Mapletree owners

mdfoy · « **on:** 22 Apr 2008, 08:03 pm »

I just placed my order an Ultra 2A SE, and it is my first piece of tube equipment

My question is about its level of hum, if any. I currently have an Odyssey Khartago amp, and Tempest pre, both solid state.

rajacat · « **Reply #1 on:** 22 Apr 2008, 08:14 pm »

I have the Mapletree line 3 SE and it emits no hum whatsoever.

-Roy

Dave G · « **Reply #2 on:** 22 Apr 2008, 09:11 pm »

Great preamp! I have the same Line 2A SE that you're getting and I can't hear any hum.

What color are you getting?

Dave

mdfoy · « **Reply #3 on:** 22 Apr 2008, 09:43 pm »

Dave,

I am getting cobalt blue, and polished aluminum.

topround · « **Reply #4 on:** 22 Apr 2008, 10:10 pm »

I have the u4SE and hum...never!

But you will be hummin soon, get some good NOS tubes and hear what that thing can do. I use Sylvania 6sn7GTA's!!

Stock tubes are OK but much more can be had.
Enjoy

mdfoy · « **Reply #5 on:** 22 Apr 2008, 10:50 pm »

Topround,

How did you determine which tubes would be good performers?

Mike

rotarius · « **Reply #6 on:** 22 Apr 2008, 11:10 pm »

Tubes for you to consider: cbs 12sn7gt, rca 12sn7gt, the new tungsol 6sn7 re-issue by new sensor. (I use to own one). From what I hear, all odyssey amp input impedance is a low 10K ohm, correct? If so, you will have a bit of bass roll-off. But this is true for most tube preamps not just this one so don't be upset if your sound is a bit lean.

Airborn · « **Reply #7 on:** 24 Apr 2008, 05:42 am »

I've got the MAD Ultra 4A SE and an Odyssey Khartago and they mate very well together. No hum (except if you turn the balance controls AND volume up past 3 0'clock you can hear some slight hiss) and I have not experienced rolled-off bass. I also was concerned by the 10k Ohm input impedence of the Odyssey amps so I asked Dr. LLoyd about it and his response was

Quote

The output impedance of the Ultra 4A SE is less than 500 Ohms and it can drive a 10K Ohm load.

Dr. Lloyd was correct, of course, and there has been no problem with the Mapletree driving the Khartago.

Finally, I agree with Mike (topround) about tube rolling, you should definitely give it a shot. I tried the Sylvania 6sn7's, but to me, the Tung Sol 6sn7's sound better in my system, but YMMV. That's part of the fun of tubes.

Good luck, you won't regret getting the Mapletree, it plays way above its price and weight class.

Steve

kyrill · « **Reply #8 on:** 24 Apr 2008, 09:42 am »

Quote from: rotarius on 22 Apr 2008, 11:10 pm

Tubes for you to consider: cbs 12sn7gt, rca 12sn7gt, the new tungsol 6sn7 re-issue by new sensor. (I use to own one). From what I hear, all odyssey amp input impedance is a low 10K ohm, correct? If so, you will have a bit of bass roll-off. But this is true for most tube preamps not just this one so don't be upset if your sound is a bit lean.

to compensate for the lowish input impedance
you can buy the Burson audio buffer, specifically designed to solve problems like this. http://www.6moons.com/audioreviews/burson/buffer.html
a newer design comes from bolder company
reviews of buffers ( especially the Burson) are favorable in audiocircle

topround · « **Reply #9 on:** 24 Apr 2008, 09:47 am »

Regarding tubes, I just tried what Andy at Vintage Tube Servives had recommended, I am going to order a set of Tungsol's as well, as your system changes so does the tubes you may like.

I used the U4se with odyssey extreme mono's to very good results.
I tried the Burson buffer as well, it was nice, but it was like a loudness button, it made things louder but obscured some detail, if you don't have an impedance issue I would stay away, just more stuff in the path. They were hot for a while but most people have moved on.

enjoy

mdfoy · « **Reply #10 on:** 24 Apr 2008, 11:00 am »

Thank you all for the responses, especially the tube recommendations. I cannot wait to get my new pre!!!!

Mike

mdfoy · « **Reply #11 on:** 13 Jun 2008, 10:01 pm »

All,

I have received my Mapletree 2A SE, and all is well, except I do have some audible hum from my speakers(8' away). Can this be a function of break in, or the tubes?

Airborn · « **Reply #12 on:** 15 Jun 2008, 06:56 am »

I don't think it's break in or the Mapletree, judging by my experience with the Ultra 4A SE, which had no hum whatsoever out of the box in my system (posted in my signature below). Therefore, I believe you probably have a ground loop; you should check your cable box connection (even if not hooked to your stereo set up), if any, and alternatively, your pre, amp, source interconnects and make sure they are not parallel to each other. Also try switching the outlets your components are hooked up to and see if that makes any difference. Are you using any power conditioners/surge protectors? If not, you may find a PS Audio or similar device solves your problems. Good luck.

ajzepp · « **Reply #13 on:** 15 Jun 2008, 08:37 am »

I'll chime in just as further evidence that the Mapletree preamps are dead quiet. I have no hum at all, so I agree that it must be something other than the preamp.

Love my little 2A SE

mdfoy · « **Reply #14 on:** 15 Jun 2008, 01:08 pm »

Airborn,

We have similar systems. I have a Khartago, and CD-5 as well. I did not have the hum with the Tempest pre-amp. I hooked the CD to the amp, and got no hum. I hooked the pre-amp to the amp, without the CD connected, I get hum. I only get the hum when the pre-amp is hooked to the amp, with or without he CD connected to the pre-amp. I plugged the system into a different plug, and still got hum. Any suggestions on how to eliminate this problem?

mdfoy · « **Reply #15 on:** 15 Jun 2008, 03:05 pm »

All,

Does the orientation of the IEC receptacle on the p pre-mp matter? The receptacle on my unit is upside down.

rpw · « **Reply #16 on:** 16 Jun 2008, 02:55 pm »

What is the difference in sound between the 6ns7 and the 12ns7 tubes. Thanks in advance.

cujobob · « **Reply #17 on:** 17 Jun 2008, 05:20 am »

Quote from: rpw on 16 Jun 2008, 02:55 pm

What is the difference in sound between the 6ns7 and the 12ns7 tubes. Thanks in advance.

From what I was being told by Andy, there should be no difference.

I'll tell you one thing, its hard to find 12sn7 tubes listed online...

Do the MAD preamps need matched tubes?

Airborn · « **Reply #18 on:** 26 Jun 2008, 07:06 am »

Quote from: mdfoy on 15 Jun 2008, 01:08 pm

Airborn,

We have similar systems. I have a Khartago, and CD-5 as well. I did not have the hum with the Tempest pre-amp. I hooked the CD to the amp, and got no hum. I hooked the pre-amp to the amp, without the CD connected, I get hum. I only get the hum when the pre-amp is hooked to the amp, with or without he CD connected to the pre-amp. I plugged the system into a different plug, and still got hum. Any suggestions on how to eliminate this problem?

Mdfoy,
Sorry for the delay in responding; I've been traveling the last few weeks and not keeping up with AC posts.

As for the hum, I suggest maybe a cheater plug on the Mapletree or your Khartago to lift the ground. If that doesn't work, try giving Klaus or Dr. Lloyd a call. Both of them are true gentlemen and would probably answer the phone themselves and be happy to help you out as an existing customer. Good luck.

mdfoy · « **Reply #19 on:** 26 Jun 2008, 12:48 pm »

Airborn,

Thanks for the reply. I got in contact with Dr. Peppard, a most excellent gentleman, and ended up sending the PS2 back for a checkup. As communicated to me, "the insulating mica shim between the regulator chip and the chassis was shorting so the power supply ground was connected to the power supply chassis and hence the power amp chassis and preamp chassis were both connected to the ac line ground. This would account for the fostering of a ground loop." He made the correction, and the unit is in transit back to me.

For the short time that I did get to listen to it, unbroken in, the midrange, voices in particular were very good.