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OPTIMIZING YOUR SOUND SYSTEM

 

 

This section is full of little hints that may help you get the most out of your stereo - and it may not cost 

anything or cost very little. Probably, you know most of this, but hopefully some of it may be new or refresh your 

memory or just be refreshing reading in a manual. 

 

A very important factor is your speakers. Hopefully you have good speakers and they are appropriate for this 

integrated amplifier. What is appropriate? Well, with 50 watt of tube power per side and probably a limited budget 

we would hope for reasonably efficient speakers so that the system will get loud enough for the music you listen 

to. The “spec” to look for is “sensitivity” or “efficiency”. A speaker that is 95 dB efficient will easily get as loud 

with these 50 watts as 85 db speakers with 150 watts. “85” will do if you only listen to folk or chamber music. 

Usually you pay about the same for high sensitivity speakers but in amplifiers more watts is more $. By the way, 

many reviewers confirm that 50 tube watts is similar to 100 solid state watts.  If you are buying speakers, it is wis-

est to carefully listen to them before buying. You will most likely like them longer if they tend to sound natural and 

real rather than over-emphasized in some area. In other words, think “accurate reproduction”, not “numbers” and 

“hype”.

 

The price of speakers is often directly related to the low frequency response. Great lows generally require 

deep pockets and plenty of power. Thanks to “home theatre” there are a lot of powered subwoofers available that 

won’t drain your resources. Get one that connects to speaker outputs (or the SUB OUT RCA jacks on your Stingray 

II) so that it follows your input selection and volume control. This makes connecting them pretty easy.

 

There are some very interesting speaker tricks. Most people just place them wherever it is convenient. Spouse 

approval is a real factor. We suggest that you experiment with speaker placement, then when they sound 100% 

better you bring in the spouse and demonstrate the difference. They should be able to hear the improvement and 

may totally agree with your choice. You should aim for equal distances between your listening position to each 

speaker and from speaker to speaker. The ideal is an “equilateral triangle”. Try to get the speakers off the floor, 

and away from the walls (both side and back). The angle of the tweeter or speaker front panel to your face is also 

critical and experiment with that too. You should be getting a smooth frequency response so that highs and lows are 

balanced and mids not too prominent or distant. It should simply sound “natural”. When we buy color TVs the first 

thing most of us relate to is flesh tones because it is something we all relate to and know when they are right. The 

equivalent thing in audio is vocal tone. We have evolved amazing discrimination for the varieties of human voice 

and much less for other instruments. Use a few well recorded CDs with vocals and adjust the speakers to get the 

most natural voices. If you are lucky, you will end up with a system that creates a 3D picture of the music that not 

only has left/right width but a solid distinct center. It should also make some sounds seem in front of the speakers 

and some behind. We have heard some systems with great components even give an illusion of the height of the 

individual musicians. Most rooms are longer in one dimension. Some systems sound best with the speakers across 

the short dimension and the listening position part way back but not right at the back wall. Some systems are better 

across the long dimension. The only way to find out is to try.

 

If you are getting this amazing imaging and soundstage, you may be interested to know why you suddenly 

have it now that you have the Stingray II. These are very audible effects that seem to be beyond normal measure-

ment technique or textbook electronic theory. This effect is directly related to the amount of negative feedback used 

in a design. The less feedback the greater the imaging. In transistor amplifiers it has been common practice to use 

more than 80 dB of negative feedback. Conventional designs need it because transistors are not particularly linear 

devices and it forces the circuit to get low distortion figures as well as very high damping factors. Tubes are much 

more linear and inherently low distortion. Tube amplifier designs use far less negative feedback (less than 20 dB) as 

a result . We speculate that the negative feedback may have a negative effect on transient accuracy. It is reasonably 

documented that the feedback does reduce the lower order harmonics in distortion but can raise higher order har-

monics that are more audible. Feedback also makes the transition from clean to clipping very abrupt and abundant 

with high order harmonics. The best audio devices always seem to be simple & aesthetically balanced, with form 

following function. 

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Summary of Contents for Stingray II

Page 1: ......

Page 2: ...INPUTS OUTPUTS THE STUFF ON THE SIDES 7 8 DETAILED FRONT PANEL FUNCTIONS 9 DISPLAY MODES 10 OPTIMIZING YOUR SOUND SYSTEM 11 12 TUBE F A Q 13 14 ALL YOU NEED TO KNOW ABOUT BIAS 14 15 REMOTE CONTROL 16 TROUBLESHOOTING 17 CREDITS 18 SPECIFICATIONS 19 FCC INSTRUCTION TO THE USER 20 rev 4 19 11 CD ...

Page 3: ...uality and build technique as all of the recent Manley products It uses the best available parts with the shortest cleanest signal path possible Visually this product is unique elegant and practical Visual beauty may be a prime factor for some but the size shape and component locations were chosen first for performance reasons Please take a few moments to read through this manual there may be feat...

Page 4: ...e Waste Electrical and Electronic Equipment Directive The purpose of the Direc tive is the prevention of waste of electrical and electronic equipment and to promote the reuse and recycling and other forms of recovery of such waste As such the Directive concerns producers distributors and consumers The WEEE directive requires that both manufacturers and end consumers dispose of electrical and elect...

Page 5: ...a 12 inches if they are the paired type or slide the loop that holds the pair together If you need to connect a turntable vinyl you will need a separate phono preamp to raise the level from the tiny signal from the cartridge to regular line levels Manley builds these as do some other manufacturers The final interconnect available is the 1 8 line input on the front panel 5 Connect the speaker leads...

Page 6: ...es it Push in the knob for 2 seconds and release it to enter Balance Mode To exit Balance Mode push and quickly release the knob For more information on these functions see page 9 NOTE The two knobs on the front panel are known as infinite rotary knobs This means they can rotate indefinitely without ever encountering an end to their rotation Rather than being a normal pot the knob is actually a Gr...

Page 7: ...rom whatever is playing and selected on your input selector Note that this is not a buffered output so if your tape deck or recording device has a low input impedance or if it does funny things like become a dead short when it is powered off like some IC inputs on certain CD recorders we do know of you will load down the input to the Stingray II or short it out altogether and get no tunes Basicall...

Page 8: ...system and your room and your speakers and your tastes and what you are looking for We do not suggest you play with this switch all the time You should never switch up and down rapidly as there are high voltages on this switch and you ll blow something up quickly by nervously fidgeting with it We strongly suggest you pick the setting you like best and just leave it there B FUSE HOLDER Should you n...

Page 9: ... Balance knob adjusts the gain in this mode The range of gain adjustment runs from 12dB in the fully counterclockwise LED position to 11dB fully clockwise Default is unity 0dB ad justment and that is signified by the 12 00 position LED on the Volume Balance knob Before you enter the Main Menu select the input whose gain you wish to change When you enter the Main Menu and select Menu Function 3 you...

Page 10: ...3 Starlight Mode Settings Speed 11 00 LED lit Only functional when Display Timeout is selected When the display times out this mode will make the LEDs twinkle in a mostly random sequence In this Display Menu selection the Volume Balance knob controls the speed of the LED s twinkling Clockwise means the LEDs will twinkle faster In Starlight Mode pressing the Volume Balance knob allows you to cycle ...

Page 11: ... The angle of the tweeter or speaker front panel to your face is also critical and experiment with that too You should be getting a smooth frequency response so that highs and lows are balanced and mids not too prominent or distant It should simply sound natural When we buy color TVs the first thing most of us relate to is flesh tones because it is something we all relate to and know when they are...

Page 12: ...s with plain painted gypsum walls and hardwood floors The simpler the decor the more intense the acoustic problems The only hints we can offer is that the wall behind the speakers and behind you are often the most important You can build some simple absorbers Simply cut two 4 X8 pieces of 2 rigid fiberglass or open cell foam rubber into 16 X8 strips and wrap some white cloth around them Easy clean...

Page 13: ...ted and in selecting that tube that will work really well for your piece of gear we probably had to throw away several In some cases we might have had to go through 30 tubes to find the quietest one or the one with the lowest microphonics or the one with the best internal matching depending on what parameters are important for that circuit That is all factored into the cost somewhat but no overall...

Page 14: ... power tubes in our amplifiers after a few years if you notice a small revolt going on where several of the output tubes are misbehaving or getting hard to bias you might consider doing a full re tube Keep the old ones that did not join the revolution as emergency spares FAQ 16m Can I change a tube myself R T F M do you call in specialists to change your light bulbs for you See page 5 for details ...

Page 15: ... above 3 or below 2 then you may be seeing a tube begin to go bad Watch it for a while or check it every few weeks noting changes This tube should be replaced probably With mains changes all the tubes drift together and you may see more long term drift Another cause is that you forgot to stop the music What if I can t trim a tube into range If all you get is zero or near zero on one terminal it me...

Page 16: ...s is pressed a red LED will momentarily illuminate at 2 00 on the Input Selection knob If the Stingray II s remote has dead batteries this red light will NOT flash and the remote will NOT function Another note To pair a universal remote with your Stingray II the supplied Manley remote control must ALREADY have been paired to the Stingray II see page 17 for details For reference the IR carrier freq...

Page 17: ...uts or not The Balance Control is adjusted for center You might try swapping the speaker interconnects at the Stingray II end If the problem swaps sides then it may be the Stingray II In that case the two most likely problems are a bad tube 12AT7 or 6414 or a blown 250 mA MDL 1 4 B fuse accessible through the sides of the unit See page 8 for details on changing this fuse TUBE GLOWS CHERRY RED This...

Page 18: ...olt with his traditional martini and EveAnna Manley with her stimulant of choice a cup of coffee She was describing a new integrated amplifier she wanted to build and proceeded to make one of those legendary bar napkin drawings Gordon remarked It looks like a stingray the fish not the car and thus in honor of Gordon we called this little jobbie The Stingray Now in 2008 we have revisited that time ...

Page 19: ...22Khz Source 1Khz Sine wave Input Impedance 12 Kohm nominal Optimum Speaker Load 5 ohms Actual Output Impedance at 20Hz 2 36 ohms at 1KHz 2 ohms at 20KHz 1 83 ohms Output Z Headphone Output 53 ohms Damping Factor 2 4 Scratch Factor Use pennies under pointed feet to avoid marring cabinetry Try quarters if you are in upper tax brackets The bargain performer would be nickels Paper currency does not f...

Page 20: ...reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient or relocate the receiving antenna Increase the separation between the equipment and receiver Connect the equipment into an outlet on a circuit different from that to which the receiver is connected Consult the dealer or an...

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