My system

[SimontY]

I thought it might be fun to post some details of my system, past and present. A story of my own personal journey to good sound.

It all started about ten years ago (when I was still a teenager) with my first separates system: Sherwood CD player & receiver, Tangent Monitor 6 speakers. All three items were poor and yet I was hooked on hi-fi for life. My first craving was for bass, a stage most people go through I reckon. I added a subwoofer (Paradigm PDR10 - awful sloppy thing), pro-logic decoder (awful again) and rear speakers for home cinema.

Next, I changed to B&W DM602 s2, a lovely speaker I still think highly of today. For me, all B&Ws sound good, apart from the treble, which is poor (tizzy) from the 600, 700 to 800 range. I then bought a Roksan Kandy amplifier, which was a mistake as the best I heard was the Musical Fidelity XA-2 - but I was young and wanted that remote control :-/

The next step was to build some DIY speakers using an 8" plastic Audax midwoofer and 1.25" soft dome tweeter (a lovely unit I feel). These were in slightly oversized 40L ported boxes. I still have these and in some ways they surpassed the B&Ws. A bit of a sideways step in truth! The crossovers were a joke - I just used some that were given to me, which were from some Monitor Audio Silver 7s. I did play with capacitor and resistor values and upgrade some of the parts but of course I was running blindly, just having fun.

I then changed my CD player to a 2nd hand Marantz CD63KI and then, later, began to modify it. I started with a simple DAC re-clock using an Audiocom DVC-1. Eventually, as my confidence and desires grew, I ended up with a bit of a monster using multiple external power supplies, low noise voltage regs, a 2nd clock (working the servo) and a decent discrete FET output stage.

http://i1191.photobucket.com/albums/z475/Simonty1/MKVs.jpg

During this time I also decided to construct some kit speakers. These were the Seas Pontus (2 x 6.5" doped paper and 1" "noferro" tweeter) sourced from Audiocom during the short time they had kit speakers available. I think they priced themselves too high to compete and then decided to withdraw. I didn't much like the sound of these to be honest, they were thin and raw, though also detailed and clear. I eventually changed the crossover to be a 2.5 way rather than 2-way D'apolito. I also shifted the mid/tweeter crossover upwards and this also pleased my ears. I changed the driver-xo wiring to Kimber 4VS, which I really like. I can't find a picture of the whole speaker at the moment.

http://i1191.photobucket.com/albums/z475/Simonty1/PICT0206.jpg

Around this time I also built a 270L subwoofer using the classic Adire Tempest 15" long-throw DVC woofer, with ports tuned to 20hz. The sub was used for music and films, coming in at 50hz. It worked fairly well, especially for films!

Later, I moved into my parents' house after university and had to give up the speakers and sub due to space constraints. I still own the speakers and they play, along with the sub, in a good friend's house.

End of part 1...

[SimontY]

Back home with no proper job and a tiny room, the system had taken a knock, but not my enthusiasm.

Prior to moving back I swapped my Roksan Kandy for a Caspian, trading up using Ebay. To be honest, although it looked gorgeous, the Caspian was also a mediocre amplifier and it didn't stay in my system for too long.

At some point, probably before moving home actually, I tried making an amplifier - a chip amp based on the National LM3886. It was dual mono and had no buffer or pre section, just using a pot for volume control. The amp is built into a home-made plywood chassis and it sounds pretty good.

I found some nasty JVC speakers at the recycling centre (aka the dump!) and experimented with these changing all three drivers, one by one. I built some wooden stands and listened to these for a few weeks. They were ok!

http://i1191.photobucket.com/albums/z475/Simonty1/closeup.jpg
http://i1191.photobucket.com/albums/z475/Simonty1/PICT0481.jpg

Next, I got excited about open baffle speakers, something I'd read a lot about on DiyAudio. I bought, on a whim, a palate of 128 7" bass drivers and had these things sitting in our attic. I used 4 of these per side in series-parallel for the bass. I used a 4" Audax plastic midbass for midrange and a 1" soft dome Wharfedale tweeter for the top end. After much messing around and learning how to measure the acoustic response of speakers (in a basic fashion) I managed to get a really good sound! It was fun and dynamic and they punched WELL above their weight. I still have these although have stripped some useful parts off for other projects.

http://i1191.photobucket.com/albums/z475/Simonty1/1-1.jpg

Amplifier-wise I had switched over to using an active preamp, in the form of a DIY box housing a buffer circuit designed by Pedja Rogic. Eventually this preamp got given copper foil internal wiring, a half-decent pot (Alps Blue) and CMC silver-over-copper RCA sockets, as well as a very oversized psu with S Power regulators. A fairly nice preamp I reckon.

http://i1191.photobucket.com/albums/z475/Simonty1/PICT0745-1024.jpg

The chipamp made way for something a bit different, in the form of a pair of Marantz MA-500 monoblocks. These are powerful amps and, whilst less clean than the Roksan amps, and less neutral than the LM3886 chip amp, the sound was sweet and warm and round. I think they're lovely amps for the money, and quite powerful on paper too. I of course modified these, adding Mundorf Supreme caps on the input, along with 6N solid core silver input wiring and CMC silver/copper input sockets. The bias trimpots were upgraded to nice multi-turn items and the bias increased. Quite good like that and I enjoyed the MA500s. They are funny cake-slice-shaped things, designed for fitting 5 on a single rack shelf for a high quality home cinema set-up. Internal power wiring (was messy) was shortened utilising Kimber 4PR. I had other mods planned but then things often don't go as planned..

http://i1191.photobucket.com/albums/z475/Simonty1/PICT0728.jpg

[SimontY]

Back to the source... well I kept breaking CD63s and after my good friend Brent (of Fidelity Audio) kindly helped me rebuild the thing a couple of times I decided to give up. The thing is, the CD63KI's charm is a fairly superficial one to me, and when modified, the nature of it becomes extremely detailed but ultimately it is a sound lacking wonderful body and true analogue type appeal. It will always excel at jazz and female vocals to my ears but I wanted a rounder appeal.

Enter my love affair with the TDA1541(A). I luckily heard some of the classic players e.g. Marantz CD85 (wow, the bass, but also too dull and soupy) and CD94 (amazing even in standard trim). I knew I wanted to start a modifying project based on this ancient and special DAC chip. I acquired a Philips CD650 and, although very shut-in, dull and harsh it had a tiny slither of the magic I craved.

http://i1191.photobucket.com/albums/z475/Simonty1/PICT2373.jpg

It got treated to the nice super regulators, output sockets, Fidelity Audio C1 clock (re-clocking three pins of DAC, decoder & digital filter) and, eventually, a Pass Labs-designed D1 FET output stage. I upgraded to a B version of the SAA7220 digital filter, and an A version of the TDA1541 (later, a Taiwan-made chip for even better sound). Pure bliss and magic, if not the last word in detail or an airy spacious top end compared to other high-end players. At this time my favourite test disc was Carol Kidd's "Debut" on Linn records, and the player hit the spot incredibly well on her vocal. It was charming.

This player sadly met its demise due to a hard-to-trace fault that got worse and worse over time. I think it might have been a connector issue or hairline crack on a PCB track. These players are known for going faulty. No big loss as this player was just to test the water and was very cheap. Probably £20 for the player and maybe, ahem, £300 in parts to ugprade it.

Next up was my current player, an Arcam Alpha. This uses a slight variation of the same chipset: TDA1541A, SAA7310 (SMD decoder) and SAA7220P/B digital filter. The power supply of this player, as standard, is better than some, as is the layout. A nice touch is that they added a second power transformer just for the main audio board (the board Arcam add to make a Philips player into an Arcam one - containing some power supplies, voltage regs (LM317 and '337), the DAC chip and output stage (op-amps, naturally). Even as standard it's not a terrible player at all. Of course, modified to the hilt it is a wonderfully musical and dynamic performer with excellent levels of detail and ambience!

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF0016-1024.jpg

The player has MANY low noise regs, HUGE external power supplies, after-market clocking, Pass D1 output stage, good socketry, upgraded audio-board PSU transformer, regulated servo drivers and a cherry on top. Actually, there's no cherry but it has more mods I won't bore you with. I'm proud of this one. It's very heavy and that must mean it's good ;)

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF0015-1024.jpg

[SimontY]

Moving back to the speakers (I'm nearly done now, more or less) I was keen enough on the open baffle sound to begin designing a speaker from the ground up, using what I'd learnt from the first ones.

I decided on this sort of a specification:

* 24mm baltic birch plywood baffle
* cheap Eminence compression tweeter (can be upgraded later)
* Eminence Beta 8A (8" paper midwoofer)
* 2 x 12" Skytronic plastic woofers (cheap with correct[ish] TS params for OB loading)

After advice from Thorsten Loesch via e-mail, I decided to make the midrange semi-open baffle, using foam blocks (detachable) behind each driver.

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF4947.jpg

I also decided to mount the tweeter in an 8" waveguide, made from plywood (turned on a lathe).

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF4938-1024.jpg

To give the bass a bit of a extra energy and musicality I opted to incorporate Graham Maynard's T-bass or Transformer-Bass circuit, which uses some passive parts including a big toroidal transformer to step-up the output at driver resonance and, according to Graham, reduce energy storage in the driver. It seems to work.

Other tweakery includes modification of the Eminence Beta 8s, including EnABLing them (Bud Purvine's patented method for improving driver behaviour), painting tacky glue in various places and other things too... The drivers are good enough to use with no low-pass filtering. The roll-off is smooth and controlled at ~5khz. The hardest part of designing an open baffle speaker is getting a vaguely flat response. The mid driver uses a low-boost circuit comprising a 7.2mH coil in parallel with a 10R resistor. It also uses an LCR filter placed in parallel with the terminals. This reduces the (very audible) peaking centred around 490hz.

Bass roll-off is countered by starting the high-pass filter of the woofers VERY low, using a big 12mH ferrite-cored coil. Padding down the efficient top end drivers means throwing away a lot of energy but it's a necessary evil on a passive open baffle design where truly good bass is desired.

Anyway, the speakers have taken me two years to design, build and tinker to the point of sounding - in my humble opinion - excellent.

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF4170-1024.jpg

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF4948.jpg

[SimontY]

Here's the current crossover schematic of my speakers:

http://i1191.photobucket.com/albums/z475/Simonty1/Schematic_exp.png

And here's the measured response in-room at about 1m (you can ignore the red line and the text, I was just illustrating the effects of different capacitor values in the mid notch filter):

http://i1191.photobucket.com/albums/z475/Simonty1/Mid_Notch_Pt2.png

[SimontY]

The keen-eyed may notice there are no padding resistors in my speakers as such. This is because I've recently been considering the bi-amping route...

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF5121.jpg

I acquired a powerful amplifier cheaply (Carlsbro Powerline 800, older type with linear supply) and, temporarily ran my speakers with it in place of the Marantz MA500s. I sold the MA500s to a friend :)

As expected the sound was quite cold, lacking in space and brittle. I'd already modified the amp to use nice binding posts and RCA sockets and a film input cap rather than a tiny electrolytic, but it needed more. Oh, I also changed the cooling fan for a Panaflo and made it run at 7V, so it's nearly silent.

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF5161.jpg

The input pots (left and right volume controls) were changed to 12-position switches containing Allen Bradley carbon film resistors (shunting to ground) and I swapped some electrolytic caps on the output board to Elna Silmics. I also removed the clipping detection circuits and wiring and soldered 2.2uF film caps in the output section for PSU decoupling.... WOW! The amp was probably now on balance equal to the Marantzes, having a MUCH cleaner and better-defined bottom end, though still lacking the enjoyable bloom in the midrange. Quite interesting. Still, the best thing about this amp is its 400WPC/4ohms power rating - the amp will become something different later. The thing uses 16 output transistors and active cooling. The transformer looks to be about 1KVA, it's very big indeed.

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF5214.jpg

http://i1191.photobucket.com/albums/z475/Simonty1/DSCF5217.jpg

[SimontY]

I'd heard enough of the Carlsbro amp, I was still hearing a peaky top end. Things like poorly-recorded guitars would hurt the ears and that just isn't on. Harshness is the number one thing I hate in a system! So the next step was to reinstate my chip amp, just running my midrange and tweeters. The padding resistors were all removed.

The big PA amp was employed to run just the woofers.

The level was easily set using the input pot on the chip amp and the attenuators on my power amp (which I'd designed for fine-tuning: 1dB increments) watching the curve on my computer as I measured using my DIY measuring set up (Panasonic electret and "Mad About Sound" kit mic preamp).

With the levels between amps set, the sound leapt forwards in quality. Suddenly I had a pleasant midrange and treble once more, and the bass remained tight and powerful. Dynamics, detail and space took on massive gains. Finally, I have what I consider to be a very good setup!!! The sound is open, rich, detailed and extremely dynamic. Things like drums are produced with stunning impact for such a modestly "priced" speaker (modest in terms of drivers used).

The next big step will be building a JLH 1969 class A power amp to replace the chip amp. I have a feeling I'm going to like that, having heard a few class A transistor amps and pretty much falling in love each time!!!

I also need to replace the bright-sounding Chord interconnect that runs from the pre to chip amp, used because my nice foil interconnect wouldn't reach :-s

Well, that's that. My systems over the years, past to present. Boring details like mains filters, room treatments, power leads, speaker cables, interconnects, weird tweaks and racks left out for now :)

I'll go and lie down now... I hope someone enjoys reading my story.

Regards,
Simon

[Ali Tait]

Well! You do have it bad,don't you? :lol: That's quite some fiddling you've done,and I thought I was bad!
You say you hate harshness. Have you considered trying a valve amp? I think that would be the sound you are looking for. Valves and OB's is a great combination imho.

[John]

Agree with Ali valves really work well with OBs I bet the system sounds really good thanks for sharing The other thing I found that helped OB was using a mounting plate for the drivers

[Marco]

Hi Simon,

Welcome to AoS - and what an introduction! :)

Very interesting system and audio journey.... Could you do me a favour though and add your basic location details to your profile, as this is info is required from all members of our community.

Cheers, mate, and enjoy the forum! :cool:

Marco.

[SimontY]

Hi guys, thanks for looking and for the recommendations.

I have considered valves but can't really afford them yet, it seems very expensive to do properly. Now that I'm bi-amping, however, I could happily live with amps with poor bass and low power as the bass is taken care of separately and my top end is quite efficient and high impedance.

As I say, the next step will be class A with transistors. By all accounts the JLH amp sounds like many a valve amp itself! I do yearn to try valves (and records) one day, it just seems very expensive to do well, especially the records as I already have a very good source.

Marco, I've added my location and some other details.

John, when you say mounting plate do you mean some kind of metal ring or extra baffle insert to mount the drivers on?

Cheers,
Simon

[Ali Tait]

There was a pair of JLH's on ebay recently. Not sure f they sold or not.

[Ali Tait]

They did-

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=190463859155&ssPageName=STRK:MEWAX:VRI#ht_504wt_913

[SimontY]

I saw those and whilst they look ok, I think I can do a better job myself. To make it easy I've ordered pre-stuffed kit boards, and very cheaply! I will just add the power supply, chassis, heatsinking, connections and upgrade the components myself. With class A CD player output and preamp, the power amp is the final piece of the puzzle to banish any remnants of bad sound I reckon :)

[SPS]

if i've not got your name mixed up.. I think i met you down at the diy audio meet in sheffield about 3 years ago

that was a good day...

cheers
steve

[SimontY]

July 2007 in Chesterfield, yep. You had 2 x 12" full range open baffles running off DIY valve amps if I remember rightly :)

I did introduce myself in the welcome area some months back, though I've not posted a lot since.