[mchuckp]

That's fine, very much within tolerance.

@L0rdGwyn,

I guess I really screwed something up as none of my readings for test points 5-18 checked out and some way out of whack. Frustrating since I tried to be very meticulous. Below is what I got. You will see multiple tests for TP5 & 6 as I tried some different tube combos to see what would happen. The Tung Sol's are new stock from a reputable seller. The KT88s are also new stock but have been used a lot in a different amp years ago. The rest are old stock from sellers with high ratings but new to me for this amp. I'm also attaching a pix of my build. I took a bunch of pix along with way if there is something you'd like to see or I can take more close up of finished build. So much for listening to my amp today.

			Tubes Used
Test Pt	DCV	Range	Rectifier	Power	Input	Comments
TP5	163	225-275	RCA 5R4GY	RCA 6V6	Tung Sol 6SL7
TP6	188	225-275	5R4GY Both RCA	RCA 6V6	Tung Sol 6SL7
TP5	138	225-275	RCA 5R4GY	GL KT88	Tung Sol 6SL7	KT88s are well used
TP6	164	225-275	RCA 5R4GY	GL KT88	Tung Sol 6SL7	KT88s are well used
TP5	144	225-275	Brimer 5R4GY	RCA 6V6	Tung Sol 6SL7
TP5	166	225-275	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP9	102	220-270	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP10	180	220-270	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP15	29.3	6-14	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP16	5.5	6-14	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP17	1.2	2-3	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP18	2	2-3	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7

 

[L0rdGwyn]

@L0rdGwyn,

I guess I really screwed something up as none of my readings for test points 5-18 checked out and some way out of whack. Frustrating since I tried to be very meticulous. Below is what I got. You will see multiple tests for TP5 & 6 as I tried some different tube combos to see what would happen. The Tung Sol's are new stock from a reputable seller. The KT88s are also new stock but have been used a lot in a different amp years ago. The rest are old stock from sellers with high ratings but new to me for this amp. I'm also attaching a pix of my build. I took a bunch of pix along with way if there is something you'd like to see or I can take more close up of finished build. So much for listening to my amp today.

			Tubes Used
Test Pt	DCV	Range	Rectifier	Power	Input	Comments
TP5	163	225-275	RCA 5R4GY	RCA 6V6	Tung Sol 6SL7
TP6	188	225-275	5R4GY Both RCA	RCA 6V6	Tung Sol 6SL7
TP5	138	225-275	RCA 5R4GY	GL KT88	Tung Sol 6SL7	KT88s are well used
TP6	164	225-275	RCA 5R4GY	GL KT88	Tung Sol 6SL7	KT88s are well used
TP5	144	225-275	Brimer 5R4GY	RCA 6V6	Tung Sol 6SL7
TP5	166	225-275	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP9	102	220-270	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP10	180	220-270	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP15	29.3	6-14	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP16	5.5	6-14	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP17	1.2	2-3	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7
TP18	2	2-3	WH 5R4GYB	RCA 6V6	Tung Sol 6SL7

B+ voltages are all low. How do the heater voltages measure?

 

[mchuckp]

B+ voltages are all low. How do the heater voltages measure?

@L0rdGwyn,

I checked them again. Seems about what I got last time other than the 6.1. See below. I am testing right for the final check, right? Meter to DCV and set it to 600 knowing the results should be 200-600. I am not getting to 200 so I turn it to 200 when I get 100-something.

Rect @ 2/8=4.8
TP3/4: 6.3
TP1/2: 6.3
TP7/8: 6.1

 

[mchuckp]

@L0rdGwyn,

I checked them again. Seems about what I got last time other than the 6.1. See below. I am testing right for the final check, right? Meter to DCV and set it to 600 knowing the results should be 200-600. I am not getting to 200 so I turn it to 200 when I get 100-something.

Rect @ 2/8=4.8
TP3/4: 6.3
TP1/2: 6.3
TP7/8: 6.1

@L0rdGwyn :

I decided to check TP5 again and let it sit for a bit and see if anything happens. When I first turned the amp on it was at 300+ then dropped down to 100-something then settled in where it did before around 160. I left for a few minutes and came back to notice it rising. It took maybe 5 (guessing) before it settled at 262!

So maybe I wasn't waiting long enough? When I saw it settle at that low number and didn't seem to be moving, I assumed it wasn't going to climb.

So assuming I wasn't patience enough, hopefully the rest of them check out as retest all of them. Correct that things APPEAR correct then?

EDIT: When I started testing TP6 the voltage was around 270 then slowly dropped to 257.

 

[L0rdGwyn]

@L0rdGwyn :

I decided to check TP5 again and let it sit for a bit and see if anything happens. When I first turned the amp on it was at 300+ then dropped down to 100-something then settled in where it did before around 160. I left for a few minutes and came back to notice it rising. It took maybe 5 (guessing) before it settled at 262!

So maybe I wasn't waiting long enough? When I saw it settle at that low number and didn't seem to be moving, I assumed it wasn't going to climb.

So assuming I wasn't patience enough, hopefully the rest of them check out as retest all of them. Correct that things APPEAR correct then?

Thanks,
Mike

You may not have been waiting long enough, the tube filaments take some time to warm up in the power supply caps to charge. A B+ voltage of 262V is more in line with what I would expect.

 

[mchuckp]

For that set of measurements that you sent, how long were you waiting before recording them? And when you say it took 5, you mean 5 seconds? If it was only 5 seconds then you weren't waiting long enough, the tube filaments take some time to warm up in the power supply caps to charge. A B+ voltage of 262V is more in line with what I would expect.

@L0rdGwyn :

First time I did it, it seemed to settle in a low number after a minute or so. When I just retested, it was maybe 4-5 minutes when it settled into 262. I just tested TP9 and after guessing 3-4 min it stopped at 226. Is this okay? It is outside your range of 5-15V lower. I then tested TP10 and got 244 which seems about right. I know I shouldn't have done it but I moved the lead back to TP9 without powering down and still got 226.

EDIT: JUST FINISHED TESTING. HOW DO THESE LOOK? I TESTED TP9 3 TIMES.
So as of now, I have:
TP5=262
TP6=257
TP9=226
TP10-244
TP15=6.1
TP16=8.4
TP17=2.6
TP18=2.8

 

[L0rdGwyn]

@L0rdGwyn :

First time I did it, it seemed to settle in a low number after a minute or so. When I just retested, it was maybe 4-5 minutes when it settled into 262. I just tested TP9 and after guessing 3-4 min it stopped at 226. Is this okay? It is outside your range of 5-15V lower. I then tested TP10 and got 244 which seems about right. I know I shouldn't have done it but I moved the lead back to TP9 without powering down and still got 226.

So as of now, I have:
TP5=262
TP6=257
TP9=226
TP10-244

The big voltage drop from TP5 to TP9 could indicate an issue with the 6SL7 on that side, it should not conduct that much current. What are the 6SL7 cathode voltages?

 

[mchuckp]

The big voltage drop from TP5 to TP9 could indicate an issue with the 6SL7 on that side, it should not conduct that much current. What are the 6SL7 cathode voltages?

@L0rdGwyn :

I think you responded when I was adding an edit with all my results. I assume you are asking about TP17 and 18.
TP5=262
TP6=257
TP9=226
TP10-244
TP15=6.1
TP16=8.4
TP17=2.6
TP18=2.8

 

[L0rdGwyn]

@L0rdGwyn :

I think you responded when I was adding an edit with all my results. I assume you are asking about TP17 and 18.
TP5=262
TP6=257
TP9=226
TP10-244
TP15=6.1
TP16=8.4
TP17=2.6
TP18=2.8

Overall those voltages look fine and the amp seems to be working, but the large voltage drop from TP5 and TP9 is unexpected. If you swap the channels of the two 6SL7, does the 226V reading change sides as well to TP10?

 

[mchuckp]

Overall those voltages look fine and the amp seems to be working, but the large voltage drop from TP5 and TP9 is unexpected. If you swap the channels of the two 6SL7, does the 226V reading change sides as well to TP10?

@L0rdGwyn :

When you say swap channels, are you saying switch the input tubes?

 

[L0rdGwyn]

@L0rdGwyn :

When you say swap channels, are you saying switch the input tubes?

Yes.

 

[mchuckp]

Yes.

@L0rdGwyn :

I switched the input tubes with each other. I still got the same results in the same location. Meaning, it is not a tube issue. After that I switched them back and tested one more time and still the same.

Thoughts? Anything I should check? Go with it? Does this effect safety and/or sound quality?

Thanks for all your help!

Mike

 

[L0rdGwyn]

@L0rdGwyn :

I switched the input tubes with each other. I still got the same results in the same location. Meaning, it is not a tube issue. After that I switched them back and tested one more time and still the same.

Thoughts? Anything I should check? Go with it? Does this effect safety and/or sound quality?

Thanks for all your help!

Mike

Can you check the resistance across the right channel choke, side with TP5 and TP9? This would be done with the amp off and unplugged and checking a resistance measurement across the two screw terminals where the choke meets the PCB, at the + and -. That voltage measurement isn't terribly concerning, but it isn't normal so I personally would want to make sure there isn't a problem. But the amp likely works and will make music.

 

[mchuckp]

Can you check the resistance across the right channel choke, side with TP5 and TP9? This would be done with the amp off and unplugged and checking a resistance measurement across the two screw terminals where the choke meets the PCB, at the + and -. That voltage measurement isn't terribly concerning, but it isn't normal so I personally would want to make sure there isn't a problem. But the amp likely works and will make music.

@L0rdGwyn :

I am assuming you are talking about the terminals for the two anode chokes where the stranded black and red go into them. Assuming you mean put the leads on the screws of the same terminal, I got 2.2 and 2.3 for each side on the 20k setting. So this would be 22,000, right?

 

[L0rdGwyn]

@L0rdGwyn :

I am assuming you are talking about the terminals for the two anode chokes where the stranded black and red go into them. Assuming you mean put the leads on the screws of the same terminal, I got 2.2 and 2.3 for each side on the 20k setting. So this would be 22,000, right?

2.2kOhm and 2.3kOhm, which is correct. Last thing to check would be the resistance between TP5 and TP9. Should measure ~4.4kOhm.