It was a half hour to 45 mins job... both channels of the DRD amplifier are installed with Mundorf 4.7uF as the first capacitor after the RCA83 tube rectifier.

First impression was that the bass is deeper and tighter... I am starting to wonder if my problem with the bass from my speakers are due to the polysterene capacitor that i used instead of the Ducati 8uF motor run oil capacitor...

I'm now listening to "Fall in Love with Olivia" on my setup as I type this blog. This cd was lent to me from a colleague. At first I thought it was Olinda... so I did not listen to the mp3 that were passed to me. After listening, I was surprised to know that Olinda has such a sweet voice.

When I saw the cd, I realized that it is not Olinda, but Olivia... It's a must buy for me, since the first track of the mp3 that I listened to.

The anticipation of this moment since early this week... i pulled together my horses and men for this session. The other source is a Marantz CD50 using a TDA1541A dac. My 5687 preamp, d3A/VV302B DRD amps and my Diatone PM610MB speakers were called to duty. Sequence of A/B is always PS1 first, followed by CD50 for each track. Discs used are 1 - Plastic Flower from Op4, Lena Park (Korean Artist), 2 - The Power of Love Songs CD1, Fish Leong (Malaysian Artist), 3 - The Hong Kong Hifi show CD (2007 I think), 4 - You'll Hear Better Songs and Memphis Tennessee from Early Hours (Hybrid SACD), Eleanor Mcevoy. Impressions are that the PS1 presents a lower output voltage to the preamp, the bass is rounder and not as profound, soundstage is less deep, and it has a more mellow presentation when compared to the CD50. It also seems veiled in comparision, with the CD50 giving a cleaner and clearer sound. Perhaps after the mods, it will be better... I can only keep my fingers crossed.

A long overdued post. You might have already seen the pics at my picassa albums. This project actually started out in June/July 2004, and was my first attempt to build a tube based amplifier. On hind sight, it was a little ambitious to build a 300B mono block as a first tube project. Nonetheless, there are people who did it. Me, I only got it right on the second attempt. Inspired by Sakuma san and Josh Stippich, I wanted to make use of those nice mercury rectifiers in my circuit. The RCA83 was bought locally at a rather high price. Netting these tubes on ebay would cost a fraction of what I paid. I did lots of reading about tubes, and also got some online education of such stuff at DIY Audio. The Net is such a wonderful tool... I even attempted to create a DRD calculator in excel that helps calculate the resistor values and B+ required when certain inputs such as driver and power tube operating points are furnished. I was suggested to use the Siemens c3g as a driver for the 300B tube. Suffice to say this this first pass project did not pass with flying colours. With a pair of inefficient (87db/m?) Totem 1 bookshelves, hum was evident even at 1.5m away. I rebuilt this amplifier around Oct/Nov 2006. This was also partly due to reading the success of Luis Gascón with his DRD using d3A/300B on diyaudio.com. I built my version with d3A as the driver, but using LED biasing. Testing this on my Mitsubishi Diatone PM610MB speakers (around 93 to 94 db efficiency), hum was only evident when my ears are around a feet away from the driver. All heaters are using AC for this build. Needless to say, I am very happy with my DRD amplifiers. ;) More pics here.

seems like an inseparable part of life... one day it works fine, and the other it does not. worse, you have no idea what went wrong. i was trying to hook up my 5687 preamp to the rest of the system that i intend to partner with, but somehow, the power supply of the preamp was giving me problems... i have a switch capable of warming up the heaters first, and then switching in the B+ on the second toggle. somehow, at the first toggle, the rectifier let out a glow, meaning that something is wrong... powering it off, i measured 120vdc from the capacitors. this does not discharge even when i switched in the rest of the circuit. maybe one of my crocodile clips on my temporary power supply are touching each other. don't have the mood to troubleshoot after i spent around 10 minutes to figure it out. i then took apart the supply and started work on laying out the components on a hammond chassis that i had on hand. think i will retry the psu when i have the time, but this round, i will make use of my 22uF GE 97F oil capacitors. i have 4 of these which were used in paralleled configuration on my previous build of the DRD amplifier.