Quad 33/405 Headphone Interoperability - UK Vintage Radio Repair and Restoration Discussion Forum

Bookman · 10th Jun 2018, 8:56 pm

My 33/405 are such that I would not wish to waste any more time or indeed money tinkering with possible alternative systems.

I have a good mix of cartridges/styli and corresponding removable head shells and wands which all sound superb but it would be nice to spend time to check out any possible specific differences through headphones; virtually still brand new Wharfedale DD1s to be more exact.
It would appear that there are several headphone amps that will accept a preamp input and main amp output with inbuilt and controllable headphone socket but they are over a grand?
However, I have a pristine Leak Stereo 30 Plus and was thinking that all I need do is disconnect the turntable (or CD) from the 33 and plug it into the "30 plus" but would appreciate any suggestions from the forum.
After all the Leak as we know is itself a very nice piece of kit.

Synchrodyne · 10th Jun 2018, 9:08 pm

Another approach might be to take a feed from the tape output of the Quad 33 into say the “Radio” input of the Leak Stereo 30 Plus. That way no “plugging and unplugging” is involved.

If the Quad 33 tape output is already “busy” feeding a tape deck or other recording apparatus, bear in mind that it is low impedance, so that splitting it to feed two items is unlikely to be a problem.

Cheers,

Bookman · 11th Jun 2018, 7:29 am

Thanks, will give it try - most appreciated.

Mooly · 11th Jun 2018, 8:00 am

If the headphones are for occasional use to evaluate system changes then another possible alternative is connect them to the 405 speaker outputs via a simple resistive L pad attenuator (to maintain low impedance across the headphones).

Bookman · 11th Jun 2018, 8:29 pm

Quote:

Originally Posted by Synchrodyne

Another approach might be to take a feed from the tape output of the Quad 33 into say the “Radio” input of the Leak Stereo 30 Plus. That way no “plugging and unplugging” is involved.

If the Quad 33 tape output is already “busy” feeding a tape deck or other recording apparatus, bear in mind that it is low impedance, so that splitting it to feed two items is unlikely to be a problem.

Tried the tape o/p suggestion but the signal was extremely low in fact hardly audible. Plugged the phono direct and it confirmed the Leak still kicks out a nice sound.
I guess a manually operated noise free two way 3 ganged switch with two female RCAs either side plus two isolated earth terminals would work nicely if such a thing is available. Would go for a powered one at a push if anyone knows if a proprietary item exists?
Two way represents main amp/pre amp and main speakers only in one position and Leak with headphones in other position.

Ted Kendall · 11th Jun 2018, 9:20 pm

Quote:

Originally Posted by Bookman

Tried the tape o/p suggestion but the signal was extremely low in fact hardly audible.

Did you use the right pins? Tape output is on 1 and 4, with 2 earth as ever.

In any case, the tape output level is selectable on the adaptor card.

You should be able to load the Radio input with no trouble at all.

Synchrodyne · 12th Jun 2018, 12:49 am

Agreed that there should not be a level matching problem between the Quad 33 tape output and the Leak Stereo 30 Plus radio input.

The Quad 33 tape output has three levels available, namely:

H: 100 mV average programme
M: 20 mV
L: 3.7

H is the normal setting, for use with tape deck/recorder “line” inputs.
M and L facilitate matching to tape deck/recorder DIN inputs.

The Leak Stereo 30 Plus has radio inputs as follows:

Tuner 1: 25 mV sensitivity, 47k impedance
Tuner 2:
HI (sensitivity) 60 mV, 50k
LO (sensitivity) 250 mV, 50k

The Quad 33 tape output set to “H”, for 100 mV nominal, should be a good match for the Leak Stereo 30 Plus Tuner 2 output set to “HI”, for 60 mV sensitivity.

Cheers,

Bookman · 12th Jun 2018, 5:41 pm

Thanks Guys,
I can confirm tape input settings were positioned using the "L" screw and that the output settings were set at "H". I have put them all in the H setting mode and have noted the difference albeit the system works in the pickup setting but not tuner.
I did try the system with input set at M but with no difference.
Only drawback is the slight hum.
In all cases I tried the 33 tape output in the Leak tape "record" input and it functioned as it should irrespective of tape O/P socket selected.

10th Jun 2018, 8:56 pm	#1
Bookman Hexode Join Date: Aug 2017 Location: Taunton, Somerset, UK. Posts: 318	Quad 33/405 Headphone Interoperability My 33/405 are such that I would not wish to waste any more time or indeed money tinkering with possible alternative systems. I have a good mix of cartridges/styli and corresponding removable head shells and wands which all sound superb but it would be nice to spend time to check out any possible specific differences through headphones; virtually still brand new Wharfedale DD1s to be more exact. It would appear that there are several headphone amps that will accept a preamp input and main amp output with inbuilt and controllable headphone socket but they are over a grand? However, I have a pristine Leak Stereo 30 Plus and was thinking that all I need do is disconnect the turntable (or CD) from the 33 and plug it into the "30 plus" but would appreciate any suggestions from the forum. After all the Leak as we know is itself a very nice piece of kit.

10th Jun 2018, 9:08 pm	#2
Synchrodyne Nonode Join Date: Jan 2009 Location: Papamoa Beach, Bay of Plenty, New Zealand Posts: 2,944	Re: Quad 33/405 Headphone Interoperability Another approach might be to take a feed from the tape output of the Quad 33 into say the “Radio” input of the Leak Stereo 30 Plus. That way no “plugging and unplugging” is involved. If the Quad 33 tape output is already “busy” feeding a tape deck or other recording apparatus, bear in mind that it is low impedance, so that splitting it to feed two items is unlikely to be a problem. Cheers,

11th Jun 2018, 7:29 am	#3
Bookman Hexode Join Date: Aug 2017 Location: Taunton, Somerset, UK. Posts: 318	Re: Quad 33/405 Headphone Interoperability Thanks, will give it try - most appreciated.

11th Jun 2018, 8:00 am	#4
Mooly Octode Join Date: May 2011 Location: Lancashire, UK. Posts: 1,351	Re: Quad 33/405 Headphone Interoperability If the headphones are for occasional use to evaluate system changes then another possible alternative is connect them to the 405 speaker outputs via a simple resistive L pad attenuator (to maintain low impedance across the headphones).

12th Jun 2018, 12:49 am	#7
Synchrodyne Nonode Join Date: Jan 2009 Location: Papamoa Beach, Bay of Plenty, New Zealand Posts: 2,944	Re: Quad 33/405 Headphone Interoperability Agreed that there should not be a level matching problem between the Quad 33 tape output and the Leak Stereo 30 Plus radio input. The Quad 33 tape output has three levels available, namely: H: 100 mV average programme M: 20 mV L: 3.7 H is the normal setting, for use with tape deck/recorder “line” inputs. M and L facilitate matching to tape deck/recorder DIN inputs. The Leak Stereo 30 Plus has radio inputs as follows: Tuner 1: 25 mV sensitivity, 47k impedance Tuner 2: HI (sensitivity) 60 mV, 50k LO (sensitivity) 250 mV, 50k The Quad 33 tape output set to “H”, for 100 mV nominal, should be a good match for the Leak Stereo 30 Plus Tuner 2 output set to “HI”, for 60 mV sensitivity. Cheers,

12th Jun 2018, 5:41 pm	#8
Bookman Hexode Join Date: Aug 2017 Location: Taunton, Somerset, UK. Posts: 318	Re: Quad 33/405 Headphone Interoperability Thanks Guys, I can confirm tape input settings were positioned using the "L" screw and that the output settings were set at "H". I have put them all in the H setting mode and have noted the difference albeit the system works in the pickup setting but not tuner. I did try the system with input set at M but with no difference. Only drawback is the slight hum. In all cases I tried the 33 tape output in the Leak tape "record" input and it functioned as it should irrespective of tape O/P socket selected.