Goldpoint help anyone?

[pro_crip]

I finally isolated the problem with my crack, I mis-wired the Goldpoint stepped attenuator I had planned on putting in there. I put in the stock unit and everything works great. The Goldpoints have an in, out and ground terminals so I wired accordingly: the wire from the rca pin went into the in terminal; the out terminal went to the appropriate input pin on the tube socket, and the black wire from the rca's went into the ground terminal. If anyone out there put a Goldpoint in their crack could they let me know exactly how they wired theirs or point out a possible error. Thanks a bunch in advance.


Rich

 

[jrebman]

Rich,

Are the two terminals next to each other the in and ground, and the one on the other side of the screw, the out?

I have one here but have not yet wired it, but I am under the impression that the one hole by itself is the output -- i.e. - wiper.

-- Jim

 

[HF9]

Could you explain what the problem you were having was while the Goldpoint was installed? Just to verify you used a 100K Stereo Mini-V?

 

[Paul Joppa]

...and the black wire from the rca's went into the ground terminal. ...
Rich

You may merely have not mentioned it, but the "ground" has to go to circuit ground as well as to the (insulated) RCA jack outer conductor.

 

[pro_crip]

Sorry for the delay, but I'll answer your questions in turn. Yes it is a miniV-100k. The terminals are as follows: G (I'm assuming that's ground) and out are on the left of the screw and in is to the right of the screw. On that terminal I wired the red and white wires from the rca-center pins on the respective decks. On the out terminal I wired to the respective pins on the input of the 12au7. On the ground terminal I wired the black wire from the rca-ground terminal and then connected the attenuator terminal to the ground on the headphone jack. The problem I was getting was sound was coming out of only 1 side, and very loudly at that. I checked all the solder joints of the resistors with a magnifying glass to make sure there were no bridges and there weren't any. Thanks for listening.


Rich

 

[jrebman]

Rich,

There's your problem -- the single hole to the right of the screw is the wiper, or out.  That directly from Arn Roatcap.  I haven't taken a meter to the other two terminals, so I can't tell you which is ground and which is in.

-- Jim

 

[pro_crip]

Let me get this right. The terminal marked in is really the output? I'm sorry but that don't make a lick of sense. When I get a chance I'll switch the wiring, the input from the rca's I'll wire into the "out" terminal and the "in" terminal will get wired to the 12au7. This might make sense to the engineers out there but to people in my shoes it's counter-intuitive. How do you use the meter to check these pins as I've got a pair of mono mini-v's scheduled to go into my foreplay iii when construction gets going on that (next in the queue) and I'd rather not go through this again. Thanks Jim


Rich

 

[jrebman]

Rich,

Sorry, you've got it right -- I misread the note Arn sent me and the one by itself is the in.

Sorry for the false alarm.

-- Jim

 

[Paul Joppa]

...On the ground terminal I wired the black wire from the rca-ground terminal and then connected the attenuator terminal to the ground on the headphone jack....

So, do any of these points go to the circuit ground? Sorry, I don't have a Crack manual at hand so I can't identify the terminals my name.

 

[jrebman]

Rich,

You wrote:

On the ground terminal
I wired the black wire from the rca-ground terminal and then connected the attenuator
terminal to the ground on the headphone jack.

There is also a ground connection from the potentiometer ground terminal to terminal strip 3 -- the center tab on the strip in front of the 9-pin tube, and also a ground connection from the headphone jack ground back to terminal 14 or 15 on the power supply.  I'm doing this from memory as I don't have my crack manual on this machine, but take a look, it appears you are missing the ground connection to the VA tube.

-- Jim

 

[pro_crip]

Yeah, I forgot to mention that the g terminal is connected to terminal 3, which in turn goes to the center pin of the driver tube. So the ground terminal on the attenuator is wired to T3 and the ground terminal on the headphone jack. If my reading of the schematic is right, T3 would be the circuit ground. I just finished the re-wiring of the attenuator with the out and in terminals switched, I didn't read here before surgery, and ended up with the same problem. All of the sound came out of 1 channel, very loudly. I need a nap, I had a fun night last night. The timing belt on my car decided it was time to retire while I was in the middle lane of the BQE doing 65. With a deft bit of driving on my part and a little luck I was able to get the car on to an off-ramp and park it while waiting for the cavalry. I'm a little tired. Thanks


Rich

 

[Paul Joppa]

...The timing belt on my car decided it was time to retire while I was in the middle lane of the BQE doing 65. With a deft bit of driving on my part and a little luck I was able to get the car on to an off-ramp ...

Bummer, man. Been there - I was about a hundred yards short of the off-ramp though.

 

[pro_crip]

Paul, were you at least able to pull on to a shoulder? The stretch of the BQE I was on is elevated and has no shoulder. The thought of being stuck in the right lane dead in the water gives me the heeby-jeebies. Anyhoo, I took a DVM to the attenuator and got some weird readings. All these numbers are with the attenuator at full counter-clockwise, the lowest volume setting and referenced to ground. On the right channel, the resistance at the out terminal reads 8k ohm and the in terminal reads 100k. On the left channel, the out terminal reads 0.4 (essentially open) and the in terminal reads 100k. Referenced to the same ground, the g terminal on the attenuator, I did a resistance check on the RCA jacks and got the same numbers as the out terminals, 8k and 0.4 on the respective jacks. Yeah, I know I need to swap the in and out wires. I hadn't read JRebman's post before doing it. Maybe I should email Goldpoint and ask them what I'm doing wrong. Thanks for listening.


Rich

 

[Paul Joppa]

...On the right channel, the resistance at the out terminal reads 8k ohm and the in terminal reads 100k....

That's not right, and would explain the unbalance! Yes, time to contact Goldpoint; they are good folks.

Yes I got the car to the shoulder.

Many years decades ago I had an accelerator cable break - on the freeway, in the left lane. The engine (VW bug) dropped immediately to idle; I did manage to get it across four lanes of rush-hour traffic and into a mall parking lot. Almost had to go shopping for a new pair of pants at that point, though.

 

[pro_crip]

Partial success to be reported. I figured out why those resistance readings were cock-eyed. When I separated the decks to install the resistors I screwed up re-installing the decks, I put the deck back on rotated 180 degrees from where it was supposed to be. One deck was at position 1 and the other deck was at halfway. Stupid me assumed that they would only fit together one way. It was only a partial success because both channels kicked in at about 10 o'clock (full ccw being 6). I do have another question, when I took a resistance reading of the out terminal (re-wired correctly) referenced to ground at full ccw I got 0.2 ohms at both channel. I got 100k at full cw. Wouldn't it be the other way round? No resistance at full volume and 100k at full attenuation? Ironic I was working on my crack today, my beloved jets pulled a w out of theirs Thanks for listening.


Rich