For those who made the CD7 upgrade. Mine was already upgraded with a board on top of the two 6H30s slots. I had to change 4 resistors on the board, add one, put the board and installed two new 6h30.
I heard the 5881 upgrade the tube is puted horizontally. Does it have a new board on top of the 6h30 slots to hold the 5881? Can someone send me some pics? I'm not in the US so i have to see if it can be done on field. |
Well guys I see most of you dont know the full history of these. ARC is trying to correct the PS problem in the CD7 for the last two years. What you are seeing is not an upgrade, but a fix.
Mine original CD7 was sttuning, live music, belive me. After sometime when I tested an SE pre-amp I noticed a hum. ARC send a kit (still in my player), a revision: 4 resistors were replaced on the side of the 6H30s and one added, a board was puted over the two sockets and two new 6H30s installed on this board. The sound of the CD7 moded by ARC this way never got close to the original, no life.
I hope this new kit (5881 tube) is all you are talking about. If not most of you only fixed a bad project problem. Note that the hum can only be heard in SE output. |
What I´m saying is not about last update, I did not installed the 5881 update yet.
I´m saying that mine CD7 have the last update before this one and the player sound better when it was new (before having the 6H30 problem).
I can´t say nothing about this upgrade I did not hear any CD7 with it yet. I´m hoping this will bring my original CD7 sound back. Also I think many guys here have the problem and dón´t know about it, so when the unit gets fixed they think it´s an sound upgrade, but maybe it´s only fixing the bad sound that goes out when one of the 6H30 drift from the other one. |
I suggest everybody to do the mod. All cd7 will show the problem if one of the two 6h30 drift from each other. The use of only one tube avoid that. On the sonic side can´t say nothing, I did not bring mine for the last upgrade yet. |
I found the minet CD7 sometimes lifeless and sound diffrent each time I turn it on, only after 3-4 hour of use the sound goes better. The sound is very far far away from the one when he came out from from box prior to the upgrade. Let's see if I will get my sound back after this new upgrade. |
CD8 is a CD7 with different chip and a fixed Power Supply. As ARC does not use the opition of upsampling this chipsets offer all you hear is a Brand difference when convertion occurs. I don't belive in great superiory. |
I think 6550 is more powerful than a 5881 (that is a smaller version of the 6L6), This tubes are being used in the PS so they are not in the path of sound, but as a part in the PS. As long as there is enough power for the audio circuits I don't think they will make any change in the sound result. But the malfunction of then (like what was happening with the two 6H30) will affect sound.
Many people here saying CD8 is better than CD7, but how manny of them had a PS CD7 fault and don't know about it. What people is saying is that a CD7 with the last update and CD8 the difference in sound is not big. |
Mbudinich, my player has the same kit of yours. Did notice something too: I have days that the player sound great in other lifeless. Does the same happened with you? |
Well mine CD7 finally is done too. Conclusion: I was listen to crap for the last 2 years. But different from most you guys I knew. My original CD7 was magical before the problem with the PS, after fixed (previuos upgrade) became just lifeless. Now it's back. I will listen for a week or two to check if it will match the original sound I had once.
Dynamics, extensions, details all raised but mostly now it's much more toneful correct and clean. It's sad ARC took so long to correct it. |
Dave, you make no sence: Ref2-MkII is 6H30+jfet based, by far the most SS like tube gear ARC ever made, also VT100MKIII and VT200MKII are 6H30+Jfet based.
I had the REF2MKII and it took 500 to burn and a lot of setup to play well, after sometime played really well. All reference gear from ARC are top sound they are only different versions. Funny the CD8 take 600h to burn since it does not have Jfets in the path of sound. The 6H30+Jfets worked very well in ARC Power Amps not so easy in the preamps.
Dave maybe you should check the cables or room acoustics, I had some problem with Synergistic Cable and was thinking it was my gear in the end was a damaged cable.
A very tube sound is good to cover bad links in the chain of sound, to use less tube gear sound like (Hi-Resolution) you have to have everything correct. ARC made a choice about 10years ago, they made the gear sound less tubed in order to gain in other aspects.
Here the REF3 and the CD7 upgrade, folowed by a 300.2 bi-amplification just play LIVE! |
I know you think that the CD7 had an upgrade in power supply. In fact it was a revision due to problem with the two regulator tubes.
The problem can be noticed when you use the unit via SE outputs if you increase the volume you can here a huge hum.
Revision 5 kit killed the hum, but also killed the sound quality. Now the revision 7 (5881 tube) brought the sound back but the also, the hum, after some use.
I had my unit upgraded. And now the hum is back. I will call ARC I think they will have to change all units again, problably using a 6550 like in CD8.
So I ask you to test your units and call ARC if you have a hum in SE output. |
Gave up on CD7, after 2 units and a lot of power supply problems upgrades. My last unit showed the SE Hum again even with the 5881 tube.
I went to a CD8, 3 hours only, in it for now. I will post about it later. |
