Hi-Fi Tunig Fuses & Parasound A21


Hi,
Have any Parasound A21 owners replaced the stock fuses with the Hi-Fi Tuning fuses in their amp? I understand that there are four 8A slow blow internal fuses and one 12A slow blow fuse on the rear panel. This is a awesome amp as-is. Just my curiosity.

Please share your experiences.

-Thanks,
128x128milpai
Indranil

"auxinput- I ended up ordering Hifi Tuning Silverstar (the main fuse) and Classic Gold (rail fuses) which are on their way. I would first try the main fuse to see if this improves the sound at all. If yes then I would replace the rail fuses. I would post all result hopefully by the end of next week.
I wanted to find if folks here have an idea of how much changing the rail fuse would contribute to the overall improvement in sound under the assumption that changing fuse improves sound quality. Any feedback would be greatly appreciated.
Also did anybody compare performance across Hifi Tuning (Classic Gold, Silverstar, Supreme) and Synergistic Research Quantum Black fuses?

Thanks.
Indranil"

I am a big believer in the HiFi Tuning silver fuses. I have about a dozen components in my system and have a similar situation as you do with my Adcom amps. I too have purchased silver fuses for my main amp fuses and, I also first bought and tried 4 gold fuses for my Rails.
My first degree was in music. While my principal instrament was the string bass and electric bass, the main focus of my study was leaning toward music arranging. I love hearing all the detsils in music. The breathiness and occational sharpness of reeds, the initial draw of a bow, not to mention all the vaious percussion instraments.
Now your mileage may vary, but clearly hearing these details is why I like the silvers so much. The silvers bring out the details that I love without sacrificing too much warmth. Seems like regardless of whether it's tubes or fuses, it's always a balancing act between sharpness/detail and/or warmth/analog. I've tried a number of different fuses, AMR, HiFi Tuning, SR, etc. I keep coming back to the silvers.
There is a BIG difference between the silvers and the golds. While the silvers are very detailed with some warmth, the golds are very warm, but you sacrifice some of the detail.
My own experience with fuses is once you have about 30 hours on them, you're going to have a pretty darn good idea of what they will sound like when they are fully burned in. They won't be doing an about-face on you.
So put the silver main fuse in your amp (on my Adcoms this made a very noticeable improvement), put some hours on the fuse and get used to what it sounds like. After that, have fun inserting the golds, doing one at a time to gauge directionality of each rail fuse.
Just a side note: Most of my components were impressively improved by upgrading fuses but a couple, like my two tube preamps, gained no benefit whatsoever - likewise in many of my components the fuse was directional, but in some areas music sounded the same in either direction. In the case of my rail fuses I didn't hear a difference based on fuse directionality.
Now, here's a little advice from tube rolling experience. Hopefully, you will like the way your amp sounds after the five new fuses but if you don't, there are some ways to ultimately get to where your ears Will be liking what they hear.  If you think the silver fuse is too bright after 30-40 hours, note how it sounds and then put the gold fuses in. The gold fuses will temper the detail/brightness of the silver and you might have good balance of detail and warmth. For me, the silver was fantastic sounding but when I added the four gold fuses into my rails, my amps sounded overly warm and I lost some of my precious detail.
Jim McShane, of audio tube fame, once told me you need to match tube types when they are a left channel/right channel pairing. So, the tubes in V1-V2 need to match, and the tubes in V3-V4 need to match, and V5-V6 need to match; but the tubes in V1-V2 do not need to match the tubes in V3-V4, etc.
So, when I put the 4 gold fuses in my Adcoms & the sound turned way too warm & analogy for my taste, I pulled one gold out of the left side and the right side rails and re-inserted one original fuse in each side giving me an original and a gold for each side. As if by magic, I now had a sound that was just a little bit warmer than before the golds were first tried and I still had my detail and slam.
I just recently bought silvers to try in the rails. I'm now using one silver and one gold in the left and right rail channels in two of my Adcoms.  unfortunately, I only have about 10 hours on them so I can't make a final decision. If you want I'll keep you posted.
I blew my hifi-tuning gold rail fuses in my Revision A+ of my McCormack DNA-1. MY bad.  After calling Steve McCormack he discussed his preference for the silver star over the classic gold and supreme fuses.  He was disappointed that Hifi-ftuning stopped producing the silver star in favor of the supreme fuses.  He tried the supremes on two separate occasions and just did not get the openness and clarity of the silver stars.

After speaking with Steve, I googled silver star fuses and fortunately, Parts Connexion had them in stock at 60% off!!  Instant order.  In the interim, I procured Bussman ceramic body "microwave" fuses so I could listen till the silver stars arrived.  The Bussman weren't bad in the sense that I had music but the subtleties were MIA.  The sound was "matter of fact".

The fully run-in Silver stars have really opened up the soundspace.  There is "space" between and around instruments allowing each contributor to shine on each cut.  Great stuff.  Steve knows his stuff.

How does the fuse add "space" around instruments? Does it make the electrons go faster? Slower? Adds molecular grease of some sort? Electron happiness? Electron purposefulness? Do the caps and diodes and transformers simple feel better working with the juice once it's been through a half inch of "special" wire? Maybe I should call Steve…he must know.
@toolbox149
I have replaced both the main and the 4 rail stock fuses of my Parasound A21 amplifier with Hifi tuning fuses. I replaced these fuses in sequence. First replaced only the main fuse by Hifi Tuning Silverstar fuse and it immediately improved the sound in all areas. What I liked the most is the blacker background and the improved clarity. Not sure how it dropped the noise floor but it did.
Then I replaced all 4 rail fuses with Hifi Tuning Gold fuses (couldn't get the Silverstar in 8A rating) with the arrow pointing to the flow of the current i.e pointing from the transformer to the capacitor. The result wasn't so impressive. While it further increased the clarity but the instruments started sounding very hazy and smeared. The overall sound was also veiled. It has been 20 odd hours since I replaced the internal fuses and they might still be going through the break-in interval. I tried flipping the fuses such that they point to the transformer to see if that resolves the haziness issue but it didn't.
Did you have similar experience when you replaced the rail fuses inside your amplifier? Did you find any break-in period with these fuses? Any feedback/help in this regard would be greatly appreciated.Thanks.
Like most anything that impacts the electrical circuit of a piece of kit, break-in is necessary. Obviously this requires patience, a virtue few of us in this hobby possess in abundance. I don’t have an electrical engineering degree that might help inform me as to why things in this quizzical hobby happen as they do but they do occur. There is plenty of anecdotal evidence of such all over this site. Perhaps the mystery is part of the appeal.

As far as Steve McCormack goes, I know what my stock amp sounded like and what it sounds like post SmC Audio mods. Nuff for me!