[DanT]

Quote:

Originally Posted by apologies /img/forum/go_quote.gif I have now changed the cable, hum is now completely gone, I have noticed some hum for about an hour after turning on, then it becomes silent, I'm not sure if this is a normal tube thing, as this is my first experience of such amps. Also my burn in time is less than 10 hours so far.

Have you tried without cable. Sometime cable can pick up interference and hum.

 

[penguindude]

Quote:

Originally Posted by DanT /img/forum/go_quote.gif Have you tried without cable. Sometime cable can pick up interference and hum.

Not if you're using a good shielded one. But it seems like some other tube amp users have reported this problem.

 

[rain_uk]

Just for the record, I didnt use the flimsy power cord that came with the LD2++, instead substituted with thicker more shielded one that came with an old arcam product I once had..

 

[penguindude]

Quote:

Originally Posted by rain_uk /img/forum/go_quote.gif Just for the record, I didnt use the flimsy power cord that came with the LD2++, instead substituted with thicker more shielded one that came with an old arcam product I once had..

We're in fact talking about the interconnect, at least to my knowledge.

But rain_uk, have you experienced what Apologies was talking about?

 

[penguindude]

Quote:

Originally Posted by jirams /img/forum/go_quote.gif This can be a function of Cathode/Heater isolation in Valves (Tubes). I have built several Class A valve amps for use with loudspeakers. I must say that I much prefer the stability of solid state electronics - you can never really relax with valve gear. I also believe that there is a lot of 'snake oil' associated with valve amp performance. IMO a well designed solid state amp with VOSFET output has many of the valve characteristics with much less hassle.

Hey jirams, can you please explain/elaborate on what that means?

thanks.

 

[apologies]

Quote:

Originally Posted by penguindude /img/forum/go_quote.gif Is anyone else experiencing this problem? Apologies, is the hum apparent in both channels or just the left channel?

I didnt notice any difference it seemed to be equal on both channels. I cant recheck now as it is has been on all day, and as i said earlier, it appeared to become silent after an hour, and there is no hum now.

p.s There seem to be some confusion as to the cable i replaced; it was the mains cable. I was converting the voltage to UK 240v, but i found out i dont need to do this. That reduced most of the hum, some remained for about an hour (I left it on and checked after an hour).

I will check in the morning, when it is cold, to see if the hum remains, and if so, for how long and in what channel etc.

 

[apologies]

Has anyone else using Grados on this amp found the treble harsh and fatiguing? I know its only had about 15 hours burn in time, but i find it hard to believe it will change so much. Has anyone got this amp that can recommend headphones that work well with it?

 

[penguindude]

Ah, i see.

 

[rain_uk]

Quote:

Originally Posted by penguindude /img/forum/go_quote.gif But rain_uk, have you experienced what Apologies was talking about?

No, iv'e had no hum's..or anything.

'Apologies' the HD650's are nice with the treble for me (havn't got any grados, 'GoStones' has though)..what is the source you are using? Did your LD2++ come with the Mullards or the Ediswan tubes?

 

[apologies]

Quote:

Originally Posted by rain_uk /img/forum/go_quote.gif No, iv'e had no hum's..or anything. 'Apologies' the HD650's are nice with the treble for me (havn't got any grados)..what is the source you are using? Did your LD2++ come with the Mullards or the Ediswan tubes?

Im using the ns-dv99, which is a pioneer SACD player, I bought a couple of years back when it got 5* in what hifi?. Im using a silver core audio interconnect (made by a small british company called Subzero, who recently died, so i managed to get some nice £120 rrp cable for £5.99 on ebay) to the ld2++. The treble isnt harsh when plugged into the ns-dv99 headphone out (with the grado). Im also using a project debut 3 with the project phono stage, which, admittedly, is less harsh with the ld2++ than the ns-dv99, but is still too harsh for me, and i find it a pain listening to a whole album.

Mine came with the ediswans (and a amber LED). Be interesting to hear what people say about the mullard - LD2++ - grado combo...

I was thinking about either the HD650s or the k701s, you havent got the k701s as well, for comparison, have you rain uk? yes i need a new cd source too

 

[penguindude]

Quote:

Originally Posted by rain_uk /img/forum/go_quote.gif No, iv'e had no hum's..or anything. 'Apologies' the HD650's are nice with the treble for me (havn't got any grados, 'GoStones' has though)..what is the source you are using? Did your LD2++ come with the Mullards or the Ediswan tubes?

Yes, LD products are tested and built upon HD650 and K501. I have a HD595 and it sounds very good with the LD2+. I'm not sure about the LD2++ so i'd have to wait until i can find it how it will go with the LD2++.

 

[jirams]

Originally Posted by jirams
This can be a function of Cathode/Heater isolation in Valves (Tubes). I have built several Class A valve amps for use with loudspeakers. I must say that I much prefer the stability of solid state electronics - you can never really relax with valve gear. I also believe that there is a lot of 'snake oil' associated with valve amp performance. IMO a well designed solid state amp with VOSFET output has many of the valve characteristics with much less hassle.
Quote:

Originally Posted by penguindude /img/forum/go_quote.gif Hey jirams, can you please explain/elaborate on what that means? thanks.

Which part ?

 

[rain_uk]

Quote:

Originally Posted by apologies /img/forum/go_quote.gif I was thinking about either the HD650s or the k701s, you havent got the k701s as well, for comparison, have you rain uk?

No I dont own the k701, all I currently have are the HD650, DT831 and KSC75. The DT831 are rather bright on the LD2++ as they were on the LD2, although surprisingly the KSC75 do sound very good with it to me. Im not familiar with your source 'ns-dv99 DVD/SACD', I would guess (if its like ones i've used) that the standard stereo rca output stage may easily be bettered by a good cd player (obviously the SACD is not an option for the LD2++)

 

[penguindude]

Quote:

Originally Posted by jirams /img/forum/go_quote.gif Which part ?

This part : "This can be a function of Cathode/Heater isolation in Valves (Tubes)."

 

[apologies]

Quote:

Originally Posted by rain_uk /img/forum/go_quote.gif No I dont own the k701, all I currently have are the HD650, DT831 and KSC75. The DT831 are rather bright on the LD2++ as they were on the LD2, although surprisingly the KSC75 do sound very good with it to me. Im not familiar with your source 'ns-dv99 DVD/SACD', I would guess (if its like ones i've used) that the standard sterio rca output stage may easily be bettered by a good cd player (obviously the SACD is not an option for the LD2++)

I just switched on the LD2++ on today there i no hum on start up. Which is nice, although im starting to question my sanity, as i swear there was hum yesterday. I might be wrong but, I thought with SACD it downmixed to stereo but kept the higher than cd resolution, unless thats not what you meant by 'not an option'.