Monday, 23 January 2012

Successful Sony Transplant

In a post a short time ago I talked about the 2 somewhat crippled vintage Sony receivers. The recap is that the Sony STR-7025 that I bought for $35 worked fine in every way but the FM tuner. The higher power STR-7035 was free, but completely non functional in the state I received it as all the capacitors had been removed (but were included) from the amplifier circuit board and the power supply.

donor and recipient

I could try to reinstall all the caps in the 7035, with the old ones or new replacements, and to that end I bought a Service Manual for it. However it is still just wishful thinking that after doing so I would end up with a working receiver.

naked 7035 boards

It was also wishful thinking that prompted me attempting the other scenario, that of moving the tuner board from the 7035 to the 7025. I had no way of knowing if this board would work any better than the other one. Well, tonight I got out my tools and went to it.


The list included:

Soldering iron & solder
Notepad and pen (to record wire positions)
Camera (same reason as above)
Martini (for fortitude)
Music in the background

side by each

There were over 20 wires connected that I had to take note of, so I took pictures and sketched the layout and marked all the pins with the wire colour coding. I also taped the string from the tuner display onto the large roller that is attached to the tuning capacitor. I have restrung tuners before but it can be fiddly and if you don't have to...


tunimg wheel tape

I removed the tuning wheel from the 7035, and started to unsolder the various wires. The majority of the connections were on wire wrap pins so really just had to be unwound, and eventually they were all undone, and a few screws were removed. The board would still not come out until I realized it was still attached by a grounding cable to the chassis underneath. Once that was unsoldered it was free.

tuner ground wire

I did the same with the board on the 7025, but intentionally left the tuning wheel in place until everything else was loose. This way I could undo the set screw and hold the wheel while I moved the bad board out and the good one in and slip the large wheel in place without the string falling off. It worked so I tightened that set screw and moved on to reconnecting wires.


Rewrapping the wires was not so easy as I don't have the wire wrap tool. However with the help of some fine tip pliers and mini screwdrivers I was able to get a decent wrap on each one, but I also soldered the joints to be sure. My soldering won't win awards but I think it turned out ok.

solder joints

I soon had it plugged back in (before closing up the case) and sparked it up. It worked! Even without an antenna I was picking up FM stations, and all the other functions still seemed fine too. Whew!

I just had to fine tune the set screw on the tuner wheel so the dial mark matched known stations. I also swapped the cases from the 2 receivers as the 7035 one was in slightly better shape. It did have a drivers license # or something scratched in the side but it was subtle and I added a bit of wood filler to hide it more effectively. I had already stolen one knob for the volume control.

Happy 7025

So now the STR 7025 is happy, but alas the 7035 is in pieces and singing the blues.

7035 pieces

Saturday, 21 January 2012

Saved some gear from the bin today...

The things I picked up today where not vintage or even particularly desirable in my world, but they were free and that goes a long way with me.

I spotted these on Craigslist several days ago, and had been in communication with the owner a few times to arrange the pick-up today. Both had "issues" and both she and I were hopeful they could be fixed.

First there was a receiver, the Harman Kardon HK3370 with only one channel working. I also received a small pair of 2 way Paradigm speakers. Her description of that sounded like damaged or rotten foam surround on the woofer.

Harman Kardon have made some very good equipment over the years and I have had some gear from them before. I think the only piece I owned was a cassette tape deck but it was a very good one that I had for 10 or 15 years. When I got out of cassettes a few years ago it went by by though. I still like the look of some of their stuff including the current models and often more than other brands. I also think it is generally well made.

Harman Kardon HK 3370

The HK3370 is a 70 watt per side stereo receiver. It's not retro in age or looks by any stretch being made up of black metal with a plastic face and with digital tuning and display, plus a remote control. It is just stereo though and is largely discrete components, or at least in the output section anyway, and does come with a quite a large power transformer and is a fairly heavy unit at about 25lbs. I am not sure the model release year but it was roughly 2000.

Anyway after finding out what model it was on Craigslist, I had no idea what I would find inside, but did have a look at images (especially on Amazon) and had some hope for an easy resolution to the "only one side working" thing. Many things that go wrong are easy fixes, but still not worth paying for professional services at $60 or 80 per hour or more. Many times a 50 cent fuse has blown or a wire is loose or something else relatively easy is all it needs. In the case of this unit there are jumpers on the back which connect the pre-amp and power amp sections so that was my first thought as the culprit. Sometimes those jumpers are simply missing and the result is that the stereo does not appear to work.

When I got it I saw the jumpers where in place, so I opened it up at home and then checked all the fuses. My meter showed continuity on all 6 or 7 of them (meaning they worked), so I played around with the pre out and main in jacks for a while. Using another receiver and the tape out loops I was able to isolate the problem to the pre-amp section, but that is actually the more complex area as all the controls are in that area. I was getting close to giving up for today when I decided to check all the jacks and plugs throughout the circuit.

HK 3370 inside

Most older gear tended to have fewer connectors that could be unplugged and more direct solder joints. Newer stuff has more circuit boards that are modular and plugged in as needed. After a bunch of prodding and flexing I found the problem! It was a loose socket at the connection to the volume control under the white ribbon cable at the lower right hand corner in the picture. Once I had figured that out I soon had the case put back together and it's now ready for either a re-sell, storage until I find a use for it, or maybe it will go in Linda's living room. I've certainly got enough for a complete system for her over there.

Friday, 20 January 2012

In the span of just a few weeks I have come across 3 vintage Sony receivers of the same series and approximate age. I bought one, the STR-7025 for $35, and was given an STR-7035 for free (though I did give the guy a Pioneer SX-535 that cost me $10), and just the other day I saw but did not buy an STR-7065 at the local Salvation Army store.

Just a bit odd to see so many in a short span, as I really never noticed this series before. The 2 I do have are going to turn into one project.

For one, the 7025 has a problem with the FM tuner but it works fine in everything but FM. The wooden case is in quite good shape and the front panel is practically mint. The 7035 has a better looking case (though has a drivers license number scratched into the side...I hate that!) and I swapped one knob from it to the 7025 but it has an even bigger issue than the 7025 so it becomes the donor to keep the other alive.

The fellow I got it from had plans to re-cap it, as in replace the capacitors on the circuit boards. The theory goes that the capacitors dry out over many years and their characteristics change which alters the sound quality of old audio gear. In a worse case scenario it will cause the entire device to fail. It's actually not a theory; it does happen. Sometimes the differences in sound though are probably overstated but they can be heard if you have the right ear and the right gear.

Anyway, the guy got to the point of removing all the capacitors from the power supply board and the amplifier board, but did not solder in new ones. I think he got bored with the process or burned himself with his soldering iron and gave up. So I got a receiver with a baggy full of caps inside it.

I knew it wasn't working when I got it from him, and he did say more or less what he did but I was still a bit surprised when I opened it up. That's ok, as it was free after all. I could sell the knobs alone or maybe get a few bucks locally or just give it away again. However I have other plans...

The tuner board seems to be intact. It also appears to be identical to that of the STR-7025 with the non functional FM section. So my plan is to swap it over. I think.

I could also replace the caps in the 7035, but that is not as easy. When I realized the extent of the situation in that unit I went looking for the Service Manual and I did find it on ebay. Having that with the schematics and parts list will help a lot as I don't know what value capacitor goes where without it. If I were replacing caps from scratch I would do one or two at a time, not "remove all, replace all" as it would get confusing fast.

One concern I have is that I don't have any way of knowing if the tuner board on the 7035 works any better (or at all) than the 7025. I also can't easily test that before making the swap. There are at least a dozen wires connected to the board, plus the tuning capacitor and display string pulley, and the AM antenna coil.

Monday, 16 January 2012

Dual HS 37

Dual HS 37 front by Buhduh
Dual HS 37 front, a photo by Buhduh on Flickr.

This old Dual all-in-one I picked up several months ago for $25, delivered.

I guess it's in not really an all-in-one as those usually have a tuner and maybe some kind of tape deck built in. This is only a turntable and amplifier but it does have inputs for tuner and tape. I've always thought my Sony ST-80F tuner goes with it pretty well. They differ in quite a few ways but have something in common as well, in the small footprint and era, plus the nice wooden cases.

Dual HS 37 knobs

The Dual is based on a 1214 automatic turntable. At the moment it is the only table I have that will play 78 RPM records. Now I don't have any 78s but if I did this would get some use. As such I have just kept it for the coolness factor. Some 78s will fall into my lap some day, giving me some incentive to keep it hooked up.

Playing 78s is also not just a matter of turning the record at the speed. The grooves in 78 RPM records are cut much wider than those for 33 and 45 RPM so the stylus or "needle" for one is NOT compatible for the other. The cartridge this Dual came with is what I call a flipper design. It has both size styli on it and you simply flip a small lever (you can just see the red thing in this pic) from one side to the other to play the different discs. I had a look at the styli under my little scope and I can certainly see the difference in size and it seemed pretty obvious to me that the 78 side had never been used.

Dual HS 37 wear

Most of the Duals of this era used an idler drive mechanism to drive the platter. Idler drive refers to a rubber roller that is pressed against the wall of the platter (usually underneath and inside), and a precisely machined shaft attached to the motor armature. The friction turns the platter and disc with it.

Dual HS 37 under side

Of the 3 styles of turntable drive systems, the others being belt drive and direct drive, the idler is the least common these days. It was quite common 30, 40, 50 or more years ago and as far as I know predates the other systems (certainly it does direct drive). It still has ardent fans among the classic audio crowd and when it is well done and properly adjusted is arguablly as good or better than the other systems.

I'm not sure the Dual 1214 quite fits the audiophile profile, but it also has fans. There were many models around this time and they shared a lot of characteristics.

The amplifier base this sits in bears resemblance to some sold under the Noresco name and they may be the same for different markets. Mine was almost certainly sourced in Europe which is of course where Dual comes from. Indicators are of course the labels in German and English and the use of DIN connectors on the back panel.

Dual HS 37 back

I've done some work on this device but still have some more to do. The old oil or grease used to lubricate the many parts of the mechanism gets gummy and things often don't want to move. 40 years on it is not surprising it has a few aches and pains. The record size change mechanism which has a lot of parts inclduing springs and bearings was especially stuck. I had to take a part a bunch of it to figure out how it worked and luckily I was able to get it back together.

The motor and drive speed has also been a bit tricky. The idler roller just did not want to apply enough pressure on the motor shaft to turn reliably or even start without help from me spinning the platter. The pulley on the motor has 3 sections in different diameters for 33, 45 and 78 rpm. Each of those are also tapered so vary in size. The speed adjustment knob or pitch control on top of the turntable moves the roller up and down on the taper to allow for abou a 3% change in speed of the platter. That pulley can also be moved on the motor shaft by loosening a set screw and adjusting the height & than re-tightening the screw. That's the theory...

I've yet to hook up speakers to this, at least partly because of the DIN connections which it uses rather than bare wire or pin connectors as in more modern & North American gear. These are not that hard to find or work around and I have some here somewhere as I do have some other things that use them. I'm just lazy, so plugging in some headphones works for now.

Below is me testing the speed by simply running a stop watch app on my phone while playing a record that had the track times listed. In this case it was not my sacrificial Frankie Laine album, but the Doobie Brothers took the hit instead.

Dual HS 37  speed test

Sunday, 15 January 2012

Mitsubishi DA-R10 Receiver

Mitsubishi DA-R10 Receiver by Buhduh
Mitsubishi DA-R10 Receiver, a photo by Buhduh on Flickr.

I've been lusting after the Mitsubishi receivers and separates of the late 70's/early 80's for quite a while. I almost won an auction at a good price for a pre power and meter kit which would have gone well with the DA-F10 tuner I had. I say had, because large separates are not great for me in my small space, and managed to sell the tuner just last week.

The Mitsu receivers don't surface often around here so I jumped when I saw this one, the DA-R10. I love the tuner design and the 'rack handles for people who never will use a rack' isn't rack mountable but they look good.

I had to drive to Surrey to get it, which was out yesterday because of the snow, but the guy held it for me. $50 brought it home.

Cosmetically it is near mint, and so far it works flawlessly. The neat thing is the guy has had it since he was a kid, so maybe 20 or more years judging his age and maybe given to him by his dad. I might be the second owner outside of his family.

Mitsubishi DA-R10 top

Mitsubishi DA-R10 Nudie

DA-R10 inside

Saturday, 14 January 2012

It was a Turntable kind of day...

Lid sanding 2

Snow in Vancouver today for the first time this winter, so I stayed fairly close to home. It was not a significant amount but nevertheless the roads around here and our drivers don't mix well in marginal conditions.

However the closest Salvation Army is easily reachable on a day like today and I found myself there about noon. As soon as I walked into the bargain basement I spied a woodgrain turntable and quickly snatched it up.

Dual 504

It turned out to be a Dual 504 and was in pretty good shape and had a perfectly acceptable belt included. Of course it had the typical scratched cover and questionable cartridge, an ION 2, whatever that is. It looks Shure-like but examination with my 60 power scope shows a stylus that seems to be completely worn out.

Dual Ortofon

The Dual tonearms are usually low mass or even ULM (for Ultra Low Mass) and tend to like lightweight cartridges. Fortunately I just happened to have a brand new Ortofon Omega I picked up on a whim a few months ago, so I gave it a try. It worked and sounded just great so this one may be a keeper!

Before doing so though I cleaned it up and polished the lid. Actually I polished 3 lids today. In fact I wore a hole in a finger today while polishing lids. When nearly done on the last of them I realized a finger on my right hand was bleeding!

Sony PS-1350 2

I have been meaning to get around to spiffing up a Sony PS-1350 I snagged a month or more ago and a Technics SL-B100 from a week ago. The intent was to get them ready to sell.

Sony PS-1350 3

The Sony I had already done some work on, such as repairing the bearing (bushing more accurately) that the spindle turns on. I also replaced the belt and ordered and installed a new stylus for the installed Sony VL 32G it come with. When I bought it the cantilever was completely gone but I managed to find a NOS (New Old School) Sony ND-134G, the OEM replacement.

The end result was pretty acceptable. The lid could still use some more fine work but the main damage is gone, but my hand couldn't handle it today. I also am going to try to get the hinges adjusted to help the lid stay up as they have lost some tension. I hooked it up and it sounded good though.

On to the Technics turntable...

SL-B100 2

SL-B100 1

The Technics SL-B100 came with a Technics SA-500 receiver and Optimus 5 speakers last week. I really did not intend to pick it but what the heck. It came in the box with a Grado GT cartridge and was in very good condition. Once again, it needed a belt and the Grado being a P-Mount design with what seemed like good life it did not take long to get it set up and running. I was also happy with the listening results. Though the lid was pretty good, I gave it the wet-sand treatment while I listened to Sly And The Family Stone.

Grado GT

SL-B100 box

I find the fastest way to get out deep or numerous scratches is wet-sanding. I start with 800 or 1000 grit and go up to 1500. After that I use NOVUS plastic polish 2 and 1 to get a clear shiny lid. NOVUS 3 is meant for deep scratches but I find the sandpaper is quicker. I'm starting to experiment with polishing discs in a drill and soon will be trying a car buffer/polisher but the manual method does work quite well.

Lid sanding

Most lids seem to need at least 1/2 hour to an hour of work for a decent result. For a very special table, especially a high quality keeper, I might spend twice as long.

So anyway, the SONY and the TECHNICS go on the market and the DUAL sticks around for now.

Thursday, 12 January 2012

Some new (old) vinyl.

I had some time at lunch today and knowing I had a package waiting at the local Post Office I whipped over.

The package was an eBay purchase of 2 classic records: Jethro Tull - Thick As A Brick and Sly And The Family Stone - There's A Riot Goin' On. In and out quickly I also barely had time to duck into the Salvation Army basement and I was glad I did.

I headed straight to the records where I sometimes find a couple of decent recordings in amongst the Nana Mouskuri and Marty Robbins.

Not having much time I scanned around to look for what appeared to be new arrivals as I go there maybe once a week since it is so close. There was a guy hunched over a box on the floor and he had already pulled out a copy of London Calling by the Clash and a Jerry Lee Lewis record plus others. I kicked him aside...I mean waited impatiently, while flipping through some others nearby, finding nothing of interest. It was obviously worth waiting for though as I saw him select about 10 more from that box.

When I got to it, I still was able to find 5 or 6 more that he rejected, plus he passed on another couple he handed to me. He was obviously not a jazzy kind of guy. :)

I've been listening to funk and jazz all night and thoroughly enjoying it.

Funky pickins

From top left, total price of $6:

Mary Lou Williams - Solo Recital
Herbie Hancock - Future Schock
Art Blakey etc. - Child's Dance
Ahmad Jamal - Outermeinner Space
Rahsaan Roland Kirk - Kirkatron
Johnnie Taylor - One Step Beyond
Ramsay Lewis - Sun Goddess
The Commodores - Machine Gun (still sort of sealed!)

It's all in good condition to practically new. The Tull (full newspaper edition, same as we had back in Shediac in about 1973), and Sly records at the bottom right I paid a bit more for but they are records I went out looking for. The others were just serendipitous.

Tuesday, 10 January 2012

Advent 300 Receiver On The Block

The Advent 300 Receiver is one of those highly venerated components of solid state audio gear. Advent was a master of the understated advertising campaign for their speakers and they had an understated thing going on with the electronics gear too.


I'll reference the excellent site of David Reaton here as he knows this receiver VERY well and provides tons of information for the 300 for those just interested, and the DIY refurbisher. Plus for those not comfortable around a soldering iron and schematic he will rebuild them. After all it was built in c. 1976 so might need some work by now.

I have one of these receivers and admit I won't keep it much longer as it is going on Craigslist. Mine probably does need work, as perhaps all the electrolytic capacitors replaced. This is pretty normal for gear of this age as they dry out and lose their capacity to...well, capacitate!


I did clean it up a bit and replace the main power supply caps, but have decided I am not going further with so will try to unload it. I also had to customize the main tuning knob for it as the one I have was missing that part when I got it.


These are very well liked for the phono and preamp sections, but I don't need it for that and have just too many pieces of gear so it has to hit the road. It does work in it's current state but caveat emptor.

Advent 300 inside

Advent 300 back

Thursday, 5 January 2012

Marantz 6300

Marantz 6300 by Buhduh
Marantz 6300, a photo by Buhduh on Flickr.

Here's the Marantz after cleaning, adjusting and levelling. No longer the questionable Frankie Laine album and the who knows how old AT cartridge, but my V15 III (also old) and brand new Ed Saunders stylus, playing Oscar Peterson et al - The Trio, not a record I want to take chances with.

It looks and sounds great! Too bad about that lid though...

Marantz 6300 , the newest member of the family

Probably more than the receivers, amplifiers and tuners I prefer turntables. Except for the mysteries of the stuff in the grooves and how it changes to music they are inherently less complex than the other stuff. You can make sound with a toothpick and a paper cup if you can find a way to spin a record under it.

Some turntables are nearly that simple. I recently sold my Rega Planar 2 table; it was one of those simple ones. Simple is good...there is less to go wrong, and as some would say to interfere with the signal but more on that later. This post is about my most recent turntable purchase and I will work backwards to some of the others including the dearly departed Rega.

The new member of the family is a Marantz 6300. I picked it up this morning (or is that yesterday?) and have been hacking around with it tonight. It dates from around 1975 according to the Legendary Audio Database though might have been made for a few years. That's about when I acquired my first stereo gear but was still using a suitcase turntable borrowed from my dad. I probably also borrowed the quarter I had to use on the tonearm to keep it from skipping on those Loving Spoonful and Grand Funk Railroad albums.

This table is a real looker and, if all goes well, will soon migrate into top spot Chez Moi. I like very much my Kenwood 2055 but it might need a break.

As usual with 30 or 40 year old gadgets it has some issues. It has some significant scars in the lid and looks like it has been melted in spots! "Yes dear, you can put the kettle on top of the record player. It won't mind." Ay caramba!

The cuing "Down" button was stuck down, there is a ding in the veneer in the front right corner, and it is a bit grimy. Someone has obviously tried to work on it before as some screws were loose or missing. The lid would barely stay up, but I soon discovered some screws that adjusted the tension on the hinge springs so that was an easy fix.

The headshell is not an original Marantz (bummer) but a JVC. The cartridge appears to be decent as it is an Audio Technica AT11e but upon examination with my 60x scope the stylus looks unevenly worn, so I won't rely on it. In the next pic I am trying it out with a sacrificial Frankie Laine album. Sorry Frankie!

I had to try an album on it to test for a few things. The cuing button freed itself fairly easily, but I had to fix the cue lifting arm. It was rotated 180 degrees the wrong way and not raising willingly or high enough to actually get the needle off the record. A set screw adjustment and some well placed oil seems to have fixed that.

Also the auto shutoff was not working well or at all. I have heard about "optical sensor" issues with these tables and I managed to figure it out without a service manual. This is one of the reasons why I like turntables! This one is way more complex than my old Rega, but I can see what is supposed to happen and work out how to adjust it.

Here is most of the exposed underbelly of the 6300. The motor is at the bottom with 2 screw holes for fine tuning the 33 and 45 rpm speed and the tonearm base at the upper right:

On the 6300 you have a full Manual setting and an Auto setting. Auto is not fully auto; it just lifts the tonearm at the end of the record so it does not click and thump incessantly at the end of the side. The tonearm does not return to the rest like most semi-auto types. Auto does less than semi-auto...???

There is beauty in this design though. The Marantz shutoff imposes no mechanical drag or impediment to the tonearm. There is in fact an LED that sits under plinth near the tonearm that directs light onto a photocell. When the tonearm travels all the way to the lead out groove, a thin metal blinder moves between the LED and the photocell interrupting the light path. This signals the electronics inside to trip a relay to lift the tonearm and shut off the motor. It's a pretty cool design.

Mine however was way out of adjustment so Frankie never did turn off when he should. But I found an adjustment screw accessible at the back of the turntable that moves the holder for the LED apparatus in and out. You can see the hole in the back of the wooden case. Playing with this fairly quickly found a sweet spot where the shutoff happened where I want it. I may need to do more with it, but this can be done without opening the case or powering down. I'll connect it to my system soon with a known good cartridge to do more testing.

The next 2 pics show the LED assembly a bit closer and the same area with the "blinder" attached to the tonearm interrupting the LED light path. It's the silvery bit you will see that has moved into view as the tonearm has approached the end of the record.