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Sansui Q15 tube preamplifier

Please advise me on the tubes used in this pre. I am trying to restore it. One of the tubes is missing.Was told that it was a 5GK4 tube.Most of the other tube have no clear marking on them.Thanks

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6 Suggested Answers

  • 31 Answers

SOURCE: Using a tube pre amp with my CA Azur 640A?

There are many answers to your questions but Ill have a go with the basics...
Audio connections should be matched.... its called Frequency impedance,.... to get a signal along wires or cables (or Fibre) the Impedance of the cables and wires must be matched to the device they are connected to transfer the signal along the cables without distortion...

Manufacturers provide many sockets on the input side of amplifiers and preamplifiers to allow the consumer to connect various devices of different impedance.

They label these inputs like CD, or Tuner, or PHONO etc etc,

That means if you have a CD player it must be plugged into the CD input socket then the impedance will be correct and the sound will transfer along the CD cables correctly, without distortion..same with the Phono input etc...
You will find on the sound output to the speakers terminals are also labelled 4-6ohm, or 8-10ohm, these are the impedance expected for the coil ratings of the speakers them selves and its important to get the correct speakers to the correct out put terminals...

In your case all you have to do is follow these simple rules and all will be well....you say you have a squeeze box well there probably isnt a port labelled squeeze box so you need to experiment and try out each input port for the squeeze box to see what input gives you the correct sound output...Watch the Phono inputs as these are very sensative to input sound levels and must be treated very carefully as they have a double stage of sound amplification and as such you need to have the volume right down when connecting up the Phono inputs then increase the volume carefully after the cable connections are completed.

If you follow these rules then all will be well,,,,there is no difference if the Pre amp or Power amp is valve or transistor or FET or has IC outputs to the speaker the same impedance rules apply..just treat it as a box with input and output terminals and all the impedance will be taken care of for you...if you read the lables...

You need to connect you signal source to the Preamp inputs the out put from the Preamp connects to the power amp input then the power amp output goes to the speakers. this is a basic configuration for sound systems, there are other variations but are outside this discussion.

Cheers From YUBEUT

Posted on Nov 16, 2007

  • 1348 Answers

SOURCE: Wanted: O-Manual or Photo, all the Labeling is gone on mine!

take the bottom cover off.look where the connectors go.the ones that go to the input selector switch are inputs.
the pair by themselves will be the outputs.

Posted on May 14, 2009

  • 1 Answer

SOURCE: Looking for Owners Manual or Photo with Labeling.

I followed the recommendation that 'kirtec' left me;

Take the bottom cover off. look where the connectors go. The ones that go to the input selector switch are inputs.
The pairs by themselves will be outputs.

I was concerned about doing this as this is my 1st preamp w/ Tubes and I didn't get any spares. I'm really looking looking for an owners manual so I can find out how it's supposed to be labeled on the back + how it rated + what tubes it uses so I can get some spares.
Please don't get me wrong, I really appreciate his help - I was hoping there might be someone that's better at surfing the Web than I am who might be able to find one; I believe the vintage in 1982-1989.

I looked at the sites that advertise on here for owners/instruction manuals & couldn't find one ~ I'm not looking for something for nothing but I'm lost when it comes to finding one right now.

Appreciate everyone's time & energy who helped - Thanks!

FYI, the PreAmp is a 'Counterpoint Electronic Systems SA 3.1 Dual Channel Tube Pre amplifier'

Sandwichjohn or John B. from Illinois

Posted on May 15, 2009

petraman7
  • 1175 Answers

SOURCE: Looking for schematic for sansui au70 tube amp

Try

www.servicemanuals.net

or

join www.audiokarma.org (its free) and ask around

PLease rate my help if this helps

Posted on Jan 26, 2010

  • 6771 Answers

SOURCE: Yesturday tube pre worked and

Chances are the tube in PreSonus TubePre Amplifier will need to be replaced.

Posted on Aug 01, 2011

omecron2001
  • 22 Answers

SOURCE: tube pre is on constant overdrive, what's wrong

Check your controls volume mite be bad or have broken leg / or for that matter anyone of control

Posted on Dec 08, 2012

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Looking for schematic for sansui au70 tube amp circa 1964.


Try

www.servicemanuals.net

or

join www.audiokarma.org (its free) and ask around

PLease rate my help if this helps

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1 Answer

Looking for Owners Manual or Photo with Labeling.


I followed the recommendation that 'kirtec' left me;

Take the bottom cover off. look where the connectors go. The ones that go to the input selector switch are inputs.
The pairs by themselves will be outputs.

I was concerned about doing this as this is my 1st preamp w/ Tubes and I didn't get any spares. I'm really looking looking for an owners manual so I can find out how it's supposed to be labeled on the back + how it rated + what tubes it uses so I can get some spares.
Please don't get me wrong, I really appreciate his help - I was hoping there might be someone that's better at surfing the Web than I am who might be able to find one; I believe the vintage in 1982-1989.

I looked at the sites that advertise on here for owners/instruction manuals & couldn't find one ~ I'm not looking for something for nothing but I'm lost when it comes to finding one right now.

Appreciate everyone's time & energy who helped - Thanks!

FYI, the PreAmp is a 'Counterpoint Electronic Systems SA 3.1 Dual Channel Tube Pre amplifier'

Sandwichjohn or John B. from Illinois

May 14, 2009 | Amplifiers & Preamps

1 Answer

No output from my receiver


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Apr 01, 2008 | Amplifiers & Preamps

1 Answer

Using a tube pre amp with my CA Azur 640A?


There are many answers to your questions but Ill have a go with the basics...
Audio connections should be matched.... its called Frequency impedance,.... to get a signal along wires or cables (or Fibre) the Impedance of the cables and wires must be matched to the device they are connected to transfer the signal along the cables without distortion...

Manufacturers provide many sockets on the input side of amplifiers and preamplifiers to allow the consumer to connect various devices of different impedance.

They label these inputs like CD, or Tuner, or PHONO etc etc,

That means if you have a CD player it must be plugged into the CD input socket then the impedance will be correct and the sound will transfer along the CD cables correctly, without distortion..same with the Phono input etc...
You will find on the sound output to the speakers terminals are also labelled 4-6ohm, or 8-10ohm, these are the impedance expected for the coil ratings of the speakers them selves and its important to get the correct speakers to the correct out put terminals...

In your case all you have to do is follow these simple rules and all will be well....you say you have a squeeze box well there probably isnt a port labelled squeeze box so you need to experiment and try out each input port for the squeeze box to see what input gives you the correct sound output...Watch the Phono inputs as these are very sensative to input sound levels and must be treated very carefully as they have a double stage of sound amplification and as such you need to have the volume right down when connecting up the Phono inputs then increase the volume carefully after the cable connections are completed.

If you follow these rules then all will be well,,,,there is no difference if the Pre amp or Power amp is valve or transistor or FET or has IC outputs to the speaker the same impedance rules apply..just treat it as a box with input and output terminals and all the impedance will be taken care of for you...if you read the lables...

You need to connect you signal source to the Preamp inputs the out put from the Preamp connects to the power amp input then the power amp output goes to the speakers. this is a basic configuration for sound systems, there are other variations but are outside this discussion.

Cheers From YUBEUT

Nov 12, 2007 | Cambridge Audio Azur 640A Amplifier

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