réglé sur l'appareil source.
Click to expand...
on one of my daily amps (a harman A300 massacred by the previous owner), I use this technique, a bluetooth receiver voice-controlled by an Amazon Alexa speaker, it works wonderfully well, including for switching on/off with a plug connected.
 
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#7
If you only will use it with your DACs rca output why don't measure if you have any DC there. If not you are good to go I think.
And the IIs need about 1,5Volt swing to reach it full capacity. So if your DAC can deliver ca 1,5v output it will be fine. But I think anything over 1volt will work properly. Personally I will mod my Quad 34 from 0,5Volt output to reach 1,5. Just a couple of resistors to change.
 
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#9
Hey there, I owned a pair for around 20 years and never used a cap on the input, it was being fed from a EAR "The Preamp" Tim's first commercial product. The IIs are a little low in sensitivity, but that is back in the days when preamps put out 250 to 400mv. You can feed this from a DAC without any issues. You can buy those plugs, or just drill a hoel and put a quality RCA socket in, there is lots of space. What tubes are in yours, do you have the original GEC?
 
#10
Dear konst,

Thank you for your useful info!
I have the original GECs and bought a set of very very old grey OSRAM's. The last thing I want to do is to modify the chassis, I want them in the way QUAD manufactured, that is why I am looking for these Jones 6 to RCA gaskets!
 
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