Tube DIY Asylum

RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell

142.127.22.126

vetmedrobert@gmail.com

In Reply to: RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell posted by kobasa@xs4all.nl on August 29, 2020 at 07:52:55

Clearly you did not read my previous post. RCA spec sheet says 22ma and 250 plate volts. And all component parts were correct, I always measure resistors before use. Unfortunately with a burned out transformer kind of hard to measure regardless of what I measured before

Follow Ups:

RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - kobasa@xs4all.nl 09:33:47 08/29/20 (9)
Which post? Where did you post RCA data?
You wrote that you use 'The circuit is the JE Labs simple 46'
So i follow that circuit and the total current is about 48mA, 23mA for each output tube and about 1mA for each driver tube. Plate dissipation is almost 6W , not 7,5W.

Edits: 08/29/20
- RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - vetmedrobert@gmail.com 09:43:54 08/29/20 (8)
  Did you read the article accompanying the schematic? JE is following the values given on the tube data sheet for the 46 triode connected, which are 22ma and 250 volt on the plate. Check the data sheet. Anyway 1ma more or less is of no great consequence, this is tubes we are discussing. And it still does not explain away my problem.
  - RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - kobasa@xs4all.nl 10:05:47 08/29/20 (7)
    They say they try to follow as close and they did....And you are right 1mA does't make the differance.
    But as i say before measure the anode voltage and kathode voltage, if that is correct then you know that this part is ok.
    You must have somewhere a huge leakage current because even de electrolytics (if new/ reliable) have not such leakage currents.
    
    Edits: 08/29/20
    - RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - vetmedrobert@gmail.com 11:23:24 08/29/20 (4)
      Well all very moot as the transformer is shot:( Have not the discretionary income at the moment to get a new one as I have been out of work for some time, COVID-19 eh?
      - RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - Boli46 11:28:13 08/29/20 (3)
        
        In Reply to: RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell posted by vetmedrobert@gmail.com on August 29, 2020 at 11:23:24
        
        Well, it's something to keep in mind when things improve. Hopefully sooner rather than later.
        
        RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - kobasa@xs4all.nl 11:29:46 08/29/20 (2)
        
        In Reply to: RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell posted by Boli46 on August 29, 2020 at 11:28:13
        
        i hope you used this before you started:
        
        http://www.duncanamps.com/psud2/index.html
        
        RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - vetmedrobert@gmail.com 11:31:53 08/29/20 (1)
        
        In Reply to: RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell posted by kobasa@xs4all.nl on August 29, 2020 at 11:29:46
        
        Have been using it for years...
        
        RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - kobasa@xs4all.nl 11:34:32 08/29/20 (0)
        
        In Reply to: RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell posted by vetmedrobert@gmail.com on August 29, 2020 at 11:31:53
        
        Did you noticed that a 58mA transformer cann't deliver 48mAdc in this amp?
    - RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - kobasa@xs4all.nl 10:09:37 08/29/20 (1)
      btw the voltage drop on the output transformer is huge for a transformer.
      Rdc more then 600 Ohm
      
      Edits: 08/29/20
      - RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell - vetmedrobert@gmail.com 11:26:10 08/29/20 (0)
        
        In Reply to: RE: New project, voltage checks good, blows fuse after 45 minutes and power transformer hellaciously hot and odd smell posted by kobasa@xs4all.nl on August 29, 2020 at 10:09:37
        
        Yes, I noticed that, mine have 280 ohms so I need even lower voltage before the output transformer.

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors:

Schiit Audio