[Yen]

Now I am totally lost with this piece of *.

Got me some new Raytheons and Sylvanias for a cheap price from ebay, but still the same problem.

The last time right side functioned well, biased 40V and sounded lovely like usual. And the left buzz and was about 70V, which is same as the 70V TP.

NOW, after resoldering and fixing the socket, the buzz has switched to the left side (!!!), and the music plays behind that buzz.

The right side is now totally silent! No buzz, no music.

The test points shows -12V, 12V and -12,6V correct. The bottom 40V (next to -12,6V TP) shows around 8Vs and is adjustable from the trimmer. The 60V and the other 40V shows 61V, which is odd too, cos when fuctioning my 60V should be around 70V. This 40V isnt adjustable...

OMG, I am close to build CKK3 and throw this piece of junk out of the window...

It's not the tubes, it's not the sockets, it's not the connections and groundings, it's not the opamp (tried many), so where is my problem? CSS?

 

[Yen]

Here are the readings of tube pins starting from the pad that is square in digis board and going CCW:

1. 3,1V when R4 trimmer is at its lowest. Reacts to R4 trimmer.
2. 0
3. 0
4. -12,6
5. 0
6. 62V (Same reading or few .x below 60V TP)
7. 0
8. 3,1V reacts to R4 and shows exact same reading with pin 1.
9. -6,3V

I hope this helped to debuging...

EDIT: My pin order is reversed to this...

 

[tomb]

Quote:

Originally Posted by Yen /img/forum/go_quote.gif Here are the readings of tube pins starting from the pad that is square in digis board and going CCW: 1. 3,1V when R4 trimmer is at its lowest. Reacts to R4 trimmer. 2. 0 3. 0 4. -12,6 5. 0 6. 62V (Same reading or few .x below 60V TP) 7. 0 8. 3,1V reacts to R4 and shows exact same reading with pin 1. 9. -6,3V

EDIT: Skip what I typed before if you saw it - my pin locations were wrong, too.

I think you have a couple of them mixed up, though.

copied from Wikipedia -

It looks like your pins 4, 5, and 9 are correct (heater filaments). However, pins 1 & 6 should be at B+ (your 62V). Pins 3 and 8 should be the 40V bias (or change with the trimmer). Pins 2 and 7 should be the signal, which may read zero or very small.

 

[FallenAngel]

Yen, I don't think you should be lowering the trimpots that low with J113 CCS. They only handle like 35V so dropping from B+ 60V to 3.1V will put way too much across them and probably fry them.

Keep your trimpots at the highest so you don't put too much voltage across the CCS. Are you sure you have everything hooked up properly in the CCS? Try to remember EXACTLY when this started.

 

[Yen]

You were right tomb.

I installed the socket right to the PCB and this piece of * became my beloved one again!

However, I did order new sockets and will make new enclosure for my amp.

Thank again for all your help.

Fallenangel: I think you cant adjust so much with the trimmer. I think if it is lowest, I got about 30V and max 50V or something. I doubt it will go down to 3V unless there is something wrong...

 

[procreate]

Hi Andreas,

Quote:

Originally Posted by steinchen /img/forum/go_quote.gif yes, you're right, good that you're asking, I forgot to mention that: with the low input impedance of 50k the buffer can be used together with the SOHA tube stage in MU-follower configuration only!

Is the v3 SOHA PCB set up for this? That's what I was going to use your buffer with.

 

[Nordic]

Yen, see if you can get a 7308 (e188cc) big quality diffirence... uses a fraction less current on the heater.. no adjustment needed.

Tried building the SOHA 3 times, only got it to work once, but heck it was so unstable, I just gave up and build an opamp hybrid for practice.

 

[tomb]

Quote:

Originally Posted by procreate /img/forum/go_quote.gif Hi Andreas, Is the v3 SOHA PCB set up for this? That's what I was going to use your buffer with.

Speaking for Steinchen, but the SOHA PCB is setup for 6 different options of CCS. It's probably what causes the most confusion. In any event, the mu-follower version is supported as an option for all three choices of semiconductor - check your documentation if you aren't sure.

No doubt, Steinchen will make this abundantly clear when he releases the boards for a Group Buy. He documeted the construction and setup very clearly for the Millett Hybrid DB's and will probably do the same for the SOHA buffers.

 

[Yen]

Quote:

Originally Posted by Nordic /img/forum/go_quote.gif Yen, see if you can get a 7308 (e188cc) big quality diffirence... uses a fraction less current on the heater.. no adjustment needed. Tried building the SOHA 3 times, only got it to work once, but heck it was so unstable, I just gave up and build an opamp hybrid for practice.

Thanx for the suggestion. I am currently running a Raytheon 5814 and OPA2107 and I am really satisfied with my build.

Also, I have recased the beast, and installed the socket straight to the PCB, as you can see from my sig.

With v3 PCB, I really havent any problems except with my socket wiring mess. At the beginning, I ordered only one socket for PCB assemble. Then I was so stupid that I didnt solder the parts on the opposite of silkscreen. Then when I had to turn the pcb upside down, then the socket order got mixed up...

Then I installed the pcb socket to a perfboard and got a lot of trouble having the socket pins soldered to perfboard pads and connections right. That's where all the problem came.

Now, everything works fine, except that tube (i guess) catches some noise. Dunno if the toroid in the same case causes these problems or my house's AC line is crap. I hear snaps everytime the fridge starts cooling and ends it... also, there is some noise when the oven is on...

 

[tomb]

Quote:

Thanx for the suggestion. I am currently running a Raytheon 5814 and OPA2107 and I am really satisfied with my build.

I have tried that exact combination and it is a very good one.

Yen, are those Auricaps, Hovlands, or what for your coupling film caps?

 

[Nordic]

Yen add the following to your circuit.

1 275VAC or higher 200nf XY cap, ask specificaly for XY caps, this is a safety rateing meaning they can be used both from L to Ground as well as N. I do not take resposiblity if you don't adhere to that.
And one 12 to 17Watt 1 ohm resistor.

Solder one leg of the resistor to one leg of the cap.

The free legs gets conected on the mains wire in parallel with the primary, this should filter out all clicks and switch pops.
While buying the caps, get a second one and put it over the terminals of the switch.

I want to build a standalone IRF610 headphone amp, and then I will try the mosfet hybrid again. Maybe do something more elegant about the heater arangement, have some ideas but need to do some research to see if they are valid.

 

[Yen]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Yen, are those Auricaps, Hovlands, or what for your coupling film caps?

None of those, sadly. They are some random and cheap films I found from a local guitar amp / diy shop when I bought new sockets. Cant say much about their sound cos I changed at the same time with the raytheon and opa. I am pleased with the current sound.

I am still waiting for PCX to stock Elnas as they have informed during their January Sale. Then I will buy Mundorfs and 'lytics for Alien and soha to save shipping costs. Yeah, I am cheap... student.

I have some regular Panasonics (NHG, some say they are ok) and Elnas (dunno series, brown in color) in my Soha right now.

 

[Yen]

Like my attached picture?

I did find only X2 "filtering caps" and this. Are they the same as XY?

Quote:

Originally Posted by Nordic /img/forum/go_quote.gif Yen add the following to your circuit. 1 275VAC or higher 200nf XY cap, ask specificaly for XY caps, this is a safety rateing meaning they can be used both from L to Ground as well as N. I do not take resposiblity if you don't adhere to that. And one 12 to 17Watt 1 ohm resistor. Solder one leg of the resistor to one leg of the cap. The free legs gets conected on the mains wire in parallel with the primary, this should filter out all clicks and switch pops. While buying the caps, get a second one and put it over the terminals of the switch.

 

[tcpoint]

I swapped out my OPA2134 (which sounded muddy in the bass) and put in an OPA2107 and I was impressed. I like the detail and sonic characteristics of this the OPA2107. Thanks for the suggestion Tomb

 

[Nordic]

no, its not the same, but I think its safe enough for this job.

the first cap in you picture should go over the switch....... on the schematic it would look like a switch in parallel with the cap

look at the bit before the transformer for the concept.