HiFi (Chifi) tube amp build - but my own design.
Posts: 1,127
Threads: 78
Joined: Jan 2014
City: Annapolis, IL
Construction has started! So far, I've gotten the power supply done and filament wiring run. The major layout is finished, have a few sketches of where things should go. I've made a few changes and moved things around. Hopefully I can start on the high signal parts, then low signal stuff. Also have the bias supply together. Anyway, here's a pic of the progress so far.
If I could find the place called "Somewhere", I could find "Anything" 
Tim
Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
It's getting along!
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 1,596
Threads: 100
Joined: May 2008
City: Omak
State, Province, Country: WA
Hello Tim,
It looks very nice so far !
Sincerely Richard
Posts: 1,127
Threads: 78
Joined: Jan 2014
City: Annapolis, IL
I got things pretty much in place, double checked, waited a couple days, did some resistance checks and powered up through a variac and dim bulb. B+ seemed pretty close to what I wanted so I brought it up enough to get something. Yup, I could get a signal if I touched the input, so I plugged in a CD player and ... AND.../// it sounded .... AWFUL! Almost no volume and was badly distorted. Did a few voltage checks and plate voltage was really high on the inverter. I could hit either side of the coupling caps with a signal and it sounded clean, hit the grid of the inverter and - nothing. It was dead. Tried another tube, same. The inverter was dead. So I studied the diagram (that I drew), everything looked ok, that is, until I rechecked the driver tube diagram. OooOooohhhh - wrong! I had the triode grid and cathode pins reversed. Well, that'd do it. I have a feeling I just looked at the wrong pinout and drew it wrong.
So I switched it tonight and brought it back up - and ... AND ... SQUEEEEAAAALLLLL SQUEAL SQUEAL! Well, shucks. Been there, so I flipped the ground and feedback and it came on quite well. So, yeah, oops! So anyway, some of the same stuff I ran into before. I don't know if flipping the plate leads would change it or if the tranny is backwards. Anyway, I haven't really done a thorough sound check, but I did note it has the same lousy 60 cycle hum as my last kit. Not bad, just kinda ... there. So I know it isn't a filtering issue. Gotta either be coming the heater or ground loop. Since this is an experiment, I'm going to try a few things. I set this up so I can isolate the ground with a bus I may try some different heater arrangements, like DC, or maybe a hum balance. But all in all, the fact that it works is an accomplishment! And, no smoke! 
If I could find the place called "Somewhere", I could find "Anything"
Tim
Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44
(This post was last modified: 11 hours ago by TV MAN.)
Posts: 15,797
Threads: 553
Joined: Oct 2011
City: Jackson, NJ
Tim
It's be interesting if you put your schematic here.
Who knows, you could get some advice from a few folks here.
That yellow tubular cap may sag over time. Long leads, perpendicular to the axis with reasonably heavy part.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Users browsing this thread: 1 Guest(s)
|
|
Recent Posts
|
|
Looking for verification of correct schematic.
|
| Klondike98,
Thank you. I'll double check that SN and get back to you.
GarySP,
Thank you for the schematic.RossH — 12:13 AM |
|
Looking for verification of correct schematic.
|
| I think you have the correct take on your set. Ron's annotated early schematics that note the below B22000 serial numbe...klondike98 — 12:04 AM |
|
Looking for verification of correct schematic.
|
| Hello Ross. The Philco Radio Library located at the bottom of the page has the schematic with the tube count you have. ...GarySP — 10:48 PM |
|
HiFi (Chifi) tube amp build - but my own design.
|
| Tim
It's be interesting if you put your schematic here.
Who knows, you could get some advice from a few folks here.
...morzh — 10:01 PM |
|
Philco 42-390, code 121 speaker
|
| Thanks for that information. It would appear from the output transformer parts list that the transformer that was origi...Stevelog — 07:21 PM |
|
Looking for verification of correct schematic.
|
| I would like to verify that my thoughts are correct regarding my Model 70 and its appropriate schematic.
My chassis inf...RossH — 06:26 PM |
|
Philco 42-390, code 121 speaker
|
| Welcome to the Phorum, Steve! The Philco Radio Library located at the bottom of the page has info on speakers and outpu...GarySP — 06:24 PM |
|
Philco 42-390, code 121 speaker
|
| I recently became the owner of a Philco console 42-390, saving it from the dumpster. It is missing the speaker. It uses...Stevelog — 12:07 PM |
|
Help identifying
|
| Thanks for the welcome, Gary. There exists only one photo of the unit in the Richard Neutra-designed home. The photo (th...Davino — 10:54 AM |
|
Help identifying
|
| Welcome to the Phorum, Davino! Not much to go on from the above pictures. Would it be possible to take a photo or two ...GarySP — 10:25 AM |
|
Who's Online
|
There are currently 1260 online users. [Complete List]
» 1 Member(s) | 1259 Guest(s)
|
|
|
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
