View Full Version : CNC Phono pre-amp, Opamp rollng and Bugle comparo-->


Fasterdamnit
08-14-2011, 05:44 PM
Afternoon, gents.

Today Bill and I took my CNC and tried out some op-amps and compared to his Hagerman Bugle. The CNC has been running about a week so it should be stable with some decent burn-in.

CNC Phono pre-amp: Two dual channel op-amps with passive RIAA equalization. Two 9VDC batteries for power supply

Hagerman Bugle pre-amp: Three dual channel op-amps with passive RIAA equalization. Hagerman +/-18VDC power supply housed in separate enclosure with umbilical.
Chip compliment: Input-> LME49990 SMD's on adapter-> two Burr Brown OPA2134A's

Used a MM cart- Ortofon OM body with Digi 200 nude elliptical stylus.
Highly modified ST70 tube amp with low gain VTA board. Passive, ladder attenuator Pre-amp.

We started rolling chips to find a "best " combo.

Pair LME49720: This was a good all around combo. Tight bass, very good detail, musical, wide soundstage and very good imaging. The CNC circuit is from the datasheet of this op-amp.

LME49720-->LME49990 (two SMD chips on an adapter): Do you like detail? Well this has it. Bass depth is just a bit less than previous but bass attack is crisp. Not quite as musical as previous combo. *Contender*

LME49990--> LME49720 position two: A step up from previous pair. Bass attack crisper, more details all the way around, vocals bit more forward. Soundstage a bit wider. Imaging just a tad more refined. You can get lost in fretwork, cymbal decay, percussion details, vocalist breathing techniques. This is you detail KING.*Contender*

LME49990--> Burr Brown OPA2134A: This is another step up the ladder- bass is deeper, soundstage once again moved a little wider and very good depth. Details just a hair behind previous combo. Vocals and guitars bit more "musical" than previous combo. Imaging unchanged. *Contender*

Burr Brown OPA2604A- pair: Newcomers to the lab. Nice price. Bass depth was lacking. Soundstage just a bit smaller. Nice mids/vocals. Competent but no "Wow!" Factor. These were tested new, no time on them.

OPA2134A-->OPA2604A: Bass is back. Close to LME49990-->OPA2134. Just a hint of a sharp edge on the highs.

OPA2604A-->OPA2134A: Similar to previous combo but now definite hard edge to highs. Vocals pushed forward a bit.

OPA2604A-->LME49990: Nice all around- again, shy of great. Detail is a shade less than previous. Slight increase in bass. Mids and vocals just a bit nicer than previous.

LM49990-->OPA637 pair on SMD adapter: Two sets of single channel, SMD chips on adapters for best physical channel separation. Result? Meh. Bass is soft, soundstage just collapsed, all dynamics are weak. Like the power was dropped by 1/3 across the board. No-Go on this combo.

How about we swap positions?

OPA637-->LME49990: Wow! What a turn-around. Sounds like the old CNC is back. All dynamics are strong, good bass attack, soundstage opened back up (about middle of the pack), imaging better and details clearer. All that said, this is a good, but again, not great duo. Just a big change from previous combo.

OPA2134A-->OPA2134A: This is it.
It is right in so many ways. All instruments and vocals are most musical with this pair. Soundstage is wide, deep and tall. Imaging matches any other combo. Excellent bass attack and best bass depth. Guitar decay is just sweet with these. You give up just a little detail to the LME49990/LME49720 combo but you gain MUSIC. *WINNER*


Your mileage may vary. Pics to come and the Bugle showdown report.

:smoke:

Fasterdamnit
08-14-2011, 06:15 PM
http://i1221.photobucket.com/albums/dd478/Fasterdamnit/CNCtestJPG.jpg

If you can tear your eyes away from the beautiful, ultimate Empire turntable, the phono pre's are the two boxes on the left. CNC in silver, Bugle in copper capped with delicious hand rubbed Walnut.

No big expository rant this time.

The CNC, once we had optimized it with the op-amps available, is within spittin' range of the Bugle. The Bugle has also gone through the same iterations to arrive at it's current configuration.

Bass attack: dead heat- slight "flavor" difference.
Bass depth: Bugle by a nose.
Vocals: Bugle by a very thin hair. You know the color I mean...
Highs: Dead heat.
Soundstage: Bugle again by a nose. Just a bit wider. We found that width in the Bugle when we put the LME49990 in position one followed by a pair of OPA2134A's.
Imaging: Tough call, personally I think it is another hairs breadth difference in favor of the CNC.
Detail: CNC by a nose. Just a bit better all the way around.
Musicality: That hard to define quality which brings our recordings to life. Bugle by a nose.

Conclusion:
A CNC can be put together for about $30 not including batteries and enclosure. A Hagerman Bugle 1/2 kit gets you the PC board, BOM and instructions for $39. Add on the Digikey parts bill and you head north of $60 before batteries and enclosure. I do give Jim Hagerman big kudo's for his 3 op-amp design. It keeps the integrity of the music intact. And you can buy a very good DC power supply for the Bugle as well if you do not want to deal with batteries (and it would work great for the CNC!)
With all that being said, on a music quality vs. cost basis I cannot recommend the CNC highly enough. It does a heck of a lot with such a simple, easy to build circuit.

Thanks go out to Hypnotoad, BigBill and all the folks that jumped into the original thread and made a little experiment in low cost fidelity a big success.

Jim Langley

HypnoToad
08-14-2011, 06:34 PM
Great review Jim, the Bugle is a good design and liked by many so to have the CNC come so close shows that it's simple design doesn't get in the way of the music.

You need to try some AD823's in both the Bugle and CNC, you might be surprised how good they are.

JBL GUY
08-14-2011, 06:36 PM
Thanks for the in depth report and comparison.

Nice job!

Fasterdamnit
08-14-2011, 06:40 PM
Great review Jim, the Bugle is a good design and liked by many so to have the CNC come so close shows that it's simple design doesn't get in the way of the music.

You need to try some AD823's in both the Bugle and CNC, you might be surprised how good they are.

They are on the way, Phillip! :thmbsp:



Thanks for the in depth report and comparison.

Nice job!

Thanks, JBLG! I can never leave well enough alone. If you don't try and improve things, they just stay the same... :yes:

Billfort
08-14-2011, 06:40 PM
Nice review Jim, thanks for posting.

ghazzer
08-14-2011, 09:12 PM
Thanks Jim & Bill - really enjoyed your review/report.

I've got two LME49720s and will try that with a stock CNC. Then I will swap in the pot to see what a tad of gain control will do.

I AM having fun!!!

Thanks to all - - -

.

Big Bill
08-14-2011, 09:12 PM
Fantastic job Jim, your report is spot on! :tresbon:

catman
08-14-2011, 09:17 PM
G'day all, nice reports. I'm glad you like the OPA2134's. I've standardised on using them a long while ago.

I think they're hard to beat for general excellence. :yes: Regards, Felix aka catman.

Big Bill
08-14-2011, 10:04 PM
G'day all, nice reports. I'm glad you like the OPA2134's. I've standardised on using them a long while ago.

I think they're hard to beat for general excellence. :yes: Regards, Felix aka catman.

+1 here Felix! They're my favorite OP amp and sort of the "gold standard" by which I now judge all others. :yes:

ghazzer
08-14-2011, 11:30 PM
Just wondering..... With that sublime dual tonearm Empire and two phono preamps, were you able to audition both preamps at the same time? Lets see - an amp or receiver with two AUX inputs and just switch back & forth. Cool.

Also wondering how an LME49990/OPA2134A would compare to a OPA2134A/LME49990 combo. Your report seems to say that this pair supports each other, but will it make much difference which is the first stage? You have concluded that a OPA2134A/OPA2134A was better than an LME49990/OPA2134A, so it may be a moot question.

.

Fasterdamnit
08-14-2011, 11:36 PM
Just wondering..... With that sublime dual tonearm Empire and two phono preamps, were you able to audition both preamps at the same time? Lets see - an amp or receiver with two AUX inputs and just switch back & forth. Cool.

Also wondering how an LME49990/OPA2134A would compare to a OPA2134A/LME49990 combo. Your report seems to say that this pair supports each other, but will it make much difference which is the first stage? You have concluded that a OPA2134A/OPA2134A was better than an LME49990/OPA2134A, so it may be a moot question.

.

We tested them back to back by switching interconnects. Both combo's of the 49990 and 2134A were tested. These had a detail improvement over the pair of 2134A's but just a little less "musical" to our ears. This difference is firmly in the realm of personal taste.

ghazzer
08-14-2011, 11:48 PM
This difference is firmly in the realm of personal taste.

And this is exactly why you suggested that I should roll a few opamps. Different amps, speakers and environments will impart their own flavor, so everyone has to find something they like.

Vive la Difference

.

dodog
08-15-2011, 12:17 AM
Would you be so kind as to provide a Digikey # for the 2134A? I wouldn't mind have a few extras on hand and to try some rolling when the time comes. Digikey leaves me baffled and beaten-down when I try to do a search.

Pio1980
08-15-2011, 12:33 AM
I think one of the points of excellence with the Bugle is the isolated power distribution to the 3 ICs.
FWIW, The e-bay Bugle knock-off comes loaded with 3 Burr-Brown OPA2134PA chips in the good sockets. This one may get set up as a battery stand-alone RIAA mag stage 'standard'.

Mr. Lin
08-15-2011, 05:41 AM
Thanks for taking the time to type all that, it's always interesting to read about.

FWIW, I don't often see Linear Technology op-amps mentioned in these threads, and some of the best results I've gotten with headphone amps have been with the LT1364, and some others. IME they tend to be very neutral-sounding, with better resolution than some of the BB op-amps.

Fasterdamnit
08-15-2011, 11:07 AM
Would you be so kind as to provide a Digikey # for the 2134A? I wouldn't mind have a few extras on hand and to try some rolling when the time comes. Digikey leaves me baffled and beaten-down when I try to do a search.

Here you go-

OPA2134PA-ND

Fasterdamnit
08-15-2011, 11:24 AM
I think one of the points of excellence with the Bugle is the isolated power distribution to the 3 ICs.
FWIW, The e-bay Bugle knock-off comes loaded with 3 Burr-Brown OPA2134AP chips in the good sockets. This one may get set up as a battery stand-alone RIAA mag stage 'standard'.


My only concern is whether the chips are real BB's or possibly counterfeit. I agree it would be a great deal run off batteries.


Thanks for taking the time to type all that, it's always interesting to read about.

FWIW, I don't often see Linear Technology op-amps mentioned in these threads, and some of the best results I've gotten with headphone amps have been with the LT1364, and some others. IME they tend to be very neutral-sounding, with better resolution than some of the BB op-amps.


You are quite welcome, Mr. Lin! I do want to test some LT's. I also like the idea of the simple headphone amps using a single op-amp. I will see about adding a pair of LT1364's the next time I have a an order. :thmbsp:

Mr. Lin
08-15-2011, 12:04 PM
You are quite welcome, Mr. Lin! I do want to test some LT's. I also like the idea of the simple headphone amps using a single op-amp. I will see about adding a pair of LT1364's the next time I have a an order. :thmbsp:

I just took these two pictures for my thread in the headphone forum. This is one of the best op-amps I've tried yet, the LT1028. As you can see, I have two SOIC 8 single-channel versions of it mounted on a Brown Dog adapter, since the amp in question uses just one dual-channel op-amp normally (one op-amp goes on top, and one underneath). I know some of you guys have already been playing around with the Brown Dog adapters.

Anyway, if you can get your hands on some version of the 1028 (I don't think I paid much for mine), I highly recommend it. For the past couple weeks I've been using the AD826 - a good op-amp - but today I installed the 1028 and there was a very noticeable increase in detail and "air." You probably know what I'm saying. :) If you read the manufacturer's description of the 1028, they emphasize the extremely low noise of this design.


http://i1202.photobucket.com/albums/bb377/daobal/rsz_p8143612.jpg

http://i1202.photobucket.com/albums/bb377/daobal/rsz_p8143624.jpg

I applaud you guys for getting so into this. The differences between op-amps are often subtle once you're using only the best ones, IME, but these differences are hardly insignificant.


...

jimreeves
08-15-2011, 12:21 PM
Great job guys!
I think the analog audio world needs more of these non-scientific head to head comparisons. It was a result of just such a test that helped us find the AD823 for dual and AD797 for single channel op amps. Well done!

VROBERTSON
08-15-2011, 04:21 PM
Fun and informative read fellas! Well written Jim. I so do love my Bugle. :music:

Fasterdamnit
08-15-2011, 07:47 PM
Great job guys!
I think the analog audio world needs more of these non-scientific head to head comparisons. It was a result of just such a test that helped us find the AD823 for dual and AD797 for single channel op amps. Well done!

Thanks JR! I am looking forward to more comparisons... :yes:

Fun and informative read fellas! Well written Jim. I so do love my Bugle. :music:

Thanks, Vince! As your Bugle has benefited from the research done on ours, I am glad it meets with your approval. :bigok:

hags
08-16-2011, 12:01 AM
Nice write up.

Do you have any plans on testing the current big buzz, the OPA1642?

I didn't see the LM4562 or LME49720HA (metal can) listed either, any plans for those?

What does your DC offset measure on the outputs of your homebuilt?

EDIT: I see your comments regarding the LM4562 in another thread.

Mr. Lin
08-16-2011, 04:48 AM
Nice write up.

Do you have any plans on testing the current big buzz, the OPA1642?


I haven't heard about that one yet. Is it new, or an older one that people are just now starting to favor for audio?

I forgot to mention the OPA2107, but I'm sure the OP and others are already familiar with that great op-amp.

hags
08-16-2011, 03:46 PM
I haven't heard about that one yet. Is it new, or an older one that people are just now starting to favor for audio?

I forgot to mention the OPA2107, but I'm sure the OP and others are already familiar with that great op-amp.

Data sheet says Dec. '09, so it's relatively new. Also, I haven't seen the
OPA2132UA mentioned.

Fasterdamnit
08-16-2011, 07:39 PM
I will gladly review any and all chips you fella's would like to send me. :thmbsp:

hags
08-16-2011, 09:29 PM
I will gladly review any and all chips you fella's would like to send me. :thmbsp:

Ha! Yeah, I was interested only for curiosity's sake with that particular circuit. I have experimented with all the ICs mentioned in my AN346 pre amp. It uses both active and inactive RIAA eq. I built mine sans the coupling capacitor between gain stages as with the more modern, lower offset ICs it's not needed.

I've had it head to head with a Bugle I owned as well a the Acoustech PH-1. In both instances it threw a noticably wider soundstage, a much deeper sound stage, went lower in the low end and was quieter than both, especially the comparatively noisy PH-1. I used a high quality shunt PSU based on the Borbely design on the AN346 and Bugle. Both the Bugle and and the Acoustech have been sold. So yeah, I'd say these application note pre amps, as simple as they are, are pretty good.

What is the DC offset on yours?

Mr. Lin
08-17-2011, 12:27 PM
Data sheet says Dec. '09, so it's relatively new. Also, I haven't seen the
OPA2132UA mentioned.

I have an OPA2132 in my op-amp box, but I don't think I've even tried it yet.

jimreeves
08-17-2011, 06:06 PM
Did somebody need a pair of OPA2134's? I have a pair I'm sure will never get used. Not my cup o' tea.

EDIT: they're spoken for by Dodog.

vincei
08-17-2011, 07:10 PM
Interesting, thanks for the comparison. :)

catman
08-17-2011, 07:17 PM
G'day all, I love the OPA2134! Here are my eight remaining spares! Regards, Felix aka catman.

Renron
12-20-2011, 12:26 PM
At the risk of showing my ignorance ....again..... I'll ask how the favored combo OPA2134/OPA2134 sounds compared to the AD823/AD823 from the CNC design & build thread?
Ron

HypnoToad
12-20-2011, 12:54 PM
At the risk of showing my ignorance ....again..... I'll ask how the favored combo OPA2134/OPA2134 sounds compared to the AD823/AD823 from the CNC design & build thread?
Ron

Chalk and cheese Ron.

The OPA2134 has the typical Burr Brown sound, warm, pleasing and laid back.

The AD823 has more detail, more controlled bass and a wider soundstage IMO.

YMMV

Fasterdamnit
12-20-2011, 01:28 PM
Chalk and cheese Ron.

The OPA2134 has the typical Burr Brown sound, warm, pleasing and laid back.

The AD823 has more detail, more controlled bass and a wider soundstage IMO.

YMMV

I found the 823 to have a bit of a hard edge so I do not like to listen to them for any extended time. I prefer the 2134's. You would have to listen for yourself to decide. :yes:

Pio1980
12-20-2011, 01:49 PM
I may have suggested previously that the $38 E-Bay phono board be included here just for gigglz. It's actually pretty good.

HypnoToad
12-20-2011, 03:12 PM
If we are using a battery supply when looking at Op Amp data sheets, you can look at slew rate, bandwidth etc, but one thing we should be looking at is the Current Supply.

For example:

OPA27GP has a current draw of 3.3ma.

OPA134 has a current draw of 4.0ma.

AD797 has a current draw of 8.2ma.

Looking at the current supply of each we can see not a lot of difference with the first two but the AD797 draws over twice as much which means running on batteries it will drain them more than twice as fast as the others.

Just something to consider when using a battery supply.

Renron
12-21-2011, 12:25 PM
Good posts, thank you all.
My speakers (small Thors) are already right on the edge of razor sharp treble, looks like I'll be rolling some OpAmps. :) once I finish all the projects I have going.....sheesh.
Rebuild Rek-o-Kut Rondine deluxe.
Finish building Schroeder tonearm Clone then install in above.
Build CNC phono pre
Then the fun begins.

Thank you for your information.
Ron

Renron
07-31-2012, 06:24 PM
Bump, anyone have any new op amps they've tried and would like to share the results with us?

Kappaholic
07-31-2012, 10:03 PM
From my opamp rolling experimentation, the paired performance, using same opamps on both input & output sockets, beats the mixed combo.

So far, paired performance of LME49990 tested in CNC & HTMCPS comes up at the top in my system when tested against OPA2134 or LME49720.

I would love to try out the paired OPA637's, though, but those aren't cheap just to play around.

Fasterdamnit
08-12-2012, 12:03 AM
Live dangerously- Mix and match, fellas! :thmbsp:

cairns4me
08-12-2012, 10:16 AM
Live dangerously- Mix and match, fellas! :thmbsp:
New recruitment catchphrase for this site " Join AudioKarma- Live dangerously- Mix and match, fellas!" Hmm actually sounds a bit different than I thought....could be an alternative to joining the Navy even...:scratch2:

Renron
08-13-2012, 01:42 PM
Live dangerously- Mix and match, fellas!
is quite different than;
Live dangerously. Mix and match fellas!
LOL,
I live near San Francisco...........

ghazzer
08-16-2012, 12:57 PM
Here is a comprehensive review of the LM833s in the CNC:

http://www.lencoheaven.net/forum/index.php?topic=9021.15

see Reply #29.

Good news travels fast. I'm suprized that Sachin can keep up with the demand for the boards.
.

Renron
11-22-2012, 10:51 AM
Bump,
Any more reviews? Opinions?
Ron

arcorob
11-22-2012, 11:13 AM
Hello, just curious, which opamps did you use on my board ? Wondering if I should swap to ones less edgy in the top end. Sorry to say but the AT SUT to ART DJ PRE beats it hands down...both in top end clarity and wider soundstage. Its not a slam, just a statement.

You had mentioned top end roll-off on the ART but that is not what I am experiencing. In a solid listening test, same material, head to head, both are playing those ultra highs where you are listening and waiting to see - does that note hit it or crack (sort of like wondering if a singer can HIT that high note). The Art hits it CLEAN, the AK-PRE folds and gives a sound bordering on painful...

In terms of soundstage, I am not getting the same width or depth from the AK-PRE

I know you tested in your setup but again, we have different configs, most especially the moving coil cart. The cart I use could get edgy if allowed to run away...lol

So I am wondering if rolling an op amp might help? I do like the AK PRE, but I do think it needs a tweak to be just right on my setup. Thanks

Please dont take this as a criticism by the way. It just is what it is, objectively measured.

62sunbeam
11-22-2012, 01:16 PM
I put a pair of 2134s in my B&K MC-101 at the suggestion of Catman and I have to say they were delicious.

They made the already very good sounding MC phono stage really lush but detailed.

I don't have much opamp rolling experience but I can say that I sorely miss the MC-101 for it's really great phono stage.

Eric