I read some diyaudio test on capacitor using large ceramic cap as bypass and have the THD scanned  with good results. Too bad, I have lost that page.

Too high voltage for OSCON use.

Use blackgates AND bypass them with WIMA MKS2s, lol, i've already got the wimas, now just trying to find the BGs.

what about 10pf film caps??
does it have the same benefit as ceramic one?

I feel its interesting to DIY and I do not have the time to do so, probably after 1 month after my finals. In the mean time I would like to read more instead of starting blindly without knowing anything at all.

What you guys said is really discouraging and turn ppl off. No wonder this thread is dead. You guys are once a newbie too. No hard feelings. Ciao~!

OK, i guess CMOY will be my first step for DIY Amp.

Thanks for the explanation bro and i might ask u where to find certain item if cannot get from Pasar Road

see your point. isnt there some advantage using PCB for double layer with proper ground plane execution.

I have a question. The below is the IV circuit that I am executing.



IDac is always zero being the virtual ground for IV Conversion. In addition to this circuit,

Instead of using 100k ohm, I am using 10k ohm to give a f 3db lower than 20Hz. This output feeds the tube amp with a 10k pot in parallel with a 470k grid resistor.

I see something wrong this circuit in the sense the input impedance for tube amp is too low. so when couple with the 10k ground leak resistor, I am having on 5k which shifts the f 3dB to 40hz?

the detail circuit is below.

Went to singapore. Look at the martin audio, well audio and larry plus adelphi.

at martin, the old lady was working on super tweeter, casing made of lighting transluscent glass. the sound really improve the high, making it more lively. That old lady mainly made the Martin class tube amp as well as speakers.

adelphil was more high class venue for expensive stuff like fm, mcintosh, MBL,etc.

---

Added on April 22, 2009, 9:09 pm

After R4, there is a 10k pot in parallel to the 470k resistor grid (to ground) inside the amp. What the cap sees is R4 and a 10k pot (neglecting 470k due to parallel).

That means the cap sees R4, RCA cable which assume inductance and cap is minimal and a 10k resistance to ground.

meaning the amp input resistance by right should be large enuf to provide independent loading to C2. if amp input resitor is high, the cut off frequency will depend on R4. If amp input resistor is low, then R4 has to be changed to suit the f 3dB. what is your thots.

However providing too large a R4, the tone phase shift will be significant at frequency below few hundred hz.

I am interested to know which is the fake. I can get back to him for the 'ransom'

---

Added on April 23, 2009, 7:40 pm

Actually R4 I have changed to 21K4 due to phase distortion at low frequency. (phase plot at low freq will show) R4 is also called the ground leaked resistor in this case is paralllel to the load resistor Rs (which is the amp pot). So the sound does depend on R4. After I put in 21k4, I am much more happy. in fact I can really hear the realisms of music now.

When the Mundorf Supreme comes, it will be a T day.

The aim is to use as least component as possible. Less is good. CCS or offset the IV has tried by many like petra rodja and Jocko which is good but more component count.

R3 is the bias for T2. R3 is not seen by C2. C2 sees the R4 (bleeder, serve to avoid C2 drifting, or else the cap can not discharge) and the Load impedance in the amp (lets call it R-load).

Do we care about R4? No, provided C2 > 1/(4 x pi x R4) and noise is depending squre root of R4. so too high a R4 not only create phase shift but noise too.