sachu888
Spare the tigers, kill me
Many thanks to Hypnotoad for R&D in Phonostages:thmbsp:
BTW your build looks neat,thanks for posting pics.
Regards,
Sachin
Here It Is: The All Singing All Dancing HTMCPS
- Thread starter HypnoToad
- Start date
Many thanks to Hypnotoad for R&D in Phonostages:thmbsp:
BTW your build looks neat,thanks for posting pics.
Regards,
Sachin
shelly_d
Not An Audiophool
I can't give you a definite answer on that but I think that OpAmps have gotten a bum rap. At least more modern ones have. They have been around for a very long time. My mid 70's preamp uses a pair in the line stage and I think it sounds great. Much more modern ones have much lower distortion, noise, transient response and common mode noise rejection that those old things, all of which provide better audio response.
Shelly_D
Op Amps certainly have a bad reputation for some reason, I actually built a discreet preamp and found that the op amp ones I had were better, and I have found that the fewer components the better.
I liken newer op amps to tubes they don't need a lot of supporting circuitry to get the job done.
Of course IMO running them on batteries makes a difference as well. YMMV.
I liken newer op amps to tubes they don't need a lot of supporting circuitry to get the job done.
Of course IMO running them on batteries makes a difference as well. YMMV.
bearchuck
Active Member
This makes it sound like there's a sonic / performance benefit to 12volts rather than 9v. Is that right?
So I posted a few weeks ago about noise / hum issues. I've done most of what was suggested (replaced the 390r with 470r, shortened the input / output wires, installed the ground nut, played around with resistor values for R2 and R10). Right now I'm still messing around with the gain, but I've got it closer to where I'd like it to be.
Unfortunately, I still have a decent amount of noise and it doesn't sound like it has anything to do with the gain. The hum is better, but still pretty bad with the unit sitting directly on top of my amp. It has become clear that eventually, I'm going to need a better enclosure to shield the unit. The heavy-duty steel unit from Hammond that I'm using for my Bugle is great, so I'll probably go that direction again.
On that note, I also discovered that I'm picking up a slight hum from the turntable when I flip the switch to "on."
There's still a few other things that I'd like to try. Again, these issues really aren't bad enough to keep me from enjoying my music and in general, I love the sound of the HTMCPS.
Anyway, just figured that I'd check in since you all were so helpful when I posted last.
Oh, here's a new photo. It definitely looks much nicer than it previously did.
Look at me!
Hum must be from an AC source nearby IMO, in all the iterations of this and other things I have built I have never had any hum when using batteries. And like others have posted the HTMCPS is dead quiet, you can crank the volume right up and hear nothing.
One question is your LED connected between the positive and negative power side of the PCB?
One question is your LED connected between the positive and negative power side of the PCB?
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bearchuck
Active Member
Yeah, I think that the new enclosure will take care of the hum. However, the noise / static is an entirely separate issue that remains unchanged.
One end of the LED is connected to the resistor, which is connected to the positive terminal on the toggle switch (the same terminal that's hooked up to the V+ on the board). The other end is hooked up to ground underneath the board. Here's a side view that you can probably see a little better.
GreatTone
Super Member
Well, there's one of your problems right there -- the neg leg of the LED should go to V-, not ground. As HypnoToad said when I asked about where to hook the LED up, the way you have it is creating an unbalanced voltage.
bearchuck
Active Member
Awesome! I really hope that's the issue because it's a simple fix. I'll get on it later tonight and report back. Thanks!
Kappaholic
Active Member
I also experience slight white noise/static when cranking up the volume, but it seems to be dependent of the speaker & the op amps being used.
This is noticeable when putting your ear close to the tweeter, in my case, emit tweeters on all three set up, but does not impact while playing tunes.
I was able to eliminate all white noise when using LME49720's & OPA2134's on HTMCPS or some of the noise was reduce when using B&W bookshelf speakers.
However, it is at a low enough level that I can live with it and can't really hear it when sitting at a listening distance.
GreatTone
Super Member
So before I receive my AT-33EV, I wanted to do some critical listening with the HTMCPS with my current cart, the SAE 1000e, so I can accurately evaluate the new cartridge. Here's what I've heard.
When I first installed the HTMCPS, it sounded grainy and constrained, to the point I thought there was something wrong with it, but that went away after a couple of album sides. It opened up beautifully and revealed its character: a very balanced sound, both musical and detailed. I had been using the 12AX7-based phono stage in my Dynaco SCA-35, so the HTMCPS is very different, though in no way inferior.
The thing I liked about my tube phono stage is the intense presence it conveys. Compared to the HTMCPS, it sounds larger than life. The downside of that is it sounds a little over-ripe, and this is at the expense of detail. I didn't realize this until I started using the HTMCPS. I didn't know how much information I was missing.
One track I use for testing is the Music Matters 45 rpm reissue of Bobby Hutcherson's "Happenings," specifically the tune "Bouquet." With my tube stage, the vibe notes are surrounded by a tremendous amount of air -- you can almost see the vibrato. With the HTMCPS, I realize that sound is not really accurate -- I can now clearly hear the mallet strike too, which was kind of lost in the overall hugeness of the notes before. Everything is kind of toned down a little, but in a good way -- it's like going from an oversaturated photo to one with more natural colors.
Another thing I notice with the HTMCPS is the image solidity. With my tube stage, things kind of moved around a little based on the frequency of the note. It's like the frequency response was a little uneven channel-to-channel, so things would wobble as the notes changed. No more. Everything is rock solid. I thought the problem was in my room, which is far from ideal, or the cartridge. No, it was the phono stage, which I never would have guessed.
I thought of a good comparison last night about the differences between the tube stage and the HTMCPS. If you know anything about vintage Martin guitars, the tube stage is like a pre-war guitar with scalloped braces -- there are tons of overtones, and the sound is huge and rich, but kind of diffuse and spread out. They changed the design in the late 1940s, to a top without scalloped braces. My 1960 D-18 is that design, and the notes are laser-like in their focus, with very few overtones. All the emphasis is on the fundamental of the note.
I like both sounds -- one is not better than the other. They are just different, with different strengths. That's how I feel about my tube stage compared to the HTMCPS. I'm happy to explore a totally different sound now.
I also listened to Neil Young's live Massey Hall recording last night, which is kind of famed as a great-sounding album. I was impressed by the clarity of the sibilants, and how I could hear into them, hear the tiny changes in "s" and "f" sounds that help shape the emotion of a performance. His guitar and piano have never sounded more solid or more real. While there is more detail, it is in no way "analytical" -- it's very musical, with all the emotion coming through. Maybe even more emotion, since those tiny details in inflection are what give a performance life.
Another track I use to evaluate things is a Japanese pressing of America's greatest hits. On "Ventura Highway" before, I was missing some things, and I knew they were missing because I've heard the song so many times. With the tube stage, the drums were distant and hard to discern. But the main thing missing was the "doo doo doo doo doot" which they sing very quickly. It was like so smeared over I couldn't pick out the syllables without paying very close attention, and already knowing it was there. Now the drums are very clear, and the fast singing is right there. There's a beautiful bass sound on that track too (the great studio player Joe Osborne), and that still comes through just awesomely.
It's a cliche, but I really am hearing lots of things I never heard in very familiar recordings. This thing is a home run. Well done.
When I first installed the HTMCPS, it sounded grainy and constrained, to the point I thought there was something wrong with it, but that went away after a couple of album sides. It opened up beautifully and revealed its character: a very balanced sound, both musical and detailed. I had been using the 12AX7-based phono stage in my Dynaco SCA-35, so the HTMCPS is very different, though in no way inferior.
The thing I liked about my tube phono stage is the intense presence it conveys. Compared to the HTMCPS, it sounds larger than life. The downside of that is it sounds a little over-ripe, and this is at the expense of detail. I didn't realize this until I started using the HTMCPS. I didn't know how much information I was missing.
One track I use for testing is the Music Matters 45 rpm reissue of Bobby Hutcherson's "Happenings," specifically the tune "Bouquet." With my tube stage, the vibe notes are surrounded by a tremendous amount of air -- you can almost see the vibrato. With the HTMCPS, I realize that sound is not really accurate -- I can now clearly hear the mallet strike too, which was kind of lost in the overall hugeness of the notes before. Everything is kind of toned down a little, but in a good way -- it's like going from an oversaturated photo to one with more natural colors.
Another thing I notice with the HTMCPS is the image solidity. With my tube stage, things kind of moved around a little based on the frequency of the note. It's like the frequency response was a little uneven channel-to-channel, so things would wobble as the notes changed. No more. Everything is rock solid. I thought the problem was in my room, which is far from ideal, or the cartridge. No, it was the phono stage, which I never would have guessed.
I thought of a good comparison last night about the differences between the tube stage and the HTMCPS. If you know anything about vintage Martin guitars, the tube stage is like a pre-war guitar with scalloped braces -- there are tons of overtones, and the sound is huge and rich, but kind of diffuse and spread out. They changed the design in the late 1940s, to a top without scalloped braces. My 1960 D-18 is that design, and the notes are laser-like in their focus, with very few overtones. All the emphasis is on the fundamental of the note.
I like both sounds -- one is not better than the other. They are just different, with different strengths. That's how I feel about my tube stage compared to the HTMCPS. I'm happy to explore a totally different sound now.
I also listened to Neil Young's live Massey Hall recording last night, which is kind of famed as a great-sounding album. I was impressed by the clarity of the sibilants, and how I could hear into them, hear the tiny changes in "s" and "f" sounds that help shape the emotion of a performance. His guitar and piano have never sounded more solid or more real. While there is more detail, it is in no way "analytical" -- it's very musical, with all the emotion coming through. Maybe even more emotion, since those tiny details in inflection are what give a performance life.
Another track I use to evaluate things is a Japanese pressing of America's greatest hits. On "Ventura Highway" before, I was missing some things, and I knew they were missing because I've heard the song so many times. With the tube stage, the drums were distant and hard to discern. But the main thing missing was the "doo doo doo doo doot" which they sing very quickly. It was like so smeared over I couldn't pick out the syllables without paying very close attention, and already knowing it was there. Now the drums are very clear, and the fast singing is right there. There's a beautiful bass sound on that track too (the great studio player Joe Osborne), and that still comes through just awesomely.
It's a cliche, but I really am hearing lots of things I never heard in very familiar recordings. This thing is a home run. Well done.
GreatTone
Super Member
Cool. Have you ever experimented with things like exotic caps in this board? Seems like the output caps would be a good place to try them and see if they make a difference.
It would be good to know what difference they make, op amp rolling is another thing that makes a huge difference sometimes better sometimes worse.
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Nice review GreatTone. I'm loving my AT33PTG/II with the HTMCPS, so I'm sure you're going to love the incoming AT33EV.
Since I have a few MC carts at my disposal, I'd like to implement two rotary switches wired with various resistors for R1/R9 and R2/R10 for easier cart swaps. Good idea/bad idea? Is there anything I should be aware of when implementing the switches?
My overall goal is to house both the HTMCPS and CNC in one enclosure, with rotary switches for cart/gain (MC side) and loading/capacitance (MM side). A separate enclosure will house a dual battery/OPS power supply similar to Qwin's setup. Overkill probably, but why not? (provided the more electronics savvy folks here think this is doable!)
I'm also dealing with some white noise, which I think may stem from selecting the proper gain for my set up, which involves the pre being fed into an E-MU 1616m digital mixer. I'll play with resistors and mixer trim settings this weekend to try and minimize the white noise. Overall, the white noise is at a fairly low level and pretty unintrusive once the music starts playing, but I'd still like to minimize it.
Since I have a few MC carts at my disposal, I'd like to implement two rotary switches wired with various resistors for R1/R9 and R2/R10 for easier cart swaps. Good idea/bad idea? Is there anything I should be aware of when implementing the switches?
My overall goal is to house both the HTMCPS and CNC in one enclosure, with rotary switches for cart/gain (MC side) and loading/capacitance (MM side). A separate enclosure will house a dual battery/OPS power supply similar to Qwin's setup. Overkill probably, but why not? (provided the more electronics savvy folks here think this is doable!)
I'm also dealing with some white noise, which I think may stem from selecting the proper gain for my set up, which involves the pre being fed into an E-MU 1616m digital mixer. I'll play with resistors and mixer trim settings this weekend to try and minimize the white noise. Overall, the white noise is at a fairly low level and pretty unintrusive once the music starts playing, but I'd still like to minimize it.
I would not worry too much about swapping out R1/R9 as it's not that critical you could put in an arbitrary value say around 30 ohms that would suit all your carts.
And for R2/R10 I often thought of a dip switch setup like the CNC with 300 ohm, 500 ohm, 750 ohm and 1k which should cover most carts in the gain dept. I may implement that if I order another batch of PCB's.
And for R2/R10 I often thought of a dip switch setup like the CNC with 300 ohm, 500 ohm, 750 ohm and 1k which should cover most carts in the gain dept. I may implement that if I order another batch of PCB's.
bobrown14
Super Member
Thats the distortion from the tube preamp that you are hearing. Most likely 2nd order distortion - something you will akin to your guitar sounds. Play a G then G2 then modal G (akin 3rd order distortion). Not unpleasant but you know its different. With stereo reproduction you dont want a dominant 3rd order harmonic (distortion) as it will change the notes originally present and change the tune, it will be subtle but since you play an instrument you will notice it since your ears are trained to hear it from practice. Most folks will hear it as well and for them it will just sound off.
With this preamp you have very little 2nd or 3rd order distortion so it sounds the way it was produced. More crisp..kinda like you hit the note perfectly with a properly tuned guitar. I guess my point is that the tube pre has more distortion than your diy pre... not a bad thing at all as your ears can handle a lot more distortion (up to say 2% or more) without noticeable degrade in sound than you think. This preamp gets you way down in distortion % and you are hearing things the way they were originally produced. Your brain and ears are a very cool thing and they play a BIG part in how you LIKE the sound.
All that said... your brain will make adjustments and WANT to hear it sounding good. The way to tell if it truly sounds good is time. Listen over time (a few hours) and if you dont get fatigued you're on the right track. I've actually not been fatigued while listening to tube gear, solid state more so, with DIY phono preamps the exception..
Cheers,
Bob
sachu888
Spare the tigers, kill me
We could for sure, some 1.5k's would be perfect, that would also allow perfect channel matching, not sure if they would affect the sound compared to regular metal film resistors though.
Now why didn't I think of that, good call Sachin.
GreatTone
Super Member
Thanks for the response. I listened for hours last night, and I just wanted to keep spinning. In fact, I kind of stayed up too late because I couldn't stop...guess that's a good sign. No fatigue, other than lack of sleep.
I'd say the only downside of the HTMCPS is it's a bit more unforgiving of record condition or poorly mastered/recorded material. I picked up a used copy of the Carpenters "Singles" album, and there is some groove damage that wasn't so apparent before, but now it's a bit grainy in spots. Not a big deal though -- most of my albums are in pretty pristine condition.
Another thing I've noticed with the HTMCPS is how much more dynamic it is than my tube phono stage. The quiet spots are much more quiet, then it can leap to thundering levels. Pretty cool.
Kappaholic
Active Member
Hm... where would you probe for a measurement, with each adjustment on the trimmer?
Sounds like a neat idea, though. Rev.2 on the way?