Deep End DIY - My first speaker project

[acg]

@musicmcthanks. 

 

I am quite the novice regarding turntables, but I'll rebuild this L75 to a relatively high standard and will use it as a point of reference for when I build my own TT from scratch.  Of all the parts of a record playing system I think the TT is the easiest thing to get right so long as I am mindful of vibrations and accurate speed control.  Making a quiet bearing and platter and an inert plinth are not rocket surgery and are comfortably within my skillset.  Making that platter turn exactly at the speed it is supposed to is more of a challenge especially when my idea is not to use any sort of instantaneous feedback system in the motor controller...I plan to design something that keeps its own speed mechanically, not electronically, and this involves concepts that some people will probably find counter-intuitive.  I'm convinced that speed control is the most important aspect of turntable design especially given the vagaries of different drive methods and the varying drag the stylus exhibits as it makes its way to the centre of the record.

 

It will all be fun, I am sure.

 

In the meantime, I have sourced a good tonearm and am considering splashing a ridiculous amount of $$ on a low MC cart, just so that I don't have to think about cartridges again for a long while.   

[acg]

18 hours ago, Mat-with-one-t said:

Perhaps just teach her how to turn on the lathe and put her to work?  Heh.  Great to get kids into making and fixing stuff.  Lost art!

seriously this project blows me away.  Haven’t seen those amps for a long time in the thread.  Like a movie character, can’t wait for their return to the epic story!

 

No doubt she will be on the lathe making dust when she gets a bit older.  Her mum does not enjoy the mess that comes with the crafting, but I encourage it wholeheartedly...using ones hands to make something can be so rewarding.

 

Yes, the amps.  I've decided that I need to concentrate on one thing and get that done rather than faffing about on several and getting nothing finished.  Horns it is...

[acg]

Best intentions for a full day of horn making turned out to be optimistic.  Between phone calls from family and friends and clients as well as the routine of the school day and afternoon sports, I did manage about 4 hours in my tiny shed.  It was long enough.  I had the first horn all turned down and sanded ready for priming in about 2 hours.  The second horn took and hour and a half.  That is soooo much quicker than when I did them the first time round.

 

First coat of primer on the first horn...

 

[acg]

I was away all yesterday so of course all kinds of stuff turned up on my doorstep and had to sit there for hours before someone got home.  My postie is very relaxed...he just leaves stuff at the front door whether it requires a signature or not...maybe it's part of the "can't be arsed" Aussie spirit, I don't know, but until something goes missing or gets proper wet in the rain (if will ever rain again!) his lack of attention to protocol makes my life easier so I like it.

 

This new vinyl fetish is taking hold.  I've bought about 100 second hand classical LP's from composers that I enjoy and the first of them turned up while I was away.  This morning I opened up a few boxes and found myself loving the hands-on aspect of vinyl...the liner notes...the ocd stuff like "I'll have to clean these before I play them"...the entire inconvenience of the medium that is lost with digital.  I found myself having to repulse an intense urge to drop work for the day and to start playing the Berlin Philharmoniker Bruckner 8 with Karajan (recorded three years after my birth) simply because the packaging looks sooo beautiful and because Bruckner 8 often brings tears to my eyes.  With my digital performances of this work all I do is press a couple of buttons and hey presto there is music.  With vinyl I have something with which to peruse and connect emotionally and a routine to follow and four sides to get through what is normally almost 1.5 hours of gargantuan bliss not to mention it is a new performance for me to explore and appreciate.

 

But I have no record player operational, and my front-line acoustic system is still "in-progress".  Oh well, until another day.

 

Yesterday, my stupidly expensive birthday present to myself also arrived: a low MC cartridge whose presence is supposed to quell all the "what-ifs" and "will this other one be more satisfying" afterthoughts from my mind.  I'll optimise my phono stages to work with exactly this cartridge and will not have to look for another good cart until I either wear this one out or cannot get satisfying results and throw my hands up in despair...at least that is the plan.  You know the thing is priced for the luxury market when it turns up in a fancy genuine wood box...see below...

 

  

[musicmc]

Oh, did it then ! Nice cart

Don't feel alone not having a turntable that isn't going, Anthony @Upfront is a prime candidate there with the nicest collection going on.

Mine was going for a year and was packed up one afternoon while listening to a CD (after months of records record fever broke) it will come out again one day I'm sure but being  lazy prefer to not get up to change over a record, but instead, tap the keyboard . While I had record fever purchased and modified a couple of phono pre amps so had that fairly right.

 

Above everything enjoy the music.

(listening to a dark piece on a royal system,  VPO Mehta_Mahler_ Sym2_01_AllegroMaestoso, in flac thankfully not recorded from a record :)

 

 

[hochopeper]

Cool stuff Anthony! I think I mentioned this article to you before when discussing the topology for gain structure around passive line level crossover. Now that you're going to go down the turntable road, a read of this article - http://www.diyaudio.com/forums/diyaudio-com-articles/163570-masters-noise-thoroughly-modern-tube-phono-preamp.html - would be worthwhile IMO. The solution might not be to everyone's tastes (he's open about that) but the theory discussed (especially using balanced connection for connection to the cartridge) would be worth at least a read for background.

 

I've spent most of my spare time lately renovating a bathroom, so I haven't had a chance to look more closely, do you mention anywhere in this thread which phono stages you're building?

[acg]

10 hours ago, hochopeper said:

Cool stuff Anthony! I think I mentioned this article to you before when discussing the topology for gain structure around passive line level crossover. Now that you're going to go down the turntable road, a read of this article - http://www.diyaudio.com/forums/diyaudio-com-articles/163570-masters-noise-thoroughly-modern-tube-phono-preamp.html - would be worthwhile IMO. The solution might not be to everyone's tastes (he's open about that) but the theory discussed (especially using balanced connection for connection to the cartridge) would be worth at least a read for background.

 

I've spent most of my spare time lately renovating a bathroom, so I haven't had a chance to look more closely, do you mention anywhere in this thread which phono stages you're building?

 

Yes, I had seen that article Chris.  So much information there for someone like me to scratch over.  The balanced connection between cartridge and phono is something that I am yet to really look at, but it does make sense and has sort of influenced what I have done so far.  The first phono stage that I am building is the Salas all opamp no feedback unit configured for MC cartridges.  It is single ended from go to whoa and uses a passive RC RIAA network.  The second phono is by Pete Millet (have a look at that page Chris, there is a link there to his ETF13 presentation on designing that phono) and with it I intend to use a pair of Lundahl SUT and therefore can go balanced wiring to the cartridge if desired.  What I really like about that phono is that the only capacitors are in the power supplies...it uses a passive zero-feedback LR RIAA network.  That ticks just about all my boxes to be honest...no caps...iron...low parts count...if only it had tubes.  

 

Ultimately though I see myself building a tube phono once the rest of the build settles down a bit.  Hopefully these two phonos (the Salas and the Millet) will help me settle any audio-philosophical questions that need answering and I can use my newfound knowledge from the past few years to cobble together my own design or maybe take on something that someone else has designed.  

 

Re-reading that article this morning I decided to do a few calculations regarding performance of my MC cartridge and phono stage.  The cart should have 50nV of noise and with 0.2mV of output will have a SNR of about 72dB.  That is a fairly sturdy task for a phono stage with such low level signals and such high gain requirements.  My ability to get the phono stage right really looks like the biggest make or break item for the whole vinyl playback.  The phono has a very difficult task, more difficult than any other bit of electronics in the system I reckon. 

 

My wife is away this week and I will have evenings to myself.  The plan is to build these two phonos at night once the b-rats are in bed.  Parts are still trickling in, but should all be here this week I hope.

[acg]

13 hours ago, musicmc said:

Oh, did it then ! Nice cart

Don't feel alone not having a turntable that isn't going, Anthony @Upfront is a prime candidate there with the nicest collection going on.

Mine was going for a year and was packed up one afternoon while listening to a CD (after months of records record fever broke) it will come out again one day I'm sure but being  lazy prefer to not get up to change over a record, but instead, tap the keyboard . While I had record fever purchased and modified a couple of phono pre amps so had that fairly right.

 

Above everything enjoy the music.

(listening to a dark piece on a royal system,  VPO Mehta_Mahler_ Sym2_01_AllegroMaestoso, in flac thankfully not recorded from a record

 

 

 

To be honest I am a bit over just clicking the keyboard (iPad in my case) to listen to music all the time.  I'm feeling a need for a ritual, a little worship perhaps.  I want my kids to understand that there is so much more to life than convenience, and that the easy way is often not the most rewarding, and that sometimes you should skin the cat in more than one way just for the heck of it.  I think that in some ways the inconvenience of vinyl can help place a value on the art...things that are too easy we tend to undervalue in my experience.

 

You have my Mahler juices flowing...I will go and put on Mahler 5 and get to work! 

[musicmc]

Keep on doing what you do Anthony, always following with interest and have done from the start.

Yes there is more to life than an I pad for musical enjoyment and something a little magic about a record that runs well.

 

What a great thing to pass on to the the Kids, nice work.

 

 

[acg]

I've been youtube schooling my kids on a lot of the music that I listened to when I was a kid and even took them to their first record shop after school this week to see if we could find any gems.  I told my son that I would buy him some Twisted Sister vinyl if he could find it (a couple of their songs have been on high rotation in the car).  The latest song that is on high rotation on the way to school is this one:

 

 

Its rough, loose, has absolutely zero subtly in its performance, looks like it has been shot in the neighbours backyard while they are out of town for the weekend and is all about hitting and strumming things as hard as possible.  Oh, and every second line is exactly the same.  It's awesome! 

[EV Cali]

I am glad you linked to the short version by Ram Jam. Their extended one take a lot of the energy from it IMO

 

Australia's own Spiderbaite do a pretty good one to.

 

 

[acg]

@EV Cali, yep it is Spiderbait that introduced me to the song...I am a fan of Kram and the Deliverance inspired film clip...and that clip was already planned for the drive out to my sons rugby game tonight...hopefully it will get him hyped up and ready to go a bit Kong at the breakdown and really drive in the mauls.

[ray4410]

2 hours ago, EV Cali said:

I am glad you linked to the short version by Ram Jam. Their extended one take a lot of the energy from it IMO

 

Australia's own Spiderbaite do a pretty good one to.

 

 

pretty cool looking 35 dodge roadster street rod,i have a real soft spot for 1936 ford roadsters my sisters boyfriend had one when i was a teenager, and all these years later i can still remember the sound of that flathead V8,great clip also.

[hochopeper]

14 hours ago, acg said:

The latest song that is on high rotation on the way to school is

 

Awesome!

 

Our not quite 3yo daughter is all about Midnight Oil - Short Memory. Every time we go for a drive we simply must listen to it or we've got a mutiny on our hands.

 

 

 

[davewantsmoore]

11 hours ago, hochopeper said:

Midnight Oil - Short Memory

Awesome!

 

I caught mine having a hilarious moment on her own head-banging to Foals - Prelude the other day....  but still usually has worse than Wiggles - Big Red Car, or Puff the Magic Dragon on high rotation.

[almikel]

On 10/08/2018 at 9:04 AM, acg said:

Its rough, loose, has absolutely zero subtly in its performance, looks like it has been shot in the neighbours backyard while they are out of town for the weekend and is all about hitting and strumming things as hard as possible.  Oh, and every second line is exactly the same.  It's awesome!

deceptively tricky timing - our band has mucked with it and failed - too hard for us bumblies

The Ram Jam version was always one of the key tracks played during the Speed Skate session in my youth at Skateway Mt Gravatt (Brisbane) - along with "I See Red" and "Radar Love"

It was fantastic when Spider Bait covered it. 

It was only looking today I worked out Ram Jam covered it also - the original is by Lead Belly from the 1930s! - possibly sacrilege but I like the Ram Jam and Spider Bait versions better!

 

cheers

Mike

 

[davewantsmoore]

38 minutes ago, almikel said:

Lead Belly from the 1930s!

TIL   

[almikel]

1 hour ago, davewantsmoore said:

TIL   

LoL - I had to look it up - "Today I Learned"...

...very rare @davewantsmoore learns from me - but I'll take it!

 

[stevoz]

3 hours ago, almikel said:

LoL - I had to look it up - "Today I Learned"...

...very rare @davewantsmoore learns from me - but I'll take it!

 

.....and you learned from him what TIL meant.

Years ago, my kids used to love Devo and were partial to a bit of Scatterbrain as well, especially the "Dude" song......but enough of this 'what our kids liked' chat.....back to work @acg !!
 

[acg]

7 hours ago, davewantsmoore said:

Awesome!

 

I caught mine having a hilarious moment on her own head-banging to Foals - Prelude the other day....  but still usually has worse than Wiggles - Big Red Car, or Puff the Magic Dragon on high rotation.

 

My 7yo daughter was up in the office behind me crafting away the other week and I had some classical music playing...Aaron Copland "Red Pony Suite"...she bops away to all kinds of pop music but she looked up from what she was doing and says "you know dad, I really like this music, it's complicated, and I think you might be able to dance to it".  It is American folk music and compared to something like Bruckner is hardly "complicated" at all but it is certainly more complicated than Katy Perry or Beyonce that she has a tendency towards. 

 

You gotta love them when they start being able to appreciate what they are listening to.

[Rob181]

2 minutes ago, acg said:

"you know dad, I really like this music, it's complicated, and I think you might be able to dance to it".

 

2 minutes ago, acg said:

You gotta love them when they start being able to appreciate what they are listening to.

Even better that she can feel the rhythm & beat...

Working out how she could dance to it...outstanding...

[zydeco]

On ‎25‎/‎03‎/‎2018 at 6:56 AM, acg said:

 

 

 

 

 

Wow. How do the 2-way speakers (ML1?) fit into the system? 

[davewantsmoore]

13 minutes ago, zydeco said:

Wow. How do the 2-way speakers (ML1?) fit into the system? 

They look like the "mid bass"     

[acg]

1 hour ago, zydeco said:

Wow. How do the 2-way speakers (ML1?) fit into the system? 

 

Temporarily.

 

Although they are the only transducers in the room pulling their weight right now...

[acg]

So, my wife was away in Bris Vegas for a few nights last week and I got to soldering.  I think that I was extremely productive and actually knocked a big dent in several projects.

 

First is the Pete Millet LR Phono...

 

It looks a bit gumby because I have used larger diameter caps with slightly wider lead spacing than the pcb can comfortably handle and I did prefer to keep them all on one side of the board rather than putting some underneath.  The heatsinks for the LDO's are actually very close to a couple of caps so I have put some teflon tape in between to isolate things a little.  Hopefully the solution will last.

 

This is the phono board by itself...

 

 

I've used good components that I am comfortable with.  This unit is tested to turn-on stage.  I've managed to trim out the DC offset at the output of both channels but the the positive power rail is a little high at 15.66V rather than 15V.  There is an error in the schematic which I found when I studied the datasheet of the positive LDO regulator and I recalculated things and am now waiting on a smaller voltage set resistor to get a spot-on +15VDC.

 

This is the PSU for the Salas Phono...

 

 

I've used EI transformers because they are much better mains filters than toroids.  These particular units are wound on bigger cores than they need to be and as a result are tightly regulated with a low temperature gain.  This PSU just regulates the AC and filters it before sending it on its way to the phono stage for further shunt regulation.

 

 

These are the mono phono stages.  I've had the big Duelund Cast caps for quite some time now and I figure I will use them in this project just because they are there.  Notice the blank areas on the pcb's:  those suckers are not going to fit but I do have a plan that involves a 25mm spacer between the cap and the pcb.  Again, I've tried to use good low noise components and hope to not have to think too much about changing this or that in the future.  Unlike the Millet phono, only the psu of the Salas has been tested but I need to find a little time to make the cap spacers, solder in the Duelunds and connect things up.  This has been a much more fiddly build because transistors and JFET;s have had to be matched and well as the voltage drop in led strings.  I have enjoyed it thus far.

 

So, with all this rampant soldering efficiency I also managed to solder up two 4 phase sine wave generators for the turntable builds as well as some smaller SMD boards for tachometers, speed controllers, RS232 Shields and even a linear regulator.  

 

The 4 phase sine wave generator board is very useful...

 

 

It generates low distortion sine waves at adjustable frequencies with its primary use to control the line frequency going to the motor of a turntable which will vary its speed.  I will use one of these with a single phase motor on the TT that I have here already, but on my from-scratch TT build I will be using an external rotor 3 Phase motor which I can drive with three of the phases of this controller.  The controller sets the line frequency which is sent to an amplifier (a normal audio amplifier) where it becomes mains voltage which controls how fast the motor turns.  I can also set the voltage going to the motor by attenuating the amplitude of the sine wave coming from the generator.  It's awesome stuff and I cannot wait to play around with it once I get the horns finished.

 

Last, but not least, is a tiny pcb that is designed to fit into a mint tin...

 

It is smd one side with the filter caps on the other, but it runs on two 9V batteries.  It is actually a Class A, zero feedback headphone amplifier that fits in a mint tin.  It sounds freakin excellent with my HD650's and absolutely eats my little FIIO F5 amplifer that I currently use.  A pair of batteries supposedly lasts 4 or 5 hours, and today I should receive a pair of nice LiPo4 9V cells and a charger to run this little beauty.  This is my travel setup: Tidal on Samsung phone >> Pocket Class A head-amp >> HD650's.  Nice!!!