Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Quickie => Topic started by: Remoter on May 23, 2013, 05:53:27 AM
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When the Q is hooked up to my SS Sansui main in jacks I get a very low muffled sound. When hooked up to my ST70 there is no sound - nothing.
Any ideas?
Dan
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Has it worked before, or are you trying it for the first time?
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I should mention that all resistance and voltage measurements checkout as per manual.
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I had it hooked up before but sounded very shrill - clearly not what I was hoping for. So I went through the build sheet from the beginning and discovered 2 issues. 1. I had soldered the 1K resistor where the 475K goes - switched them around and all was well with my resistance values. In checking voltages I discovered that I had 1 dead 9 volt battery - replaced it with a fresh battery and voltages are within a couple of percentages of manual.
Also discovered that terminal 5 on the rotary switch moves freely. It moves laterally when you turn the switch. This terminal goes to the lower input rca. I have requested a replacement switch so in the mean time I am using the other inputs.
Dan
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If voltages are good, here are some possibilities for why the output is low or not there at all:
Input and output cables reversed.
Input or output jacks shorted by a solder bridge between the center pin and the outer shell.
Switch contacts compromised from overheating - I suggest this because of the loose lug you mention.
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If voltages are good, here are some possibilities for why the output is low or not there at all
Voltage good
Input and output cables reversed.
Hooked back up to Sansui making sure cables not reversed. Same low volume muffled sound.
Input or output jacks shorted by a solder bridge between the center pin and the outer shell.
I don't see any bridging
Switch contacts compromised from overheating - I suggest this because of the loose lug you mention. The switch may have been damaged by heat but I don't know how to determine that.
Here's a pic
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Another observation - There is a hum that is not affected by volume. Hum doubles in loudness when I turn the amp off and then fades to no sound within 5 seconds.
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OK, you had sound initially, and then you changed some stuff and now you have no sound. So go back and inspect the things you changed. Are the reconnected parts connected to the proper terminals?
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As you are going to replace the switch anyway , why don't you remove it and wire one set of inputs direct...John
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Okay I've gone through all the changes that I had made I don't see anything askew and again all values are as they should be.
I'm hoping the problem is the switch.
Dan
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Sounds like its going to be a few days before BH has the switch in stock. To take the switch out of the equation as John suggests am I simply connecting the red wires from the right and left jacks together?
Dan
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I don't have a Quickie so I am guessing a bit. I am thinking that there are 2 or more sets of input jacks that go to the switch, then from the switch to the pot.
If that is it, for the right channel, disconnect the wire that goes to the pot at the switch side and disconnect the wire from the center pin of one of the R input jacks and connect these two wires together.
Do the same for the Left channel and cover the connections with a bit of tape...John
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This is one of those 'opportunities' to try to get your head around what each wire does, which one is hot, which is ground etc. I tell ya though, once you get to know this little puppy inside and out, its really fun to mess with it. Now that I think about it, removing that switch was the first mod I did. I didnt need more than one input.
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I'll tell you Eric when I retrieve the little bastard from the roof I would like to ask you specifically how you wired the RCA's. it looks like I would simply run the wires from left and right RCA's that currently go to the switch and connect them. Yes?
Dan
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Right. I just looked at the Quickie manual to remember what to do, I didnt use their wire so my wires are all the same color, but basically, the switch is wired into the positive circuit, but it is easy to take it out. What you need to follow, is to first identify what is positive, negative, and ground on the pot. There are three poles for each channel. One channel stacked on the other. Looking down on the pot from the bottom, going from left to right, the poles are positive, negative then ground. On the bottom of the RCA jack the middle post is positive, and the outer ring is ground. You will notice that all the grounds are hooked together. When you take the switch out you want to wire one pair of RCAs directly to the pot. Positive on the left pole, negative in the middle, ground on the right. The only wire you are changing is the positive. That is the one that gets routed through the switch. Both negative and ground stay the same. Hope that helps!
Cheers - Eric
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I just received my Quickie kit yesterday. When I turned it on there was a clear volume balance issue with the left and right channels, also when I try to raise the volume of my amp clicks off and sends sporadic portions of the signal to the left and right channel. Any suggestions?
I appreciate the help, this is my first tube build.
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The first thing to check is to be sure that you have the 1.07K and 475K resistors in the correct positions, as they look the same. (How did the voltage checks go?)
As always, you will want to power up your power amp last.
-PB
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Thank you for you reply,
The resistors are in the correct place, one of the resistors was not working properly when I first soldered it in so I had to replace it with a 1k 1/4 watt resistor from radio shack. When I hook up the pre-amp to my Mcintosh amp the clicking off disappears but the left and right volume issue is still present. I shall continue troubleshooting and keep you updated.
-david
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You may also want to measure the impedance of the pot,if both channels are the same. I eventually upgraded my pot, which solved the problem I had.
Michael
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How much rotation of the volume control are you able to use? If you have a very sensitive, high gain system, it may be that you are only using 5-10 degrees of the pot rotation, and that would account for what would normally be a bit of low volume channel imbalance.
Otherwise, try swapping the tubes to see if one of them may be weak. (Also try swapping D-cells for that matter). A weak tube, however, would exhibit voltage issues that would be quite noticeable (high plate voltage, low cathode voltage).
With your McIntosh off, measure the resistance between the chassis of the amplifier and the shell of its input RCA jack. (This should be very low impedance)