[guido]

I have a MAD Ear+ HD High Definition Headphone Amplifier which I built up 3 years ago [s\n 0204149]
 
I have only recently started using it with my HD650s [everything was in storage for 2 years] but It seems to have very little soundstage and bass definition...I am comparing it to a Xin Supermacro 4
 
Is it possible the valves are out of spec or not working to their full potential?
 
I see the 2 RCA 12B4A valves are slightly different...one has black labelling and one is red [they also look different inside]
 
The V1 is a Sovtek 5751 ...I have tried a 12AX7 but the problem persists.
 
What should I try?

 

[guido]

I have oredered the following tubes to play with...perhaps things will improve

2x 12B4A NOS General Electric   

1 x 5751 NOS Telub (Military spec)
1 x 5751 NOS Gold Aero
1x  12AX7 Electro Harmonix

What are recommendations with HD650s?

 

[guido]

Am a little embarassed...one of the output transformers had the connections inverted...I was listening to the amp out of phase...all is well again

 

[rclanger]

Well, at least you found the problem instead of giving up on the thing  Enjoy!

 

[lbj]

Yeah, you fixed it, and now you have some extra tubes to roll.  Have fun!

 

[detoxguy]

My Ear+ HD is finally in progress!! 
 
I don't really have anything else to say...I've avoided the urge to start buying tubes to play with as I'm going to spend some time with the stock tubes so that I learn the amp's baseline and will actually be able to judge the improvements in sound as I tweak it with tubes in the future.

 

[jtinto]

Heh detoxguy,
It's worth the wait. You're gonna like it.
I've had my Ear+ HD for only two weeks, but it makes my RS1i sing like nothing I'd heard before.
Cheers

 

[PanamaRed]

Me too! You must be right in front of me on the queue. I can't wait to compare it to the RA-1
 
Quote:

My Ear+ HD is finally in progress!! 
 
I don't really have anything else to say...I've avoided the urge to start buying tubes to play with as I'm going to spend some time with the stock tubes so that I learn the amp's baseline and will actually be able to judge the improvements in sound as I tweak it with tubes in the future.

 

 

[detoxguy]

Oh great. Canada Post has locked out all workers and all mail/parcel service in Canada is now stopped. Dr. Peppard ships using Canada Post, I'm hoping he'll send mine with UPS or something instead but I also have a headphone stand from Woo Audio already in transit as well as an LOD cable from headphonebar.ca....neither of those are going anywhere...

 

[jtinto]

You're right detox. Canada Post is locked out in most rural areas. I think that would apply to Lloyd's location. Patience. He'll likely use a different carrier.

 

[jtinto]

Why not call Lloyd and ask him to ship with a different carrier and offer to pay the difference?
Like buying a little peace-of-mind insurance ...

 

[PanamaRed]

In anticipation of my new MAD Ear + HD I already have a small collection of tubes forming:
 
So far, 2 pairs of 12b4a GE Red labels.
 
Mullard 12ax7 Longplate Halo Getter
Telefunken Smooth Plate
Telefunken Ribbed Plate
Sylvania Triple Mica Gold Brand
So I have a great deal of testing to do....

 
I'm thinking of perhaps getting some additional 12b4a's for more possible combinations.
 

 

[lbj]

Quote:

I'm thinking of perhaps getting some additional 12b4a's for more possible combinations.
 

By all accounts, different 12B4A's have minimal effect on sound.  Just something to think about before you throw too much money at multiple pairs.
 

 

[PanamaRed]

Quote:

By all accounts, different 12B4A's have minimal effect on sound.  Just something to think about before you throw too much money at multiple pairs.
 

 
Ahh thanks for the tip. Yeah, in that case I'll invest more in 12ax7's instead.

 

[tme110]

Quote:

In anticipation of my new MAD Ear + HD I already have a small collection of tubes forming:
 
So far, 2 pairs of 12b4a GE Red labels.
 

 

But where did you find those red lablels already?  Though very low on my list of priorities I did try to find the GE red's without any luck.