Showing posts with label 5687. Show all posts
Showing posts with label 5687. Show all posts

Wednesday, July 7, 2010

The good news and some 'bad' news..

Okay, the good news is, I have completed the tube preamp, hurrah!!! That was about a a week ago.
It was worth the wait (and the agony of waiting)! The preamp was connected to a discrete 40 watter (nicked name,D'Bomb) and the sound is simply marvellous albeit some issue which is irritating me right now.

One, I have humming issues, then buzzing then 'crackling' issues.. After much googling and reading more about tube amp designs.. I managed to solve the buzzing by opting to use DC heater as opposed to AC heaters. BTW, I have read and done all the do's and don'ts about tube amps building thingy, like wires crossing at 90 degrees etc.
The humming and 'crackling' although very soft and only audible when I am not playing anything, it is just 'psychological annoying'... Since I used some 'alternate' (read cheap and what is avail.) parts to what was being specified in the original design, now that I have heard how good it is and believing that there is a potential for it to become 'better'), I think it's worthwhile to invest in quality/premium parts and I have decided to buy the 'good stuffs' online.. I also found the TUNGSOL 5687 is kinda 'microphony' and it is known for that! There are other drop in replacement for this 5687 but I would not do it till further listening. Since this is my first tube project, I just want to have some experience and maybe moving on to other popular tubes. More updates later..

The casing used (like a metal pizza box) was bought cheaply from a manufacturer excess stock meant for something else.. hehe

Pic shown the preamp during the 'wet-run'. Speakers used was the Gale 3030 floorstander and I could not believe the amount of good solid bass coming out!


Saturday, February 13, 2010

5687 preamp progress...

Took deliveries of two major components:


The main power tranny.. specially ordered that took about 4 days.

  
One of the two 30H@100mA chokes that is required for the B+ supply. Took delivery about 2 days ago from my usual supplier..

The only thing I am short of now is the tube sockets, a 7 and 9 pin but a friend has a set and will get that soon from him.. Then I can start to build this long awaited project..
Cheers!

Thursday, December 3, 2009

New Project : 5687 tube preamplifier from diyparadise.

I have been fascinated by tube amp for a long time. What prohibits me from owning one is the PRICE! Had a chance to own one tubed headphone amplifier(Made In China product). It was 'okay' and I sold it soon afterwards as it runs too bloody HOT, could surely cook and egg (or two!)

A recent 'groupbuy' was initiated in one of the threads in lowyat.net forum and that rekindled the 'burning' fascination for tube amps that I ordered 2 sets of 5687 and 6X4 for the project! I read about a simple 5687 preamplifier awhile back. Link at the end of the page.


This is the 6X4 rectifier tubes made by National. Was on sale for USD9.95 at tubedepot.



The 5687 preamp tube made by Tung Sol, also on sale for USD9.95 from tubedepot.

Now I got to get the rest of the components.. The bulk of it will the the power transformer.. Will be going to Jalan Pasar this saturday to order a custom made tranny, having 350-0-350 and 6.3 secondary voltages...
my other worry would be the chokes which is part of the power supply.. 

Details of the project is here.

More later...