Bottlehead Forum

Bottlehead Kits => Eros Phono => Topic started by: PaulG on April 12, 2020, 05:36:58 PM

Title: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 12, 2020, 05:36:58 PM

I just got the kit all built and soldered with no leftover components and did the resistance check on pages 75 and 75 of the instruction.
Nearly all of the measurments are within the 10 to 15% range but there are a few that are about 20% higher than optimum in the instructions.

Terminal Strip
2. Should be 71K ohms.  It reads 85.5K with one meter and 83.4K with the other.
4. Should be 60k ohms.   It reads 75K with one meter and 73.3K with the other.
12. Should be 60K ohms.  It reads 74.9k with one meter and 72.8K with the other.
14. Should be 71K ohms.  It reads 85.3k with one meter and 83.8k with the other.

Nine pin sockets
A6. Should be 60K ohms.  It reads 75k on one meter and 73.3K on the other.

B6. Should be 60k ohms.  It reads 74.9k on one meter and 72.9K on the other.

C1. Spec is 39K ohms but it measures 46.7k
C2. Spec is 60k ohms.  It reads 75.1k on one meter and 73.6K on the other.
C6. Spec is 39K ohms but  it measures 46.6 ohms.
C7. Spec is 60K ohms.  It reads 75K on one meter and 73.1K on the other.

Is it okay to put the tubes in and go to the next set of measurements?  Visually it all looks right. 
Interesting that A6 and B6 measure the same.
The meter that reads a little higher is a Klein Tools and the second readings are from an inexpensive Gardner Bender

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: Paul Birkeland on April 12, 2020, 05:38:36 PM

Yes, go ahead and move onto voltages.

-PB

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 13, 2020, 07:33:08 AM

Thank you for the encouragement.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 15, 2020, 03:45:12 PM

I went ahead an installed the tubes but neither of the russian V177 tubes that have 6x32 printed on them lit up.  The fuse is still good.

I think I screwed up by only being concerned about the measurements that were too strong and not just giving you all the measurements in the first place.

I re-examined the resistance figures and noticed the following differences between 9 pin Socket A and 9 pin Socket B: and what they are supposed to be doing.

Socket A                                                                                                Socket B
pin 1  doesn' t wander  solid 0 measurement                                              very solid 26.95K
Pin 4  solid 618 ohm                                                                                 very solid 623 ohm
Pin 6 75k Ohms not 60K                                                                            74.5k not 60K

on Socket C, which did light the tube up, the following readings are out of spec.
Pin 1 46.7k Ohms, not 39k
Pin 2 75k ohms, not 60k
pin 3 0
pin 4 a very steady .618k ohms  not infinity
pin 6 46.6k ohms, not the 39k specified
pin 7 measures 74k ohms, not 60K ohms
pin 8 doesn't wander but is a steady 26.93k

All of the LEDS were lit but with the two tubes not lit but only the BA voltages are correct .

Thinking I should declare victory, box this up and send it in.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: Paul Birkeland on April 16, 2020, 06:16:00 AM

How about posting your voltage measurements?

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 16, 2020, 08:12:03 AM

I guess that would be a lot more helpful than pouting about the fact that I've screwed up!

These are the voltages as we work our way clockwise around the left half of the photo on page 77 of the manual starting from the left C4S board

Location           Specification      Actual
Kreg                approx 1VDC      107.5mV it climbed very slowly
breg                 100 VDC            0
OA                   170 VDC            8.94 VDC
IA                    225 VDC            222.8 VDC
bA                    0 VDC               0 VDC
OB                   100 VDC            2.24 VDC

Right half of the photo starting from lower right of the right C4s board
Kreg                approx 1 VDC     1.6 VDC
breg                100 VDC            98.4 VDC
OA                  170 VDC            168.5 VDC
IA                   225 VDC            222.5 VDC
bA                   0 VDC               0
OB                  100 VDC            96.5 VDC

I will swap the tubes in the A and B sockets and see if that changes the measurements.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 16, 2020, 08:32:56 AM

Changing the Russian tubes from side to side had no effect on any of the voltages.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: Paul Birkeland on April 16, 2020, 08:52:56 AM

I would be interested in seeing some build photos. 

One side of your Eros at least is working properly.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 16, 2020, 07:19:45 PM

These are pictures of the left C4S board. 

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 16, 2020, 07:24:53 PM

More pictures

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 16, 2020, 07:30:23 PM

last photo batch

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: Paul Birkeland on April 17, 2020, 06:31:20 AM

If the leads in the red circles touch, things will go very south in a hurry.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 17, 2020, 04:28:46 PM

In 3 d space the wire in the last pic have a reasonable amount of clearance.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 17, 2020, 04:35:21 PM

Must be time to dismount the left C4S board.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: Paul Birkeland on April 17, 2020, 04:41:42 PM

Well, you have a working board and a non working board.  You can pull each C4S board out and move it to the opposite channel to see if the issues move with the board, or you can reflow all the joints on the offending side and see if you notice any differences in the wiring/installation.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 17, 2020, 08:15:01 PM

Success! :) :) :)
As I was going through the instructions in reverse order to pull out the Left (A side) C4S board on page 66 I realized that instead of instead of the Black wire from C3 being wired into the breg I had soldered it into dB.
I corrected it, checked that all the other wires are in the correct location on the A and B boards and did all my resistance checks. 
The weird measurements are gone.
The tubes have been carefully inserted all the way into the sockets.
The voltage checks are also correct now.

In the morning, I'll put it into the system and see if it sings.
Thanks again for all the feedback and calm encouragement.

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: Paul Birkeland on April 18, 2020, 05:36:40 AM

Hey, well done! 

Title: Re: Eros build of a kit that has been waiting since 2015 makes it to pages 75 & 76
Post by: PaulG on April 20, 2020, 04:30:10 PM

I have listened to over 20 albums since installing the Eros into the system and have gotten jacked enough to retrieve 3 boxes of old favorite albums from storage.  I really like it!
Thanks again for all your support!