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Millett "Starving Student" hybrid amp - Page 12

post #166 of 6828
I agree with Nate that mu on this tube is way to high for this to be a reasonable preamp. This is best used with high Z phones.

Quote:
Originally Posted by -=Germania=- View Post
Also, anyone know any other compatible dual triode tubes?.
Unlikely. There are a 5V (5J6) and 6V (6J6) version, and lots of variations on the 6V version, but none of these can be used here without circuit modification which will destroy the elegance of the heater supply/biasing mechanism.

You could use the triode section of a 19CL8 here (other section is a tetrode). It will still make a lousy preamp (mu=40), and it might make a lousy headphone amp too, but the heater will work the same, and the triode section might work. Same for the 19EA8 (same triode as the 19CL8, but has a pentode instead of a tetrode for the other half.) Neither will like the low voltage. I'd get the thing built before you start thinking about swapping tubes in and out.
post #167 of 6828
Quote:
Originally Posted by dsavitsk View Post
I agree with Nate that mu on this tube is way to high for this to be a reasonable preamp. This is best used with high Z phones.
I've seen this mentioned a few times and I have no idea what Z is. Can someone enlighten me.
post #168 of 6828
Z is impedance.
post #169 of 6828
I dont know how much diy I am going to be doing... just pinched a nerve in my pinky. pain to type right now - using only 6/10 fingers.


EDIT: With be making originally as a high power output on the RCA's - want to try out possibilities as a speaker amp or pre-enegizer stax amp (need stax though).
post #170 of 6828
The recommended film caps on mouser are obsolete, and the mouser-linked alternatives are back ordered. What exactly is it i'm looking for in finding a replacement; do I just need to find some .1uF 100V 'film' capacitors? Are there different kinds of 'film'? The low-ESR electrolytics are backordered on Mouser too.
post #171 of 6828
These should work.

HERE

The only difference is termination style of axial versus radial.
post #172 of 6828
before you edited your post, you recommended a different cap that appears to me, would have worked equally well. What is it I'm not seeing about choosing caps like this, is there some difference in the data sheet? Is it just reputation? What do you go on when recommending a cap? What's the difference between these two?
MKT1818410015
160104K100C-F

Plus, what about the electrolytics? I don't even get any hits when filtering for 100V 220uF aluminum electrolytics. And the BOM for the Starving student lists 150uF electrolytics but the part number is for 220uF ones.
post #173 of 6828
post #174 of 6828
I think Ill give this thing a shot. Anyone have any experience with this amp with K701s or 650s?
post #175 of 6828
Thanks for the cap recommendations! I have K701s too.
post #176 of 6828
Another killer project from Pete!! I can't wait to test it out! plus it makes an ideal amp to have at work (sp. if you're an IT guy I can plug it anywhere I have POE!!

For those looking for the power supply, don't agonize over ebay, these PSUs are pretty comon nowadays and you may get a better deal locally, just look for POE (Power Over Ethernet) power supplies; they're used to "inject" 48V through CAT5 cabling, and are widely used in VoIP and Wireless Setups to either power phones with the same cable used to network them, or power WiFI access points/repeaters/bridges w/o having to run an extra DC cable when you have them on top of a mast or building, etc.

Popular VoIP Phones are Cisco, Grandstream, Thomson, Polycom, Sipura etc. Cisco are easily the most outrageously expensive. But beware not all VoIP POE phones bring a 48V switched adapter. Thomsons for example have 9V linear unregulated ones though they work fine with std. 48V POE.

There's a lot of chance if you have a WiFi centric shop near you they'll have those PSUs.
post #177 of 6828
And here I was thinking that you were talking about this POE.

post #178 of 6828
Very cool. I just ordered some tubes and all the rest off of Mouser.

Any recommendations on a power supply project to compliment it?
post #179 of 6828
Quote:
Originally Posted by HypnoLobster View Post
Any recommendations on a power supply project to compliment it?
You mean other than the supply already discussed at length in this thread?
post #180 of 6828
Quote:
Originally Posted by n_maher View Post
You mean other than the supply already discussed at length in this thread?
This will be my first real project, all this talk of LM317's and such just zooms straight over my head.

Let me rephrase that; anyone have a suggestion for a nicely predetermined power supply project
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