• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

Simple SE - Right side with low volume and crackly sound

Status
Not open for further replies.
Jump to Latest
S

Salsero

Member
Joined 2003
#1
I assembled my simple SE and must say, the left side rocks. The right side, well it does not sound nearly, nearly as loud as the left side and it is crackly. I have tried re-melting the solder to the tubes sockets and caps, resoldered some odd looking resistor joints, checked the input and output connections, switched transformers, etc..... and nothing. I will report the separate voltages at different points later today.
In the meanwhile, I did notice that there are two open connections around C22 that I have nothing connected to. However, the picture in the website shows solder in those two holes (one of the holes sits on the outer diameter of C22). Am I missing a component in these holes? They are not marked as anything........
Secondly, I soldered a three way connector to the input of the right channel and later notices that it uses only a two wire connector. Is this a big issue?
Thanks for your input
Salsero😕
 
#2
Left vs Right side measurements

OK, here are some measurements,

Primary transformer - 427V, both sides
Primary transformer to the UL connection = 4V, both sides
Voltage drop across the transformer primary - 10V both sides
C21 and 22 = 228V, 222V respectively
R17 and 27 = 36V drop across resistor
C10, 20 = 1.88V
R14, 24 = 83V drop across resistor
R13, 23 = 2.8V
R13 and 23 to ground = 230C and 224V respectively
R19 and 29 to ground = 231 and 225V, respectively

Is this 6V difference between left and right a concern?

I noticed that when I switch transformers, my problem tracks with the transformer since the good sounding side switches. This indicates that the circuitry most likely is OK.

If I switch speakers, my problem also switches indicating that the speakers are OK.

So I assume I have a transformer problem. How can I fix or verify this prior to sending these GSX Edcors back?

😕Thanks
Salsero
 
#3
So I assume I have a transformer problem. How can I fix or verify this prior to sending these GSX Edcors back?
Click to expand...

There have been two or three SSE's that had a bad channel upon initial power up. Most have been traced to a problem with the speaker jacks. The simplest way to test for this is to disconnect the output wires on the OPT from the rest of the amp and connect them directly to the speaker using clip leads. If this results in sound then there is a problem with the speaker jacks or the wiring.

The voltage readings that you posted look OK.
 
#5
Right side clear, but still low volume

OK, thanks for the ideas. I cleaned up the crackly sound by working on the speaker connection. However, the right side is still lower than the left and the bass is not as full.

Note - I am running ultralinear without Cathode Feedback.

Can the six volt difference between left and right be indicative of a problem with the ultralinear connection/circuit - I am tempted to resolder all UL connections.

Could the CFB feedback capacitor be the problem although I am not running CFB mode?

Thanks
Salsero
 
#6
The slight difference in plate voltage is normal behavior from the CCS forcing the plate current for each tube to be the same. Also, you have to take into account the 5% tolerance of R14/24. Measuring across R13/23 instead of relative to ground would be more telling and I suspect you will find they are within 1%.

Check you solder work around C12/22. Also try disabling CFB for both sides and see what happens.
 
#8
.........and we keep going here

Russ,
I am not running the CFB connections, they are shorted to each other as in the wiring schematics. What do you mean by "try disabling the cathode feedback"?

Thanks, gracias, merci
Salsero
 
#10
and it keeps going........

Russ,
The T2SEC terminal 1 is connected to T2SEC terminal 2.
The T3SEC terminal 1 is connected to T3SEC terminal 2.

Does this disable CFB? or should I disconnect terminal 1 and terminal 2 for T2SEC and T3SEC?

Thanks for your time. I feel I am close but still not there yet.

Salsero
 
#11
That looks fine. The voltages all look correct. Some things to look at:

- Double-check the UL wiring. Connect the screens to the plates instead to try triode mode if need be.

- Try swapping OPTs on the PCB leaving the secondaries untouched. If the problem side moves, then you know the issue is on the PCB.

- Try removing the CFB jumpers from both sides. This will take the cathode bypass cap out of the picture. The gain will go down, but you are looking to compare the two channels.
 
#12
Not the CFB cap I think......

I removed the T2SEC and T3SEC jumpers and the difference between the two sides is still there - I believe this rules out the cathode bypass capacitor (C12 and C22). I will be trying triode mode next, to rule out the UL connection.

However, keep the ideas comming.

Thanks
Salsero😕
 
#16
I switched the sides of the primaries on the output transformers but the problem did not switch sides indicating that the PCB is likely OK. It may be the output transformer....how do I test it? What may be wrong with the trnaformers??

Are the left and right sides of the PCB connected the same way to the transformers (red cable - UL cable - blue cable) from left to right for both sides??

I set the primaries in triode mode but the problem persisted.

I switched the input connections to the board and got no difference.........

Any ideas???????????

Salsero
 
#17
Salsero said:
I switched the sides of the primaries on the output transformers but the problem did not switch sides indicating that the PCB is likely OK. It may be the output transformer....how do I test it? What may be wrong with the trnaformers??
Click to expand...

I have a feeling you may still have an issue with your speaker jack wiring. Next most likely cause is perhaps a mis-wiring of the OPT secondary (maybe they used the wrong color wire on one?). Less likely is a problem with the OPT itself, but it is possible.

Maybe it's time to post some pictures of your wiring, especially around the OPTs.

Salsero said:
Are the left and right sides of the PCB connected the same way to the transformers (red cable - UL cable - blue cable) from left to right for both sides??
Click to expand...

Yes, that is right.
 
#18
Are you sure you have your speaker terminals isolated from the chassis? Have you used a multimeter to make sure you have infinite resistance from each pin of the speaker terminal to chassis. Don't have the schematic with me, but you may need to disconnect the wires to the terminals to prevent odd readings. Also check no copper 'whiskers' from the wires shorting on the terminal blocks.

Good luck!
 
#19
speaker terminal isolation

I have the speaker terminals grounded to the inlet power ground for both channels. I also grounded the chasis to the inlet power ground. Wouldn't this imply that my speaker is grounded to the chasis? Is that a problem?

Thanks
Salsero😕
 
Status
Not open for further replies.
Top Bottom