Bottlehead Forum
Bottlehead Kits => Mainline => Topic started by: Tabaia on March 24, 2025, 06:35:35 PM
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Hello , I am just staring on the Bias / Regulator board, first stumble is the 499 ohm resistor - which way up/down?
Yellow on the top or red on the top?
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Resistors are not directional.
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great , thank you.
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hence no info added about the direction in the manual :)
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Could i please get confirmation that this capacitor is in the correct position.
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I think i figured it out - Could someone confirm the position of the film Capacitor
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The second way is more correct than the first, but both would work.
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Hi Paul,
Thank you for your feedback.
Would it be ok to send you pictures of the boards with components and soldering for some feedback?
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You can post them here. So far, I'd suggest either turning the iron temp up all the way or holding on the joints a little longer so they flow out a bit more.
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Hi Paul,
Here are the pictures.
Thanks for your support
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Definitely more heat is needed, and a tiny bit of extra solder.
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so, my understanding is that I should go over all the solder joints, reheat and add a little solder as well.
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Yes, when you get the solder hot enough, it will suck into the board a bit.
https://www.youtube.com/watch?v=EN16Pi7pcfk (https://www.youtube.com/watch?v=EN16Pi7pcfk)
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Hi,
I am going to get a copper chassis made and hopefully a brass plate for the dials and switches.
Would you have a DXF available ?
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I have done some re-soldering according to what I think is correct from the instructions given.
Would you kindly have a look and let me know it this is better?
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here is another photo
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I'd leave your iron on those joints a bit longer.
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Hi Paul,
I have done a fair bit of reworking and I think it might be good now,
Would you kindly have a look over the solder as well as the component placement.
I think is all correct however since i'm a first timer it would be great to have it looked over by someone in the know.
Looking forward to your response
Many thanks Tunji
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The 1N5820s and the 5W resistor have not been heated enough to be properly soldered.
https://www.youtube.com/watch?v=EN16Pi7pcfk (https://www.youtube.com/watch?v=EN16Pi7pcfk)
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can you provide some constructive feedback please
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can you provide some constructive feedback please
The 1N5820s and the 5W resistor have not been heated enough to be properly soldered.
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The bigger a part is, the more heat you need to apply to get the solder to flow out properly. The two big resistors on your C4S boards in the R2 positions need more heat for the solder to flow out properly, and the MJE5731A transistors also need a lot more heat. You can set your iron on one of these solder joints, add a little bit of solder, then count to 5, then pull it off. You'll also see the solder suck into the board at some point when it has gotten hot enough, and you want to leave the iron on just a little longer after that happens.
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Hello Paul,
I just wanted to ask a question regarding the first volt rest for the Mainline.
A little confusing as we are on 240V here in Australia.
My test read 247V.
How should I proceed?
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Actually its 275V
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After turning a few pages I found the 240 V section.
Mostly its around 245 V so I have opted for that connection.Greater than 235V and less than 245V.
But the power her varies a lot. still it seems that is the best optioj.
Let me know if that is OK.
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Now I did the snd Voltage test with no reading?
Hmmm what have I done.
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The Volume switches,
These are not straight.
So they are out of alignment.
Please see photos, any suggestions will be welcome to fix this.
I measured with a calliper The bottom of the shaft near the screw measures just under 82mm and the top measures just over 80mm so at least 1.5mm out of alignment.
Tunji
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There is a tab on the rotary switch where it goes against the panel, and a slot in the panel hole that the tab should be put into. Loosen the nut and turn the switch body until the tab drops into the slot, then retighten the nut.
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It looks like you might have the toothed lockwasher on the attenuator switches in the wrong spot. It needs to go between the nut and the panel for each switch.
Yes, wiring for the 240V nominal primary when you have 247V is the way to go.
No voltage on your transformer test would have me looking at whether the fuse is installed properly in the IEC power entry module.
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Absolutely Perfect :)
Test all excellent and switches installed properly.
Thank you.
Your experience is invaluable.
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275V test.
Reads 366V
What to do?
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What AC line voltage did you measure and how did you wire your power transformer primary?
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What AC line voltage initially measured between 230 and 247
I used the wiring for Greater than 235V and Less than 245V.
Also Reading the manual and getting my head around this i realise that the reading I have for the board 235V is probably OK.
Manual says it should read between 300-500VDC , mine reads 366VDC.
I assume that is fine?
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Yes, all is well. The voltage at that node will be relatively high when there's nothing built in the amp to load it down.
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Great !Im on track.
Thank you.
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Hello,
I have finally come to the point of checking the Ohm's
Here are my current issues:
Mostly where it say 0 - my multimeter reads Ohm
And on terminals 19 & 22 i get a reading of 200Ohm's.
What could be the issue?
Looking forward to your response.
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Could you post some pictures of these readings as they appear on the meter?
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Here are the readings of terminals 19 and 22
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That's 200K, which is 200,000 ohms.
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Ok thanks Paul.
Are those readings ok for those terminals?
The m,anual says otherwise.
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Ok thanks Paul.
Are those readings ok for those terminals?
The m,anual says otherwise.
For which terminals?
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Terminals 19 and 22
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You have 200K at terminals 19 and 22, which is consistent with what's written in the manual.
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Hello again,
Just wanted to run my tests by you.
Here is a completed list of all the terminal tests.
It seems that the terminals that have no connection and no grounding all read zero.
Kindly have a look and let me know if there are any issues.
Many thanks
1 - 39.84kΩ
2 - 2.1Ω
3 - 1.2Ω
4 - 1.1Ω
5 - 39.87kΩ
6 - 1.6Ω
7 - 1.3Ω
8 - 1.2Ω
9 - 1.2Ω
10 - 1.2Ω
11 - 1.2Ω
12 - 0.L (zero reading)
13 - 1.3Ω
14 - 0.L (zero reading)
15 - 210.6Ω
16 - 1.3Ω
17 - 0.L (zero reading)
18 - 1.2Ω
19 - 201.5kΩ
20 - 12.20Ω
21 - 1.2Ω
22 - 201kΩ
23 - 1.3Ω
24 - 0.L (zero reading)
25 - 210.2Ω
26 - 1.2Ω
27 - 0.L (zero reading)
28 - 1.3Ω
29 - 0.L (zero reading)
30 - 2Ω
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Could you double check terminal 20?
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Terminal 20 now reads - 11.9Ω
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Re-Check Terminals :
30 - 11.88Ω
20 - 12.1Ω
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Can you show me what your meter is displaying on both of those terminals?
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Here they are:
Terminals 20 and 30
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That's 12,000,000 ohms.
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Thank you Paul.
So does this mean I am good to proceed with the next next step?
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I don't see any resistances that look out of line.
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OK WOW
ALL DONE NOW.
Thanks for your support.
So far its sounding really great , I imagine it will take a while for it to sound its best.
In Anycase its already sounding really nice.
I started listening to Miles Davis - The Complete "In A Silent Way", I wondered why there was so much hiss, thought the amp had an issue then listed to other more modern recordings such as Nik Bärtsch's Ronin, of course no background noise at all. Also the amp is quite revealing.
Thank you for again for your support , it has been a massive learning curve, first time build etc with very minimal soldering experience.
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There's definitely nothing wrong with double checking and taking your time. I'm glad it's all up and running!