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Millett "Starving Student" hybrid amp - Page 463

post #6931 of 6937

I'm thinking to buy the "Starving Student" hybrid amp kit and i have some questions:

1. If you compere the "Starving Student" amp to other tube amp witch it would be?

2. I didn't understand the the point that i must "warm up" the amp b4 i plug my headphones and unplug b4 im done>why?can someone explain me?

2.1 How long do i need to warm up?:confused_face_2: Coz nowdays i don't use an amp and mu headphones plugged directly to my "Roland quad capture".

3. What do you think is worth to invest in a tube amp with k702 headphones?

post #6932 of 6937
1. It's sort of like the Millett Hybrid MiniMAX, but a bit less refined/featureless and with much more current capability.

2. See above.  One of the lack of "features" on the Starving Student is a headphone relay-delay.  Upon turning an amp on, a relay-delay keeps the headphone jack disconnected until the output coupling capacitors have had a chance to charge up.  Tubes are biased above a DC voltage of zero.  In the case of the Starving Student, 18VDC are on the headphone jack until the capacitors charge up and start blocking the DC.  Interestingly enough, this usually coincides with how long it takes the tubes to warm up.  So ... once warmed up, it should be safe to plug the headphones in without worry of exposing them to direct DC voltage.

This situation is common to all OTL tube amps and most tube hybrids.  Unless a relay-delay is employed, you could perhaps damage your headphones if you had them plugged in when you turn the amp on.

2. 30-45 seconds is safe.  When you see the orange glow as very bright in the center of the tubes, that means the heaters have heated up fully and the tube is warmed up. Again, it's really whether the capacitors have charged, but you can't "see" them. So we look at the tubes, instead.

3. I don't understand the English in this question.  Are you asking how much should you invest in a tube amp for the K702?  Or are you asking whether it's worth it to invest in a tube amp for the K702?
Edited by tomb - 5/15/15 at 5:41am
post #6933 of 6937

3. Im asking Whether it's worth it to invest in a tube amp for the K702? and if yes how much should you invest in it?

post #6934 of 6937
Quote:
Originally Posted by SlimSwaly View Post
 

3. Im asking Whether it's worth it to invest in a tube amp for the K702? and if yes how much should you invest in it?

 

Well if I was really a smart*ss, I might say ... "Yes - $10,000" and leave it at that.

 

That wouldn't be very nice, but it does sort of make a couple of points:

  • No one should tell you what makes a truly worthy investment or how much to invest - in anything.  Even qualified financial consultants present recommendations that are full of disclaimers and caveats.
  • There's an opinion that's widely shared: the AKG K7-series of phones are one of the truly great headphones.  Before the advent of $1000+ headphones, there were three series that stood at the top of the world: AKG K7-series, Sennheiser HD580/600/650, and Beyer DT880 (impedance ranges).  It's safe to say you can throw ever-increasing quality amps at these phones and they will respond with ever-increasing improvements.  As with most things, you end up in a diminishing returns condition that at some point will reach the limit of your financial capability.

 

You should be careful with tube amps concerning the AKG K7-series, though.  IMHO, OTL tube amps are not appropriate.  This is because the K7-series is known for needing a lot of current.  An OTL (output transformer-less) tube amp will be very limited in current capability.  A output transformer-coupled tube amp will work well, as will a tube hybrid, such as the Starving Student.  The Starving Student has enough current to power even the most stubborn planar headphones, much less the K701/2/12/etc.

post #6935 of 6937
Quote:
Originally Posted by tomb View Post

Well if I was really a smart*ss, I might say ... "Yes - $10,000" and leave it at that.

That wouldn't be very nice, but it does sort of make a couple of points:
  • No one should tell you what makes a truly worthy investment or how much to invest - in anything.  Even qualified financial consultants present recommendations that are full of disclaimers and caveats.
  • There's an opinion that's widely shared: the AKG K7-series of phones are one of the truly great headphones.  Before the advent of $1000+ headphones, there were three series that stood at the top of the world: AKG K7-series, Sennheiser HD580/600/650, and Beyer DT880 (impedance ranges).  It's safe to say you can throw ever-increasing quality amps at these phones and they will respond with ever-increasing improvements.  As with most things, you end up in a diminishing returns condition that at some point will reach the limit of your financial capability.

You should be careful with tube amps concerning the AKG K7-series, though.  IMHO, OTL tube amps are not appropriate.  This is because the K7-series is known for needing a lot of current.  An OTL (output transformer-less) tube amp will be very limited in current capability.  A output transformer-coupled tube amp will work well, as will a tube hybrid, such as the Starving Student.  The Starving Student has enough current to power even the most stubborn planar headphones, much less the K701/2/12/etc.

If you double/triple etc csthodr followers in an OTL you can, in theory, provide massive currents smily_headphones1.gif but it takes up too much current from transformer to heat more tubes

I wanted to build an amp with 4 12AU7 per channel, but that went downhill lol

Anyways, the K7__ series is fantastic. When I owned mine, I didn't find any tube amps that worked well, but the Starving Student seems to be a good option. I wasn't DIY capable at the time. I think the SS is a good project because of its simplicity and relatively low voltages, so it is easier to work with. The SS uses a MOSFET as a follower (like a tube cathode follower) to provide current, which will allow the K701 to pair well, since it has plenty of current and a low output impedance, which is crucial since the headphones are only like 62ohms
Edited by DutchGFX - 5/17/15 at 7:14am
post #6936 of 6937

Hello,

 

Recently I upgraded my setup with Objective2 amplifier :P

 

Since I am a new "audio enthusiast" I want to build Starvig Student as well.

 

As far as I looked on the net, I saw only great reviews about this amp.

 

 

My question now is:

 

Is it possible to get a PCB somewhere ?

 

I texted user Fred_fred2004 about buying few PCBs, but he didn't replay.

 

 

Regards,

Z

post #6937 of 6937
I am selling the original Starving Student that was based on Pete Millett's design. It uses the 19J6 tubes as in the original. The PCB was designed by dsavitsk of ECP Audio.

However, I am only selling full kits, not separate PCBs. The kits were last sold in 2010. It's taken that long to find enough 19J6 tubes to make it worthwhile to sell kits again - but the stock is limited. When these run out, it could be another 5 years before they're offered again, if ever.
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