pass labs x2-1

Status
Not open for further replies.
Jump to Latest
#4
llwhtt said:
Mouser has 880 Ohm 25 Watt chassis mount Dales in stock. Four in series/ parallel will give you 880 Ohms@50Watts.

Craig
Click to expand...

I used a resistor in a TO-220 case that can be heat sinked to the chassis. I got them at Mouser.

This resistor will get very hot. I'd recommend oversizing it. 4 in a series/parallel combination is a good idea unless you have a large heatsink. It's difficult to find standard axial carbon or metal film resistors at that power level. DON'T use wire wound inductive resistors. Make certain they are a non-inductive type.
 
#7
I'm not sure what you're trying to do here. Are you trying to build a DC supply to run the filament of a 300B? If that's the case, then I suggest looking at an LM317 voltage regulator IC. Or you can follow what I did in this thread.

You will need a rectified DC voltage of at least 7.5 V at the input of the LM317 (or LMZ12002). Use a 9 VAC transformer that can supply the needed current (1.5 A per 300B). You'll need a diode bridge that can handle the current with plenty of margin - KBPC2504 would be practically indestructible in your application. Then add a 10000 uF cap on the output of the diode bridge. The cap should be able to handle at least 25 V.

The LM317 will dissipate up to 10 W so it will need a fairly big heat sink.

For the 6SN7 filaments, you can go with AC -- or if you insist on using DC, you can do the same as above. However, as the 6SN7 needs 6.3 V, you'll need a transformer that can supply 12 VAC. The feedback resistors on the LM317 will be different than those used for 5 V. There's an equation in the data sheet for calculating those resistors.

Does this help?

~Tom
 
#9
Yeah, the cap should be able to handle the ripple current. Low ESR is a plus. I'd also put a polypropylene cap, 100 nF ~ 1 uF in parallel with the big one for better performance at RF. The LM317 (and LMZ12002) requires an input cap for stability anyway.

~Tom
 
#13
Google Translator say:
" hello I want to change the capacitors by better and if you can make some improvement in other components " 😀

Yes, for sure...you can change cap's to better performance.
What X2 version do you have?there are X2 1's version, 2's and 3's version. And, avaliable schematic just for X2 1's version...
 
#15
The X2 have a good capacitors inside, IMMO a step up capacitor (In quality) are too big for this unit (V-Caps or something like this). My advice is leave the unit like is, and make a new X2 with a proper size pcb for big capacitors.

P.S. I recently bought a Aleph L with a disastrous mod, someone changed the resistor level control by a Alps blue potentiometer, arggg!.
 
#18
KatieandDad said:
What should the Aleph L have had as standard ?
Click to expand...

Have a stepped attenuator (resistor) (Much better track than a Alps) close to Goldpoint units
ultraverveGoldpointBlueRes.jpg


The v1.2 have the same attenuator with two circuits (Part of the run are in passive mode)
 
Status
Not open for further replies.
Top Bottom