[koike]

No tweaks* - the E90CC/5920 is a drop-in replacement for the 6J6, but it is quite a bit superior - less noise floor, less distortion.  An additional benefit is that they are tall enough that you can swap them out without taking the case lid off.


* Just to be sure, you need to implement both the zener diode tweak and the heater rectifier snubber caps.  Those are the primary differences from the early Torpedo prototypes and kits versus now.  Both make a huge difference.

I can't quite remember when I built my torpedo. I believe it has the Zener diode tweak. But regarding the heater rectifier snubber caps. I don't believe I've done that.

I think I built mine when you first released black cases.

 

[tomb]

 

No tweaks* - the E90CC/5920 is a drop-in replacement for the 6J6, but it is quite a bit superior - less noise floor, less distortion.  An additional benefit is that they are tall enough that you can swap them out without taking the case lid off.


* Just to be sure, you need to implement both the zener diode tweak and the heater rectifier snubber caps.  Those are the primary differences from the early Torpedo prototypes and kits versus now.  Both make a huge difference.

I can't quite remember when I built my torpedo. I believe it has the Zener diode tweak. But regarding the heater rectifier snubber caps. I don't believe I've done that.

I think I built mine when you first released black cases.

 
You should do the snubber cap tweak.  It finally removes all noise.  The noise we thought was power supply ripple was actually around ~160 Hz.  It was caused by the power transformer picking up the switching noise from the rectifiers and injecting it through the rest of the amplifier circuit.  It's also very simple to fix - you just solder some small ceramic axial caps across the leads of each heater rectifier (D5, D6, D7, D8) on the bottom of the PCB.  It helps to replace the rectifiers, too, to ones that were not so super-fast in their switching cycle (BY228GP).  I thought that I had this detailed on the website, but I'll fix that today.
 
PM me your address and I'll send you the caps and the rectifiers for free.

 

[JimL11]

New topic:  I just published a modified version of the Stax SRX DIY electrostatic headphone amplifier in the November and December 2015 issues of AudioXpress.  The improvements consist of adding constant current sinks on the the input and output differential amp tails and constant current loads on the output stage, plus a simple shunt regulated power supply.  Dr. Kevin Gilmore kindly designed a circuit board for the amplifier.  There is no circuit board yet for the power supply but it is simple enough to be built point-to-point.

 

[NiHaoMike]

My best friend and I designed a combined DAC/headphone amp a few months back.
https://github.com/NiHaoMike/OpenDAC-HD

 

[Siddhant Merh]

http://phonoclone.com/diy-sapp.html

I've heard this amplifier many times with hd600, hd650, hd800, he500, hp1, t50rp (modded) and many others.. in India somes of us prefer it over Eddie Current Black Widow..

 

[HiGHFLYiN9]

http://phonoclone.com/diy-sapp.html
in India somes of us prefer it over Eddie Current Black Widow..

I'd love to hear how they compare. I've been debating building the Sapphire for a while now, it's a nicely designed, no-nonsense diamond buffer headphone amp.

 

[rendyG]

Noob question, should I even consider building an amp when I´m willing to invest around $100? I´m using Fiio K5 now.
And what about a dac?

 

[JimL11]

Noob question, should I even consider building an amp when I´m willing to invest around $100? I´m using Fiio K5 now.
And what about a dac?

As a rule of thumb, the ratio of parts cost, including case, to finished amp is about 5 to 1, give or take. Now it may be less for a $100 amp, and manufacturer's do get quantity discounts on parts, so perhaps your $100 amp has $30 worth of parts. So, you figure it out.

 

[rendyG]

Thanks for reply, this I obviously understand.
Could you, please, recommend me some amps in this budget range? Preferably with fool-proof tutorial, if it is possible

 

[JimL11]

No personal experience with amps in that price range. If you haven't built anything before, it is easiest to start with a kit, that way you will have instructions to follow and all the parts, circuit board and enclosure. There is a list of various designs at the start of this thread, and there are probably posts throughout mentioning other designs, but some of the info may be out of date. You will have to get a soldering iron and electronic solder (there are different kinds of solder, the type you want is specifically for soldering electronic parts and have rosin flux in the solder - some of the new solders are "lead-free" due to concerns about potential lead poisoning. If you don't know how to solder, you can do a Google search for electronics soldering tutorials. Of course you'll also need basic tools such as screwdrivers.

DIY may seem to be lower cost, but of course you are paying in terms of your time and effort, and if you screw up, you may have to replace parts which have been damaged, and figure out what you did wrong. On the other hand, there is the pride of completing a successful project. And there are some designs that are DIY only and not available commercially.

 

[rendyG]

No personal experience with amps in that price range. If you haven't built anything before, it is easiest to start with a kit, that way you will have instructions to follow and all the parts, circuit board and enclosure. There is a list of various designs at the start of this thread, and there are probably posts throughout mentioning other designs, but some of the info may be out of date. You will have to get a soldering iron and electronic solder (there are different kinds of solder, the type you want is specifically for soldering electronic parts and have rosin flux in the solder - some of the new solders are "lead-free" due to concerns about potential lead poisoning. If you don't know how to solder, you can do a Google search for electronics soldering tutorials. Of course you'll also need basic tools such as screwdrivers.

DIY may seem to be lower cost, but of course you are paying in terms of your time and effort, and if you screw up, you may have to replace parts which have been damaged, and figure out what you did wrong. On the other hand, there is the pride of completing a successful project. And there are some designs that are DIY only and not available commercially.

I have some experience with soldering cables and changing capacitors, shouldn´t be a problem for me..
If there is anyone who has experience with some cheap diy amps, please let me know

 

[HiGHFLYiN9]

Noob question, should I even consider building an amp when I´m willing to invest around $100? I´m using Fiio K5 now.
And what about a dac?

Sure, check out the Pass Labs WHAMMY ... you won't find much competition in this price range.

As far as DACs, there is the o2 DAC and the PupDAC, I haven't heard either but they're close to your price range.