[particleman14]

have you thought about glassjar audio kits? the price for the parts you get is pretty reasonable..

 

[ujamerstand]

Oh, I'm getting parts from Jeff alright, just handed over a bunch of monies to him. But I want to do some modding to the power supply. This thing here. I don't want to worry about not being able to regulate them to 250V with regal mod. I'm building my build with these mods in mind in the first place. That and the fact I'll need to place a mouser order for replacement gamma-2 parts anyways means that it'd be more economical if I just order everything in one go.

Edit: runeight recommended changing the 4k7 ohm resistors in the mod to 10k ohm and use the EZ80 rectifier if things were getting too hot. personally I'm getting the beefiest heatsinks to handle the power dissipation. I hope it'll all workout.

 

[particleman14]

ahh i guess I don't have to worry about that since i'm usa power (still reading the thread though). ya making mistakes just gives me an excuse to order a different project along with my 1$ in replacement parts; i always cite shipping costs to justify this habit lol

 

[ujamerstand]

Yeah, I might just get some parts for the BantamDAC pcbs that I have left, the parts just keeps on accumulating. But the mistake I made on my gamma-2 ain't cheap. I think I f'd up the most expensive chips in there...

Anyways, on the subject of the Bijou, anyone know of a cheap place to get ECC99 tubes? I'm not ready to spend 30 dollars on a pair of tubes just yet.

 

[bhjazz]

370DAX just arrived today. Thanks, Angela Instruments! I had an idea how big it was, but it turned out to be bigger...and heavier. This will change my direction for case size. I very much like the HIFi 2000 cases, and was initially thinking of a short, 12x11 and 3 inch high case, whith parts on top and wiring underneath. Now I see that is just too small for my, uh, style. No, this trafo means I need to step up to big boy cases. Yes, I think a HiFi 2000 "Heavy" case at 17x12 and either 4.72 or 6.5 high will be perfect. I want something to proportionally contain that kind of bulk!

I've become quite inspired by antique radio designs. Art deco design cues are something I want to include in my case. One unit that seems particularly good for copying would be the EH Scott Full Range High Fidelity Receiver of 1936.

I'm going to try to include the simple stair-step look on the front, with fewer tweaky knobs. Somehow. A pilot light would be cool, but LEDs....well, you know I loves me LEDs. MIght be a way to do both, but I'm not sure just yet. I think a few evenings with Google SketchUp might clear it up in my head. At least I don't have to try to accommodate that many tubes. Sheesh.

 

[Olli1324]

Bijou up and running in its case. The transformer is in a nice wooden box I made. Considering it is made out of wooden drawers that are 1 billion years old and curved, it isn't too shabby. The NFB pot is giving a little bit of hum, but I am planning on ditching it anyway, so it's just flopping about. The lid also isn't on. Some bigger hole drills and some sexy aluminium washer type jobs to hide them will need to be made this coming week.


Oooh just noticed something. Norah Jones' voice is quite heavily to the left (a little coming from the right cup) and when she puts a little oomph into it, she distorts kind of into the right cup.. Because the amp is not warmed up (been on for 20 mins so far)? James Hetfield's voice is quite recessed in The Unforgiven... But the guitar at the beginning sounds pretty damn 'atmospheric'.

 

[Olli1324]

This is all through AKG K701s. Senn 650s should arrive tomorrow.

Hmm. I just turned it up really loud, and got some horrendous PHHARRP sound. But I just carefully tried again and it didn't happen.. Odd, eh.

 

[adamus]

not odd..... not good at all!

I would nto have expensive phones plugged in whilst its doing that.... although the large otput caps do offer some protection.

first thing to do is swap the tubes and see if the problem follows.

 

[bhjazz]

I'm with adamus, you definitely want to use only throw-away headphones before you completely test out the amp. I'd vote for something small, white, that often comes free with another purchse...

If you don't immediately find the problem, post some pics and we'll give you a hand with troubleshooting.

 

[Olli1324]

Hmm the PHHARRP sound seems to be quite nicely centred, so perhaps the tubes aren't screwed? Or perhaps just both channels are screwed

I'm listening now through my ms1000s and I just turned it all the way up and no PHARRRP (using the volume pot). However, turning NFB to the other side gives some more tasty phharrpness.

I got it! It sounds like a fog horn. If that is any help...

I did test it using cheaper earphones and it sounded fine. It also sounds fine (most of the time) through headphones, bar the hum from the poorly executed (on my part, not Mr. Cavalli's) NFB (I am chopping it out soon anyway). But yeah, I'll leave the proper 'phones out until I fix the problems

I have no idea what is going on (as may be evident).

I'll post pics tomorrow when I find a camera.

(I used too many brackets).

 

[ujamerstand]

Let us know what may have caused it if you do find out what happened. It may help the rest of us out greatly.

 

[Olli1324]

Cool. so this morning I am not getting the loud hum (pharp)by twiddling the volume pot, but I do get it if I turn NFB right up. Am I to assume that this is definitely not normal?

One thing I do notice is that when the volume is turned right up, it sounds pretty congested, muddled and generally not-very-head-fi. Bass is also lacking. I am sure this amp shouldn't sound like that; my cmoy sounds better! Thus, I believe perhaps there is something, somewhere, wrong.

My 650s arrived today btw

Currently have them plugged into the M3 - not the Bijou yet!

Anyway, I'm about to go and get the camera, so hopefully you guys will be able to see something I can't!

 

[Olli1324]

Tucked away in there is star ground. It is connected to that stand between some washers. Excuse the crocodile clip holding NFB to ground

Tranny in a box.

General shot.

The right channel

The left channel

All

I like this photo. That is what it will vaguely look like when done. This photo is particularly good because you can't see how bad a fit the holes in the lid for the tubes are

And there is no headphone socket at that stage...


If you want more photos, feel free to ask. If you really want me to take the boards out and show the undersides then fine, but bare in mind it took me ages to do the bloody wiring

I fiddled about with tubes; no effect on issue.

To clarify, the issue appears to be general low quality of sound, and loud hum suddenly trips in as the NFB pot is turned up.

 

[tamu]

I would say check the suspicious looking solder joints first.

 

[Olli1324]

Could you specify which ones you think look suspicious? My inexperienced eye can't see many toooo shabby joints.. My dad (years of electronics experience) checked the solder joints when I finished them and he didn't point out anything which needed reflowing which hasn't already been done.