SimontY said:
My pre-amp is two gain stages and I tried a few things:
a) instead of splitting the gain between the two stages I increased the gain of the 1st (though still lower overall) and tried BUF634 in the second.... sounded sweet but not very lively... ultra smooth though (perhaps why it suited FM so well in my tuner?).
b) Using LM6182 in 1st stage (current-feedback so requires arsing about with resistor values) and LM6172 in 2nd stage. Bass was awesome but lacked a bit of HF air and the image was small. Smooth and powerful though.
c) Back to original circuit but with 2xAD8610 (on dog) followed by LM6172. Balanced and lively and imaged much better. Still using this combo.... though now I have some LM4562 my screwdriver hand is itching again....
Anyway, the original Marantz circuit has 10k in parallel with the output after the coupling caps. When I removed the caps, muting, et al, I removed these also. I just have a 50ohm series followed by the 100k to ground from the original circuit. It would not surprise me if it sounded worse with this 10k still in circuit (so HDAM is driving this as well as the 47k odd of the pre-amp). I may be one of the few to try HDAM without the 10k load?
Currently burning in some LM4562 - in conjunction with a Tent XO2 + XO supply my CD67se is starting to sound rather sweet indeed.
Another thing - if you guys are not adding extra decoupling to these fast op-amps (particularly high BW ones like LM6172, AD826, AD8065/6) you may not be hearing their full potential. Even if they are not oscillating they may burst into damped oscillation (ringing) with the music.
I get great results with ultra-low inductance stacked-film polyester caps across the top of the chip. The Siemens-Epcos ones. The 1uF/100V ones are EXACTLY the right length to fit diagonally across the op-amp needing only a couple of mm of lead. This will guarantee stability of the most unruly of of-amps.
Peter Venema said:
Glad to hear it - I have some burning in right now!
All you need between output of HDAM or op-amp is a series resistor of about 50 - 100 ohm followed by the 100k to ground that is already there. The op-amp or HDAM do not like to see a capacitive load such as your interconnect, and the series resistor isolates the op-amp/HDAM from the interconnect to ensure stability. Robert Noriega (aka 'Bobwire') on AudioAsylum found that when he took the HDAM on his '63 below 20ohms it started to oscillate. I think I used 50 though it may have been 100....
I tried to attach an image in my last post of my decoupling for fast op-amps but it didn't work (too big I think) - I shall try again....
Attachments
Hi Glenn,
I curious what your findings are with the LM4562.
With the HDAM removal at first i didn't remove the 10K
but after removal the bass got a little better.
But i dont have the 100K in place, should i replace it?
Peter
I curious what your findings are with the LM4562.
With the HDAM removal at first i didn't remove the 10K
but after removal the bass got a little better.
But i dont have the 100K in place, should i replace it?
Peter
Glenn2 said:
Hi Glenn, and welcome to this thread 🙂
The thing you describe sounds an awful lot like the passive filter + discrete output-stage that was discussed here earlier. But then without any feedback 🙂. If you do a search you'll see what I mean.
Regards,
Ray
Peter Venema said:
Hi Peter,
Dunno if a lower resistor will do something with the bass, but you can give it a try. I assume you've bypassed the HDAM circuit, and since most opamps don't mind some capacitive load, I see no problems if you remove it.
Ray
Peter Venema said:
What Bobwire did was:
So he got rid of the 10K's to ground along with the RF filtering cap to ground and dropped the output impedence to 20+20=40 Ohms from the original 100+100=200 Ohms?
It was a long time ago, but I think I used a single 200 Ohm series resistor when I disconnected the muting transistors and left C659/660 (100pF) in place. My HDAM jumpers are wire and not 10 Ohms.
So for me, I can drop my output impedence from 200 Ohms, down to 50 or so, and get better bass?
Any debates on the worth of C659/660?
(as an aside, the LM4562's amaze me more and more with each listen! I can't imagine anything else sounding better than simply swapping in these opamps. Oh yes, mine have low ESR caps around them - too low I worried because the opamps sounded brash before break in).
Peter Venema said:
Difficult to say at this stage as it's still burning in and the Tent XO2 is also new. Sounds fab at the moment though I'll have to compare with some other favourites and report back.
I have AD826 and LM6172 - also decoupled as pic above - and also AD8065x2 on Brown Dogs.
The AD826 is a very thrilling listen but perhaps a bit too forward. Very much like the LM6172 in fact. The AD8065x2 is very sweet and seductive and ultra-clean... but more laid back than the other two.
I also have tried OPA2604, OPA2134, OPA2132, OP275, 2xAD825 and 2xAD8610.
The 2xAD8610 was actually very good but I've used up one of my modules in my pre-amp now.
I'd put back the 100k if I were you - I believe it is for 'DC bleed'. Not quite sure why but I think it's quite important. Maybe a DC path to ground for the op-amp o/p or the amp i/p?
BTW folks, I know you've all read Thorsten's mods (c'mon) but I read in a forum post of his that he subsequently put back the HDAM.
In noticed there's a skipping CD-63SE on eBay.co.uk with a day to run if anybody is interested. Someone with a hot-rodded CD63SE might want it for spares - or for a reality check!
You'd only have to lift out your transport and insert it to hear a 'stock' performance - would take a minute (unless you've coax on your RF).
Also, last time I checked, VAM1202 was only about £20.
Also a couple of 53s.
I think the broken ones are where the bargains are to be had (unless you lot have been near any of them.😀 )
You'd only have to lift out your transport and insert it to hear a 'stock' performance - would take a minute (unless you've coax on your RF).
Also, last time I checked, VAM1202 was only about £20.
Also a couple of 53s.
I think the broken ones are where the bargains are to be had (unless you lot have been near any of them.😀 )
Peter Venema said:
Oh my God, how many discs in your crates guys? If I have to listen to all my music each time I upgrade the player, it's around 900 CDs to listen to, so with an average 50 minutes per CD it's 27 days of music non stop...
I've always wanted to ask you guys what is your testing playlist (maybe less than 10 CDs), I mean not your favorite discs but the ones wich make the CDP's upgrade show up.
Here is mine :
Propaganda "P-Machinery" Old school electronica, very detailled and react strongly to upgrades.
The Almighty "Powertrippin" The bass get clearer more and more on last track. Before we just know there is a bass 'coz there is the name of the bass guy!
An externally hosted image should be here but it was not working when we last tested it.
Stina Nordenstam "This is Stina" Flawless disc and artist. Song "Welcome to happiness" uses bass quite hard to come on my Quad.
Nouvelle Vague "Nouvelle Vague" Voices, mainly the one of Camille, are perfectly recorded. And what a voice!
Holden "Chevrotine" Mainly because it's in the air and a very good french news.
Bonus in case some of this may sound really better :
Alif Tree "Spaced" Sounds perfect, needs perfect stuff.
Ensemble Harmonium "Chants de l'église Milanaise" Voices again, but very very hard to play. Maybe one day I'll be able to know how much they are and where.
Cheers brent and andy, that really helps me with my problem finding. Il examine that area carefully when im back up at uni on sunday night.
Can't wait to get my baby back to full health again, then proceed with more mods 😱 😱
😱 😱 😀 Clock+PSU, and 5V reg board needs to go in, with the 12V audiocom superregs also for the op-amp power.
Right im off to watch stealth 🙂
Can't wait to get my baby back to full health again, then proceed with more mods 😱 😱
😱 😱 😀 Clock+PSU, and 5V reg board needs to go in, with the 12V audiocom superregs also for the op-amp power.Right im off to watch stealth 🙂
Malefoda said:
Stina Nordenstam "This is Stina" Flawless disc and artist. Song "Welcome to happiness" uses bass quite hard to come on my Quad.
Good one - I didn't think anyone else had heard of her.
'The World Is Saved' is the only one I have and I love it.
LM4562 update - it's certainly up there and ahead of the AD826 and LM6172 (I think - but I change my mind a lot). Maybe not as sweet as the AD8065x2 on Brown Dogs, but perhaps punchier... and still burning in.
BTW - I have two Brown Dogs left and a pair of SOIC LM6171 samples arrived with my LM4562 samples, so I think I'll make some with LM6171 as diff. amp (its symmetry makes it work well here I reckon) and something else as filter to balance it out as an LM6172 gives too much of the same flavour.... I have OPA627, AD8610, AD825 and AD8065 SOIC singles I could use - any suggestions folks?!
Also, I still have the Cerafines at the op-amps - I'm thinking Nichicon Muse KZ but I've been out of the modding game for a couple of years and don't know much about the Rubycons people are mentioning (and of course there's BG's)...
Glenn2 said:
Good is not enough for me 😉 I've got almost all of her, she is quite famous in France. The World is saved is maybe her disc I like the less... People who want to discover her (How can you live without Holly Stina in your life??) may take a hear at "People are Strange", only cover songs, but really in her style. (yes the title is the song from The Doors). Sorry I'll not speak of music too much, this is a CDx3 & CDx7 thread... 🙂
About LM4562, for me it's the one. Even if I did not try many, I've got what I want : voices of Stina an Björk move me as never! (As good test disc is "Selma Songs" from Björk, wich I can't listen too as my room can't stand so rich songs!).
Glenn2 said:
I have tried the Panasonic FC's (low ESR) at the OPAMP. I didn't like them, they killed the music. Reverted to the Cerafines and the music came to life. I might try again, just to be sure.
Malefoda said:
Well I decided to try a 'hybrid' using SOIC singles and two Brown Dogs. I took two op-amps that I like but have very different sonic characters, hoping to get the best of both worlds. I chose LM6171 and OPA627.
The next decision was which way around. The OPA627 would maybe be an easier load for the DAC and the LM6171 has a very robust output stage but I decided to put the LM6171 first because its symmetry makes it ideal for a differential circuit, and it should be better at handling the RF coming from the DAC. This will be much less by the time it gets to the slower OPA627. I mounted a 0.1uF low-inductance stacked-film cap across the +/- pins of the Brown Dogs to ensure stability.
At the moment they are burning in but a brief listen showed a very detailed sound with a very large soundstage.
I'll do some comparisons with LM4562, 2xOPA627 and 2xAD8065 later.
I also found some Vishay Siliconix CRDs in a drawer - has anyone tried biasing the OPA627 into class A?
avr300 said:
That reminds of a similar thing I tried in my old CD63 years ago(now at my mum's). I swapped the Cerafines for Silmics and the result was lifeless.... so I put them back. (It's a '67SE I'm molesting at the moment.)
One of the best mods I did on the '63 was regulating the servos amps with LM317/337 - exactly like those Raygulators as it happens! I think I took them down to +/-8V but not sure. The bass took a giant step forward.
I've had good results with Nichicon Muse KZ in op-amp decoupling, but I always stick to 100-220uF.
avr300 said:
Don't bother putting them back in! The Low ESR is not a good match for the analog section. You need to stick with a quality audio cap here such as CeraFine or Black Gate. I run Black Gate Standards in my analog section and after they burned in for about 30 hours, they sound PHENOMENAL!!! Never heard the Muze, so can't comment.
Just keep the FC's for the Power Supply and Digital decoupling where they belong! 😎
Silmics do seem to work universally. Unfortunately - in my opinion - they also have the effect of appearing to compress things somwhat giving a kind of fat, rich sound tht actually lacks dynamics. Why this is, I dont know, but it's often preferable to the sins of other electrolytic caps. I'd use film types if the application allows - though that often brings other problems!
Anyway - raher than add to the bonfire of opinions, here's a superb article on the subject of bypassing: Power Supply Noise Reduction, from the Designer's Guide webite.
Anyway - raher than add to the bonfire of opinions, here's a superb article on the subject of bypassing: Power Supply Noise Reduction, from the Designer's Guide webite.
Help!!!
Hi there,
I have a big problem: the headphones socket sounds far better than the RCA output!!
I've changed very few: just bypassed the R619/620 10ohms from the output filter to the first R at the RCA, changed U200 for 470 inductance, finished the Drivers upgrade (100n X7R only and R127/128), changed L601 L602 (on the new list), put a 100n bypass under U813 and changed the last diodes in PS and that's all!!
( and also the 22 cer on HPhones with the MKS left from C801/802but I do not see if any link as even without (feeding caps removed) LIN and RIN to headphones it still sounds awful 🙁 ).
As the headphones still sounds good now, I don't see why RCA has felt! It only occurs on bass, maybe even from low middle... they are gone!
I don't know what to do... go back each step?? Put U200 back? Remove the bypass?
Heeeeellllpppp!!!!!!
Hi there,
I have a big problem: the headphones socket sounds far better than the RCA output!!
I've changed very few: just bypassed the R619/620 10ohms from the output filter to the first R at the RCA, changed U200 for 470 inductance, finished the Drivers upgrade (100n X7R only and R127/128), changed L601 L602 (on the new list), put a 100n bypass under U813 and changed the last diodes in PS and that's all!!
( and also the 22 cer on HPhones with the MKS left from C801/802but I do not see if any link as even without (feeding caps removed) LIN and RIN to headphones it still sounds awful 🙁 ).
As the headphones still sounds good now, I don't see why RCA has felt! It only occurs on bass, maybe even from low middle... they are gone!
I don't know what to do... go back each step?? Put U200 back? Remove the bypass?
Heeeeellllpppp!!!!!!
An externally hosted image should be here but it was not working when we last tested it.
Re: Help!!!
Relax, don't panic, it's just a cd-player... give it some time to run-in properly. Your mods look neat, everything seems ok, nice picture. Did you change L601/602 to 470uH? Make sure C605/606 are 430pF then, and R605/606/611/612 are 14k. It looks like 12k1 in your picture. Did you mix up the 63 and 67 filters? If you still don't like it after one week, you can always take it back step-by-step. And remember: what's the definition of 'better' ? Most headphones have a lousy frequency curve.
Ray
Malefoda said:
Relax, don't panic, it's just a cd-player... give it some time to run-in properly. Your mods look neat, everything seems ok, nice picture. Did you change L601/602 to 470uH? Make sure C605/606 are 430pF then, and R605/606/611/612 are 14k. It looks like 12k1 in your picture. Did you mix up the 63 and 67 filters? If you still don't like it after one week, you can always take it back step-by-step. And remember: what's the definition of 'better' ? Most headphones have a lousy frequency curve.
Ray