1bit

woo didn't know there's a transparent one does it shrink also?

 

the resistors in question are R8 and R4

 

the input caps and these resistors make two high pass filters, one for each channel

 

i think you can also bring down the cutoff frequency by increasing the resistance for R8 and R4, but it might reduce signal/noise ratio

 

mm is there a red shrink tubing?

i always use the black one

any difference beside the color?

** Its a fast recovery diode... what it means??

iirc it means that the diode can recover quickly from blocking (due to reverse bias) to conducting

so the transition time between blocking/conducting when the bias is changed is shorter

 

hey guys, a bit lazy here. since you've been discussing about the tube amp quite long already, i might as well ask: actually what's so different with the 3 hybrid amp design between SOHA, YAHA, and MHHA?

 

i'm getting the sijosae's MHHA kit from neutralzz next week so i'll try building MHHA first

 

anybody built the multi-hybrid amp already?

i know kippei and squalle is building the SOHA, how about kross and huangyong?

one thing to note about adjusting gain with trimpots, you'll need two trimpots for both right and left channel

when you set them you need to match their resistances properly with a multimeter to avoid volume imbalance between the right and left channel

 

so practically not a very good idea imho

happy new year! woo hoo

ooh i first thought dcc= digital compact cassette

what's a suppressor?

kippei, if you need money for the shipment of the millet boards let me know

thanks

paul mc cartney - band on the run dcc

 

wow! papaya86, you've got a dcc player?

or did i just mistaken dcc with something else

mm i think you can try using different headphones to test

if the fuzzy sound still persist, most likely it's not the headphone fault

 

no experience with grattle, but from what i read it refers to the rattling sound sometimes found in grado headphones

 

digital clipping will distort the sound very heavily, it'll sound unbearable (piercing high frequency noise) so i don't think this is the case. but small clippings might happen during spikes in the sound signal. it'll distort the sound a little, try lowering the gain setting.

 

usually drivers refer to the transducer parts of the headphone (i.e. the speaker) that convert the electricval signal and drive the soundwave to our ears. so if you wanna check for damaged headphone drivers try swapping headphones or the source. then you can locate the problem

 

the problem you mentioned that requires fiddling with the volume control is because the potentiometer (the volume control) is faulty (it has tracking problem)

 

hope this can help

http://www6.head-fi.org/forums/showthread.php?t=154664

 

free millet boards!

 

omg! i want one! i wonder if he's willing to mail the board to sg

hi kippei

i'm interested to get 1 of the pcb clones

although before i start i think i need to learn more about the characteristics of the tube

so it's gonna be a long project for me

 

about the tubes, where can i get them anyway?

seen the well audio website sometime ago, is that the only way to get the tubes?

whoops a bit late but

merry christmas everybody

you've got mail!

Browndog adapter there you are

wow that's rather miraculous, huh? lol

well looks like the internal components of the tripath for the two negative terminals sort of adjusted themselves

 

lol wow

well you can try these earjams

 

i wonder if it'll affect the sound in anyway

not sure if it'll fit your e888 though

you need to do this kind of modification to your headphone to use it with the t-amp.

 

hi warlock

well the hissing noise could be caused due to a variety of reasons, but there's one apparent problem in your setup.

 

the sonic impact t-amp uses a tripath ta2024 for its amplification

a quick peek at its datasheet, in page 5 the schematic shows that the chip has a differential output

it has two active outputs: the positive (red connector at your t-amp), and negative

tripath has an explanation of differential output here

 

so basically in the t-amp case you cannot connect the 'ground' terminal from left and right channel

lol

the mighty cap and those puny smd parts

 

xchagg perhaps you should test it out using a multimeter

tle2426 is a buffered rail splitter, and it has a low output impedance of 7.5 mOhm (typ) according to its datasheet.

 

however as pointed out by tangent, tle2426 lacks the ability to supply higher current needs. its max output current is 80mA, in actual use it could be around 20 to 40 mA

 

lm6171 can output up to 135 mA.

 

klernie, if you want to use the original cmoy2 circuit with 2 resistors and a buffer ic, perhaps you can try ad817an as suggested by tangent. according to its datasheet it "drives unlimited capacitive load, 50 mA minimum output current". and the best thing is that it's available at rsphilippines

 

you can also try to find buf634p, it can drives up to a whooping 250 mA. unfortunately rsphilippines only have the 5 lead version (buf634t). if you can find the pdip version (buf634p), i think it is pin compatible for replacing lm6171 in your cmoy2.

 

another solution is to find lm6171 somewhere else. it looks like farnell has a distributor there. you can try to call them and ask if they can get you lm6171. i got my lm6171 from singapore's farnell anyway.

 

so in conclusion i think you can still use tle2426 and modify the circuit a bit, the output current might be enough for the cmoy2 right and left voltage gain set at 2 (the original cmoy2 settings with 10kohm R2 and R6) see calculation below

 

or the other easier option is to use 2 resistors and find a replacement opamp for buffer either ad817an, buf634p, or lm6171 (get from farnell)

 

addendum:

trying to calculate output current requirement, please give comments and/or correction for this

 

assume typical line output rating from audio source= 250 mV to 10kohm

(i get this number from sharp minidisc mt888 page, not sure if it is max or rms voltage)

 

cmoy2 voltage gain= 2

 

headphone= 16 ohm (worst case)

 

output current required= 250*2/16= 31.25 mA

if the voltage rating is in rms, max output current=31.25*sqrt(2)=44.2 mA

 

so tle2426 with 40 mA output current is at the borderline, it might be enough for some application but not optimal.

yes, i agree with heady

i hope i didn't confuse you with the long post i made

you're welcome klernie

always glad to help

 

using 1uF input caps will bring down the cutoff frequency to around 16 Hz, it'll be sufficient

but i was not really happy with 1 uF, i changed them to 3.3uF to give more bass, although i need to bend the lead to accomodate for the bigger size

here's a good article about input cap

 

if you wanna use tle2426clp, you'll need to modify the circuit a bit

refer to tle2426 and lm6171 datasheets

they have different pin configuration

 

tle2426clp is packaged in a 3 terminal packaging just like a transistor so it's still possible to solder it to the pcb with a bit of bending the lead here and there

 

refer to cmoy2 schematic below, in particular the ground channel

 

i think it's still possible to use tle2426clp, but you need to make the following modifications:

1. solder (or push in to the ic socket) the in pin of tle2426 to pin 7 on the pcb, common pin to pin 4, and out pin to pin 6

2. short pin 3 and 6 on the pcb (you can do this by connecting a wire between pin 2 and 3 btw)

3. you don't need R9 and R10 anymore, no need to solder them

 

iirc here means "if i remember/recall correctly"

forgot to add: be careful if you want to change the input caps, the soldering pad on the pcb could fall off