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Fuses for Heathkit AS-103A.....


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Hi ...newer member here. I recently acquired a set of mint Heathkit version of the AR3a and a pair of mint AR2ax's. I have become smitten with the 103's with that bass but the ax's have their moment also.

Anyways....was playing the Heathkits thru my 9090 and the fuse blew on the right channel. The volume was only set on third notch if halfway is six so not on loud.

Does anyone have a clue to why that blew? Also...where do I purchase these fuses? I am sure they are special for this speaker.

I did have the Heathkits on a G-6700 and it would shut down the receiver to protect mode on any volume over three notches. I thought it was because the Sansui hadn't been recapped yet. The 9090 has been redone but the speaker fuse blew instead. Will I always have trouble with these being 4 ohm? Thanks for any help.

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Sansui Owner's Manual and Service Manual are available here:


If the 'sui is only rated for 8 ohms (which apparently it is) then yes--you will always have a problem.

If you look at the fuse and find out the part number, just google that and you should find some. I don't know what fuse is needed.

Good luck.


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According to the Heathkit Assembly Manual for the AS-103A speakers the parts list calls for a 3-ampere fuse (3AG-3A). Heathkit part # was 421-2. Price was .10 cents.

I ordered the fuses from PE..thanks! I hoping the Sansui's can play the AR's and Heathkits. I will have to look into this but thought other owners had done this and had no problems. The 103's sound incredible to me but would oocasionally, like to hear them with a little more volume. The bass is wonderful.

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Kent's comment may be the key to this puzzle. Is it possible that this beast-of-a-receiver is incapable of driving 4 ohm speakers? Five minutes of research yields inconclusive results, but you should get to the bottom of this issue before resuming use of this combination of components.

This partial 'spec' mentions load impedance at 8 ohms.


This link mentions power ratings at both 4 and 8 ohms.


This 9090 owner states that the receiver itself states 8 ohm output.


This link gives power ratings only for 8 ohms.


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There is a thread on AK re; this concern.


On this thread....( mine is a recapped and cleaned 9090 by Dr. Audio)).....

I am not a technician so I can not guarantee anything, but I owned a 9090 and took it to a qualified tech for repair and he told me that I could play that beast all day long into 4 ohms and all I had to worry about were the speakers. He told me that after he repairs a unit, he always tests it against a 4 ohm load.

That may not be true with all units, or all speakers, but the 9090 appears to built like a tank. It certainly passes the “weight test”.

As I said, I’m no technician so it all may be all talk, but he owns a shop called “The Audio Wizard” in Scottsdale, AZ. He has been at the same location for 34 years and before that ran the warranty repair facility for a major Japanese manufacturer, can’t remember which one. He’s handled all my repair work for 10 years and I never had to take anything back.

It would be helpful if someone else more qualified than I would chime in. It’s an interesting question.

Soooooo.... something else blew the fuse...maybe age?....will get new ones and try those. Thanks for the links. It answered my question.

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Hi there

This Heatkit brand topic would be more suited to the, "Other speakers and electronics" topic.

The 3 amp glass fast blow fuse is readily available at almost every electrical hobby shop for about $0.25 each and you should always keep extras onhand.

The chassis mounted fuseholder that Heath used was not the greatest idea, it holds in heat but, at least they provided one.

My comment is because an open style fusehoilder allows the fuse to cool itself naturally.

A consideration also would be to derate the fuse downward to perhaps 1 1/2 - 2 amps, to even better protect your investment.

Understand that no fast blow fuse will blow in time to save your speakers if they were accidently plugged into a wall electrical outlet.

The Heathkit speakers model AS-103/103A should have a clean and stable amplifier that can swing from 20 - 100+ watts continuous from 20 - 20,000 hz with low distortion.

Impedance can swing from 2 - 30 ohms over the entire frequency range.

The biggest job is driving the woofer under perhaps 100 hz at loud levels.

An amplifier that is rated down to 4 ohms, or even better yet, 2 ohms, is at least a more compatible amplifier.

Most older classic amps are not suitable and even less so receivers, with few exceptions.

If only low level listening is done, then all requirements are less critical.

Receivers such as Heathkit AR-15/1500 or similar, due to age, are not a great choice unless you or a friend can service them.

Same with most classic amps.

There are some classic amps that were more suitable, old, but suitable, Crowns DC-300/A, Phase Linear 300/700, Bose, Heathkit, and McIntosh of course.

A Crown amp of very attractive specs and priced at $300.00 is available to investigate and at least read about.

I am pleased to read that someone is looking after fusing their valuable investment.

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