[psryan]

My Singlepower ES-1 Amp (with HE-90) crackles only in one channel with or without source and it is intermittent.  Actually it comes and goes for days at a time and is very hard to duplicate on demand.  If I unplug the power supply for a day it will usually behave for a few days.
 
I know nothing about electronics.  I had a local tube amp wizard go through the amp and all was OK and he could not duplicate the problem.  He did not however go into the power supply.
 
Should I try a  power conditioner?  It is just plugged into the wall and there are lots of other things on the circuit.  If so, what is recommended?
 
Thanks,
PSRyan

 

[spritzer]

Given the fact that all ES-1 and ES-2 amps are by definition malfunctioning it could be a number of issues.  The ES amps aren't dual mono despite the marketing BS Mikhail spew at the time so everything in the PSU is shared between the channels.  A fault in one channel points to that channel being the culprit.  If you've used this set of tubes for any length of time then that will be my first port of call as the shared filament supply dramatically shortens their lifespan and they will start becoming unpredictable.  Knowing Mikhail then everything inside the amp will either be rated way under spec or best case, right on the line so resistor or capacitor failure is something to look for. 
 
Given that somebody has taken a look under the hood and didn't run away in horror shows they don't know the circuit and what it takes to make it work.  EL34 cathode sitting at -300V on the cathode is something which should worry any tube tech. 

 

[psryan]

Thanks,
 
Well he was horrified, and cleaned up a bunch of stuff but he didn't find the problem.  The tubes tested OK.
 
Shall I just buy the "upgraded" tube types Mikhail sent or is there some magic formula of tubes you would recommend?
 
The tubes have run 2-3 hours per day, every day for about 5 years.
 
Thanks so much.
 
PSRyan
neophyte

 

[spritzer]

If he didn't' rip out the DC filament supply then you are still going to have problems with the tubes.  No tube tester I know of tests the tubes for this kind of damage so they could be fubar but with normal emission ratings. 
 
I would just recommend any matched quad of EL34's and 6SL7's for the driver tubes.  No other tubes should be used there for the amp to function as it should.  6SN7 works but not really. 
 
You should also read this if you are bored...

 
http://www.head-fi.org/t/431581/the-single-power-es-1-2-repair-and-restoration-thread

 

[psryan]

Thanks again,
 
The first thing we did was swap the tubes left to right and the crackle stayed in the right channel.  Still think its the tubes?
 
I am not bored by the link, just totally bewildered!  I will send it to my tube amp guru.
 
PSRyan
Neophyte

 

[spritzer]

If the problem doesn't follow the tubes then they aren't the issue.  One thing that springs to mind are the adjustment pots as they are rather crude and could be a source for some noise. 
 
That amp was very scary but after I rebuilt it it was very nice indeed.  The ESX circuit is still one of my favorite circuits and it sounds amazing for something designed in 1968. 

 

[rosgr63]

Spritzer how much has tube amp circuit design improved in the last 50 years?

 

[spritzer]

Leaps and bounds but the core circuits still remain the same.  It's what's done around them which has improved so much.  By using the tubes just for the signal path and using solid state parts to support the tubes you get the best of both worlds.  Sadly most "designers" just rehash the same circuits time after time and given the quality of transformers these days, modern tube amps are much worse than the old ones.  There are exceptions but they are rare. 

 

[rosgr63]

Thanks spritzer.
Which SS parts would you say have improved the most?

 

[spritzer]

The greatest contribution would arguably be the silicon diode and how it has allowed to make proper power supplies.  The valve rectifiers were always a great obstacle and if you wanted to do a fully regulated PSU then it would require a metric crapload (i.e. a lot) of tubes.  Unreliable gas tubes now replaced by zeners and transistors instead of pass tubes. 
 
Transistors are also very good for setting the operating point for the tubes accurately and maintain it into any desired load.  A resistor is always a crappy current source by comparison. 

 

[rosgr63]

Can the above components be implemented on a point to point wiring construction/design?

 

[spritzer]

Anything done on a circuit board can be done with wire.  It's also the other way around as you can even have transformers built into PCB's.