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The sound of a modded line magnetic LM-502CA – modded by Lansche plasma guy (LPG)

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Guest Muon

Yep I had a suspicion it was the case that it may not work without the opamps. For some heavy modifications you can put a Salas HV & LV regulator circuit disconnect the existing one. You can also rebuild the tube output stage completely and omit the opamps with its own I/V and connect it to the ESS Sabre chips.

Red pointed out on page one ages ago that they are always in circuit.

 

You were there, so was I.

 

Both have short memories ;)

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Red pointed out on page one ages ago that they are always in circuit.

 

You were there, so was I.

 

Both have short memories ;)

 

Yeah I went through the thread when you mentioned it, I have a tendency to forget things...

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Guest Muon

Yeah I went through the thread when you mentioned it, I have a tendency to forget things...

I'm guilty too, this getting old is getting a bit old, I still would like to find the guy that said life begins at 40....so I can slap him :)

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Bump!

 

I've had Reds 502 on loan for a bit and its great. Finally landed my own. Gotta say, the synergy with the rest of my gear is great.

 

Even in stock form its one helluva DAC.

 

Red was kind enough to allow me to swap out some parts. For my money, the GEC rectumfrier is the first go-to. Get one of them up ya 502:thumb:

 

Next came the 12AU7's. I was lucky enough to score some good ones with the DAC. Possibly even better than Reds ones. No beuneo, the stock ones need to go.

 

then came the OP amps. I'm pretty nieave with this stuff, but it was soon apparent the Burson V5 and V4 made a drastic improvement to an already good thing.

 

I'm so happy I think a bit of wee came out in my pants.

 

And this was all just using the optical with flac files from an iMac. The future is so bright I gotta wear shades.

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6 hours ago, darth vader said:

Bump!

 

I've had Reds 502 on loan for a bit and its great. Finally landed my own. Gotta say, the synergy with the rest of my gear is great.

 

Even in stock form its one helluva DAC.

 

Red was kind enough to allow me to swap out some parts. For my money, the GEC rectumfrier is the first go-to. Get one of them up ya 502:thumb:

 

Next came the 12AU7's. I was lucky enough to score some good ones with the DAC. Possibly even better than Reds ones. No beuneo, the stock ones need to go.

 

then came the OP amps. I'm pretty nieave with this stuff, but it was soon apparent the Burson V5 and V4 made a drastic improvement to an already good thing.

 

I'm so happy I think a bit of wee came out in my pants.

 

And this was all just using the optical with flac files from an iMac. The future is so bright I gotta wear shades.

I bought the OP's LM502 and like you quite like what it does.  Mine has upgraded tubes and from memory I think they're the same as yours.  Are the op amps a pull out/plug in affair or are the surface mounted?

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quick add to this thread, my lm502 has only had 1 mod up until yesterday which was 2x telefunken smooth plate tubes

yesterday i did my very first bit of electrical DIY work, basic, basic stuff for most but new for me so i had detailed custom written instructions from the supplier of the parts

 

1. different tubes, NOS Radiotron 12BH7 and 6X4 rectifier, bit of an experiment as the telefunken are very nice

2. i soldered new caps onto existing, piggyback style, 4 in total, the 2 bigger black ones pictured and 2 smaller white (power) ones, excuse the tech. jargon   :unsure:

 

i understand caps need burn-in time like everything else but first impressions are very positive indeed, if its gets better from here then i will be mighty happy, potentially a massive return for little investment  

 

dac1.thumb.JPG.bc4a8fece81f788859fbda5119cc6f61.JPG

dac2.thumb.JPG.851dd242d16fb827d688283170e88f84.JPG

 

 

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I'd forgotten about this thread. Must re-read it as I have one of these dacs. Does anyone know whether the op amps are single or dual and would bursons plug straight in?

 

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Posted (edited)

The op amps are all duals.  I have tried Burson Gen 3 (lots of body but clarity could be better) Gen 4 (no body compared with Gen 3, but better clarity) and Gen V, the red ones.  Realistic body and nice clarity.

 

I also tried three x SPARKO dual.  They had a bit more gain, but didn't really cut it, I preferred the Gen Vs.

 

They have a new Gen 6 out about a month ago, in two different flavours, I have not tried them.

 

I have a few glitches with my 502 and have not used it for a while.  I think it needs a redesign on the AC mains incoming filter and all the reistors changed around the valves, then I will give it another run.

Edited by Red MacKay

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I am curious - what brand are the seasfodna rebranded caps?  Are they Duelands?

 

But why put your own reseller sticker all over them and make them look like yours....  Kind of crass and BS.

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8 hours ago, Red MacKay said:

I am curious - what brand are the seasfodna rebranded caps?  Are they Duelands?

 

But why put your own reseller sticker all over them and make them look like yours....  Kind of crass and BS.

 

Not Duelands, not rebranded anything, they are Sias Fodna own brand

sorry i dont know much about them but i will find out more and post if you like?

i know they have been in development for years and these first production ones are very new for the guys involved, so i guess some final testing going on

i trust the guy i know 100% with anything electronic so when he said put them in your dac let me know what you think.... i did

 

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17 hours ago, Red MacKay said:

I am curious - what brand are the seasfodna rebranded caps?  Are they Duelands?

 

But why put your own reseller sticker all over them and make them look like yours....  Kind of crass and BS.

 

OK.  I happily will retract all the above if that is the case and offer an apoligy.

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