Cornet - Ceramic Fuse

tianguis · « **on:** 14 May 2004, 01:05 am »

Folks:
Through a CDP mod (Toshiba 3960) I learned the value of ceramic fuses in cleaning power. Don't know why, but obviously it's the construction. It must be due to the physical damping of the filament and its composition. I also use balanced and filtered power for all my components.
I ordered some 1A ceramic fuses in my last DigiKey order, with the specific intent of sticking one in the Cornet. Stuck one in tonight. These are not slow blow, but there was no problem on power-up.
The difference is very noticeable. My first impression was of the increased definition, crisp and immediate. There's a minute "grain" which has disappeared at the same time that an increase in micro detail has been revealed. It's an easier sound, just flows, with more space. There may be a slight bias toward the top end, though no loss of bass. I've been doing A/B's with several of my reference LP's and there's no contest.
I haven't done any tube rolling in a while, with Tele ECC803, Holland Bugle (same), Tele ECC802 and Sylvania Gold 5Y3 in the line-up.
Part number is DigiKey # 283-2392-ND, made by Buss.

Regards,
Larry Welsh

hagtech · « **Reply #1 on:** 14 May 2004, 10:59 pm »

Wow, that is so cool! A colleague was recently explaining how he liked a certain brand of fuses - one with a very different structure. The internal wire was flat and shaped like a lightning bolt. Looked to be low inductance, probably lower impedance. I also have to wonder if the microphony differences between glass and ceramic have anything to do with it. Construction of components can have a great impact on sound quality.

Keep up the experimentation! I'll look into making this part standard. Then again, I just bought 200 of the glass ones...

jh

tianguis · « **Reply #2 on:** 14 May 2004, 11:28 pm »

Jim:
At $1.12 each, they're kinda pricey, but cheap at 10 times the price. I stuck one in my Transcendent Grounded Grid today (still working on the Clarinet case, the board was a snap) with a similar effect. I believe most of it's effect is due to a reduction of microphony caused by the vibrating filament, though someone on AA dissected one and said the materials are different. Neat stuff!

Larry

GRD · « **Reply #3 on:** 29 Jul 2004, 03:14 pm »

I tried switching to the ceramic fuse last night, and it does make a difference. I heard the same effects you mentioned. I have no idea why it should have an impact. But it does and it's well worth the extra $1.00 versus the original part.

Thamks again for the tip.

Grant

tianguis · « **Reply #4 on:** 29 Jul 2004, 06:46 pm »

Grant:
Glad it works for you. It's always good to have these things confirmed independently.
Here's my latest: demagnetize the tubes. After a discussion on the Bottlehead and AA Tube DIY fora (which included scope traces before and after) I demagged the Cornet tubes. Noticeable improvement in detail and reduction of tube rush. I've since demagged the other 14 tubes in my analog path and the improvement is dramatic.
You can use a bulk tape eraser or make a coil, but I used a hair dryer: unshielded motor, strong field. With the dryer on, slowly bring the tube and "cold" end of the dryer together from arms' length to about 1/8" and rotate the tube for abiut 10 sec. Without turning the dryer off, move them apart to arms' length.
No, I haven't lost my sanity, although the process confused my wife and amused the cat.

Regards,
Larry Welsh

Marbles · « **Reply #5 on:** 29 Jul 2004, 07:00 pm »

any idea what the fuse part # would be at Radio Shack?

tianguis · « **Reply #6 on:** 29 Jul 2004, 07:03 pm »

GRD · « **Reply #7 on:** 29 Jul 2004, 07:11 pm »

Actually, the demag makes sense. There are magnetic materials in the tube structure. I'll have to give it a try. Innovative use of a motor (hair dryer) for creating a magnetic field for the demag.

The fuse effect is still a mystery to me. I would think that after the mains current traversed the transformer and went throught those big capacitors, there would not be an effect. Not true. So, thanks for the tips.

Regards,

Grant

hagtech · « **Reply #8 on:** 30 Jul 2004, 05:24 am »

As Larry pointed out, make sure you move the hair dryer (mag field) far away from the tube before turning it off. The 60Hz field has to decay in strength very gradually. A sudden transient will actually have the effect of magnetizing the tube.

You could try a degaussing coil from an old TV (color). But I'd think the VCR tape eraser as the best solution. No motor brush electrical noise.

jh