[the_equalizer]

Quote:

Originally Posted by SteveC89 /img/forum/go_quote.gif Ok, so I am about to start my build, but I just realized I ordered 220uF capacitors instead of the 150uF specified. I noticed in the original BOM notes it says any value > 150uF. I was just wondering how the higher value caps might effect the sound.

This is my understanding of what increased cap values does in the MSSH.

In the C3 and C5 positions higher value caps will extend the lower end frequency response with lower impedance 'phones. As mentioned in another post some have put 1000uF caps here. The only possible downside to this is that this will also increase the strenght of the turn on/off thump.

Higher values for C1, C6 will improve the power supply filtering/decoupling thus producing a tighter, less sagging sound in loud transients.

cheers!

 

[Llama16]

Good news and bad news!

Happy NEW YEAR GUYS!!!

If you look back at my obnoxious post, I was complaining about a right channel that has an increased volume. I set the left channel to an additional 17 percent volume!!
When i switched the tubes, the left channel was alot louder (also noticable do to that extra 15 percent). So it's the tubes!!!! The bad news is: it's the tubes... sigh, bummer.
The good news is, I was so clever enough to order a second pare of tubes also from beezar before the kit (the tubes that are bad are from the kit). So hopefully they're better, else I'm screwed.

Allthough I'm bummered that I know can't really make a second p2p standalone SSMH without constantly using the tubes of the kit. To bad the tubes are bad :S. A well i'm already glad that it's nothing else.

Fingers crossed that the other tubes are better

I'll keep you posted.
ATM I'm listening to the bad tubes still, allthough with the left channel increased in volume, it's amazing!! I'm stunned with the sound quality. It's my first experience of tubes... well my first experienced with a desktop amp even!!!

I'll keep you guys updated.

EDIT: SUCCES!! the second set of tubes (and actually alot prettier

) are alot more balanced. I'll have to do with these two.
For the p2p build, can I still use the 'bad tubes' and just install a resistor (as the balance unbalace is conistent

 

[SteveC89]

Ok, just finished my build and I'm having issues. So, when I turn on the amp with the source running, I can hear it slowly come up to volume, presumably as the tubes warm up. My problem is that full volume is only about unity gain with the original signal. Also, the tubes don't get hot at all, and the heat sink only gets maybe just above room temp. I know you guys like to have pictures of theses things, and I can probably post some soon, but in the meantime, any ideas?

 

[tomb]

Quote:

Originally Posted by SteveC89 /img/forum/go_quote.gif Ok, just finished my build and I'm having issues. So, when I turn on the amp with the source running, I can hear it slowly come up to volume, presumably as the tubes warm up. My problem is that full volume is only about unity gain with the original signal. Also, the tubes don't get hot at all, and the heat sink only gets maybe just above room temp. I know you guys like to have pictures of theses things, and I can probably post some soon, but in the meantime, any ideas?

When you say the tubes don't get hot, do they light up?

The MOSFETs are supposed to be tied to the tube heaters. So if things don't get warm on both ends (tubes and heat sinks), something's wrong with those connections.

Yeah, pics are needed ... although if it's P2P, you're the best one to find the problem first. Also, measure pin 3 on each MOSFET to Ground and see what you get.

 

[Juaquin]

Also, don't have headphones plugged in when you power up (if you like your headphones). It can damage them because there is a large DC offset until the capacitors charge and everything warms up.

 

[SteveC89]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif When you say the tubes don't get hot, do they light up?

Yes

Quote:

Originally Posted by tomb /img/forum/go_quote.gif The MOSFETs are supposed to be tied to the tube heaters. So if things don't get warm on both ends (tubes and heat sinks), something's wrong with those connections.

Everything seems ok here

Quote:

Originally Posted by tomb /img/forum/go_quote.gif Yeah, pics are needed ... although if it's P2P, you're the best one to find the problem first. Also, measure pin 3 on each MOSFET to Ground and see what you get.

One thing I forgot to mention, it is a 12sr7 build.
Ya, its P2P, and I figured to get anywhere I would need some pictures.

So I measured pin 3 to ground and only got 5.6v. I believe Logistic said this should be 12v. So, curious, I measured the r13/c6 node that is supposed to have 48v to ground and it was only at 27.7V. I measured the power supply to find that it was only supplying, suprise, 27.7v.

I am using the PSA18U prescribed in the original BOM. So, do you all think if I order another power supply that will fix my problem? For some reason, the seller I bought the PS from sent me a second PS. This one is 48v @ .2A. I know this is almost half the current of the other one, but would it be ok if I tested it out with this one, or would that fry something?

Quote:

Originally Posted by Juaquin /img/forum/go_quote.gif Also, don't have headphones plugged in when you power up (if you like your headphones). It can damage them because there is a large DC offset until the capacitors charge and everything warms up.

I did not know that, thanks for the tip. I was sort of working off the idea from guitar tube amps that you could damage the tubes if there is no speaker hooked up. Do you know how this relates here?

 

[Juaquin]

I don't know much about guitar amps so I can't comment on that, but the SSMH website specifically warns against it:

Quote:

There are some precautions you should take while enjoying your SSMH: 1. Wait until the tubes are glowing (the orange cathode, not the tube LED's!) before connecting your headphones. 2. Disconnect your headphones prior to turning your SSMH off. The SSMH output is referenced at 19VDC. The output coupling capacitors prevent this DC from reaching the headphones, but there is a delay when turning on the amp before the caps fully charge. For similar reasons, you may experience a turn-off thump as well. So, #1 and #2 above are prudent precautions.

 

[the_equalizer]

Quote:

Originally Posted by SteveC89 /img/forum/go_quote.gif Yes Everything seems ok here One thing I forgot to mention, it is a 12sr7 build. Ya, its P2P, and I figured to get anywhere I would need some pictures. So I measured pin 3 to ground and only got 5.6v. I believe Logistic said this should be 12v. So, curious, I measured the r13/c6 node that is supposed to have 48v to ground and it was only at 27.7V. I measured the power supply to find that it was only supplying, suprise, 27.7v. I am using the PSA18U prescribed in the original BOM. So, do you all think if I order another power supply that will fix my problem? For some reason, the seller I bought the PS from sent me a second PS. This one is 48v @ .2A. I know this is almost half the current of the other one, but would it be ok if I tested it out with this one, or would that fry something? I did not know that, thanks for the tip. I was sort of working off the idea from guitar tube amps that you could damage the tubes if there is no speaker hooked up. Do you know how this relates here?

A 0.2 A power supply will not do it. EACH tube filament needs 0.15 Amperes. The current demand will overflow the PSU and it'll shut down. You need at the very least a .35 A PSU.

It's amplifiers with transformer coupled output sections that get damaged if there's no load connected to their outputs (the transformer secondary winding). This includes not only guitar amps but also some headphone and speaker hi-fi amps.

The SSHM does not use a transformer to couple its output MOSFETs to the 'phones and thus it's immune to this kind of damage, as are most (though not all) amplifiers with solid state output sections.

cheers!

 

[SteveC89]

Quote:

Originally Posted by the_equalizer /img/forum/go_quote.gif A 0.2 A power supply will not do it. EACH tube filament needs 0.15 Amperes. The current demand will overflow the PSU and it'll shut down. You need at the very least a .35 A PSU. It's amplifiers with transformer coupled output sections that get damaged if there's no load connected to their outputs (the transformer secondary winding). This includes not only guitar amps but also some headphone and speaker hi-fi amps. The SSHM does not use a transformer to couple its output MOSFETs to the 'phones and thus it's immune to this kind of damage, as are most (though not all) amplifiers with solid state output sections. cheers!

Thanks for the info. That makes sense about the output transformer.

BTW to all I have a new power supply on its way and I'm crossing my fingers that that will fix it.

 

[th3bl0b]

Hi,

This is my first post here. I've been reading along and finding this thread really useful! I've been trying to build the SS in a P2P version. For the MOSFETS and heatsinks, am I supposed to connect these with a special adhesive like arctic silver? the MOSFETS came with some special sticker. Should that do the trick?

Also, are the kits still being sold or have you stopped making those? (I was thinking of using a kit to make another one after I finished making it P2P : p)

Thanks,
Ben

 

[th3bl0b]

Hi,

This is my first post here. I've been reading along and finding this thread really useful! I've been trying to build the SS in a P2P version. For the MOSFETS and heatsinks, am I supposed to connect these with a special adhesive like arctic silver? the MOSFETS came with some special sticker. Should that do the trick?

Also, are the kits still being sold or have you stopped making those? (I was thinking of using a kit to make another one after I finished making it P2P : p)

Thanks,
Ben

 

[Llama16]

Hello

Yes, Arctic silver should do the job extremely well. I think there are some other thermal compounds that are more suitable for the job in terms of use and finish, but I used some könig compound myself and I feel the case warm up just as much as the heatsinks which means that it has an excellent thermal conductivity.

I'm not sure about the sticker tomb'll know for sure. I don't know if it's already applied to the mosfet and sticks or it came sperately. It's probably indeed thermal pads, but you should be sure on that. Maybe it's mentioned on some data sheet of the product.

About the kits, If I recall correctly, I've read that tomb mentioned a final run for the kits. When, how many and if it's still on, you should ask him

.

Welcome to head-fi and the world of DIY, enjoy!

BTW: To the rest: I owe you guys some pics about my build

, it's finally completely cased up and all the little buggers are out of it. I know you've seen these same pics over and over again (it's the same kit), but don't you try and mess with my chance of glory

hehe. the 'post your builds...' thread will hear from me as well

.

 

[tomb]

Right now, it looks like there may be 35 kits and perhaps 2-3 partial kits available late-January to early-February time frame. They should be the same price, but I can't guarantee. I'll have to compare the pricing, but everything is ordered or already delivered - I just haven't compared that to the existing BOM. As most of you know, some of the prices on electronic parts are changing as we speak.

There's another thing that bears repeating - tubes will go by first come, first serve basis. What I mean by that is that there aren't enough tubes to provide matching in all cases. You need about 3X tubes to provide 1X matched pairs. There aren't that many left anymore. So, we'll practice the following order until the stock gets depleted, based on first-come, first-serve:

1. regular matches first - brand, construction, and testing;
2. tube construction and test matching;
3. just construction matching;
4. two tubes - pot luck.

 

[th3bl0b]

Thanks for getting back to me so quickly!

The sticker thing I got was included in this heat sink mounting kit in the BOM. So, will that work? otherwise, i'll have to go out and buy some more stuff...

I've finally understood how much of a pain it is to go ahead and do the casework yourself especially when you don't have a machine shop.

 

[tomb]

Quote:

Originally Posted by th3bl0b /img/forum/go_quote.gif Thanks for getting back to me so quickly! The sticker thing I got was included in this heat sink mounting kit in the BOM. So, will that work? otherwise, i'll have to go out and buy some more stuff... I've finally understood how much of a pain it is to go ahead and do the casework yourself especially when you don't have a machine shop.

Yes, the "sticker thing" will work. Just don't torque down on the MOSFET so much that the metal tab cuts into the "sticker thing."