Post pics of your builds....
Nov 28, 2013 at 4:27 AM Post #9,451 of 9,811
  Very nice... I'm a fan of unique case work, very nice...12 volts on the heaters seems a bit high.


12.6v is the normal value for ecc82 (heaters wired in serie).
 
@Roberval: very nice build btw, very clean looking. I would have wired the output opamp in non-inverting configuration to avoid using such high feedback resistors (it increases noise a bit) but it is only a minor concern.
 
Nov 28, 2013 at 6:32 PM Post #9,453 of 9,811
I really need to get a digital camera...
 
Anyway, here's a 2K, 36 steps volume control. It's made of a 12 positions shorting switch, for -2 to -24db attenuation in 2db increments (+/- 0.1db, since I used "common" resistor values), and of a 3 positions switch, with pads for -0db, -15db, -30db. Thus three overlapping ranges, depending on needs.
 
It is for the output of dac. 2k is high enough to be driven by the dac output stage and low enough to drive the input stages of my amps. The -2db first step, rather than 0, provides protection for the output stage (it always sees a 430 resistor even if the output is shorted).
 
It is a reasonably cheap built. The big switch is 5€, the lorlin 2€, the 34 resistors about 3€ so 10€ total (+ shipping of course).
 

 
Nov 30, 2013 at 9:05 PM Post #9,454 of 9,811
I recently completed a pair of Decware zkit1 amplifiers for my father-in-law.  He calls it SteamBilly.  It's not 100% done, but DIY projects like this rarely are.  I realize it's different from what a lot of folks on here are into, but here it is.
 

 
 
 
 
Tube glow
 

 
Nov 30, 2013 at 9:24 PM Post #9,455 of 9,811
1st build, a DIY rechargeable CMOY,

 
2nd build had a bit more class, an RA-1 clone in a cigar box,


Latest build, the Bottlehead S.E.X.

 
Nov 30, 2013 at 10:02 PM Post #9,456 of 9,811
  I recently completed a pair of Decware zkit1 amplifiers for my father-in-law.  He calls it SteamBilly.  It's not 100% done, but DIY projects like this rarely are.  I realize it's different from what a lot of folks on here are into, but here it is.
 

 
 

OUTSTANDING !!!!
 
Nov 30, 2013 at 10:35 PM Post #9,457 of 9,811
  I recently completed a pair of Decware zkit1 amplifiers for my father-in-law.  He calls it SteamBilly.  It's not 100% done, but DIY projects like this rarely are.  I realize it's different from what a lot of folks on here are into, but here it is.
 

 
 
 
 
Tube glow
 

That (excuse my teenage lingo) looks sick.  How does it sound?
 
Dec 2, 2013 at 3:24 AM Post #9,459 of 9,811
My Prototype of Project Palaios, PP-P?, finally has a case. XD











^ I hate multi-stranded wire...the things broke twice on me >.>

The potentiometer turns really easily, but luckily the 6.3 mm hole I drilled in the case has a snug fit and it's harder to turn now.
 
Dec 2, 2013 at 8:27 AM Post #9,460 of 9,811
Multi-stranded wire should hold up if you tin it first i.e. twist it and apply some solder to the end. That's at least what I've found.
 
Dec 5, 2013 at 7:43 AM Post #9,461 of 9,811
Let's continue with accessory builds. Here's a small transformers box. The aim is to provide impedance matching in between high-gain, low-current amps and low impedance headphones (anyone remembers the Audiovalve "Impedanzer" ?). It uses 100v line transformers from monacor. Two positions: 5:1 and 10:1 (voltage ratio).
 
Most probably very low inductance so best driven from a low impedance output. It is intended to complement my current headphones amp. It sounds "right" using the hd650 on the 5:1 tap but I'll have to measure the FR one of these days.
 

 
Dec 8, 2013 at 11:34 PM Post #9,463 of 9,811
I got some wiring done this evening, I am trying to keep the power trans as far from the OP trans as possible. I bought a 12x12x4 enclosure, so with some luck there should be plenty of space between the transformers. I intend to put the power switch in the back and a 1/8 mini in front to keep the wiring simple and keep the input away from the A/C stuff...
 

This little toggle switch on the left will let me switch between the 300 and 600 Ohm taps on the output transformers.
 

 
Dec 10, 2013 at 5:32 PM Post #9,465 of 9,811
My first EVER project requiring a soldiering iron: a very ugly mono LM386 pocket amp. Im proud, but also humbled by some of the stuff you other guys make.



Watch all three parts of this tutorial and you will be able to solder anything.

http://www.youtube.com/watch?v=J5Sb21qbpEQ&sns=em
 

Users who are viewing this thread

Back
Top