[mordy]

Well folks, hit a dead end. After some 3-4 hours the transformer suddenly cut out. I assume that the overload circuit was activated.
 
I am not giving up yet; I'm going to get rid of that hum!

 

[Acapella11]

Gain Setting?

Yes, indeed. Thanks for reminding. Set my gain 2 years ago to 10 and forgot about it.
 

  Interesting, more neutral  you say, is that with the Senns and by the way nice aquisition .MK4 has different sound signature ,does that mean better sound quality

 
Thanks, well at the moment I have like no time to listen to it. The MKIVSE may also need to burn in properly. Unfortunately, I don't have the MKIII any more around, so my comparisons are not very accurate. However, I did notice, the MKIVSE sounding more neutral, less "tubey" (less euphonic), a bit brighter, less coulored maybe. When I listened to the 6SN7GT, which sounded quite mellow but detailed before, they now sound like a better match with the HD800s, just more lively. On the other hand, the Tung Sol 5687WA sounded very nice on the MKIII, as in very vibrant, but on the MKIVSE, I was rather feeling that I would get a listening fatigue. The slightly darker Siemens 5687WB (supposedly relabelled Raytheon) were a better and good match now. This is all still prelimniary. The only other detail I think I can point is out is that the MKIVSE stage was wider and deeper.

 

[Oskari]

  Have two questions: The unit is rated 0.69A input and 0.625A output. It is getting somewhat warm to the touch, but not hot. Is it safe to use with a PC with a 420W PS?

 
We don't know how much the computer actually draws but I don't think it's safe. 120 V * 0.625 A = 75 VA which is quite a bit less than 420.
 

  Well folks, hit a dead end. After some 3-4 hours the transformer suddenly cut out. I assume that the overload circuit was activated.

 
I guess so. Did it reset?

 

[i luvmusic 2]

It could be from the adapters?
 
My C3g's are Dead quiet all the way to the max of the volume pot but occasionally i knocked the adapter out of place and it will hum.

 

 

[mordy]

Hi Oskari,
 
Thankfully, the isolation transformer just shut off from thermal overload, and it works fine. Decided to try the transformer with the LD MKIII plugged into it. The LD is rated at 30W so this would be a much better match.
 
Another dead end - the sound was clearer, but there was a hollow and thin quality to the mid and low bass that wasn't satisfying.
 
Another anomaly: when testing for hum with my laptop connected, it was quiet at low volume, then hum appeared between 11 to 15 (clockwise) and disappeared again at high volume. The same hum appeared at the same levels without the isolation transformer plugged in. In any case, this hum is much lower than from my PC and only noticeable when the music isn't playing.
 
I realize that the transformers used in the amps and in the system have an effect on the clarity of the sound. Don't know how important this aspect is in the total presentation.

 

[TrollDragon]

A standard Cooler Master RS-460-PSAR-J3 460W power supply will haul down 8.5A @ 115Vac under full load. Since you are only using the 12V rails the AC current would have to be measured to get an accurate reading but I know it will be well above the 0.6A ration of that isolation transformer.

 

[mordy]

Hi TD,
 
Here is a picture of the specs of my PS that I use to power the heaters on two 2.5A 6080 tubes for my LD MKIII:
 

 
I am correct in that this is 115V/10A PS that supplies 15A at 12V? Using a 15A voltage regulator, how many amps are available at 6.3V?

 

[Acapella11]

I'd guess 7.875 A.

 

[TrollDragon]

  Hi TD,
 
Here is a picture of the specs of my PS that I use to power the heaters on two 2.5A 6080 tubes for my LD MKIII:
 
I am correct in that this is 115V/10A PS that supplies 15A at 12V? Using a 15A voltage regulator, how many amps are available at 6.3V?

Yes that power supply under full load would draw 10A from your AC Mains.
 
There should be 15A available for 6.3V, the regulator will only give you on the output what is available on the input. If there is 4A available on the input there there will only be 4A available on the output.

 

[Artsi]

I have finished my newest DIY amp. Sadly no headphone connect (yet?). I bought Russian 6F6S tubes because of this effect.

With 6F6S's around 2x13w triode connected and pentode connected 2x18w. So these small powertubes are giving their max. Of course this amp is designed for KT88's, and with them i get much more power. And here is the amp with 5U4G, 4 6F6's, 2 6SN7 and 12AV7.

I had so many different 12A*7 tubes from little dot times, so decided to use these as driver tube and they tolerate more voltage than 6DJ8. Transformers and choke are from old Hammond organ amplifiers. 4 inputs and again selector switch from old organ, since it was way better quality, than new small plastic knob. 6SN7's are connected as long-tailed-pair phase inverters. There is small switch for triode-pentode change behind powertubes. It seems to be mostly as for experimental and not for real high-end sound with pentode connection.
 
Amp size is 50x37cm and weights 20kg.

 

[siles1991]

ah crap ahahaha i think 1 of my power tubes are dying, i swapped them left to right and i can confirm that 1 of them has lost a bit of volume and its dimmer then the other so I guess i'll be getting a power upgrade before my drive hahaa

 

[mordy]

What tube is it?

 

[Acapella11]

Just a brief MKIVSE / 5687 update: Either it is gear or brain burn in but I am not perceiving the MKIVSE as hard anymore, such that the Tung Sol 5687WA black plates are now a very good match. In fact from all power tubes that I have heard, they come closest to the Reflektor DN30P-DR (1983). I wouldn't yet say that they are superior because the resolution of the DRs is really outstanding but they are close and match in signature.
But, I must say that I find the 5687 bass more 'visceral', it seems to extend deeper.

 

[Acapella11]

  Well folks, hit a dead end. After some 3-4 hours the transformer suddenly cut out. I assume that the overload circuit was activated.
 
I am not giving up yet; I'm going to get rid of that hum!

 
Have you considered to use a form of uncoupling of your external DAC and laptop, e.g. galvanic uncoupling?

 

[i luvmusic 2]

  I have finished my newest DIY amp. Sadly no headphone connect (yet?). I bought Russian 6F6S tubes because of this effect.

With 6F6S's around 2x13w triode connected and pentode connected 2x18w. So these small powertubes are giving their max. Of course this amp is designed for KT88's, and with them i get much more power. And here is the amp with 5U4G, 4 6F6's, 2 6SN7 and 12AV7.

I had so many different 12A*7 tubes from little dot times, so decided to use these as driver tube and they tolerate more voltage than 6DJ8. Transformers and choke are from old Hammond organ amplifiers. 4 inputs and again selector switch from old organ, since it was way better quality, than new small plastic knob. 6SN7's are connected as long-tailed-pair phase inverters. There is small switch for triode-pentode change behind powertubes. It seems to be mostly as for experimental and not for real high-end sound with pentode connection.
 
Amp size is 50x37cm and weights 20kg.

Very nice!How i wish i can read schematics so i can build my own amp.I'am a sucker for DIY Amps