Wednesday, July 30, 2008
On my thrift trek with Bill I found three items of note. The first was a respectable Radio Shack STA 225 receiver. It was the top of the line in '76 and retailed for $400. It sort of works and looks quite nice:This is one of the '70s quasi-quad units with Q Vox. I imagine it is pretty much the David Hafler Dynaquad.Yeah, it set me back $24.99. I ain't proud.
Plus, I found a vintage Magnavox FD 1040SL CD player in excellent condition. This is the second generation Philips player and absolutely built like a tank. It was built in '85 and Orion says it retailed for $390:Inspired by this find I purchased this third generation Magnavox CDB-460 the next day. It had been sitting in another thrift for about a month. This is the same model as my first CD player purchase ever and is from '87. It retailed for $250. I recall awaiting a Target sale on this player. It is a featherweight compared to the 1040:And I found one more interesting item with Bill, but I will save that for a later post. Into the queue they go!
Tuesday, July 29, 2008
Here are the cards, the smaller at the top are the output drivers:The cards are nice to work on once you get past the axials mounted radially and the several oddball values by modern standards. The cap stash was short of 68 and 15 mfd caps so it was time for an order to Digi-Key. But getting to the point where you can pull the caps was the trick.
The case is constructed around the chassis like a wooden puzzle. Top, bottom and sides all come apart, with several screws placed in not so obvious spots. Sheesh.
A relatively modest 24 caps were replaced, with the main output coupling caps modestly beefed up from 2200 to 3300 mfd. Here is the completed chassis:Build quality is very good, but odd. The front panel is just dangling.The transformer at the upper right is mounted upside down from what one usually sees. Next to the transformer are 3 fuses, but the main fuses for each channel are just visible above the transformer. They crumbled in my hand when removed. The amp was advertised as working, but one channel was blown when a resistor went south. Mike had vintage outputs handy, thank you. Mike also swapped small transistors on each card for stability, we spritzed the controls and it was time for a listen.
The Wharfy has loads of punch, slam I guess the British would say. Despite its small size it plays big. Its ergonomics are interesting. The switches in front are a bit odd by American/Japanese standards, and 'phono' is 'disc'. There is a shortage of inputs, so tape in will get a work out for your cd player. But the bottom line is it sounds great and has a very stylish, mid-century Euro look about it. Here it is in full frontal:
Wednesday, July 23, 2008
I had the pleasure of accompanying the king of Thrift store forays on an introductory round of the local treasure trove hide outs. As our main contributor, my host Nat said several times, you just never know....
After what started out as a pleasant jaunt about town with a chance to talk we came across some fine bargains, never know indeed.
Because you see so much stuff that is instantly dismissed one can easily overlook what turns out to be a great bargain. Case in point, office chair!
I had seen a dozen or so half broken cheaply made crap chairs not worth a sit down when a small strange looking blue office chair with a very small back is spotted with a $12.99 price tag. A quick sit down and “wow that's comfortable!” me of the back surgery multiple spinal injury type yelps...
A quick look underneath confirms this is a very quality carefully made item with the Soma Ergonomics name on it. Scarfed it up. Back home after a quick comparison I immediately got rid of my computer chair and have been in seated bliss since!
A quick search on the net informs me this chair sells for $500! This is beyond bargain, this is Christmas!
What does any of this have to do with stereo?
Well besides Nat's great score which I'm sure he'll be writing up in the future, I spotted two fabulous CD players from yesteryear.
A TEAC PD-500 from the late '80's and a DENON DCD-1100 from 1985. Both of these things had $49. price tags on them and had been sitting there for 6 months. A little friendly chit chat with the manager resulted in an 80% discount! Ten bucks apiece!
I figured they were semi functional at best but would be useful in my ongoing soldering/overhaul education with little risk of costly disaster. Well they both work, amazingly better than expected.
The TEAC was obviously a high end unit. Gold plated outs and no less than 10 Rubycon Black Gate capacitors inside. The DENON too was heavy and worked well. Neither liked burned CDs very much but this is par for units from this era. The sound is lovely, very musical across the spectrum. Not quite as many sparklies at the top but a very natural sound.
The build quality of both these units is shockingly superior to the modern mid class stuff available today. Samsung giant killer previously written up is case in point.
Future articles will detail the refurb of these beautiful relics. I plan to put them to work after rejuvenation!
Thrift-O-Rama indeed! A fine day. Thanks Nat for the edumakashun!
Tuesday, July 22, 2008
I confess I had never seen a KLH receiver in the flesh before the relatively basic 51 arrived.
This unit was clean and in working condition with a modest case of slightly damaged switches. The years tend to be unkind to exposed switches on electronics. These were repaired after this photo was taken. All the bulbs worked and the 51 is quite attractive when lit, blue on silver. Note the KLH logo on the left. Mike likens it to a sonic pressure wave. Whatever, it looks cool.
Here are the innards:
The 51 is a simple 3 board receiver with a two gang tuner section at the right. The amp/preamp board in the center (half of which is visible) had the the two large caps replaced with Sanyos after this photo was taken as a last minute precaution. They tested fine, but it seemed prudent. Not visible is the preamp section underneath the shield just in front of the output stage. The power supply board is at the left. The inputs along the back, just behind the heatsinks, are shielded. It should be noted the vinyl covered exterior case was shielded on the inside, a rare touch in this price class. KLH obviously cared about shielding.
A total of 41 capacitors were changed, mostly with Panasonic FCs.
Back in the '70s a relatively modest receiver was a sonic bargain. Despite relatively modest wattage they could drive a reasonable set of speakers to unreasonable sound levels with grace. The KLH 51 is no exception. The FM tuner sounds good. Even the AM tuner sounds good. And it looks good.
First, I would like to make clear the owner graciously consented to this blog post.
The M8 is shockingly heavy for a preamplifier, and for the best of reasons. It is chock full of high quality, hand crafted parts with enough silver wire to make a Hunt brother hyperventilate. And it sounds marvelous.
All is not perfect, however. The case is only so-so. And the reason for the visit was a very small toggle switch in the back that had been sheared off. Small exposed switches on very heavy gear seems to be sub-optimal. So much for perfection.
A pair of photos, hastily shot on the workbench:
Note the dual mono construction with 3 (count 'em: 3!) transformers per channel. Yow. It is probably not clear from the photos, but the construction is essentially double decker with extremely large (presumably) silver foil film caps hiding underneath several of the boards.
$35k is a bit much for a preamp, but this one delivers high quality sound with more than a whiff of unobtanium. It does not rate particularly high on the bang for the buck meter, but Mike and I gave it two thumbs up for uncompromising quality.
Wednesday, July 16, 2008
In a word Performance. Musical performance in this case.
Why the 841 and not some other medium player? The HD841 is that great combination of high quality critical parts, low price, and roomy enough to allow for extensive modification. It was produced by Samsung for barely a year and was somewhat of a "loss leader" for them. Many features, low price. The original list price was $299. at which price it was already a bargain, but was later reduced to $179 and even lower.
A good friend who owns 2 of the Austin Stereo modified HD841s had the chance of an A/B comparison with a $7K unit made by the German hifi manufacturer T & A in one of St. Louis's high end audio showrooms. Although the T & A sounded great, the modded HD841's sound was preferred! You can imagine a very surprised and somewhat miffed salesman...No lie, no exaggeration.
Tuesday, July 15, 2008
I was looking for an easy project and what could be easier than a preamp? My C2 had a channel out so why not? What was I thinking?
The C2 is a very nice sounding preamplifier with high quality components, but it is pan built. There is no bottom plate to remove to get access to the controls and boards, you have to disassemble the entire unit. This is not for the spatially challenged. Here is my C2, de-origamied:Yowza. This is how the C2 looked just before I started reassembly.
The main board at the right has to be lifted to replace the caps. It is beautifully made and the caps were high quality Elnas. I am not sure if they existed 20 years ago, but many of the original caps were the distinctive Silmic brown.
There are actually 3 boards at the left for the tone controls. The two larger ones are stacked on reassembly. The smallest is still attached and contains the headphone jack and control. This board has 4 caps and was very difficult to work with. (Fateful words.)
There is a very small board at the front that contains the source selector LEDs. The selector switch itself is still attached to the front panel and has the long blue ribbon that connects in the back right corner to the angled switch.
Next to the selector is the small board with the phono switch.
At the far right is the very lovely blue Alps volume pot.
Here is the C2 partially assembled:
The boards at the left have been positioned and the front and back tacked on. Now the story gets ugly. After connecting enough of the unit to test it I discovered that it had a noisy headphone level pot. Noisy to the point that it seemed damaged. This was very possible since the small knob is exposed at the far left of the unit plus it was the source of some handling when replacing some caps. When not being adjusted the unit was quiet and sounded very good, but when adjusting it was subject to hum and drop outs. I needed some consultation.
I took the preamp by Mike's and managed to lose the knob for the headphone level on the trip. Acck! Losing a knob is just awful beyond the loss of utility. Mike recommended resoldering the pot as a first step, but it might have to be replaced. So, a photo and final wrap up will have to wait a bit. Who'd a thunk a preamp would be so exasperating?
NAD solves all this by starting with the 3o20 with a spartan front panel with lots of space for a tuner display. The power LEDs are sacrificed for the tuning knob, but otherwise the family look and feel is retained. And sorry, no meters, just a pair of LEDs under the glass. Here is the NAD 7020:
I have had this unit in my possession for about 10 years. It worked well for the first several, but developed a significant amount of noise and was shelved. I finally got ambitious enough to get it back on the road. Here is the unit under the hood:
The layout has been modified to accommodate the tuning capacitor in the middle of the unit. Immediately to the right on the main board is the AM section and much of the FM section. At the far right is what looks to be a large single board which is in fact two boards. At the front is the FM finals. In back is the phono board. They are both stabilized by the metal connector in the middle that attaches to the side of the chassis.
The main amplifier section is no longer on the main board but is mounted vertically right in the middle of the unit. It is a dead ringer for its analog in the 3020.
The output transistors have been rotated 90 degree and are clearly visible just to the left of the main amplifier board.
The tone control circuitry is strung out at the front, just behind the controls and appear identical to the 3020.
It should be noted that the very convenient horizontal back deck of the 3020 has been sacrificed to accommodate the added circuitry and maintain a similarly sized box. Too bad.
All 3 boards were easily popped from their connectors and a total of 79 capacitors were replaced with new Panasonic FCs. It should be noted that I really dislike replacing the pair of small value caps around the bass control. Next time I will find some smaller fingers. As with the 3020 the main power supply capacitors were modestly upgraded to 3300 mfd.
The 7020 sounds as nice as the 3020 with the benefit of a very nice tuner. The tuner has only a centering mechanism akin to the Advent 300, but is very musical.
A final note: the front panel of the 7020 is much stouter than that of the 3020 and not nearly as prone to damage at the corners.
Saturday, July 12, 2008
Mike has been a solder-sans-silver sort of guy since he was about 12, but has recently started using solder with a 4% silver content on occasion and has suggested a discussion of the topic on this blog. It should be noted that at least one customer requested a major resoldering of a unit and even provided the boutique solder to accomplish it. On listening this customer found the previously listenable unit rendered unlistenable, so Mike has a bit of a negative bias regarding silver solder.
Here are some pros and cons of silver solder, as suggested by Mike:
- Better conduction,
- A harder bead (which might be beneficial for some high stress connections),
- A higher melting point (which might be beneficial for some high temp situations).
- Faster cooling/setting which can cause imperfect connections,
- Higher melting point makes it more difficult to desolder,
- Fouling of the soldering tip,
- More expensive, sometimes ridiculously so,
- A tendency to bead rather than flow into the connection,
- A tendency to look like a cold solder joint even when properly completed.
Anectdotally, we have at least one example of a consumer of silver solder unhappy with the sonic outcome. But the circumstance was essentially a substantial resoldering of entire boards which is different from what I do. I have used the Dayton 4% silver solder with very positive results, but it is very difficult to distinguish the effect of 40-80 capacitors replaced vs. the solder used. (Not to mention cleaning pots and switches!) In my experience the very popular Radio Shack silver solder, which I believe is 2% silver, is easier to use. So, I have no answers to all this at the moment. I tolerate the slight additional difficulty of using the Dayton product and trust that it is a better product at some level.
At some future time we need to take two vintage components and refurbish them identically with the exception of the solder used. All solder joints in the unit should be redone, one with a high quality conventional solder and another with a 4% silver solder. And then call out the golden ears in the group to see what they hear, so to speak. I think two modestly sized, high quality receivers would be the best targets for this effort since they are relatively cheap to acquire, tend to occupy a sonic sweet spot, and provide a variety of areas to test (e.g. tuner, amp, preamp, tone control.)
This topic is very similar to one that has made the rounds lately at Austin Stereo, the effect of using presumably 'better' capacitors in speaker crossovers. A number of recent examples have resulted in emphasized high frequencies, the dreaded shrill speaker. Better components do not guarantee better sound, ultimately. Look for a more thorough discussion of this topic in the future.
Monday, July 7, 2008
After reading Nat's fine article lauding the sonic reverie of baby Sansui I was compelled to introduce one of my favorites, the Sansui G-8000!
This 60 pound behemoth from 1978 was technically the number two receiver right behind the flagship G-9000. Practically identical innards made up for the few less whistles and bells of the big dog.
While the 9000 was rated @ 165 wpc, Sansui down rated the 8000 to 125 wpc so as not to take market share from their flagship.
In reality both of these beasts put out an honest 200 wpc, measured, before any distortion set in.
A quick look under the hood will show all that marvelous engineering and that enormous toroidal transformer dominating the landscape. It also has a switch for the option of either capacitor or direct coupling.
At 22" x 17" x 8" and a sea of glistening chrome, glass, and rosewood cover, this is truly a sight! Just those volume knobs go for $50 now!
The sound was and still is some of the finest audio I've ever heard from a receiver.
After receiving the once over from Austin Stereo which included a dozen new caps and a few additional bypass caps, this beauty is singing through a set of refurbished JBL Jubals like none of those black boxes at Circuit City ever dreamt of!
True electronic art of a very high order that we will not see again, certainly not available for the middle class for which it was designed.
In 1978 this fabulous receiver sold for $990. When you convert just for inflation since then it equals $3,800.!! Even so, when inspected inside and out by engineering experts, the opinion was that to manufacture the same item today, including machining, parts, and labor, you would be looking at $5-6000 dollars!
What middle class family today could afford such luxury?
At the ridiculous price of $4-600. for this unit on the used market, it doesn't take a geneticist to realize, DEAL!
The superb construction of these great Sansuis will allow lifetimes of use with the periodic (20-30 years) maintenance that any fine machine requires.
Long Live Sansui! A great standard bearer from that golden age of receiver art from Japan, 1967-1982.
Sunday, July 6, 2008
It worked, sort of, on initial power up on the variac, but was very shakey with a channel imbalance and very dirty controls. The tuning capacitor was especially noisy, sounding like raking gravel. Here how it looks with the top off:
This is a two board unit with the upper being the tuner. The Toshiba outputs are mounted on the very simple heatsink mounted vertically just in front of the transformer. In the photo above it runs from the left to the middle of the unit. There is very little power supply capacitance, just 3 1000 mfd caps just in front of the heatsink. The phono section is shielded and just to the left of the internal antenna. The shield was removed when this photo was taken.
I re-capped the entire unit, a mere 36 caps, and spritzed the controls. Voila! The sound was clean as a whistle. While not exactly a power house the amp had lots of life from the positively cute Toshiba output transistors. The FM tuner was surprisingly sensitive and picked up numerous stations without benefit of an antenna. The AM section was decent with the internal ferrite antenna. No 'not a handle' warnings needed for this unit. Here is a view of the front.
The sound was surprisingly musical. The treble control was a bit heavy handed; bass and loudness were a bit bloomy in quality but serviceable. All in all this would have been a sonic bargain in 1973 from one of the finest of the era's manufacturers. Mated with efficient speakers this would be the perfect foundation for a vintage dorm room system.
Friday, July 4, 2008
Build quality is uneven. The front panel is plastic and prone to damage. Four small screws attach it to the chassis (two are seen above) and bumps to the corners crack the very thin plastic at the screw holes. The chassis itself is a bit flimsy and is built with 3 rails, two of which are visible at the ends. The third runs underneath the middle of the unit and is secured by 4 screws, two of which are visible above between the output transistor pairs and just north of the 4 main filter caps. The middle rail must be removed to access the caps. Despite some cheesiness in the overall build quality the solder work was decent and the traces were stout enough to stay put during desoldering.
There was no indication of prior work on this unit, and the amp was functional although a bit muzzy sounding with the usual pot grunge evident. All capacitors were replaced with Panasonic FCs with the exception of a pair of small, low voltage 1000 mfd caps adjacent to the main filters. My higher voltage FCs were too large to fit so lower voltage Sanyos were used. The 4 main power supply caps were modestly upgraded from 2200 mfd to 3300 mfd. Pots and switches were cleaned with Deoxit Gold and Blue Stuff as appropriate.
The results of the refurb were very positive. This is a great sounding amplifier with excellent bang for the buck. Despite the 20 watts per side it rocked the test bench Boston A40s with 'Enter Sandman' and barely lit the 5 watt LED on the display. One last pic for posterity: