ARC SP8 as Phono Stage


Thanks to an A'gon transaction, an LS17 should be arriving in the near future to replace my SP8. So one simple question, and one subjective one:

The easy question (really looking for confirmation): I would like to use my SP8 as a phono stage, while letting the bank account rebuild, and then watch A'gon to see if an ARC PH5 appears. I believe that if I connect the line-outs from my SP8 to the phono-ins on the LS17, that will effectively use the SP8 as a phono stage, correct?

Subjective: Would anyone venture what level phono stage I would need to better the SP8-as-phono set-up? In other words, would virtually any dedicated phono stage be better, or would I need a $1K stage to better the SP8, etc. (if I don't go the PH5 route)?
palewin
Yes. Plug your table into the phono input on the SP8, then the preamp outputs of the SP8 to any line level input on the LS17. Use the volume control on the SP8 to match levels and your good to go.

The SP8 has a pretty decent phono stage, so you would have to go to a PH5 or PH7. A PH3SE might be a little better.
Use the record output from the SP-8 connected to the phono input on the LS-17, or any other input they are all the same.

Using the main outputs on the SP-8 will include the line section of the preamp as well. Since you just need the phono section this will be needless additional circuitry in the signal path and will degrade the overall performance of the system.

If you use the Tape Record Out like Kentaja recommends, you will also bypass the volume control. You might not have enough gain. It would be a cleaner signal, but the gain can't be adjusted. Try it both ways and see what sounds better. Also, some tape outs are buffered, not sure if the SP8's are or not?
According to the specs on the SP8, the phono input to tape output is 34db of gain. The phono input to main output is 60db of gain. So, it would depend on what the output voltage of your cartridge is. 34db is a little on the low side.
So the main output has 26 db more gain than the phono through tape out; will not this be made up by the gain in the line stage? I have used a tube pre in this manner and never had gain problems.
The SP8 has an MM phono stage. It is not meant to be used for MCs. If you do not have enough gain on the input of the LS-17 from the SP-8's tape outputs, then get a phono stage that is appropriate for your cartridge. DO NOT use the preamp outputs or you have all of the SP-8 line stage circuitry as noted above. The SP-8 along with the SP-10 had horrible line stage performance.

The SP-8 is a great product but has limited usage. You can easily sell it and get a PH1, PH2, PH3 or PH3SE for the SP-8 price or even less! And your problem of gain will be solved and ultimately far better results.

There are other ARC line stages, most notably the LS5 and LS25 Mk I, that sell for much less than the LS17 and would significantly destroy the LS17 in musical performance. Give these consideration as well if you want to stay in the ARC domain.
Stanwal,

The LS17 has only 12db of gain through SE and 18db through balanced. Again it would depend on the cartridge's output.

I agree that a standalone phono stage would be the way to go.
Hi,
I would not say that the SP8 and SP10 had "horrible line stage performance". More recent preamplifiers can be more transparent and better sounding, but one great system I heard included a Meridian CD player, an SP8, and Electrocompaniet amplifier and Quad ESL63 speakers. Surely not a system for rock, heavy metal or loud listening, but it sounded fantastic with acoustic, jazz and classical music.
Although I do not have it anymore, my SP10 also sounded very good with CDs.
Re SP10II line stage and assumedly the SP8 as well. I was able to do some A/B of the line stage with a passive line stage as well as another less pretentious tube line stage. With the passive line stage, as well as the lesser tube line stage, the imaging was slightly smaller, less dynamic, BUT more focused (better resolution) and with more apparent 'depth of image' but with slightly less height and width. Sort of a trade off. If optimum pin point imaging, especially depth of image which accompanies a high degree of resolution, is not a big deal then the SP10 is a great pre-amp with an excellent phono stage. Sort of like comparing the sound of large panel speakers to high res box speakers. Courses for horses I think.

Re Jafox's comments, consider he has a history with ARC products behind his observations, and he has posted his opinions often, however these observations on the SP10 are IMHO more specific to the relative quality compared to his other ARC products which he feels greatly improved on what was originally a SOTA pre-amp.

They (SP10s) are what they are, but they are by no means horrible. That is just attention grabbing hyperbole, IMHO.

Newbee couldn't agree more. The SP-8 and SP-10 are decades old products and in it's day the SP-10 was considered SOTA. The SP-10 had an awesome phono stage in it, much better then the SP-8, whose phono stage was almost identical to the SP-6 series consisting of 2 12AX7's and a 12AX7 cathode follower (buffer). BTW that was the same circuit as the Marantz 7 and the McIntosh C-22. The SP-10's line stage was good but nothing special. When it was designed, the focus of the SP-10 was it's phono stage. It also had plenty of gain, and could be very quiet provided it's supplied with low noise tubes. Dampers were a must due to the gain of the circuit.
To quote Dr. Frankenstein, "Its alive!" The LS17 arrived today, and I have just spent several hours enjoying it. I connected the LS17 to my 150.2 amp using Mogami Studio Gold mic cables for the balanced connection, in order to get the full 18 db of gain from the pre amp (using SE connectors would have been only 12 db of gain). A quick thanks to "Almarg" who recommended the Mogamis over in the cables forum.

Anyway, the point of this post is to say that the SP8 works as a phono stage. I connected the "tape out" from the SP8 to the "aux in" on the LS17, using the Hero ICs which I had previously used to connect the SP8 to the amp single-ended. The "tape out" bypasses the line section of the SP8. Despite using a LOMC Benz cartridge (.5mv output), with the LS17 volume at 16 (out of a possible 20) I have all the volume I need through my Maggies (and as far as I can tell, no background noise from the SP8/LS17 combo). In fact the last record I listened to was the Sheffield direct-to-disk of Wagner's "Ride of the Valkyries" and "Siegfried's Funeral March" and it gave me goose-bumps, my ultimate test!

I'm watching the A'gon listings daily for an ARC PH5 phono stage, but in the meantime the SP8 is working very nicely as an interim solution. Thanks to all for your advice earlier in this thread.
Hi,could I suggest,and could be wrong,changing the subject a little.I have spent a k on my sp8c.The money spent has made the sp8 very musical and transparent.Maybe the ls 17 is good for the second system now. ?