Bottlehead Forum
Bottlehead Kits => Mainline => Topic started by: isldkid on August 28, 2013, 09:52:53 PM
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Sorry guys please disregard my last post I hit the wrong button.
Just did the resistance and voltage checks on my just completed Maineline, and have some weird readings.
Ohm readings on terminal:
1. 39.8
2. 0
3. 0
4. 0
5. 39.9
6-10. 0
11. 0
12. -
13. 0
14. -
15. 220
16. 0
17. -
18.0
19. 218?
20. 3 meg?
21. 0
22. 218?
23. 0
24.-
25. 220
26. 0
30. 1 meg?
Voltage readings all DC
Should read. Measured
275. 277
6.3. 6.325
275. 276
275. 275.6
Berg B
220. 154?
Berg A.
220. 272
Note: All 6000 LEDs measure 274 volts DC and are lit except two LEDs on on the C4S board above the C tube socket on the "B" side of the C4S board the two LEDs are not lit and measures only 153 volts DC. Also switched out the 12au7 with the same results.
Any and all help on this matter would be appreciated.
Thanks and regards,
FC
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Ok pulled off both c4s boards also the regulater board, will check all three boards for correct wiring and switch c4s boards to see if trouble follows the boards.
Will report back results tomorrow.
FC
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Can you post the terminal numbers where the voltage issues are? (something like 6.325V where there should be 6.3V is not worth mentioning)
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Paul, thank you for your reply, will try to get back with the terminals numbers and voltages after I check wiring on the boards and assembly.
FC
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Paul, ok pulled out both C4S boards and check and compared side C (the side with the low voltage reading on 1B ) against each other all components and wiring checks out good.
Checked the regulator board all components and wiring is good.
Switched the C4S boards and the problem with the low voltage on terminalred that 1A still remained on board closer to tube C which should read 220vdc but reads 147vdc, side A should also read 220vdc but reads 272vdc.
The regulator board's voltage checks out good with the exception of the B side Berg that reads 147vdc instead of the correct 220vdc. Side a Berg should also read 220vdc but I read 272vdc.
Let me also add that after I first applied power power to the Mainliner I discovered that two 100 ohm resistors were switched so I corrected that.
The all resistance checks out ok.
Please let me know if you need more info.
Thank you,
FC
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Looks to me like it may be the tubes - swap tubes and see if the wrong voltage moves with the tube.
If so, I'd give the high-voltage tube a few (dozen?) hours to see if it settles it.
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Paul, switched out the tubes and voltages changed however the voltages on the C4S board closer to tube C on average remained Lower.
Will see how it sounds and report results.
Thank you for the help.
FC
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How are your Kreg voltages?
What happens if you run the Mainline w/o the 12AU7?
Your regulator is essentially not working, this could happen if if the Kreg or +Reg wires happen to be switched.
-PB
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Paul B, You may have addressed my problems here as after PJ's recommendation on switching the hi- voltage tubes (results are in my last reply) I adjusted the bias voltages, I was successful in adjusting both to 145, however the trimmer's adjustments were switched on the regulater board.
I might not be able to do any more work on the Mainline until later tonight, as for today my brother in law needs help tuning his "65" E -Type, and later go fly my U-Control "stunt" planes.
Thanks to the two Paul's for their help, I truly appreciate it. FC.
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P.B., ok was finally able to get back to my mainline trouble shoot.
Kreg voltages with 12au7 plugged in:
A kreg 2 vdc
B kreg 23vdc
Kreg voltages without 12au7:
A kreg 1 vdc
B kreg 1 vdc
Would switched wires on kreg and reg also cause tube bias adjustment to reverse?
Thanks, FC
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Went through all wiring again for both C4S and regulator boards, everything checked out except for a broken lead that went to 16u.
Repaired the lead, and took a voltage check, all voltages looked good with the exception of unbalance voltages that switched sides when the high voltage tubes were moved.
PJ pointed this out and stated that it might take about 50 or so hours for the tubes to stabilize.
Have about 4 hours on the Mainline now, had to reset tube bias a couple times, but the amp is now sounding pretty good.
Listening through an HD-800 with Doc's Hybrid Anax 2 mod, unbalanced high impedance.
Thanks again to both Pauls for their help, I appreciate it.
FC
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Ah, most excellent, let us know how you like the amp!
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Paul, having had the privilege of listening to a crack speedball amp for awhile before building the mainline I felt that the upgraded crack sounded very good and a good basis for this comparison.
Well happy to report that after only about 35 to 40 hours of run in, the mainline is showing that it 's presentation, is more refined in handling mid and high frequency's transients without sounding strained, the low end has tighten up to where it has excellent impact and detail.
Just got a Justin Essig built balanced cable for the HD- 800 so will be listening to the mainline in the balanced mode now.
Thank you Bottlehead for another fine product and the excellent support.
FC
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Thanks Francis! That's exactly how I would describe the sound of Mainline.
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Francis,
I'm psyched that you got your HD800 cable from Justin. I love his work. If its not too much effort, would you mind posting a picture of the cable (might as well throw in a picture of the Mainline, too!)?
Best regards,
Adam
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Adam,
Am also very happy with Justin's cables,
with just have a few hours on them the sound stage is much bigger along with better detail (as compared to OEM) the workmanship is also second to none, Justin is a joy to deal with like all those here at Bottlehead.
The Mainline, HD800 and JE cable combo is certainly a joy to listen to.
Have taken pics of the Mainline, Justin's cable and the adapter for the Crack on my I-Pad but have not as yet posted any pictures on Bottlehead. I think the fastest way to get the image to you is if you email me your address, you can find my address in profiles.
Best,
Francis
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Francis,
FAQ #7 (http://bottlehead.com/smf/index.php/topic,2408.0.html) will tell you two ways to post pictures on this site.
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Grainger,
Ok will try posting picture, requested by Adam, Thank you.
The JE cannon/phone adapter is for the Crack amp.
Best,
Francis
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Francis,
Very cool looking, but sideways. Are you using an Apple product? For some reason they don't allow you to pose the picture before posting.
My brother uses an Apple phone. It takes great pictures, but often sideways.
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Thanks, Francis. I'm curious...is the right angle XLR 3-pin or 4-pin? I haven't seen a right angle 4-pin XLR anywhere, so I would be most interested in knowing the answer.
Grainger,
That's funny! My wife and I spent forever trying to figure out why we couldn't get a picture to upload to eBay with the proper orientation from her iPad. I thought we were just dumb. Good to know it is an Apple issue!
Best,
Adam
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I haven't seen a right angle 4-pin XLR anywhere, so I would be most interested in knowing the answer.
1 (http://www.mouser.com/ProductDetail/Neutrik/NC4MRX-B/?qs=sGAEpiMZZMv0W4pxf2HiV%252bQN6WG%2fIhAga%252b%252bAQAlVKg8%3d)
2 (http://www.mouser.com/ProductDetail/Neutrik/NC4MRX-BAG/?qs=sGAEpiMZZMv0W4pxf2HiV9y0EyfHsAgRQvx93bMZohg%3d)
3 (http://www.mouser.com/ProductDetail/Neutrik/NC4MRX/?qs=sGAEpiMZZMv0W4pxf2HiV%252bQN6WG%2fIhAgMYEEeeFnKsI%3d)
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Yeah, I get it. I looked a while ago and combed the Neutrik website from top to bottom, but didn't find any. Anyway, I'm glad to see they now exist. Or maybe I just missed them all before, in any case, it's good to know.
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Hi guys, in the interest of bandwidth efficiency if you all don't mind, will answer all three question in this post , also have a question for P.B..
Grainger, yes posted image with I-Pad.
Adam and Paul B, yes the 90 degree Neutric XLR is the 4 pin.
According to Justin of JE they were not available last year, he did not say when it was put on the market.
Question for Paul B.: The bias voltages on the Mainline's output tubes have stabilized, however one tube has a lower audio output.
Have checked this by switching channels, low audio output follows the one tube, also no light up on two of four LEDs on C4S board on the low channel. (The two unlit LEDs follows the low output tube)
Also the bias voltage adjustments switches sides along with he tubes.
Suggestions please.
Best,
Francis
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Hello Francis,
I'd suggest leaving the Mainline on for a few days to cook the tube. What is the the bias voltage on the offending tube? (OB or OA, look for the white wire leaving and heading to the sockets containing the iffy tube)
It may be that a little cooking time will help with this, but knowing the bias voltage will provide some clues.
-PB
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Hi Paul,
The bias voltages have recently both held at 145.
However switching the tubes gives these bias readings:
The low output ( offending tube) will read 130 and the other (good?) tube's reading will be 167, and will take about four complete revolutions of the trimmer adjusting screw to bring them both back to 145, one going clockwise the other counterclockwise.
Where ever the offending (low output) tube is the two LEDs out of the four are hardly lit, and only read 130 always on the B side, all the rest of the LEDs will read 266, this condition occurs halmost exactly the same on both channels when the tubes are switched.
Will try leaving unit on for a couple days and see what happens.
Thanks again,
Francis
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Sorry, I should've specified that the bias voltage comes off the center PC board. I'd expect it to be between 0.8V and 2V.
-PB
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Paul, Not a problem, thanks for sticking with this.
Both OA and OB read close to 2vdc, additionally bias on both sides reads 145.
Will continue leaving unit on for another day or so. Best, FC