spritzer

They are all in 100ft lengths so quite pricey. Take a look at this link but be warned, it will change your region settings at Mouser: Tubing & Sleeving - (Non-shrink)

The headphone socket turned out to be quite a complex beast so I just decided to leave it be. There is a switch attached to it which engages resistors to lower the speaker output once the headphones are connected. That is a good feature to have so I'll just have to live with an adapter. KG also helped me figure out the 4 remaining caps which had rather odd markings so now they are gone as well: Now I had no excuse not to power it up so after hastily constructing a 5-pin domino DIN headphone adapter and a 5pin DIN to RCA input cable I flipped the switch... ...and it works perfectly. I still haven't tried it with speakers but it works pretty well as a headphone amp.

Happy Birthday!!!

I have piles of those, I always buy 100 at a time so I get them in the small box. I still want to test why the Japanese high end always turned to Riken for the most crucial resistors in any circuit. Look inside any high-end Sony, Denon, Yamaha etc. (and I'm talking about the true state of the art stuff here, what they normally only sold in Japan) and they are filled with those lovely carbon film units.

Rake Who knew Australian TV was this good...?

1/2" makes me happy as I can use my carbon films...

The drivers on those are very different so they will behave differently. Your best bet would be to try the set with another amp. I do think that dust inside the SR-007 is not very likely unless somebody did something horribly wrong when changing pads...

The local store really came through on this one with a nice stash of Philips/BC caps so I just scrapped all of the electrolytics. Here is the end result: There are also some caps which I had at hand, including the rather nice Nichicon ES non-polars. I also changed out the rectifier for a RS402 unit and the Wima filter cap next to it: Here is that Wima cap next to the modern version. I haven't fired up the amp yet (I'm going to do it with fresh eye's) but I must say it has been a pleasure to work on this amp and the person who did the PCB layout really knew what he was doing. There were often multiple holes for each cap and the true dual mono layout makes it much harder to mess up something. Here is the underside: Now the next step is to swap out the crazy DIN headphone socket. This amp will most likely never be used as a speaker amp but it could be ok with headphones. While I can live with my nice, all metal DIN input plugs the same doesn't apply to the very fiddly headphone connector. Time to retrace this pile of wires:

It could be dust or it could just be the Exstata bias supply acting up. Let's just say that Stax would never put something like that in their amps...

Turns out the local store has a large stock of axial caps so I'll drop by later to see what they have for me. Most of these are standard values except for the three 2500uf caps. 2200uf is close enough or I can just go to 3300uf for the main PSU cap. I managed to cut and desolder enough to free the small PSU board and the bridge rectifier looks to be a Silicon part: I can't find a datasheet but it has all the markings on it plus the same on the bottom of the PCB. The red part behind it is a very old Wima MKS cap. Sadly that's one of the toys I lack. I could fire it up at 100V with a transformer, then go to 120V and then full power but just replacing the lot appears to be the way to go.

This amp (plus the matching tuner and a Sony reel to teel) has been sitting at my parents house for as long as I can remember, completely untouched. I was finally curious enough to open it up recently and it is really something special in a vintage kind of way, a germanium SS amp with output transformers. I'm not sure how old this is but late 60's would be a good guess. Now it is about the same size as the larger Stax amps so no powerhouse but I'm a bit interested in hearing it. So here is what it looks like on the inside: Here is the back panel, DIN connectors everywhere plus the output transistors: It is a pretty neat layout and the assembly is brilliant for something of this vintage. The PCB's are well made and some thought has gone into the layout. This thing even has a bridge rectifier and the speaker outputs are PCB mount. The whole chassis acts as a ground plane even if it isn't earthed. Now the issue here is whether I should risk powering it up as it is or just start to replace parts right away. The caps could be drained but still operational or they could be utterly toast and take out the rest of the circuitry when they fail. Same goes for the bridge rectifier, I've seen my fair share of diodes from that era in the Stax boxes and they don't age well.

Nothing even remotely true about that. Drivers in the Mk1 and Mk2 are pretty much identical. The SR-Omega drivers can indeed fail but I'm 95% sure that is is due to the chassis and not the drivers.

PRP is a solid choice and they continue to work fine in the BH amps I've built. I'm on a bit of a carbon film binge these days but you really have to match them as most are 5-10%.

On my todo list is designing a new PSu for amps like the GES so doing something from scratch is always an option. Could very well be but isn't it the modder tradition to receive something that works just fine and send back something that doesn't? I could always do DC filaments Rudistor style, 7808 regulator with a resistor to drop the voltage...

Yup, nothing to hide here. We will never post the original Stax T2 schematic but nothing wrong with this. I'm also going to use that PSU for the milled from solid BH amps but with a delay circuit all on one board. That way I don't need to buy new transformers...

Indeed they are heaters. It's the same word in Icelandic for both of these so I do mix it up all the time. The plan is to get rid of the hiss which so bloody annoying. Now I'm never going to reach complete silence but making it mostly inaudible would be a good start.

He probably can't solder it though. He's still weighing his options about which end of the soldering iron he should hold...

I think sand just refers to the silicone substrate of solid state devices. In tubes the glass is just the packaging around the active parts. My namesake (

I think Kevin was referring to the F1 which is very picky indeed.

People who like distortion and SET amps? While some of them are good, some are truly horrible designs. The same crap recycled over and over again...

I've been running it with purely my testing components (Pioneer DV-525 DVD player, Noble 10k pot as a passive preamp and Tannoy R2 speakers) but it is very good indeed. Far better than my Gainclone but the true test will be firing up the new Lundahl transformer boxes. I'm with Marc though, lack of distortion is so often misunderstood.

If there were extra boards then sure, you can do something like that but it would be a lot of work. The modushop boxes are also very poor compared to the custom made unit. Since there aren't any extra boards this is a moot point really...

I just spoke to Stuart and he gave me the green light to do what ever I wanted to. This amp does indeed have the custom transformer with white tape around it. Having no markings at all made me more than a little worried when rewiring for 230V... So the plan now is rewiring the tubes for AC and add a small transformer to power them, install a resistor instead of the filaments, change all the rectifier diodes, replace the rest of the caps and try to separate signal and power the best I can by cutting traces. Perhaps a choke in the PSU would be a good idea as well?

Time to close this case once and for all, here is the finished article sitting on its new rubber feet: The back panel is pretty nasty and somebody really should have told the original builder about the magic of masking tape when doing chassis work. Still, it's not like anybody can see it or the truly horrific bottom panel.

Thanks for that Ari. The ECC82 was the alternative I was looking into but since I didn't have any at hand I dismissed the idea. This one has an access panel in the bottom so when I turn it off now I'll take a look if there are any wires underneath the PCB. It's a bit odd though that there are two wires going to the PCB from the pot, per channel. Both go underneath the board so I don't know where they go exactly. I for one have had no issues with AC heaters in the past so that is an option. Not sure what voltage the transformer outputs as this might be a custom model. Not a single marking anywhere except for numbered terminals. One odd thing, the channels were reversed inside the amp. Might have been part of the original tweaks...