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Hoffman Amps Forum image Author Topic: Illinois Caps  (Read 19920 times)

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Offline bluesbear

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Re: Illinois Caps
« Reply #50 on: March 19, 2011, 04:27:15 pm »
To be perfectly honest, I've never had ANY new cap be bad or go bad on me. I did fix an 18 watt for friend of mine who couldn't make it work and it turned out to be a new Sprague Orange Drop that was defective. That's the only bad cap I've seen except for old ones. Given that, it doesn't make sense for me to pay a premium unless a customer insists. Then it's on HIS dime!
Dave

Offline EL34

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Re: Illinois Caps
« Reply #51 on: March 19, 2011, 04:39:26 pm »
Quote
So, maybe, just maybe, Gerald Weber's continual trashing of Illinois Caps is not true?

No, that can't be?  :l2:

I don't know K O'c dude
Who knows what his beef is, I can only go on my real world results.

Maybe Fender had a batch made for themselves that is different from the off the shelf Illinois.
Maybe they wanted to shave another $.030 off each crappy cap they had made for their application?
Maybe they are operating the caps too close to the working voltage limit?

Could be many things.
The number of users who use the Illinois and have had no issues speaks volumes.

Offline ThermionicEngine

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Re: Illinois Caps
« Reply #52 on: March 20, 2011, 09:31:35 pm »
It's dectective work 101. If all the failures seem to come from one amp company (Fender) and most of them from one model (Blues Junior), it would be considered admissable evidence that Fender got a bad run of caps. I've never had a bad Illinois cap and I've used a lot of them. On the other hand, my son's first amp was one of the earliest Blues Junior's. I bought it for him new and it still is just fine... and doesn't sound bad either, BTW. I'd bet the amps with bad caps were all made about the same time. If so, I'd consider that proof!
Dave
I'm a retired investigator who repairs a lot of Fenders. I have observed failed IC caps in the Tweed/Hot Rod series of amps as well as the Blues Junior and one Custom Shop Tweed Twin.  I wasn't keeping track but it would be fair to say at least 20 amps in the last five years.  Most had some discharge from the positive end.  I don't think IC caps are bad- Fender used(s) them exclusively in tube amps for 15+ yrs and I would say less than 1% of the Fender amps I've serviced had IC caps fail (amps dated from abt 1994-2010) Factor in the zillions that have not come in for repair and I bet any cap manufacturer would have the same or worse failure rate. I'm pretty sure that if IC's were bad, Fender would have switched vendors way before now.  I replaced them with IC's, Spragues, and F&T (whatever I had in hand and fit) and none came back with the same issue.  (I like F&T and Atoms in my builds but it's probably superstition)
V= IR; Everything else is derivative...

Offline bluesbear

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Re: Illinois Caps
« Reply #53 on: March 20, 2011, 10:16:13 pm »
I use the JJ multisections for filter caps, except for bass amps and I've only gutted and rebuilt those so the cap cover was already there. I've never had a bad one. Doug sells them. They take up very little real estate and I like to make the amps as small as safely possible.

"Factor in the zillions that have not come in for repair and I bet any cap manufacturer would have the same or worse failure rate."

I agree. I've never gotten a bad electrolytic from anybody.

Dave

Offline RicharD

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Re: Illinois Caps
« Reply #54 on: March 20, 2011, 10:49:41 pm »
>Maybe they are operating the caps too close to the working voltage limit?

I wondered about this too.  I noticed from perusing various Blues Jr schematics that the voltage rating on the power rail caps is 450V on some schematics and 525V on others.  What is the voltage spike = to before the tubes start conducting? 

IC is just fine and dandy.  I find it a little interesting that the only comparisons are drawn to Sprague and F&T.  Nichicon and Chemicon both make a far superior cap, but only in radial leaded.  From reading speculation sheets, Panisonic makes a good cap too but I have no experience with them.

Cap failure is nothing new to tube amps.  We all know this to be true.  We also know that Fender has a 60ish year history of power supplies that just barely cut it.  Who is at fault, IC or Fender?  Many would argue that a barely adequate power supply is a big contributor to tone.  Personally I think a weak power supply is the root of all that is evil.

Offline ThermionicEngine

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Re: Illinois Caps
« Reply #55 on: March 21, 2011, 12:30:02 pm »
It's dectective work 101. If all the failures seem to come from one amp company (Fender) and most of them from one model (Blues Junior), it would be considered admissable evidence that Fender got a bad run of caps. I've never had a bad Illinois cap and I've used a lot of them. On the other hand, my son's first amp was one of the earliest Blues Junior's. I bought it for him new and it still is just fine... and doesn't sound bad either, BTW. I'd bet the amps with bad caps were all made about the same time. If so, I'd consider that proof!
Dave
As a retired investigator I'd like to share my investigative results and conclusion.  I don't have precise numbers but I have observed about 12 IC failures in Fender Tweed/Hotrod Dluxe and Dvilles as well as Blues Jr.  ALso 1 Custom Shop Twin.  Amps were produced in the 1994-2010 timeframe.  I replaced them with ICs, F&Ts, and Atoms (whatever I had on hand and would fit)  None came back for cap issues.  I would say they accounted for < 1% of Fenders I serviced/repaired since 1994.  Some residue or actual dishcharge of material, 120 Hz hum etc.  So in my experience the observed fail rate is < 1%.  Now factor in the thousands they have built that did not come into the shop.  The fail rate drops below .001%  Please stipulate that anyone's caps would fail at or above the same rate.

Fender has used IC's almost exclusively since 1994 in most of their tube amps.  They would have switched vendors long ago if the product wasn't up to the job.  I bought an early VibroKing (#488) and had issues w/reverb.  I talked with Bruce Zinky and in the conversation mentioned the IC caps.  Bruce told me to call him when one of them failed.  I'm still waiting for one to fail...

My bet is the jury will find IC not guilty of bad cap charge.  Of course, we all know that not guilty is not the same as innocent...  (I use Atoms and F&Ts in builds, but it is probably cap profiling...Or superstition, or just habit.  I can't say I heard any difference.)  Interesting topic and responses. 
Larry
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Offline Willabe

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Re: Illinois Caps
« Reply #56 on: March 21, 2011, 08:39:51 pm »
I talked with Bruce Zinky and in the conversation mentioned the IC caps.  Bruce told me to call him when one of them failed.  I'm still waiting for one to fail...

Is'nt he the guy who said in the book that he wrote on tube amps the way to discharge filter caps is to take a - Big - screw driver with a plastic handel and lean the shank of the screw driver on the side of the chassis and keep it there and then touch the tip of screw driver to the positive terminal of the filter cap.        :w2:


           Brad         :think1: 

Offline ThermionicEngine

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Re: Illinois Caps
« Reply #57 on: March 22, 2011, 12:37:16 am »
I talked with Bruce Zinky and in the conversation mentioned the IC caps.  Bruce told me to call him when one of them failed.  I'm still waiting for one to fail...

Is'nt he the guy who said in the book that he wrote on tube amps the way to discharge filter caps is to take a - Big - screw driver with a plastic handel and lean the shank of the screw driver on the side of the chassis and keep it there and then touch the tip of screw driver to the positive terminal of the filter cap.        :w2:

           Brad         :think1: 
Never read that one, Brad.  :laugh: I guess it would drain them, but a bit noisy.  No mention as to the status of the power and standby switches?  Anyway, he called the IC cap quality right.  I am new to this forum but so far I've seen a number of well-known-if-not-respected guys take hits.  Of course, if the shoe fits they gotta wear it.  This forum is no place for sensitive egos!  They might be trying to make a buck, but who isn't?  They all believed in their product.  Thirty-five years ago, I would have died for the resources we have now on line or published books.  On the other hand I could get a decent 7025 or 6L6 at the local drug store... Man, I should have bought those cases of tubes in the basement...

What I like(d) about Gerald, Fischer, and Pittman is/was their willingness to share their knowledge and experience with everyone.  For the price of a guitar mag or the Angela catalog, you could get information that was not forthcoming elsewhere.  The books came and I got a lot out of them.  I now have a cabinet full of reference material.  (The gem of my collection is most of the Fender service manuals and bulletins from about 1965 to 1985.  Some stuff from FMIC. Inherited them when we discontinued being a service center.)

Well I think I gone on way too long.  I appreciate the insight from all.  (I'll probably keep using the Atoms and F&Ts, and yes, I use JJ's too- I forgot about them.  I keep a few DeVilles worth of IC's in stock also. )
Semper Fi, Larry
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Offline Frankenamp

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Re: Illinois Caps
« Reply #58 on: March 25, 2011, 09:55:28 am »
I talked with Bruce Zinky and in the conversation mentioned the IC caps.  Bruce told me to call him when one of them failed.  I'm still waiting for one to fail...

Is'nt he the guy who said in the book that he wrote on tube amps the way to discharge filter caps is to take a - Big - screw driver with a plastic handel and lean the shank of the screw driver on the side of the chassis and keep it there and then touch the tip of screw driver to the positive terminal of the filter cap.        :w2:


           Brad         :think1: 


On a slightly diff'rent tack, I have a standard bit screwdriver that someone tried that trick with in a Toyo Si150 injection molding machine's servo power supply rail by accident (it was locked and tagged out). It has a couple farads worth of 500V capacitors behind said rail... took a few minutes with a grinding wheel to fix it. I left a bit of the damage as a reminder to be more careful next time. Fortunatly the guy had hold of the insulation instead of the shank. I been looking at the caps on a fried servo amp, but the caps are a leeetle too big for thermonic work. <snicker>
This problem calls for a bigger hammer!

Offline RicharD

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Re: Illinois Caps
« Reply #59 on: March 25, 2011, 10:09:11 am »
Probably not the "best" method to discharge a cap, but certainly the fastest.  Reminds me of Discharging a CRT.

Offline softwarejanitor

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Re: Illinois Caps
« Reply #60 on: March 25, 2011, 10:36:58 am »
I talked with Bruce Zinky and in the conversation mentioned the IC caps.  Bruce told me to call him when one of them failed.  I'm still waiting for one to fail...

Is'nt he the guy who said in the book that he wrote on tube amps the way to discharge filter caps is to take a - Big - screw driver with a plastic handel and lean the shank of the screw driver on the side of the chassis and keep it there and then touch the tip of screw driver to the positive terminal of the filter cap.        :w2:


           Brad         :think1: 

I accidentally crossed the terminals with a screwdriver tip on a big cannister cap in an old Yamaha G100-210 solid state amp I used to have and it went POP and blew a big chunk out of the tip of the screwdriver...  I didn't get hurt and it didn't hurt the amp, but I sure wouldn't recommend discharging caps like that.

Offline phsyconoodler

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Re: Illinois Caps
« Reply #61 on: March 25, 2011, 10:52:14 am »
Quote:"I've never gotten a bad electrolytic from anybody."

I have.A super reverb I re-capped had one bad 22uf/450v cap in it.The owner played it for an hour and then it emitted the magic smoke.I checked it over very thoroughly after and nothing was amiss.I replaced the cap and all was well.It's still ok after 5 years now.

It happens.Just not very often.
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Offline Willabe

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Re: Illinois Caps
« Reply #62 on: March 25, 2011, 11:41:33 am »

Probably not the "best" method to discharge a cap, but certainly the fastest. 

That has not only got to be hard on the screw driver, but very hard on the cap.


           Brad        :icon_biggrin:

Offline LooseChange

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Re: Illinois Caps
« Reply #63 on: March 25, 2011, 11:53:50 am »
I can't remember the brand but I had a cap (installed correctly) that boiled over when powered up...
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