Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: pbman1953 on September 05, 2013, 08:24:24 am
-
One of my Sunn's has Weber copper caps and my other has tubes in the rectifier area. I'd like to try a solid state this time. My amp tech said to look for one with the highest "PIV"
Does anyone have a suggestion?
Thanks
-
Just get four 1N5408s. Put two in series for each HT lead. That'll give a safe rating of 2000VPIV and 3A. B+ will increase. Hope the filter caps are rated for it.
-
Some types of Weber SS rectifier has an incorporated (SAG) resistor
I think it will be easy to you to verify if your's has a resistor and the relative resistance
so you can duplicate the circuit by yourself using the 1N5408 diodes
K
-
There are 4- 1000 uf caps rated at 350v
-
I saw that Tube depot same units in a plug in at $10. I may go with that. This way everything stays on the stock side
http://store.tubedepot.com/ssr.html?vfsku=ssr.2&gpla=pla&gclid=CN3r_sy4tLkCFQyk4AodWEoAfQ (http://store.tubedepot.com/ssr.html?vfsku=ssr.2&gpla=pla&gclid=CN3r_sy4tLkCFQyk4AodWEoAfQ)
the link shows the internal parts and connections
-
There are 4- 1000 uf caps rated at 350v
Wow! Those are some biggggg caps. Those are likely to really strain a tube rectifier if not outright kill it.
-
I saw that Tube depot same units in a plug in at $10.
I highly recommend you don't put that unit in those Sunns. The tube depot unit with only two diodes is only rated at 1000VPIV. Those Sunns will exceed that PIV rating. That's why I suggested to use four diodes. You can bust the glass from an old octal tube and mount four diodes in the base if you want a cheap plugin module. Even fill the base with epoxy if you like.
-
so you're saying that I can duplicate the The Tube Depot one but with twice the parts
-
I say plus 1000 for SL's right-on opin and sugg. do the 4 diodes for a cost of 1.20 or less. your tech should be easily able to put 'em in there.
It's not so much 2x the parts as it is installing something that gives a safety cushion for the rest of your amp. You're already doing the work so put the right parts in 'er.
SL....love the epoxy idea.....i gotta try that m'self. :icon_biggrin:
-
That diagram, from TD, was a top view right?
-
Also, while I have you guys, I need to install a speaker selector 4/8 ohm switch.
What value should the switch be?
Thanks for all the help!!!
-
That diagram, from TD, was a top view right?
Yes. But the important thing is to connect the diodes to the correct pins. Pins 4, 6, and 8 are the ones you want.
I need to install a speaker selector 4/8 ohm switch. What value should the switch be?
Get the switch that Doug stocks. It's up to the task for big amps.
-
Awesome , Thanks
-
Here's an adjusted pic....it's not to scale, but at least it'll keep you on the right track
-
After looking at the amp, I could do it inside the chasis. It doesn't look like a big deal
Thanks
-
There are 4- 1000 uf caps rated at 350v
Wow! Those are some biggggg caps. Those are likely to really strain a tube rectifier if not outright kill it.
Interesting you say that. years ago , when I bought the amp, it already had the caps installed. The amp has been noisy due to tube socket wear. I figured to test the tubes while it was out of the cab and now one of my Mullard's is dead. I have one good one. After poking around I see that they are big money prompting the going the SS route
-
There are 4- 1000 uf caps rated at 350v
Are you sure they are one thousand µF? Two pairs of series connected one hundred µF would be more likely in a tube amp.
-
Busted!
You're right 100 uf :laugh:
-
My previous post was in reference to this Weber solution
https://taweber.powweb.com/store/modkits.htm#SSRT (https://taweber.powweb.com/store/modkits.htm#SSRT)
(https://taweber.powweb.com/store/ssrt_schem.jpg)
---
About the 100uF are they in series two by two with resistors in parallel ?
(http://www.el34world.com/charts/images/seriescap.gif)
if so the result would be a pair of 50uF 700v caps
---
Doug rotary impedance switch
(http://www.el34world.com/charts/images/rotarydiagram2.jpg)
K
-
About the 100uF are they in series two by two with resistors in parallel ?
Yes
Will probably go for a high volt toggle, but I already have an on-off-on but I'd rather a on-on.
Thanks
-
I'm at a parts supply store and they do not have the 5408. Are they any other values that I can use?
-
Actually I'm all set. The store guys went on their vendor site and cross referenced and found that they do have them. Grabbed 4