How do I plug a pair of headphones into a Yaqin MC100B with no headphone jack?

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scuba

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After having pissed off the Mother_in-law who lives downstairs, I am looking to hook up a pair of headphones to my Yaqin MC100B. Much to my dismay, I just realized that it has no headphone jack. I am faced with the dillema of pissing off my mother-in-law:no: with loud music or pissing off my wife:scratch2: with yet another piece of stereo gear. Of the two, by far the least scary is pissing off my wife, therefore, is there anyone out there who could recommend a decent (200 to 400$) tube headphone amp to drive my AKG Q701's? Also, how would I go about hooking up the whole shebang?
Any advice would be apreciated as I have never had to resort to separate amp just for headphones:music:
 
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I had a similar issue with my Motorola's; wanted cans, but speaker ourputs.

I saw this talked about in an old posting; someone had posted the headphone output from a Sansui tube amp; I copied its idea.

Basically, you want to load the transformers, and pull your cans off the speaker taps. I did a posting on this, I can't find it in tapatalk.

Essentially you want to find some non-inductive power resistors to provide a proper load. My Motos were listed 6 to 8 ohms in Sams, so I picked up some 8ohm non-inductive "audio resistors" from radioshack. Actually, I did everything with radio shack parts. I mounted it in a small project box.

Anyway, power resistors across the opts, 100 ohm resistor off the positive lines in to a volume pot, then from the pot to a headphone jack. The grounds are connected together and connected to the ground side of the cans.

This *can* make for noisy output, you'll hear a LOT more noise than you would with speakers. Which is why I say add a volume control. I usually dial the noise back and just increase the output.

Its a simple circuit that works well. I get outstanding output without the worry of arcing in the output tubes. Should work with anything that doesn't mind having its grounds combined. So my tubes are fine...as the ground on the speakers is chassis ground on both.

If your unit has floating output grounds (like a lot of solid-state units), might not work.

Again, this is just how I do it, without looking at a schematic, I can't say for sure.

http://dewdu.de/table.jpg is a picture I took of my "outdoor" headphone rig.
 
Do not use subwoofer. It may resolve your problem for now. Generally it is a bad idea to use tube POWER amplifier to drive headphones.
 
Bi Amping?

Would bi-amping, where the second amp has a headphone out jack be a possible solution?:scratch2: Sounds expensive though. Any thoughts?
 
for_p1 said:
Generally it is a bad idea to use tube POWER amplifier to drive headphones.
Click to expand...

No so, but you may have to build or buy an adapter to load the amp safely and correctly. If the tube amp is low power (e.g., el84 push-pull) and your headphones are hard to drive (e.g., high impedance and/or low sensitivity), you can get away with driving the headphones directly off the speaker taps. I do this with my modded Fostex T50RPs and a Scott 299A because the lowest resistance 20W adapter at the link below attenuated the volume too much.

Using headphones with a tube amp speaker outputs is discussed here: http://www.audiokarma.org/forums/showpost.php?p=5742692&postcount=6
 
for_p1 said:
Generally it is a bad idea to use tube POWER amplifier to drive headphones.
Click to expand...

Generally, yes. It's a BAD idea to use your power amp to directly drive headphones. Most headphones are a impedance much higher than what the OPT was designed for. This can be fatal to the amps and transformer if HV happens to arc back in to the amp. The chances of this increase the more you push the tubes.

However, if you keep the transformers loaded properly; you eliminate the risk of anything happening to the amp. Sure, it's kind of a waste; but if your main goal is to prevent amplifier damage, it's perfect.

The only thing left to damage (aside your hearing) is the headphones. Most headphones don't want a lot of power. Sure, the loading resistor does take some of that power away (in theory), but what you pull off the loaded output is probably still a bit much. Which is why I recommended adding some additional resistors and a volume pot. Those resistors can also get hot if you're pushing a full load through them.

Realistically, if you're going to be listening to the headphones; it'll get EXTREMELY loud before you run the risk of doing damage to them from too much power.

I do it all the time; I'm doing it right now. I use the volume on the adapter to drop the "ambient noise" level in the cans so it's not as audible (there's a bit of hum audible at full-open). I don't actually touch that control much, I adjust the level I'm feeding them from the DAC (since my amp's volume controls have been essentially bypassed too).

http://www.audiokarma.org/forums/showthread.php?t=401313 is the thread I created that goes in to a bit more detail.
 
Thanks guys. I like the idea of an external box such as the one mentioned by Patrice B as well as dewdue's set-up. I will work on this and let you guys know how it comes out.. Thanks again for the help.
 
Essentially, the only dfference between the two circuits are the value of the resistors.

I used 8 ohm as it was appropiate for my amps. The other circuit, being built in, uses a 60 ohm resistor across the 16ohm taps, which is where its pulling the signal for the cans.

What this does is load it enough that the parallel load of the cans maintains a proper load. I can't remember if it also used resistors in-line with the headphone signal.

With my circuit, the 100ohm resistors and volume pot essentially raise the amount of load across the speaker taps so it has very little effect on the load to the transformer. It also prevents you from having a direct short situation when inserting the headphone jack. If I omitted all the small resistors, any accidental short would directly short the transformer. For example, if the total load with my headphones (phones, 100ohm plus volume) is 1k, the value on the transformer drops to 7.94.

If you're building an external box, you probably don't need auto-shutoff for speakers.

Don't let the two circuits confuse you, they are just essentially loading the opt and pulling from it.

Good luck. If you have any specific concerns, feel free to contact me.
 
I use a Little Dot Mk III and AKG K701 for headphone duty. I run my CD and TT into a dual output passive attenuator/switch box then out to an SE EL84 amp and the Little Dot.

Since you wouldn't need volume control, a simple switch box would allow you to use one set of sources for both your main amp and a headphone amp. The switchbox could be built for next to nothing and a Little Dot can be had for ~$230 shipped.
 
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Yaqin MC100B Headphones

I had a similar issue with my Yaqin YAQIN MC-13S.
My set up is MacMini --> HRT Music Streamer II --> YAQIN MC-13S. I then added a Mr. Nixie Mini Dual Tube Headphone Amp, but had no way to connect it to my setup.

So what I did was use a Y cable out of the DAC. One Y cable for each channel. This works great. If I just want to use my headphones, no need to turn on the tube amp.

I'm pretty happy with the setup. Sounds great!
 
I just added this circuit to my lil Maggy tube amp. At low volumes, it does well, but once I turn it up, it starts popping out of both sides, and it wont go away.
 
olds442111 said:
I just added this circuit to my lil Maggy tube amp. At low volumes, it does well, but once I turn it up, it starts popping out of both sides, and it wont go away.
Click to expand...

For the future reference of anyone who finds this thread; I helped Olds fix his circuit. What he described sounded to me like a loading problem. After looking at pictures, I was able to confirm where he made a few simple mistakes in adding this circuit to his Maggy. After he rewired the circuit, he reported no problems with it.
 
switching MC-100B output

I have a similar but a bit different situation.

My L/R main speakers are shared by a MC-100B and a Yamaha Receiver.

I use Niles SAS1 + two Niles SPK1 to handle the switching, SAS1 is controlled by the trigger signal from Yamaha, while the other two SPK1's are triggered by SAS1 in sequence.

For safety, I also added another two 8 ohm 200W Non-Inductive Dummy Load. When Yamaha is on, speakers are switched to Yamaha, MC-100B's output will be switched to Dummy Load.

My question is, during this transient moment while relays switching speakers, MC-100B will be under no output loading. Though it is just a fraction of a second, would it hurt the tubes? or the output transformer?

Thanks!!

jsnh62
 
A fraction of a second shouldn't hurt. The real question is if there's any kind of audio being pushed through it.

I've run them unloaded at work, you only run the risk if you're pumping power through them. The solder joint on my box gave out last night, ran one transformer unloaded for about 5 minutes.

It didn't hurt the amp. As long as there's no click from input change or something, you're good. Again, fraction of a second shouldn't hurt, the transformer will be loaded.

Going on the opinion of my boss, you only run the risk of that if your output transformer is "worn out".

I think you're fine.
 
Thanks !! dewdude.

Using auto-switching, it is mainly for safety reason. Under normal situation, i would not turn on both amplifiers at the same time. Just in case when I got some "curious little fingers" at home.
 
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