[timmyGCSE]

seems I have a problem... :-/

I noticed the left channel was louder and more bassy than the right. Unplug the left phono, and no sound in the left ear, as to be expected. Unplug the right phono..and umm..sound in both ears, much bassier but much more veiled :-/
I've quadruple checked everything, made sure there is no cross contact between any wires, traced the circuit in both channels to see if I've crosswired something..nope. I must be missing something..there must be a wire touching somewhere but I'll be darned if I can find it...

 

[tomb]

Quote:

Originally Posted by Fitz /img/forum/go_quote.gif You catch on quick. Casework can very easily make up most of the time and money spent on a DIY project.

Yep. Ditto on the casework.

Quote:

Originally Posted by timmyGCSE seems I have a problem... :-/ I noticed the left channel was louder and more bassy than the right. Unplug the left phono, and no sound in the left ear, as to be expected. Unplug the right phono..and umm..sound in both ears, much bassier but much more veiled :-/ I've quadruple checked everything, made sure there is no cross contact between any wires, traced the circuit in both channels to see if I've crosswired something..nope. I must be missing something..there must be a wire touching somewhere but I'll be darned if I can find it...

Well, you're correct to assume that the signal wires are crossed somewhere.

Look carefully over the signal input wires from the RCA jacks to the pot and then look at the output to the headphone jack. Somewhere, you have the ground crossed with the Right channel.

 

[ezzieyguywuf]

I think I'll get a case from Radioshack, drill some holes in it, and then do my build around that. I was originally planning on building the whole thing, and then casing it, but figured it'd be hard to get mosfets through the holes with the wires on them. I dunno though. Oh, and the tube sockets. I think I need to mount them before connecting any wires to them.

<edit> I can't seem to PM Fitz, so instead, I'll just say on here that I have received the mosfets you sent in the mail today. Once again, thank you very much for your contribution.

 

[timmyGCSE]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Well, you're correct to assume that the signal wires are crossed somewhere. Look carefully over the signal input wires from the RCA jacks to the pot and then look at the output to the headphone jack. Somewhere, you have the ground crossed with the Right channel.

yea...must be somewhere but I've checked, checked and checked again..its going to be somewhere real awkward and stuff.

but my PCB is finished for the Dsavitsk 12AU7 version, the BOM comes to £30 from rapid including PCB making materials, so I've got an ebay auction finishing on Saturday and depending how much that goes for I will buy the stuff and make a PCB version. I've got the parts for a mini3 being delivered (today I think!) but I'm a bit scared to make it lol! and I may also order a batamDAC for the mini3 after the SSMH PCB and mini3 are done hmmmm

 

[m11a1]

Does anyone ever had a problem with volume imbalance on the SSMH before?

I feel like the right side is always a bit louder so I decided to open it up and check it out and accidentally switched the mosfets and now the higher volume is on the left side. So, is one of the mosfets the true culprit?

 

[Juaquin]

Well, if you switched the MOSFETs and the channel imbalance followed it, then yeah, probably the MOSFET. I don't recall the MOSFETs ever having caused an imbalance, but it seems to be the case here. Maybe one is slightly damaged?

Also, how do you accidentally switch the MOSFETs? Are they not soldered in?

 

[m11a1]

Quote:

Originally Posted by Juaquin /img/forum/go_quote.gif Well, if you switched the MOSFETs and the channel imbalance followed it, then yeah, probably the MOSFET. I don't recall the MOSFETs ever having caused an imbalance, but it seems to be the case here. Maybe one is slightly damaged? Also, how do you accidentally switch the MOSFETs? Are they not soldered in?

Yea I was testing it out before I soldered it. But now thats its solder it's going to be annoying to remove. Now I have to replace both since I don't know each is the defective one. Also, do you know where I can even buy replacement/high quality mosfets that I can use since Beezar no longer sells them?

 

[nullstring]

while they are extremely expensive, you can get the IRF510's from radio shack..

cheaper after shipping...

EDIT:
also, they look -exactly- the same as the mosfets from mouser, so, they aren't some cheaper version.

 

[tomb]

Give me some time this weekend and I'll put the IRF5150's on the store. I've got about a hundred of them that aren't going anywhere soon.

Meanwhile, shoot me a PM with your address. m11a1, and I'll send you a pair gratis.

 

[Entropy1]

Hey, so I just came into inheritance of maybe 30 tubes and apparently there's a another chest of around 400 tubes somewhere. My grandfather use to repair TV's and worked at a radio station so there's quite a bit of stuff, including a massive 40lb tube used on one of the radio towers. I'll try to get some pictures taken of them as they are quite impressive. There is also a tube tester and some other supplies that will keep me busy for quite some time. Anyways, I suppose the only relevance to this thread is possibly finding other compatible tubes in the massive stash. Losing my 19JS's is kind of a big concern to me because my amp goes on and off around 5 times a day. I'll post pictures and post if i find anything interesting.

 

[FallenAngel]

Catalog them all, make a big list and you'll be sure to find something of interest (while being able to find them later).

 

[Juaquin]

Awesome, can't wait to see some pictures (especially of that monster 40lb one)

 

[hss3]

so after finishing the build, plugged it in...

i could hear something from the left side faintly even though it wasnt switched on...

but when i switched it on, sparks and popping came from the unit underneath the heatsink/tubes. My mosfets sit close to the tubes... and i think i may have accidently grounded the heatsink?

now i dont hear sound at all from the unit, even when its off.

so right now.. despair!

 

[nullstring]

should it matter if you ground the heatsink?

everything should be isolated from the heatsink..

 

[n_maher]

Quote:

Originally Posted by nullstring /img/forum/go_quote.gif should it matter if you ground the heatsink? everything should be isolated from the heatsink..

Everything should be but that doesn't mean everything is.

That's where I'd start with the trouble shooting, check continuity between the metal tab of the FET and ground.