1st time DIYer - tales of my build - questions in 1st post
- Thread starter wullymc
- Start date
Well I finished the build! Yay!......but...
Measured the resistance and got the following:
Terminal Resistance Should be - Manual
1 1 *
2 1 *
3 0 ohms 0 ohms
4 1 *
5 1 *
6 2.4k ohms 2.4k ohms
7 2.8k ohms 2.9k ohms
8 0 ohms 0 ohms
9 2.8k ohms 2.9k ohms
10 2.4k ohms 2.4k ohms
12 1 0 ohms
13 1 * will climb slowly toward 270k ohms
14 1 0 ohms
20 1 0 ohms
22 0 ohms 0 ohms
B3 2.8k ohms 2.9k ohms
B6 2.8k ohms 2.9k ohms
RCA jacks:
Ground 0 ohms 0 ohms
Center pin 95k ohms 90k ohms - 100k ohms
In the manual it says to use terminal 12 for ground, however I get a 1 ohm on that terminal. If I use terminal 12 I don't get any readings other than 1 for anything. For example when I have the black on 12 and test B3 or B6 I get 1.
It doesn't look good eh? When mention Terminal 12 is that 12U or 12L or does it matter?
.....feeling discouraged. Maybe I should have just paid the $150 fee for making one and just said that I did it
I am currently looking at my connections but am having a tough time deciding which ones are good. I think I may have a problem with 14U. There are 4 wires there and I am not confident about the solder job.
I would say the toughest parts with the soldering were 14U, 15U.
Measured the resistance and got the following:
Terminal Resistance Should be - Manual
1 1 *
2 1 *
3 0 ohms 0 ohms
4 1 *
5 1 *
6 2.4k ohms 2.4k ohms
7 2.8k ohms 2.9k ohms
8 0 ohms 0 ohms
9 2.8k ohms 2.9k ohms
10 2.4k ohms 2.4k ohms
12 1 0 ohms
13 1 * will climb slowly toward 270k ohms
14 1 0 ohms
20 1 0 ohms
22 0 ohms 0 ohms
B3 2.8k ohms 2.9k ohms
B6 2.8k ohms 2.9k ohms
RCA jacks:
Ground 0 ohms 0 ohms
Center pin 95k ohms 90k ohms - 100k ohms
In the manual it says to use terminal 12 for ground, however I get a 1 ohm on that terminal. If I use terminal 12 I don't get any readings other than 1 for anything. For example when I have the black on 12 and test B3 or B6 I get 1.
It doesn't look good eh? When mention Terminal 12 is that 12U or 12L or does it matter?
.....feeling discouraged. Maybe I should have just paid the $150 fee for making one and just said that I did it
I am currently looking at my connections but am having a tough time deciding which ones are good. I think I may have a problem with 14U. There are 4 wires there and I am not confident about the solder job.
I would say the toughest parts with the soldering were 14U, 15U.
fullheadofnothing
Moderator
Quickly glancing at the manual, it doesn't look that bad. The terminals with an asterisk are going to vary from meter to meter, and it seems that your meter is just reading those as 1Ω. 14 and 20 are a little odd since they should be zeroed, but they are jumpered together, so my brain is thinking that it's a good thing they at least read the same. One other thing to bear in mind is that your probes will have some resistance of their own. If you hold the two together, what does your meter read? Remember to subtract that out when you're making very low readings (I know my meter reads about 0.7Ω, so if I see that, I'm really seeing zero). Most of your readings are within the 10-15% ballpark, which is good!
It doesn't matter where you make the reading on a terminal, they will read the same U or L since it's a solid chunk of metal.
Re: 14U, those big caps can be a bit finicky about being attached to terminal strips (and they really hate being hooked up backwards... trust me on that!). If your joint looks bad enough that you're questioning it, it might be worth clearing it off and re-soldering. The good news is with four things jammed in the terminal, you're probably making pretty good physical contact.
It doesn't matter where you make the reading on a terminal, they will read the same U or L since it's a solid chunk of metal.
Re: 14U, those big caps can be a bit finicky about being attached to terminal strips (and they really hate being hooked up backwards... trust me on that!). If your joint looks bad enough that you're questioning it, it might be worth clearing it off and re-soldering. The good news is with four things jammed in the terminal, you're probably making pretty good physical contact.
Thanks Joshua
I really appreciate your help.
I have edited my post 2 up. I get 1 ohms when touching terminal 12 and it should be a ground so that I can take readings but I don't pull any readings if I use it as ground. I used the RCA ground for my readings. I put my DMM red and black together and I get a 1.
I am concerned with the terminals should have a *. In the manual I states that terminals that have a * "should wander in the tens to hundreds of Kohms or higher range. What you want to watch out for is a zero reading which would indicate that something is mis-wired."
I would hate to continue to the voltage taking and really mess something up.
Take care...Dave
I really appreciate your help.
I have edited my post 2 up. I get 1 ohms when touching terminal 12 and it should be a ground so that I can take readings but I don't pull any readings if I use it as ground. I used the RCA ground for my readings. I put my DMM red and black together and I get a 1.
I am concerned with the terminals should have a *. In the manual I states that terminals that have a * "should wander in the tens to hundreds of Kohms or higher range. What you want to watch out for is a zero reading which would indicate that something is mis-wired."
I would hate to continue to the voltage taking and really mess something up.
Take care...Dave
Grainger49
New member
Dave,
If when you touch your meter leads together you get 1 ohm, you are measuring your meter lead resistance. That should be considered zero ohms.
Is your meter one where you select the resistance range or does it "autorange?" This can make a difference if you have to select the range.
The terminals with * usually are either high resistance or connected to a capacitor that will charge ending with a very high reading. Some meters will say "OL" some will say "HI" some will read "--". The problem is that different meter manufacturers give different indications.
These * terminals are not critical that you get a definite reading. But, as mentioned earlier, the power supply capacitors will be ruined if put in backward. The diodes are another thing to triple check.
Terminal 12 is the power supply ground, as are almost all of the terminals you get a reading of 1 on. T12 should give you good resistance readings and should be grounded to the chassis at terminal 3. I had to look through the manual quite a bit to find the grounding point. Maybe try your meter grounded at T3 and consider 1 ohm zero ohms.
Look in your manual at page 22, the middle picture. There is a black wire that ties all the audio signal grounds and power supply grounds to terminal 3. If it is not properly soldered you don't get ground on anything else. Measure resistance from the lug with the black wire on it (in the manual, I don't know if you have the same wire in the kit) to the chassis. It should be near zero ohms.
I am pretty sure your grounding problems are here.
FYI, the circuit common/ground starts at the top plate at terminal 3, goes to volume pot left hand lugs (as you look at it while assembling), to the 1/4" headphone jack lugs closest to the top plate, to T12, to T14, to T20. It may seem to jump all over the place but it is one nice clean sweep from T20, the power supply grounding point to the RCA Jacks outer conductor brought to the volume pot.
Every one of these terminals get their ground at T3.
If when you touch your meter leads together you get 1 ohm, you are measuring your meter lead resistance. That should be considered zero ohms.
Is your meter one where you select the resistance range or does it "autorange?" This can make a difference if you have to select the range.
The terminals with * usually are either high resistance or connected to a capacitor that will charge ending with a very high reading. Some meters will say "OL" some will say "HI" some will read "--". The problem is that different meter manufacturers give different indications.
These * terminals are not critical that you get a definite reading. But, as mentioned earlier, the power supply capacitors will be ruined if put in backward. The diodes are another thing to triple check.
Terminal 12 is the power supply ground, as are almost all of the terminals you get a reading of 1 on. T12 should give you good resistance readings and should be grounded to the chassis at terminal 3. I had to look through the manual quite a bit to find the grounding point. Maybe try your meter grounded at T3 and consider 1 ohm zero ohms.
Look in your manual at page 22, the middle picture. There is a black wire that ties all the audio signal grounds and power supply grounds to terminal 3. If it is not properly soldered you don't get ground on anything else. Measure resistance from the lug with the black wire on it (in the manual, I don't know if you have the same wire in the kit) to the chassis. It should be near zero ohms.
I am pretty sure your grounding problems are here.
FYI, the circuit common/ground starts at the top plate at terminal 3, goes to volume pot left hand lugs (as you look at it while assembling), to the 1/4" headphone jack lugs closest to the top plate, to T12, to T14, to T20. It may seem to jump all over the place but it is one nice clean sweep from T20, the power supply grounding point to the RCA Jacks outer conductor brought to the volume pot.
Every one of these terminals get their ground at T3.
Dave,
It's actually good that you questioned your abilities when you thought about having BH build it. You'll soon see how easy and straightforward it is to troubleshoot and repair these things and as a result your confidence willl double and your ultimate satisfaction in a job well done will just feel all that much better.
There is value in making mistakes, finding them and fixing them yourself -- don't be discouraged.
-- Jim
It's actually good that you questioned your abilities when you thought about having BH build it. You'll soon see how easy and straightforward it is to troubleshoot and repair these things and as a result your confidence willl double and your ultimate satisfaction in a job well done will just feel all that much better.
There is value in making mistakes, finding them and fixing them yourself -- don't be discouraged.
-- Jim
Thanks guys for your encouragement and help!
Grainger!
You were absolutely right. It was a bad ground connection. I worked my way through each ground starting with 3. I ended up resoldering 2 locations - 12L and the inside volume control......and it worked!!
Thank you so much.
Rather than start testing with the voltages I think I am going to take a break tonight and bask in the success of the resistance test!
Thanks again to everyone for there help. This is a great board and I truly appreciate it!
Grainger!
You were absolutely right. It was a bad ground connection. I worked my way through each ground starting with 3. I ended up resoldering 2 locations - 12L and the inside volume control......and it worked!!
Thank you so much.
Rather than start testing with the voltages I think I am going to take a break tonight and bask in the success of the resistance test!
Thanks again to everyone for there help. This is a great board and I truly appreciate it!
Sorry guys, I have another question!
I am going to be testing the voltages and don't totally understand this:
1.-Attach the negative lead of a volt-ohm meter to ground. A good spot to do so is at terminal 12. Use of a clip lead to connect the black test lead to the ground will free one hand, making testing much easier and safer.
2.- Turn the chassis over and reconnect the negative lead of the volt-ohm meter to the ground buss.
I understand #1 and I know to flip it over so that I can turn on the amp but I don't understand to reconnect the negative lead to the ground buss. Is the ground buss still Terminal 12? Shouldn't it still be attached?
Please say a prayer for me. Don't really want to stop my heart with measuring voltages!!...plus I want to hear the amp before I go! ;D
Thanks everyone!
I am going to be testing the voltages and don't totally understand this:
1.-Attach the negative lead of a volt-ohm meter to ground. A good spot to do so is at terminal 12. Use of a clip lead to connect the black test lead to the ground will free one hand, making testing much easier and safer.
2.- Turn the chassis over and reconnect the negative lead of the volt-ohm meter to the ground buss.
I understand #1 and I know to flip it over so that I can turn on the amp but I don't understand to reconnect the negative lead to the ground buss. Is the ground buss still Terminal 12? Shouldn't it still be attached?
Please say a prayer for me. Don't really want to stop my heart with measuring voltages!!...plus I want to hear the amp before I go! ;D
Thanks everyone!
Grainger49
New member
It sure sounds like you are doing the test lead twice.
Just be certain that you attach to a good ground, you have several now, I like T3 the best, and use one hand to make measurements. Don't touch the chassis or any other ground with your free hand while making measurements.
I've been shocked several times. It may have hastened my needing a pacemaker. The Pacemaker was going to happen because of A/V problems but it may have hastened it.
Just be certain that you attach to a good ground, you have several now, I like T3 the best, and use one hand to make measurements. Don't touch the chassis or any other ground with your free hand while making measurements.
I've been shocked several times. It may have hastened my needing a pacemaker. The Pacemaker was going to happen because of A/V problems but it may have hastened it.
Noskipallwd
New member
Dave, T12 was where I connected my meter to ground. When I took voltage readings I installed the tubes and put the amp in its base upside down, ran the power cord under the base and after connecting my meter to ground reached under the base and turned the amp on, worked well for me anyway.
Cheers,
Shawn
Cheers,
Shawn
Thanks guys,
Excellent idea Shawn. I will flip the chassis and put it in the wood base.
I just powered up the amp. The 6080 lit up fine, however the 12au7 did not exhibit any light. My thoughts are that I will check the A* terminals for any what looks like bad connection. It would be the red wires for power right?
Would it be bad to go ahead with the voltage check for all terminals and report back?
The fuse seems to have worked fine!
Thanks!
Excellent idea Shawn. I will flip the chassis and put it in the wood base.
I just powered up the amp. The 6080 lit up fine, however the 12au7 did not exhibit any light. My thoughts are that I will check the A* terminals for any what looks like bad connection. It would be the red wires for power right?
Would it be bad to go ahead with the voltage check for all terminals and report back?
The fuse seems to have worked fine!
Thanks!
Grainger49
New member
For the 12AT7 check voltage from either tube pin 4 or 5 to pin 9. There should be 6.3V AC between these points. It is low voltage and should be safe. Just don't short pin to pin.
Hey guys,
I did the voltage checks. My dmm is a cheap one with no auto-range.
So for my DCV I have the settings 200m, 2000m, 20, 200, 1000.
For the voltage test I used the setting of 1000.
Also, both LEDs did not light up and like I stated in a previous post the 6080 lit up but it doesn't seem that the 12AU7 lit up.
Warning: below might hurt your eyes!
Terminal Voltage S/B Manual
1 228 90
2 233 170
3 233 0
4 228 170
5 233 90
6 233 0
7 233 100
8 233 0
9 233 100
10 233 0
11 233 0
12 0 0
13 233 170
14 0 0
15 233 185
20 0 0
21 234 206
A1 288 90
A2 234 0
A3 233 1.5
A4 0 0
A5 0 0
A6 228 90
A7 234 0
A8 234 1.5
A9 0 0
B1 229 90
B2 234 170
B3 234 100
B4 229 90
B5 234 170
B6 0 100
B7 0 0
B8 0 0
I tried taking the voltages by grounding first at Terminal 12 and then took the readings again grounded at Terminal 3.
good news: I didn't see any smoke. A lot of numbers seem to be the same. ie. 234, 233, hopefully this indicates an easy enough problem....hopefully.
I checked the fuse and it is okay.
I might try to borrow another dmm but this one worked for the resistance checks.
I kindof stuck again. Thanks...Dave
I did the voltage checks. My dmm is a cheap one with no auto-range.
So for my DCV I have the settings 200m, 2000m, 20, 200, 1000.
For the voltage test I used the setting of 1000.
Also, both LEDs did not light up and like I stated in a previous post the 6080 lit up but it doesn't seem that the 12AU7 lit up.
Warning: below might hurt your eyes!
Terminal Voltage S/B Manual
1 228 90
2 233 170
3 233 0
4 228 170
5 233 90
6 233 0
7 233 100
8 233 0
9 233 100
10 233 0
11 233 0
12 0 0
13 233 170
14 0 0
15 233 185
20 0 0
21 234 206
A1 288 90
A2 234 0
A3 233 1.5
A4 0 0
A5 0 0
A6 228 90
A7 234 0
A8 234 1.5
A9 0 0
B1 229 90
B2 234 170
B3 234 100
B4 229 90
B5 234 170
B6 0 100
B7 0 0
B8 0 0
I tried taking the voltages by grounding first at Terminal 12 and then took the readings again grounded at Terminal 3.
good news: I didn't see any smoke. A lot of numbers seem to be the same. ie. 234, 233, hopefully this indicates an easy enough problem....hopefully.
I checked the fuse and it is okay.
I might try to borrow another dmm but this one worked for the resistance checks.
I kindof stuck again. Thanks...Dave
According to your numbers, you have voltage on T3 which is a ground. Im assuming you listed that voltage from clipping the ground on T12 and measuring at T3. Obviously there are other terminals where you list high voltages where there should be none. But just looking at that alone ... I would double check your wiring. If it were an autoranging meter, I would think maybe you were reading millivolts but you stated that it isnt. Someone smarter with this stuff will chime in and narrow it down but seems that to have voltage on a ground when measuring from what should be a ground termial to ground terminal, something is either wired wrong or you have leads touching between two terminals or something. Also, make sure your transformer is labeled correctly. I dont know if that would cause all the measurment anomalies but worth a check. The stickers have been placed on upside down/reversed in atleast one instance. You can check by looking for the terminal numbers on the white terminal insulators and comparing to the label/sticker.
Grainger49
New member
Your tubes are not turning on. You should see an AC voltage, 6.3V AC, from the 12AU7 tube pins 4 or 5 to tube pin 9 that is the heater. You would have gotten an odd reading there to ground set on DC.
For all your measurements you can choose 200V after the problems are cleared. All voltages should be under 200V. But for now, 1000V is fine.
If none of the LEDs light then check to see if they are in with the silver band toward terminal 3.
As Desmond above says, you shouldn't get voltage from a "ground" lug to another "ground" lug. This indicated that your grounding scheme is off.
Terminals 3, 8, 11, 16, 17 and 22 are all grounded. The list of signal grounded points is in my previous post. Before turning it on again verify that they all measure zero (one ohm on your meter) to each other. 233V on T3 and others means that there is still a problem in the grounding scheme.
For all your measurements you can choose 200V after the problems are cleared. All voltages should be under 200V. But for now, 1000V is fine.
If none of the LEDs light then check to see if they are in with the silver band toward terminal 3.
As Desmond above says, you shouldn't get voltage from a "ground" lug to another "ground" lug. This indicated that your grounding scheme is off.
Terminals 3, 8, 11, 16, 17 and 22 are all grounded. The list of signal grounded points is in my previous post. Before turning it on again verify that they all measure zero (one ohm on your meter) to each other. 233V on T3 and others means that there is still a problem in the grounding scheme.
Thanks Desmond, Grainger,
I went back and checked the ground connections. It looked like my terminal 12 was not working. I resoldered it but it didn't make a difference. I then went and looked at the black wires coming from it and going to it and noticed that my connection to the headphone jack had come loose. Resoldered and everything checked out okay for resistence.
Next: I fired it up and tested the voltage.....I did it!!!!1 I am sooooo happy.
My new numbers are:
Terminal Voltage S/B Manual
1 81 90
2 169 170
3 0 0
4 169 170
5 83 90
6 0 0
7 103 100
8 0 0
9 104 100
10 0 0
11 0 0
12 0 0
13 170 170
14 0 0
15 191 185
20 0 0
21 212 206
A1 82 90
A2 0 0
A3 1 1.5
A4 0 0
A5 0 0
A6 81 90
A7 0 0
A8 1 1.5
A9 0 0
B1 81 90
B2 170 170
B3 104 100
B4 82 90
B5 170 170
B6 105 100
B7 0 0
B8 0 0
....and both LEDs lit up!!!
And for the headphone TRS jack the readings I got when I turned it on were:
Tip - very quickly goes to 12.1 but then quickly down to 0 within I would say 2 sec
Ring - fast 16 then down to 0 in 2 seconds.
I am thinking about trying headphones now do you think I should be fine. I guess that if it reaches 0 your headphone will be fine? Is that right?
I have read not to start the amp with headphones plugged in but to wait a little while and then insert the tip into the headphone jack with the volume at 0.
Thanks for all your help. I am feeling realllllly good!
Take care.....Dave
I went back and checked the ground connections. It looked like my terminal 12 was not working. I resoldered it but it didn't make a difference. I then went and looked at the black wires coming from it and going to it and noticed that my connection to the headphone jack had come loose. Resoldered and everything checked out okay for resistence.
Next: I fired it up and tested the voltage.....I did it!!!!1 I am sooooo happy.
My new numbers are:
Terminal Voltage S/B Manual
1 81 90
2 169 170
3 0 0
4 169 170
5 83 90
6 0 0
7 103 100
8 0 0
9 104 100
10 0 0
11 0 0
12 0 0
13 170 170
14 0 0
15 191 185
20 0 0
21 212 206
A1 82 90
A2 0 0
A3 1 1.5
A4 0 0
A5 0 0
A6 81 90
A7 0 0
A8 1 1.5
A9 0 0
B1 81 90
B2 170 170
B3 104 100
B4 82 90
B5 170 170
B6 105 100
B7 0 0
B8 0 0
....and both LEDs lit up!!!
And for the headphone TRS jack the readings I got when I turned it on were:
Tip - very quickly goes to 12.1 but then quickly down to 0 within I would say 2 sec
Ring - fast 16 then down to 0 in 2 seconds.
I am thinking about trying headphones now do you think I should be fine. I guess that if it reaches 0 your headphone will be fine? Is that right?
I have read not to start the amp with headphones plugged in but to wait a little while and then insert the tip into the headphone jack with the volume at 0.
Thanks for all your help. I am feeling realllllly good!
Take care.....Dave
fullheadofnothing
Moderator
Congrats Dave!
Your next post will be your most important: how the thing sounds! It is a known fact that a piece of gear you build yourself always sounds better than anything else.
You're right on with those safety precautions for protecting your cans.
Pick out a good track you love and prepare to be blown away!
Your next post will be your most important: how the thing sounds! It is a known fact that a piece of gear you build yourself always sounds better than anything else.
You're right on with those safety precautions for protecting your cans.
Pick out a good track you love and prepare to be blown away!
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