Nice pictures, beautifull work.
for the zip ties I was refering to the way you cut them. Take a look here; Cut Zip Ties The Proper & Painless Way - Car Guy Reviews
for the zip ties I was refering to the way you cut them. Take a look here; Cut Zip Ties The Proper & Painless Way - Car Guy Reviews
I figured there was a good reason. That certainly is one, even if I still don't understand why.
on my edcor xpwr144 transformer for a point to point wired 300b/6sn7 set the 6.3v winding had a centre tap. enquiring about where to put this, it was advised to connect to the ground bus. i have not tried leaving it unconnected though. @tubelab_com or others may wish to confirm as to the correct terminal on the pcb to connect this if at all.
Nice build btw, like your methodical approach. being a noob and frightened to turn my amp on for the first time I piked and engaged a local guitar amp tech to check things over. all was fine though. Looking forward to the outcome of your project.
Thanks for the positive comments everyone!
Thanks for the link potepuh. I would not want to poke my hand on something sharp that might cause me to jerk my hand into a bad spot in the amp!
cogitech, I have no idea either. The more I think about electricity the less I understand it. I'm actually reading a good book that was written for people like me who have to visualize things to understand them. It's called: There Are No Electrons: Electronics for Earthlings, by Kenn Amdahl. I recommend it.
Very nice Duke58. I'd like to experiment with UL and CFB down the road. I'm guessing that works better with some tubes than with others. I think George said somewhere that EL34's might sound best in basic triode. That's what I'm using for now.
Thanks woodo. I haven't come across any recommendations to ground the 6.3 center tap. Hopefully someone with an SSE will comment. Yep, I'm nervous about powering up for the first time. I also thought about calling around town to try and find a good amp tech. But, I'm just going to make a dim-bulb tester and let it do whatever it does!
Thanks again.
Thanks for the link potepuh. I would not want to poke my hand on something sharp that might cause me to jerk my hand into a bad spot in the amp!
cogitech, I have no idea either. The more I think about electricity the less I understand it. I'm actually reading a good book that was written for people like me who have to visualize things to understand them. It's called: There Are No Electrons: Electronics for Earthlings, by Kenn Amdahl. I recommend it.
Very nice Duke58. I'd like to experiment with UL and CFB down the road. I'm guessing that works better with some tubes than with others. I think George said somewhere that EL34's might sound best in basic triode. That's what I'm using for now.
Thanks woodo. I haven't come across any recommendations to ground the 6.3 center tap. Hopefully someone with an SSE will comment. Yep, I'm nervous about powering up for the first time. I also thought about calling around town to try and find a good amp tech. But, I'm just going to make a dim-bulb tester and let it do whatever it does!
Thanks again.
I assembled a 200w dim-bulb tester. I've re-checked everything in this amp many times over. I have no excuses left at this point.
First, I apologize for my lack of knowledge and experience in this process. So, I have some basic questions.
1) Do I power up the amp for the very first time WITHOUT tubes? Or, do I install some or all of them for the first power up?
2) I made some 25W 8Ohm dummy loads. Will these be adequate?
3) If the bulb stays dim, and I don't see smoke or flames, or smell anything burning, should I hook up a music source and speakers?
Really, thanks very much for help with this.
First, I apologize for my lack of knowledge and experience in this process. So, I have some basic questions.
1) Do I power up the amp for the very first time WITHOUT tubes? Or, do I install some or all of them for the first power up?
2) I made some 25W 8Ohm dummy loads. Will these be adequate?
3) If the bulb stays dim, and I don't see smoke or flames, or smell anything burning, should I hook up a music source and speakers?
Really, thanks very much for help with this.
Well, I made a diagram following Ty_Bower's guide. I flipped the image in Photoshop so it matches what I'll be looking at from beneath the board.
Ty did not say which ends of R10 and R20 to test when checking for the 12AT7 cathode voltages. I put a "?" there. Can someone tell me which end of the resistors to connect to?
In the same thread, SGregory said to check for AC out. I assume he meant to measure AC at the speaker terminals? How would I do this?
Here's my plan:
1) Power up with no tubes and watch for problems. Power down.
2) Power up with tubes and dummy load and watch for problems. Power down.
3) Check B+ voltage at R4. Power down.
4) Check Cathode voltages at R17 and R27. Power down.
5) Calculate current draw and power dissipation for the EL34's.
6) Repeat steps 4 and 5 for R10 and R20 (when I know which end of the resistors to connect to). Power down.
7) Post my measurements and calculations here and wait for comments.
Ty did not say which ends of R10 and R20 to test when checking for the 12AT7 cathode voltages. I put a "?" there. Can someone tell me which end of the resistors to connect to?
In the same thread, SGregory said to check for AC out. I assume he meant to measure AC at the speaker terminals? How would I do this?
Here's my plan:
1) Power up with no tubes and watch for problems. Power down.
2) Power up with tubes and dummy load and watch for problems. Power down.
3) Check B+ voltage at R4. Power down.
4) Check Cathode voltages at R17 and R27. Power down.
5) Calculate current draw and power dissipation for the EL34's.
6) Repeat steps 4 and 5 for R10 and R20 (when I know which end of the resistors to connect to). Power down.
7) Post my measurements and calculations here and wait for comments.
Attachments
All the tubes are glowing to what I would call a dim orange.
The 200 watt dim bulb has a low orange glow.
I did not hear any noises, and I can't smell any smoke.
I let it sit like this for a few minutes.
I did notice that it was several seconds before the dim bulb started to glow. I'm guessing that's due to the CL-90, D3, D4, TR1, and the 5AR4 warming up? Is that normal?
Does it sound safe to power up without the dim bulb?
Thanks in advance!
The 200 watt dim bulb has a low orange glow.
I did not hear any noises, and I can't smell any smoke.
I let it sit like this for a few minutes.
I did notice that it was several seconds before the dim bulb started to glow. I'm guessing that's due to the CL-90, D3, D4, TR1, and the 5AR4 warming up? Is that normal?
Does it sound safe to power up without the dim bulb?
Thanks in advance!
You know, you really should hear Bill Frissell's Shenandoah through an old pair of Radio Shack 4" full-range 40-1197's...
And, a functioning Tubelab SSE!!!
A HUGE thank you to George for making this project possible, and a HUGE thanks to everyone here who took time to answer my questions and provide advice.
But, this is enough excitement for one morning. Later, when my heart rate is down, and I'm relaxed, I'll take some voltage measurements.
For now, I'm really happy!
[My phone camera makes the tubes look brighter than they actually are.]
And, a functioning Tubelab SSE!!!
A HUGE thank you to George for making this project possible, and a HUGE thanks to everyone here who took time to answer my questions and provide advice.
But, this is enough excitement for one morning. Later, when my heart rate is down, and I'm relaxed, I'll take some voltage measurements.
For now, I'm really happy!
[My phone camera makes the tubes look brighter than they actually are.]
Attachments
Congratulations on the birth of your new Tubelab SSE amplifier!
It’s been a long time in the works but totally worth it, enjoy!
It’s been a long time in the works but totally worth it, enjoy!
dwinstonwood,
Congratulations on your successful Tubelab SSE build. Yes, our thanks to George - it is a very nice tube amp project. 🙂
Enjoy the amplifier (and of course the music), and stay safe!
Congratulations on your successful Tubelab SSE build. Yes, our thanks to George - it is a very nice tube amp project. 🙂
Enjoy the amplifier (and of course the music), and stay safe!
Thanks everyone! I'm glad I made it through that part.
A few observations:
The amp is dead quiet through my speakers, no hum.
However, there is a very, very low hum that sounds like it's coming from the transformers. This hum seems external. All three transformers are cool to the touch.
I'm not sure how brightly my EL34's should be glowing. They are bright orange in a dimly lit room. But, I do not see any redness. I guess I won't know more until I measure voltages.
I would appreciate any comments on those observations - whether or not they represent red flags, or not.
Thanks again!
David
A few observations:
The amp is dead quiet through my speakers, no hum.
However, there is a very, very low hum that sounds like it's coming from the transformers. This hum seems external. All three transformers are cool to the touch.
I'm not sure how brightly my EL34's should be glowing. They are bright orange in a dimly lit room. But, I do not see any redness. I guess I won't know more until I measure voltages.
I would appreciate any comments on those observations - whether or not they represent red flags, or not.
Thanks again!
David
I've played it for about three hours.
I really can't believe how good it sounds.
What an awesome, fun and rewarding project. I learned a ton, gained a lot of confidence, and now have an amp that sounds amazing.
I really can't believe how good it sounds.
What an awesome, fun and rewarding project. I learned a ton, gained a lot of confidence, and now have an amp that sounds amazing.
