SP3 Update from ARC

[DonH50]

I wandered over to the ARC site hoping to find a replacement manual and noticed they have a $1295 (direct only) update for the SP3 series of preamps. May have to think about shipping my old SP3a1 in for updating instead of selling it!

I wonder if they got rid of that string of 47 V zeners...

FYI - Don

 

[MylesBAstor]

I wandered over to the ARC site hoping to find a replacement manual and noticed they have a $1295 (direct only) update for the SP3 series of preamps. May have to think about shipping my old SP3a1 in for updating instead of selling it!

I wonder if they got rid of that string of 47 V zeners...

FYI - Don

A lot of solid-state components have been discontinued. That happens with great regularity with even today's solid-state devices, complicating their design considerations.

 

[mullard88]

Hi DonH50,

If your SP3 is still working, I suggest you keep it and try to source 8 pieces of military grade Telefunken 12AX7. There is a lot of musical magic when the old capacitors are given the chance to work with military grade Telefunken tubes.

 

[DonH50]

@Myles -- I suspect those zeners are still there as they appeared in numerous ARC products over the years, but it's possible they have moved on to a different regulator scheme. Than ran those 5 W zeners on the hot side, and they just did not seem to last (I had to replace one or more about every 3 - 5 years).

@mullard88 -- Hmmm, thanks, but actually (a) I have tried those (and yes they were nice), (b) I have not checked its current status but given it was built in 1973 and I have not switched it on in 10+ years I suspect the caps need some TLC anyway (I am not sure if I replaced them previously, but I have had to rebuild the supply a few times when zeners blew and took out the series-pass transistor in the regulator circuit so it is possible), and (c) I am planning to sell it along with the rest of my older tube equipment. I love that old stuff but alas no longer have space, time, and $$$ to rebuild it. I noticed the advert on the ARC site when I was trying to find a downloadable manual for my SP3a1 and D-79 (all my manuals have vanished into the black hole of boxes from various moves through the years).

Thanks! - Don

 

[mullard88]

Hi DonH50,

I think you're right in selling it.

I have first hand experience with the Audio Research SP3 factory update. The new capacitors makes the updated unit look twenty years younger. The sound though was not the same and unfortunately was worse. All my listening buddies asked me why it did not sound as nice as before. To date, I have discovered that it can sound nice when Amperex tubes are used for the three phono tube sockets, Mullard tubes installed in all the other tube sockets; and the Sensory Power power cord is used.

I can not forget the D 79. It is an incredibly powerful 70 watter. I have heard another hobbyist's unit use it the drive his Infinity IRS speakers. It simply effortlessly filled his big room with beautiful music. As for my own unit, I had reliability problems and gave up. I still remember that its sheer weight made my thumb bled when it got stuck under the D 79.

 

[DonH50]

Thanks, it is with great sadness that I am getting rid of what is essentially my first "high end" system but it needs to go to somebody who will take care of it and use it.

I suspect it was tubes, the revamped power supply, and rebiasing that changed the sound, not the power supply capacitors. Back then (late 70's early 80's) the SP3a1 was considered one of the best and last, preferred over the SP3Bxx, SP3C, and even the SP6. Mine also has the black face plate with gold trim, a bit unusual now with their silver look.

I loved my D-79 and it had the best bass of any tube amp I heard at the time, but couldn't match the bass of the big SS amps so I eventually bi-amped my Maggies with it on top and a Counterpoint on the bottom. Mine lasted perhaps 15+ years before a power tube shorted and (I think) took out a couple of parts in the power supply. It is going to a fine new home for TLC and a second life. - Don

 

[MylesBAstor]

Thanks, it is with great sadness that I am getting rid of what is essentially my first "high end" system but it needs to go to somebody who will take care of it and use it.

I suspect it was tubes, the revamped power supply, and rebiasing that changed the sound, not the power supply capacitors. Back then (late 70's early 80's) the SP3a1 was considered one of the best and last, preferred over the SP3Bxx, SP3C, and even the SP6. Mine also has the black face plate with gold trim, a bit unusual now with their silver look.

I loved my D-79 and it had the best bass of any tube amp I heard at the time, but couldn't match the bass of the big SS amps so I eventually bi-amped my Maggies with it on top and a Counterpoint on the bottom. Mine lasted perhaps 15+ years before a power tube shorted and (I think) took out a couple of parts in the power supply. It is going to a fine new home for TLC and a second life. - Don

Don't forget about the SP3A-1 Van Alastine mod. A local dealer has had a ARC SP3A-1 for sale in his window for a year now. He's asking $1500; way too much considering probably needs new tubes and other parts such as power supply caps that have dried out.

 

[DonH50]

Wow, memories. I met Frank (van Alstine) several times, and spent hours on the phone with hm way back then. He wouldn't remember me (I was a smart-a** snot-nosed kid; I'm not a kid anymore ) but he had a lot of influence on me and audio, including bolstering my MO mule skepticism with a dose of why some things sounded and measured they way they did, how subjective impressions can lead to better understanding and engineering, and why so many claims were/are (insert polite term for b.s. here). It was on his advice that I changed the tube filaments to d.c. instead of a.c. and tweaked the feedback network a bit for a better RIAA match.

I have seen a few SP3a1's go for over $1k on eBay; seems high to me, but what do I know? Make me an offer!

I wonder if a member's only for sale forum would fly here? I know from experience it's a major pain to keep under control, however.

 

[mullard88]

Hi DonH50,

Glad to know you're also a Maggie user. I used to match my Maggie to Audio Research tube amps too. Nowadays, I have discovered that I like Maggies driven by Spectral solid state amps. But that's just my personal preference. I have heard a very nice Maggie set-up driven by a re-tubed Audio Research amp.

 

[DonH50]

Yup, and it was neat when Magnepan and Audio Research were sharing, with each having the other's gear in the factory listening rooms. Miss those days! Still listening to my old MG-IIIa's, though, but with Emotiva amps these days. Can't afford "the good stuff" with a couple of boys to put through college!