From Russia with Love
A quad of 6D22s from Russia. Gonna use them in my 808 build. ;)
A quad of 6D22s from Russia. Gonna use them in my 808 build. ;)
I did not take a peek under the hood until a few nights ago. The parts under the hood were made up of some good stuff. I saw Mundorf Silver Oil coupling capacitors, Black Gates, very nice wire wound rheostats, japan made 100R 2W pots, aluminium-clad power resistors, James 6123HS output transformers and a 10H James choke, and a large power transformer that can be used for 808!
I have the 30W version of the same James output transformer which I initially reserved for the 808 build. Guess I can use this 20W version since the 808 would be around 10W. I just need to get a transformer for the fixed grid bias and I'm ready to do some prototyping.
Spent the afternoon removing the parts.
It's been some time since the last post.
We went to one 15 degrees where we chartered a yatch to bring us and some friends out to the southern singapore waters. It started with a quick tour around Sister's Island, St. John's Island and Lazarus Island (supposedly a failed land reclamation project by the government to turn it into a holiday island resort).
We stopped to get onto the beach at Lazarus island and were greeted by 2 islander cats at the jetty. The nicely built, but unoccupied Visitor Center is a stone's throw from the jetty. It's just there collecting dust. The beach on the other side of the island had nice fine sand nearer to the water breakers and is a nice spot for swimming with the kids.
The kids also took turns on a jet ski when one of the owner of the charter came to say hello.
After the beach, we went back to the sea for some fishing. My initial thought was that "there's no fish in Singapore". This was based on my own experience more than a decade ago when fishing with my dad and sister in Singapore seas. I could feel the fish biting, but their mouths must be smaller than the hooks we used. Prior to this, we fished exclusively off Malaysia, many hours off into the South China Sea where heavy lines were used for baracudas, snappers, parrot and other fish.
It was to my surprise that we got a total of 5 fish around Lazarus island. The sonar really was accurate. Lucas started the spree with a small fish. The largest one was hooked by Aik Peng just seconds after she cast the hook. I had the pleasure to reel it in. Quite a good fight put up by the promfet looking fish. I was trying my best not to break the line.
It was a fun trip and we may want to do just a fishing trip next.
On the audio front, I will be back to work on my DAC which was long left to collect dust. Future projects would be to get rid of the cd player in my audio chain. I want to move to CAS so that i can organize my digital songs. Just deliberating between the Mac Mini or the Macbook Air as the source. MBA is due for a refresh in April/May, but it does not seem to be a quad-core addition... And maybe, build my ultimate tube project... the 808.
More pics here.
We celebrated Lyra's third birthday yesterday (actual date is today). She had 2 of her child care friends over, and some of her child care teachers, as well as other friends and relatives.
One of her gifts was a wooden mamooth that had to be fixed together. More a boy's toy, so Lucas got a bonus gift. Took us a couple of hours to put together. It walks and roars like an elephant. ;)
Like Lucas's previous birthday, guests were encouraged to bring a cheque made to World Visions instead of bringing gifts.
Lyra and Lucas are supposed to sleep in their room with the newly added bunk bed tier from today onwards. But of course, it's not smooth sailing. San had to sleep on the floor to accompany Lyra.
I was up doing work with the newly created space vacated from where their matteresses used to be.
It's a place that I've been wanting to visit when I saw it on the locality map at the MRT. Since I had to bring Lyra somewhere while Lucas was having his lesson, I brought her to the "balancing" playground opposite our place to play for a while before bringing her to look for the Japanese Cemetery Park.
The cemetery turned out to be around 29000 square meters in area, and has 910 tombs within it's grounds! It used to be a rubber plantation owned by a Japanese brothel owner who then used part of his land as a burial ground for Japanese women who died in destitution. During World War 2 (1942 - 1945), the cemetery was used to bury Japanese civilians and solders who lost their lives in the battlefield or illness.
According to the plaque, this cemetery park, it is the largest in South East Asia.
So I measured the cathode resistors just to be sure the voltage drop is correct and that it is not due to the CCS. One tube measured 1.058v and the other measured 1.048v. On the spot as far as I'm concerned! (The cathode resistors are Kiwame 820R and the Rset on the LM317 should be some Dale 1% 1k resistors. But this just shows how accurate the CCS is!) This can only mean that even the 5691 can vary from tube to tube! And the ones I have are matched to 58/60 and 58/68 according to the guy I got them from...
Well... anyways, next would be to put these stuff together with the Sabre32 dac and the Placid power supply.
I'm doing the DN2540 cascode with LM317 so that i can set the current to exactly what i want. In this case, it is to load the RCA 5691 red base tubes with just 1.2mA of current per tube. This should be sufficient for voltage gain from the Bufallo DAC into the BCF, more importantly, I can draw from the same B+ rails that powers the BCF.
With the previous MJE350/BC557C and LED version, I could not get the resistors for the B+ correct. Quite frustrating when this has worked for me before...
Schematic is the same as Figure 13c from Jung. Rset is 1k to give 1.25mA.
It's past the tourist season and there was not much crowd anywhere. Restaurants are mostly empty except for Orkid Ria. We had dinner there one of the days and there was this singing and music in the background. I went to see if there was someone next door singing, and it turns out to be a cd playing from the restaurant. I asked them for the artist and they told me the cd is "Best of Noon". Ok... quite skeptical that there is such an artist, but I managed to find one such cd from Gramaphone.
I got the last Noon - Better Than Anything cd. The thing that caught me is Noon's different rendition of the jazz usuals that I heard in the restaurant. Hope this cd is just as good. Have not had a chance to listen to it yet.
More pics of the trip can be found here.
I'm expecting the DN2540 DMOSFET to arrive today. Don't think I'll be up to building the CCS replacement for the Buffalo2 project tonight. The ones that I did based on MJE350 had difficulties getting the correct resistor settings even after following the instructions to a T. The DN2540 cascode with LM317 in theory will make it easier to set the current. ;)
If all goes well, I may be able to solder up the connections tonight. I was listening to the amps with crocodile clips from the power transformer to the IEC inlet yesterday afternoon. Got some new cds - A Mei's Are You Watching Me (she's one of my favourite mando-pop singer), Eason Chan's cd with a duet with Faye Wong and the new Lady Gaga album - Born This Way. My ex-colleague gave me 2 pcs of signatured Olivia Ong posters (thanks Angie). Maybe I should frame it up for my room...
Of another note, I put in an order for 100pcs of Supertex DN2540 from Mouser this morning. Gonna share it with Yeo and Sanjay. I should be able to proceed with my Bufallo build soon.
Btw, I surfed to JC Morrison's website over the weekend. Interesting read... check it out if you have time.
