Fisher 500c tube noob

[notdigital]

Ok, I'm starting to make a list of to dos.......What else? Top priority is to make it safe.

Best advice is to read the various 500-C/800-C threads. After a few, you would have been exposed to virtually all the modern adjustments to make your unit safe. Many are essential, some are discretionary, but all are in keeping with the original design adapted to contemporary usage. Based on your experience, the DIY approach would certainly be a rewarding if not enriching experience.

 

[thornev]

I found this in the Tube forum, speaking of Dave et al:

Output Tube Assessment
The Mighty Bogen MO-200A
Modifying the Fisher 400 with EFB
Improving the Fisher 400
Improving the Fisher X-101C
Improving the Fisher SA-100 with EFB II
Dynaco ST-70: Base Line Testing
A Little Help For Eico's HF-81
The Fisher X-1000 and EFB
A 400C Transformation
The Fisher Phono Preamp, and RIAA
A Diamond in the Rough: Polishing Heath's AA-30 (AA-111)
Gilding the X-202B
A Songbird of a Different Color
Teaser Pics -- Fisher SA-100 clone in progress
KX-100: Fisher's intro Stratakit
KX-100/X-100B -- Fitting A New Output Transformer http://audiokarma.org/forums/index....100b-fitting-a-new-output-transformer.854714/
FM-200-B Refresh http://audiokarma.org/forums/index.php?threads/fm-200-b-refresh.630801/
The End of an Era: The Fisher 55-A http://audiokarma.org/forums/index.php?threads/the-end-of-an-era-the-fisher-55-a.646003/

 

[larryderouin]

Fred. Solid State knobs were squared off with either a RIBBED(pre 68) or SMOOTH(post 68 up thru 71 or so (pre japanese/Asian manufacture)) side. The brights had a squared off edge vs. beveled and were FLUSH against the sides. All except for the tuning knob had a raised indicator rib.

Larry

 

[fred soop]

Right, Larry, but where was the non tapered rib used?

 

[Lo-Fidelity]

I found this in the Tube forum, speaking of Dave et al:

Output Tube Assessment
The Mighty Bogen MO-200A
Modifying the Fisher 400 with EFB
Improving the Fisher 400
Improving the Fisher X-101C
Improving the Fisher SA-100 with EFB II
Dynaco ST-70: Base Line Testing
A Little Help For Eico's HF-81
The Fisher X-1000 and EFB
A 400C Transformation
The Fisher Phono Preamp, and RIAA
A Diamond in the Rough: Polishing Heath's AA-30 (AA-111)
Gilding the X-202B
A Songbird of a Different Color
Teaser Pics -- Fisher SA-100 clone in progress
KX-100: Fisher's intro Stratakit
KX-100/X-100B -- Fitting A New Output Transformer http://audiokarma.org/forums/index....100b-fitting-a-new-output-transformer.854714/
FM-200-B Refresh http://audiokarma.org/forums/index.php?threads/fm-200-b-refresh.630801/
The End of an Era: The Fisher 55-A http://audiokarma.org/forums/index.php?threads/the-end-of-an-era-the-fisher-55-a.646003/

Wow! Very nice!

 

[Carbon13]

Very nice indeed! Think I need to look for those safety resistors.

 

[larryderouin]

Fred; Everywhere except the tuner knob to my knowledge.

Larry

 

[fred soop]

I think you are misinterpreting my question. What I'm referring to is (post #14 photo) one knob having a rib that is higher toward the back of the knob while the other has a rib that is the same height above the knob front to back. The latter I have not seen.

 

[larryderouin]

(Back to post #14) Never seen the straight rib knob on Solid State, except for the split knobs for Tone controls, which have a straighter rib, but still angled some. The smooth side knob is a console knob. Stand-Alones got a ribbed side knob.

 

[Carbon13]

Thanks to Rufleruf for helping me out with some original knobs!

The cab has been stripped and refinished with danish oil and the unit is at the tech for the full laundry list of mods (thanks to all the terrific info here). I'll post a pick when it's all finished.

 

[Carbon13]

Just got my 500C back from the tech. Sounds amazing!!!

Here's some pics naked and dressed.

 

[thornev]

Nice ! What next? Tube rolling?

 

[Carbon13]

Well, just installed all new Tubes (except for 2 which tested good; mostly replaced with Tung Sol tubes) which was very pricey! So I think I'll live with it for a while before I start rolling too much (unless I can source some cheap tubes somewhere...).

 

[Catmanboo]

First time ive seen re-stuffed caps un-canned , you may start a new fad there. Get that thing out in the free air, NO GEAR on top, no obstruction of the back half of it. It must breathe, them output tubes put out beaucoup BTU's!. How about a close-up underbelly shot so we can see what all was (or not) done. Thorne, quit giving him ideas, he's likely got a wheelbarrow full of $$$in this thing already!

 

[thornev]

Hey, Cat. I'm always looking for new commiserationists !

 

[Carbon13]

LOL!! Yes, it feels like a wheelbarrow full of $$$. I've even started a bit of a sell off of some of my other gear to fund this (a Technics 5760 went up today and on deck are a Yamaha YP-701 and Pioneer SX-650). Hopefully that will help cover some of this venture into the world of tubes

As for an underbelly pic, stay tuned. I'm going to just enjoy this for a few days before I pull it out and apart again.

 

[Carbon13]

Underbelly pics as requested.

I have been listening to this for a few days now and I'm just blown away by the detail and soundstage. This was an expensive venture but I do now get what all the fuss about tubes is about (which was the whole goal of this exercise).

 

[baconbadge]

Underbelly pics as requested.

I have been listening to this for a few days now and I'm just blown away by the detail and soundstage. This was an expensive venture but I do now get what all the fuss about tubes is about (which was the whole goal of this exercise).

I was under the impression that adding a grounded three-prong plug wasn't a good idea because of possible ground loop issues? Them's some fancy output couplin' caps too! Enjoy it!
-k

 

[Carbon13]

Not having any issues yet. In fairness, the tech had to deal with some prior mods that probably weren't the best. Said he got zapped by the chassis at one point before adding the new grounded outlet scheme.

 

[larryderouin]

He probably got zapped due to C103 breaking down or shorting completely. He should have replaced that with an X-Y type Safety cap that fails open. Then no real need for an IEC plug with grounding. But watch out for ground loops when you connect "ungrounded" sources. If you get a HUM, 1st thing to do is to reverse the wall plug on the external source. That should in most cases alleviate the hum.