Beresford 7520 + Gator problems

[Paul]

HI all,
Just thought I'd post this just incase anyone else is having issues with the above .

I was having problems with the sound from the headphone side of my TC7520 and Gator combo , the problem was distortion in the mid - higher frequencies.

I had sent it back to Stan some time ago in March to reduce gain on the Gator as I was having issues with slight distortion from both headphone amp and rca outputs which was resolved untill now .

After a little tinkering I found the problem to be with the opamp I was using . I had an AD826 fitted , swapped it for one of the LM4562NA's I had in the origional board and all is well , for some reason this opamp is either up the creek or doesn't like being in my DAC.

On the plus side thes headphones sound great ,much , much better than the cheep Sennheiser eh150's I've been listening to and a bairgain at £40:eyebrows:

Cheers

Paul

[StanleyB]

I recommended the LM4562 in preference to the AD826 for the Gatorized TC-7520 in a thread somewhere, and even had that as an option when I listed the TC-7520/Gator/LM4562 combination.

[Paul]

Scrap that , its back .
Swapped it for the origional opamp board and now it's sounding smooth again,even with the AD826 fitted .:doh:
The only I can think is there's a problem with my Gator board, would someone be able to test it for me ?

Stan , I remember the thread you mentioned but I thought I'd give it a try with both types of opamp , turns out it not at fault now anyway ( listening to it as I type )

[StanleyB]

Send it back and I'll try it in my test TC-7520. Maybe the Gator needs a different setup for the TC-7520. Are you using the 12V or 15V power supply? The 3V difference is critical on wide dynamic range type of music.

[Paul]

Im using the 15v supply I recieved from you with the Gator Stan , I'll send it back for you to test .can you please email me your postal address .
Many hanks
Paul

[Paul]

Got the new Gator today , many thanks to Stan for that.

Just fitted it and unfortunatly it sounds the same as the old one, I dont know what's wrong but it cant be the Gator , can it?

The only thing that I can do to make it sound good is run it from my pc via coax with the master volume/ output turned down to 60 , then it sounds superb.

I have tried via coax on input 1 from my Arcam Alpha 5+ = distortion .
the same when using USB and again if pc volume is turned up to 100 on input 2 .
It's the same when using headphones and on fixed and vairiable outputs .

I have also tried my standard 12v psu with no difference.

The standard board doesn't distort but is alot less detailed and open.

The only thing I can think of is reduce gain by around 40% or just only listen to it via pc with reduced volume , I don't want to give up on the Gator !

I was wondering also if something else on the main board could be wrong as I never had this problem when I first used the Gator back in March.Plus I've not had my 7520 a year yet , bought it back in November 2010.

Any help very much appreciated
Thanks
Paul

[Fi-Wi]

I experienced the same distortion at high frequencies (vocals/jazz/classical) when listening to sub 256 kbs streaming (320 kbs and lossless sounded excellent), but only through headphones. I send my Caiman/Gator with AD826 back to Stan, who replaced the opamp (but didn't lower the gain). It didn't fix the problem though.

I stopped using the headphone output for sub 256 kbs streaming for a while, but when I bought a better psu to feed my main source (Squeezebox) the problem was (and stil is) solved!

I am not a technician but apparently the problem was not in the Caiman but in the signal that feeds the Caiman.

[Paul]

Sorted, I think.

Took it out again today to check for a dry solder joint or if I couls see something , turns out I hadn't pushed the gator on the motherboard enough and I guess the pins weren't making a very good connection. I think it was something to do with me putting a thicker sticky pad under the new Gator ,took it out and all is well.

Thnaks again for your input and a BIG thanks to Stan for being so patient and understanding with my lack of know how.

Cheers
Paul

[Fi-Wi]

What's the purpose of the sticky stuff there anyway?

I'm not going to basketball with my Caiman so why the concrete to glue the Gator to the Caiman motherboard?

Good to hear it's sorted out for you Paul.

[slate]

I guess that it is there to secure the small pcb during transport

[Fi-Wi]

Yes but given the force I had to use to push my (sharp) knife to carefully cut it without destroying the rest of the Caiman content or even harm myself, I think a little less would suffice. :scratch:

[Paul]

I can understand why they stick them in so well as most people who buy one will never open the box and therefore shouldn't have this sort of problem.

I was wondering if the pins on the Gator are slightly shorter as my standard board showed no signs of distortion , or it could be the Gators better detail showed it up as it was only audaible in the top 1/3 of the frequency range, it only realy became an issue with female vocals and treble , the rest of the time I could'nt honestly say I could hear it, although now it does sound 100% smooth, before it was a touch 'grainy'.

I may well just solder it in.:eek:

Paul

[Paul]

Hi again , once again I am the bearer of bad news - it's back.

For some reason I thought I'd sorted it with the board pushed in fully but alas no,something on the motherboard doesn't like the Gator as far as I can tell .

Had a good few hours on friday evening listening to the Gator and all was well , switched it on yesterday and it sounded distorted again , took the Gator out and refitted with no difference, put the old baord in and all sounded good , no distortion whatsoever.:scratch:

It has now got to the point of no return and I'm giving up on the Gator , when I fitted at the begining of March it was fantastic but noticed a slight problem about 6 weeks ago, so now I just cant seem to resolve this so I give up.

Unless someone knows something I dont??

Paul

[Gazjam]

Hi Paul,
I had a similar problem with my Gator board...in fact had the same problem with two different boards...
It turned out that it was my amp that didn't like the gator, resulting in the same distortion you wrote about.
The Gator boards were fine and had no faults.

No idea what the cause was, tried asking but no further forward. Tried the dac with a different amp - worked fine.
Honestly, in my opinion I'm not sure the the idea with the Gator being a more "system friendly" route to the benefits of the "passive mod" is 100% right...BUT most folk dont have issues and its not Stans fault.
Just my bad luck with amps!

Try another amp with it if you can, might do the job for you. Failing that I'd look into the "passive mod" for the Dac, which is real easy to do.

My concern for my system is that i will be upgrading my amp soon, so fingers crossed I've no problems again! :)

[Alex_UK]

I have had the same experience with my Gator/Amp as Gary has too Paul - If you can live without the headphones and lower gain, then the passive mod is definitely the way to go in this situation, IMO/E. The distortion on my Gator was so small it took me weeks to even confirm it was there into my Creek amp, but when we used it over at hifi_dave's neither I, Dave nor DSJR noticed it, (and those are some illustrious ears!) and I also didn't get it using it as a pre into an Audiolab amp in Power amp mode, so as Gary says, just one of those things I think with specific amps. I actually prefer the sound passive anyway after going back, so for me it was a non-issue in the end.

[Gazjam]

Hi Alex,
just out of curiosity.... :eyebrows:

What caps are you using in your Dac for the passive mod?
I was running the big yellow film caps that Stan recommended a while back to good effect.

[Paul]

Thanks for your input on this one guys.

I use 2 amps ,1 via fixed into a denon AVR-1910 using Mark Grant Canares and the other using the variable into dual gainclone monoblocks via belkin pure av leads, I swap the speaker wire from one to the other so apart from that everthing is the same , same result from both amps .
I also use the headphone out into a set of AKG K530's so the passive mod would be no good.

I do have the use of another amp if I want to try it , I think it's an Audiolab 8000p , and was going to try it just incase it was my setup at fault.
I was also going to try it in a fairly high end Music fidelity amp setup with a Meridian transport into Mission 735i's at my Fathers house.

I know my speakes and amp combo produce a fairly bright sound but the Gator was great when first put in , then I noticed slight distortion , told Stan who reduced the gain on it which worked for a few weeks( around 50 hours of listening) now it seems to come and go, more often distored than not.

I'll take it round the old mans and let you know how I get on , either that or try sorting out a Caiman instead.
:cool:
Cheers
Paul

[Alex_UK]

Hi Alex,
just out of curiosity.... :eyebrows:

What caps are you using in your Dac for the passive mod?
I was running the big yellow film caps that Stan recommended a while back to good effect.

Yep, them big old buggers are still doing the business for me! :)

[StanleyB]

I still have a couple of those big yellow caps left if anyone is interested. PM or email me.