Mod your Beresford 7520

[Covenant]

I am surprised about the bass complaint made with the LM4562. It sounds far deeper and with more musical content to me and a few who tried it against the DAC1 (NE5532) and the DacMagic (NE5534).

The K701 has a dead low end on most headphone amps. So when you use it with the TC-7520 the enhanced bass can appear to 'sink' the midrange.
For K701 users and anyone who enjoys a wider bass range via headphones you can try the THS4032, or alternatively swap over the 47nF caps ( those big yellow ones on the top PCB either side of the headphone amp opamp, for a 100nF. I have instead soldered a 33nF cap in parallel with the 47nF from underneath the PCB so that I didn't need to desolder the 47nF. But that's for use with the K701. The added bass might sound a bit too much on the HD650 and other headphones that already have a fair amount of bass.

I added a modification page on my website at www.beresford.me that shows a number of the pictures taken by various AoS modders. I put some text with them as well. I hope to add and improve on that page over time. I hope it is helpful for a lot of people who don't know where to look for the various info.
Any useful suggestions on how to improve on that?

Stan

Agreed that its deeper but, to me, it sounded 'lazy'-like the bass notes were hanging around a bit longer than they should. Very probably this is caused by my system/room and wont be a problem for most people.

[StanleyB]

Agreed that its deeper but, to me, it sounded 'lazy'-like the bass notes were hanging around a bit longer than they should. Very probably this is caused by my system/room and wont be a problem for most people.

. It's the decay of the signal that you are hearing. People pay a fortune just to get their equipment to produce that level of accuracy.

Stan

[Covenant]

This is an interesting point you raise Stan and one I have thought about a bit.
Exactly how long should the decay last? I know you are going to say however much is there but sometimes it leads to the following notes being obscured-drowning in bass if you like. After a while it can become tiring so personally I prefer a somewhat sharper sound.
This becomes worse when you are listening to floorstanders close up in a small room.
Dont ask me to change my speakers because I love them!

[Gazjam]

Hah, that really tickled me for some reason.

Anyway, this MLC mod has me intrigued now. I might pick up a pair of 4562. How do those of you who have heard both compare the 4032 to the MLC modded 4562? Gaz?


EDIT: BTW, it would probably be helpful if we all specified what headphones we're using as that can really affect how we perceive different opamps etc. I'm on Grado SR225i.

Hey Lingling,

See my post #931 for this.

Gaz.

[Gazjam]

Agreed that its deeper but, to me, it sounded 'lazy'-like the bass notes were hanging around a bit longer than they should. Very probably this is caused by my system/room and wont be a problem for most people.

Jerry,
I experienced this too, but I found it goes away with the MCL5/6 mod.
More clarity across the board, just a WEE bit less deep bass.

[leo]

I am surprised about the bass complaint made with the LM4562. It sounds far deeper and with more musical content to me and a few who tried it against the DAC1 (NE5532) and the DacMagic (NE5534).

The K701 has a dead low end on most headphone amps. So when you use it with the TC-7520 the enhanced bass can appear to 'sink' the midrange.
For K701 users and anyone who enjoys a wider bass range via headphones you can try the THS4032, or alternatively swap over the 47nF caps ( those big yellow ones on the top PCB either side of the headphone amp opamp, for a 100nF. I have instead soldered a 33nF cap in parallel with the 47nF from underneath the PCB so that I didn't need to desolder the 47nF. But that's for use with the K701. The added bass might sound a bit too much on the HD650 and other headphones that already have a fair amount of bass.

I added a modification page on my website at www.beresford.me that shows a number of the pictures taken by various AoS modders. I put some text with them as well. I hope to add and improve on that page over time. I hope it is helpful for a lot of people who don't know where to look for the various info.
Any useful suggestions on how to improve on that?

Stan

Looking good, it just needs the text 100nf changing to 100pf for MLC5 & MLC6

Also I think some noted problems if using THS4032 in both line out and HA positions where as it was ok if used in one side only

[Covenant]

Jerry,
I experienced this too, but I found it goes away with the MCL5/6 mod.
More clarity across the board, just a WEE bit less deep bass.

Thanks Gaz,
Well it looks like I am going to have to try this mod. I think I have a rusty old pair of pliers where I keep the car jack and other tools. So after I have ripped out these bits do I need to solder a bit of wire in their place? Thats what I do when the fuse blows.
Only joking I'll be careful

[Codifus]

Hi Zebu-(please explain your cattle based name). Thought I would add my two pennies worth. The 4562 has some lovely qualities especially in the mid-range. Acoustic guitar for example is a delight. Its about as close to being there as is possible. The reason I changed to the 4032 was because of a problem with excessive one note bass. I use floor standing speakers in a small room and consider the 4562 amplified the problem. The 4032 solves this for me but some may describe the sound as clinical or etched.
The ML5/6 mod plus 4562 may be an alternative but up to now I havent had the courage to try it.

Covenant,

I think my stereo setup is similar to yours. I have floor standing speakers with spiked feet. They are the Cambridge Soundworks Tower IIs with dual 8" inch woofers and a bass port in the back. They produce a strong bass down to 30 Hz. My stereo room is small, about 11 feet by 12.

My observation with the stock opamps in the 7520 were very nice, and no complaints of the bass. I went straight to the LM4562NA with the ML5/ML6 mods and found that the quality improved immensely, it was nearly perfect.

My observations match Gazjamz in that with the LM4562 in the line-out driving my system, the low bass is just very slightly dialed back. the LM4562s go deep, they just don't go strong as before. My feet want to tap energetically to the music but feel there's something missing down low. From 50 Hz up, though, the LM4562 with ML5/ML6 is pretty much perfect, and if not for the bass, my 7520 modding would have been done.


Also, I just wanted to add that I was one of the 1st buyers of the 7520, so it came with that other PSU. When Stan sent me the upgraded PSU, the sound improved considerably, especially with the bass. These PSU observations were all with the original opamp.

I wonder then, if the Caiman PSU will improve things with the LM4562 and ML5/6 mods. We'll just have to wait and see

CD

[Gazjam]

Thanks Gaz,
Well it looks like I am going to have to try this mod. I think I have a rusty old pair of pliers where I keep the car jack and other tools. So after I have ripped out these bits do I need to solder a bit of wire in their place? Thats what I do when the fuse blows.
Only joking I'll be careful

I used a breadknife....

[StanleyB]

I wonder then, if the Caiman PSU will improve things with the LM4562 and ML5/6 mods. We'll just have to wait and see

Jeez, and I was trying to keep that a secret till the time is nigh. You guys can predict the future.

Stan