That's the spirit, don't quit when you've come so far. The tubes are in the mail and should be there tomorrow. Don't let the boxes fool you, they are 12AT7's and should have markings on the tubes. And don't think about sending me $$ either. If I had a dime for every time someone in this hobby has helped me out I'd be a rich man. As it is I've just got a lot of really cool tube gear to show for their kindness. I think you need some inspirational photography.N1ESE said:
This is what I'm listening to right now.
N1ESE said:
I agree, don't give up when we are in the middle of a good mystery. One thing that can happen is resistors off by magnitudes of 10 or 100 or even 1000, which escape because we are expecting and see the correct 3 digit numbers. I doubt you have done this, but it has happened before. And no, I'm not revealing how I came to know this.
Sheldon
tubelab.com said:
I tried to look over his board today in the photos and match color bands with what should be what and I think he's got the right resistors in those positions but it'd be pretty sweet if he didn't and having 220k in front of the grid would certainly choke the life out of the signal, wouldn't it?
tubelab.com said:
Not according to the schematic I used to assemble the board!
http://www.tubelab.com/SimpleSE_schematic.htm
^ R16 & R26 show 220K and R15 & R25 should be 100 according to that schematic.
First, I must apologize for the grief caused by a mistake in my Visio drawn schematic. The Eagle schematic shown on the same page is correct although hard to read. This error was brought to my attention about a year ago and I fixed it. I some how got the old schematic back onto the web site, likely when the web hosting company suffered a fire in the server room, and I scrambled to rebuild the site. This was 6 months ago. Most builders just stuff their boards by using the parts list as outlined in the instructions, so this error went unnoticed.
I will fix the schematic tomorrow, its too late tonight.
I will fix the schematic tomorrow, its too late tonight.
Actually the 220K grid stopper resistor will cause a rollof of the high frequqncy response. Its the 100 ohm load on the 12AT7 that kills the gain.
tubelab.com said:
Gah! Warming up the soldering iron as we speak. I know I bought extra resistors, hopefully I bought extras of these values. I always build from schematics, not parts list. Damn.
Checking resistor inventory and hopefully this will finally all be resolved in a little bit. Thanks George.
N1ESE said:Resistors on hand, time to get to work.
On the positive side you should be rolling old production input tubes into a working amp before the end of the week. Feel free to hold onto those tubes for the time being, I've got another 10 or so to play with and won't miss them. 🙂
HOLY COW! It works! Much, much better!
Damn schematic. I don't always have the luxury of building from a parts list so I naturally build from a schematic. I'm really glad George was able to come on tonight and find this problem with the schematic. Wow.
Thanks to all.
Damn schematic.
I don't always have the luxury of building from a parts list so I naturally build from a schematic. I'm really glad George was able to come on tonight and find this problem with the schematic. Wow.Thanks to all.
There you go!
So you now have a great amp! Congratulations!
Well, for your troubles you have managed to help Tubelab fix his web page, and probably help fix a bunch of headaches for future builders!
Let us know how you like the amp!
Chris
So you now have a great amp! Congratulations!
Well, for your troubles you have managed to help Tubelab fix his web page, and probably help fix a bunch of headaches for future builders!
Let us know how you like the amp!
Chris
Who would have known? I've learned something new today. Glad to hear it's working now.
I never even saw that "other" schematic. I always referenced the one here:
http://www.tubelab.com/AssemblyManualSimpleSE/schematic_SSE.htm
I never even saw that "other" schematic. I always referenced the one here:
http://www.tubelab.com/AssemblyManualSimpleSE/schematic_SSE.htm
Ty_Bower said:
Which is wrong too. 😀 I used the other one because this one you just linked is too small to read on my big monitor. However, looking closely I can see that this one has the swapped values as well.
I can't believe the fix was so simple, ugh!
I must say, for a little amp this thing really puts out now. I listened to it most of the night. The KT88 and CXSE combination really pumps out some decent bass as well to these junk speakers. Going to be really interesting to hear how it sounds on some real speakers.
You sure about that? On my monitor that schematic correctly shows R16 as a 100ohm grid resistor and R15 as a 220k resistor to ground. On the other, incorrect schematic the resistor values and placement are correct, it's just the text label for each that is in the wrong spot.N1ESE said:
If it were me I'd be dancing that the fix was easy. Better that than a shorted trace on the pcb or something like that (don't ask me how I know how much hell that can be to find).
Now I'm getting psyched about working on mine again. 😀
Both schematics appear to have the correct values on them. I think George fixed it last night or this morning. Probably need to hit "refresh" on your browser, otherwise it might be showing a cached copy.
Not fixed yet. The resistor values have always been correct on the schematic, just the lables R15, R16 are switched.
There is a more serious issue with the schematic, the name. About 6 months ago I received correspondence from the company that owns the trademark on the word "simple se" without the space between the simple and the se. It was agreed that to avoid legal issues I would never put those two words together in print again. I fixed the schematic at that time, but now it is obviously unfixed. I am off to work now, but I will come home at lunch time to fix this before I get in trouble.
OK, the schematics are now correct. It seems that there were three different versions of the Simple SE schematic resident on the web hosting server. Two of them were referenced by the actual web pages, neither were the correct one.
I have added PDF versions of the schematics and PC board outlines for both boards.
I have learned to beware the words" Let Front Page merge the changes". I still don't know what that means but I now now how to fix it. Delete the entire site from the hosting server and reload it.
I have used Microsoft Front Page for the Tubelab web site since day one. It is no longer supported and I am slowly learning Expression Web. I have started on a new Tubelab web site but haven't had the time to finish it.
Agian, I apologize for the confusion this has caused.
I have added PDF versions of the schematics and PC board outlines for both boards.
I have learned to beware the words" Let Front Page merge the changes". I still don't know what that means but I now now how to fix it. Delete the entire site from the hosting server and reload it.
I have used Microsoft Front Page for the Tubelab web site since day one. It is no longer supported and I am slowly learning Expression Web. I have started on a new Tubelab web site but haven't had the time to finish it.
Agian, I apologize for the confusion this has caused.
- Status
- Not open for further replies.