Panasonic SA-XR70S - On It's Way To Colorado

StevenACNJ · « **on:** 29 Nov 2004, 04:19 pm »

I had OneCall drop ship a brand new Panny SA-XR70S (S stands for silver) to Wayne for a full boat mod package.

OneCall has the Panny in stock and is offering 10% off plus free FedEx 3 day shipping. Is a good deal from a reputable supplier, so I jumped on it.

Wayne should get the 70 by the end of this week.

I will let Wayne detail the mod package if he wants.

Should be interesting!

Wayne1 · « **Reply #1 on:** 2 Dec 2004, 04:30 pm »

The Panasonic SA-XR70 was delivered by FedEx yesterday afternoon. It arrived double packed with anti-static styrofoam peanuts between the two boxes. The receiver arrived in perfect shape.

I pulled the cover off and took a picture of the guts:

It uses the same amplifier output configuration as the SA-XR50. The power supply is also similar to the SA-XR50. It does not use a power supply as sophisticated as the SA-XR45.

I left it playing overnight. This morning the sound is very clear and clean. It does sound a little "light". The bass fullness is not quite there. Of course I have been listening the the JJAZ 1000 watt mono-blocks in the system with a tube preamp for the past week

Panasonic has chosen to add another speaker relay for the Bi-amp/Bi-wire feature. There is additional speaker wiring running to the relay board. This should be replaced and it will add a bit to the cost of the mod.

Most of the mods I have come up with the the SA-XR50 should work in this model. I will let this unit run in for a bit and wait for the service manual.

Wayne1 · « **Reply #2 on:** 2 Dec 2004, 06:53 pm »

I just got off the phone with Panasonic. The service manual is only going to be available on CD-ROM. They do not have any. It will take about 3 weeks for them to get it written to CD and then ship it.

The Jensen four pole capacitors I use for the main power supply cap replacement are out of stock in the US. I have ordered some from Denmark but it will take some time to get them.

Mods are on hold for a bit.

Andrew JC · « **Reply #3 on:** 2 Dec 2004, 08:16 pm »

Wayne, If you don't mind please post comments on the sound quality differences on the stock 70 vs stock 45. After the 70 burns in of course.

Thanks...andy

StevenACNJ · « **Reply #4 on:** 2 Dec 2004, 08:46 pm »

Wayne,

From what I have read of your posts so far, I gather that the stock 70 has fewer caps & overall capacitance in the power supply section than does the stock XR 45.

Why cant (or maybe you will) add more capacitance to the XR 70 power supply mod to equal out to what was there in your modded XR45?

Wayne1 · « **Reply #5 on:** 2 Dec 2004, 09:03 pm »

The caps are just what is visible from the top of the board. There is actually some fairly complex circuitry involved. That section is part of the varible voltage circuit used on the outputs in the 45.

The PS caps will be replaced with some higher value Nichiconsand a Jensen 4-pole, but I cannot add in that circuit.

I have not heard a stock 45 for quite some time.

I may be getting one in for mods in a week or two. I am not sure how long the 70 will remain stock

I also have a JVC F-1 waiting for mods and a Teac digital power amp. However I simply don't have the time to let them all burn in and do a comparison of them. I am sure their owners would like to get them back at some point

Wayne1 · « **Reply #6 on:** 6 Dec 2004, 11:55 pm »

The Jensen caps are on their way to me today, from denmark.

The XR-70 has has been playing on FM for some time now. The mids have opened up nicely but there is still some compression. The bass doesn't extend quite as much as I remember from the 45.

StevenACNJ · « **Reply #7 on:** 7 Dec 2004, 11:03 am »

Wayne,

How is the FM reception?

Thanks

Wayne1 · « **Reply #8 on:** 7 Dec 2004, 01:18 pm »

I have alway liked the FM tuner in the Panasonic receivers. I am about 40 miles from the transmitter and I am fairly close to the foothills, which can cause multipath distortion. The Panny has no trouble pulling in the signals.

Sonically, the FM section is very good.

tianguis · « **Reply #9 on:** 7 Dec 2004, 04:33 pm »

Wayne:
I, too, find the XR50 tuner very good. I never used to listen to FM here in New Yawk due to the difficulty (!) of good reception. What 'tenna are you using?

Regards,
Larry Welsh

Wayne1 · « **Reply #10 on:** 7 Dec 2004, 04:46 pm »

I am using the single wire that comes in the box for FM.

I am getting better reception with that than with a Sansui TU-719 hooked up to a Magnum Dynalab ST-2

StevenACNJ · « **Reply #11 on:** 10 Dec 2004, 11:48 am »

Wayne,

Question:

If you were going to use the 70 for a 2.1 channel system with just single speaker cables running to main speakers (no biamping or biwiring main speakers).

What is the best way to integrade and hook up the subwoofer? Would I use the front speaker B binding posts to send a speaker line level signal to the sub and just let the sub crossover do the work. If so does the unit have to be run in bi-amp mode.

Or is there a better way to do this?

Thanks

Wayne1 · « **Reply #12 on:** 10 Dec 2004, 01:54 pm »

The best way would be to run the mains off of speaker A and take the sub signal off of the line level sub out.

Set the mains to large and the sub to 100 Hz.

Then adjust the crossover point at the sub to 80 Hz or less.

I hope you are planning on using a self powered sub. The Panny does not have enough power to drive a sub through speaker outputs.

If you are going to use a passive sub, consider a plate amp with built in crossover or a Pro Audio amp with an inexpensive electronic crossover just for the sub.

StevenACNJ · « **Reply #13 on:** 10 Dec 2004, 04:20 pm »

Wayne,

Thanks for clarification.

Question:

"take the sub signal off of the line level sub out" I assume your talking about the RCA female sub audio out jack - right?

Also just want to make sure, I think as part of your mod package you going to replace that RCA female sub out jack with a better quality one?

Thanks

Wayne1 · « **Reply #14 on:** 10 Dec 2004, 04:34 pm »

I believe I can replace the sub out jack with a Canare gold plated RCA. I won't know for sure until I start ripping it's guts out next week

Wayne1 · « **Reply #15 on:** 14 Dec 2004, 11:19 pm »

I started ripping into the SA-XR70 today.

The sub out jack CAN be replaced with a Canare RCA.

I also met with the machinist today. I should be getting plates made so I can replace the speaker connectors in a week or so.

There is only enough room for main A & B speakers and two suround channels and center channel. The rear center channel will have to be sacrificed.

StevenACNJ · « **Reply #16 on:** 16 Dec 2004, 11:17 am »

Quote from: Wayne1

I started ripping into the SA-XR70 today.

The sub out jack CAN be replaced with a Canare RCA.

I also met with the machinist today. I should be getting plates made so I can replace the speaker connectors in a week or so.

There is only enough room for main A & B speakers and two suround channels and center channel. The rear center channel will have to be sacrificed.

Good news on the sub out RCA jack replacement.

I have no need for a rear center channel - so trash it.

Just keep ripping it apart.

GefellTaper · « **Reply #17 on:** 16 Dec 2004, 01:34 pm »

Since me xr-50 is on it's way to Colorado now, I need to score a power cable that is worth a darn. Can someone tell me whether the 50/70 uses a ground? I want to just make my own following the VH instructions, so I need to know which "flavor" to try.

Thanks

Daryan

JoshK · « **Reply #18 on:** 16 Dec 2004, 01:39 pm »

The Panasonic receivers don't use the ground. Even if an IEC is put in by Wayne, I believe he is still not earthing the ground, so if you are building VH power cords, try the raw wire without the ground.

GefellTaper · « **Reply #19 on:** 16 Dec 2004, 01:43 pm »

You helped me in my planning a ton. Have a great day all...off to work!

Daryan