*** The DIY Audio Thread ***

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Hi all,

Great thread this, decided to have a pop at a CMoy amp myself, could someone take a look at my PCB and tell me if it looks OK?


Click Me!!

Thanks

James
 
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Hi All

I need some help with some vintage Wharfdale speakers. I got a pair of Wharfdale Denton 2XP's cheap from a charity shop. I gave them an audition last night and I must say they sound very good. However, one of the tweeters has blown.

I have searched around the web and I think it is a non starter trying to find a like for like replacement tweeter. So can I buy two tweeters, not sure which ones yet, and just install them, connecting them to the current crossover? Or will I have to make adjustments to the crossover? I have no information on the specs of either the mid range drivers or the current tweeters, or the crossover.

Should I quit now and just forget about them?
 
Soldato
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This thread isn't as popular as it used to be! Time for a bit of an update from me anyway. It's copy'd and pasted from another forum I frequent so may include too much basic info for the experienced DIY'ers but I thought I'd leave it all in for any people new to this sort of thing.

This update as come about as I left Ireland 6 months ago for a bit of world travelling. We hadn't expected to enjoy Australia as much as we have so it's now apparent that we won't be leaving any time soon. Now that we're spending some time stationary, I've really been missing having music to listen to as this was pretty important part of my life. I still had all of my hifi gear at home which is fairly decent stuff so I had 2 options - ship it over or buy new. A quick look at some shipping costs confirmed that speakers would cost a fortune to get here as would my heavy amps. Couple that with the damage that they could sustain in transit, I decided to start again but with a slightly different view.

I dabbled with DIY hifi before, being an early adopter of Tripath amps and playing with Non-Oversampling Dac's. However there was one aspect which I had never tackled and was really keen to - speakers!

The aim: To build a 2 channel amplifier and set of speakers which would perform as well as possible for under $500.

The amplifier
In the past I had had a few DIY amps (TA2020 bi-amped and TA2024) and a few commercial amps (Arcam 8r, Leak 20, Meridian pre/power combo). I really liked the tripath stuff but I always found it a little bit gutless only being 20wpc. It did however compare admirably with the Meridians which are a couple of grands worth.

After a bit of research, I found that the TK2050 chipset was now being used and was available in a few different forms:
Sure Electronics
Hifimediy
Dayton Audio
41hz Monoblock

The TK2050 differs from the more popular tripath chips as it ideally needs 28v to operate which gives it a bit more juice and generates 75WPC into 4ohms @ 0.01% distortion. The Dayton is a great option for plug and play but only runs a 24v power supply so for this reason and also due to doubts on build quality I discounted the Dayton Audio. I discounted the Sure Electronics amp having read that the sound was superior to the Dayton but the build quality was sub standard. That left the 41hz amp and the hifimediy. To be honest, the 41hz amp probably would have worked out as the best option but it was twice as expensive and you have to build it yourself. So laziness and tightness won and the hifimediy amp was ordered with some RCA connectors. A suitable SMPS power supply was also ordered from ebay.

The Speakers
This was the part of the system that I deliberated over a lot. I wanted something simple to build as I have no tools here and I wanted the materials to be cheap to build the speaker. I was interested in building a loaded horn design using a full range driver as I'd read a lot of positive reviews and it's a much simpler design requiring no crossover. The mark up on commercial speakers is huge and most commercial speakers can be built for about 10% of their retail cost.

After lots of reading, I was looking mainly at Fostex drivers as they are efficient and designed for loaded horn designs. However, after some suggestions, I drew up a shortlist which included the following:
Fostex FE206En
Fostex FE166En
Fostex FE126En
CSS EL70

To be honest, I hadn't really considered the CSS EL70s until they were recommended by someone with experience of all the above drivers. After a bit of research and the fact that they worked out the cheapest, I was sold!
I went around lots of designs but finally decided on the inverted BiB derived horn as it is incredibly easy to construct, is designed to sit in corners and looks pretty good. It appeared a good time to master google sketchup too. After inputting the speakers parameters into the BIB calculator, I was given the dimensions I needed to work with.
el70.jpg


This is the design of the speaker:
sideej.jpg

The bottom of the speaker is open and is raised off the ground by approximately an inch and I will eventually cut karllson slots into the side which will improve the sound further.

I ordered the EL70s from Canada and then bought 2 sheets of plywood and got them cut to size.

The Source
The only bits I will be shipping from home will be my TDA1545a DAC and my projector. They'll come over sometime in July in someones luggage to save cost!
All of my music is electronic at the moment, so I wanted an all in 1 job to play my music, my movies, watch&record tv. The most obvious selection was the Playstation 3, so I purchased one of those the other day which isn't exactly in the spirit of cheapness, but it's a bonus that I can play Gran Turismo ;D

Costs so far:

Amp
Hifimediy T2 & RCA: $59
SMPS: $34

Speakers:
Drivers: 124
Plywood: $90
Cutting: $10
Glue: $12

Total spend: $329 which is pretty much exactly £200!

I don't have any other necessary expenses to complete the project, but I will be trying to pick up some cheap solid core Cat 5 for speaker cabling and try and find something I can use as a case but that could end up being another cost.
 
Soldato
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The weather today was about as miserable and wet as any I've seen in the UK or Ireland. That made it the perfect day for working inside on some speakers!

Unfortunately, tools are sparse but I managed to get my hands on a VERY wonky jigsaw and 2 half broken clamps. Oh yes, this was already shaping up to be a successful build...

Anyway, with holes (which looked like they had a stroke) cut for the driver, it was time to start glueing it all together with the help of Selleys Aquadhere. It was at this point that I noticed that matey at the builders merchants had given me warped plywood. Nice one, thanks. I'm too impatient to get it all done again so I figured that, as this is my first speaker project, I'd persevere and see how it goes.

Some Pictures from todays action:

Glueing the second piece (note the expensive water bottle weight)
img2550t.jpg


Glueing down the baffle:
img2552.jpg


Glueing down the other side of the speaker. I needed this much weight to try and un-warp the wood
img2554m.jpg


Sticking on the top piece of the speaker:
img2555g.jpg


I'm using some pretty ropey speaker cable that came free with car speakers I bought for the Falcon, but that's easily changeable as I'm going for a binding post free design. Less connections = good.

The speakers still need the front fascia putting on which will be primed and sprayed Matt black as per my image above. I reckon this will look pretty good and I may be able to get away without veneering the speakers as the ply finish isn't too bad. We'll see.

In other news - I received a note that I have a parcel waiting for me at the post office :D All I need to do is to find a soldering Iron for 2 connections on the amp and I'll be listening to music !
 
Soldato
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I'm in regional Australia so I couldn't find any more clamps but the broken ones. However, the fact that the wood was warped meant that I could actually do the gluing in 2 stages. It seems to have worked pretty well as the speakers seem strong. More updates later.
 
Soldato
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This thread isn't as popular as it used to be!
I know, a bit of a shame, it went off my radar so a bump is always good. :)
The aim: To build a 2 channel amplifier and set of speakers which would perform as well as possible for under $500.

The amplifier
In the past I had had a few DIY amps (TA2020 bi-amped and TA2024) and a few commercial amps (Arcam 8r, Leak 20, Meridian pre/power combo). I really liked the tripath stuff but I always found it a little bit gutless only being 20wpc. It did however compare admirably with the Meridians which are a couple of grands worth.

After a bit of research, I found that the TK2050 chipset was now being used and was available in a few different forms:
Sure Electronics
Hifimediy
Dayton Audio
41hz Monoblock

The TK2050 differs from the more popular tripath chips as it ideally needs 28v to operate which gives it a bit more juice and generates 75WPC into 4ohms @ 0.01% distortion. The Dayton is a great option for plug and play but only runs a 24v power supply so for this reason and also due to doubts on build quality I discounted the Dayton Audio. I discounted the Sure Electronics amp having read that the sound was superior to the Dayton but the build quality was sub standard. That left the 41hz amp and the hifimediy. To be honest, the 41hz amp probably would have worked out as the best option but it was twice as expensive and you have to build it yourself. So laziness and tightness won and the hifimediy amp was ordered with some RCA connectors. A suitable SMPS power supply was also ordered from ebay.
I'm running 2 x Tk2050 Sure boards in a bi-amped setup, they sound awesome, and they almost too good for my speakers, if that makes any sense.

It's hard to describe the TK2050 sound... It's like like a TA2020 with just as much detail but better dynamics. It's also got plenty of power, more than enough for lower sensitivity speakers.

The hifimediy boards are a nice choice, it's pretty similar to the Sure board, but sounds better straight out the box while the Sure really needs quite a bit of modification in order to get it so it reaches it's pull potential. Output choke swap and input DC blocking capacitor are pretty easy to swap but if I had the choice again I'd also go for the hifimediy boards... I bought my Sure boards before the hifimediy boards were around.

If you've already ordered your PSU's, then 28v will be fine.

I run my Sure boards at 32v and the dynamics to improve when you use a higher voltage, but 36v is the limit of the TK2050 so you don't really want to exceed that so I allowed a little margin for error.

If you still have not chosen your PSU, I can recommend the 27v Meanwell 320W SMPS. These can be adjusted from ~25v-33v which is ideal for almost any TK2050 board.

If you want to see a commercially sold TK2050 amp, check out Red Wine Audio, then check out the price, then be glad you've got the skills to DIY so you don't have to pay $10,000+ for an amp! ;)

(It's also worth noting that these amps run rather nicely off batteries, which is what Red Wine Audio recommend. I've got quite a few old laptop batteries that I have wired in series which gives 32v when fresh off the charger. I would say that the amp sound different when running on batteries, but only slightly, SMPS' work really really well with TK2050 based amps in my experience...

I often use this amp to power speakers outdoors or in rooms without power and it's nice to have something that sounds great yet is still easy on the batteries also...)
The Speakers
This was the part of the system that I deliberated over a lot. I wanted something simple to build as I have no tools here and I wanted the materials to be cheap to build the speaker. I was interested in building a loaded horn design using a full range driver as I'd read a lot of positive reviews and it's a much simpler design requiring no crossover. The mark up on commercial speakers is huge and most commercial speakers can be built for about 10% of their retail cost.
Having no crossover is great, this solves many potential issues....

I love horns, they sound effortless and again they sound like nothing else if they are well designed and built. I would class myself as a horn nut! :D

I've only built a couple of largish sub bass horns, so I'd be interested to see what you think of your full range horns once they are all up and running.

Finally, I'm only going by your sketchup diagram of the internals, but would I be right in assuming this is a tapped horn design?
 
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Soldato
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Hey Mike,

At first I was looking at the Sure amps, but I was persuaded to go for the hifimediy boards by the guys on DIY audio. Hopefully I won't regret my decision!!

I didn't think it was possible to bi-amp the TK2050? Must be plenty of power! Talking of power, I picked up a 27v 350w SMPS powersupply manufactured b B&G. It's identical to the meanwell in spec and look and was nice and cheap!

It's a tapped horn yup! The speakers are now in my possession and in about 1 hour it will all be hooked up and ready to play. To say I'm excited is an understatement!

Unfortunately my source at the moment is either an ipod or a DVD player as I won't have my NOS dac until July. Still should sound fantastic!
 
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Hey Mike,

At first I was looking at the Sure amps, but I was persuaded to go for the hifimediy boards by the guys on DIY audio. Hopefully I won't regret my decision!!
You won't regret your decision, sorry for waffling on so much, I'm at work with nothing better to do... ;)

The hifimediy boards beat the Sure boards in pretty much every way, PCB build quality, component selection, Sure did cut some corners with their TK2050 board for sure... This is why I swapped out lots of components on my Sure board, which made it sound better. The only department the Sure wins on is cost, and but the time you've bought the extra components to upgrade the Sure, there's probably not much in it.

The hifimediy board comes with these 'upgrades' already soldered on when you buy the board, so you're hifimediy board will be on par or even better than my modded Sure boards... :)
I didn't think it was possible to bi-amp the TK2050? Must be plenty of power!
When I say bi-amp, I'm powering some 2 way speakers with a woofer on channel 1 and the tweeter on channel 2, and running an active crossover.

The is the proper way of bi-amping, you need to totally do away with the passive crossover to see the benefits of bi-amping.

My woofer is 4ohm, so yep there's more than enough power when running 32v into my Sure boards...

Talking of power, I picked up a 27v 350w SMPS powersupply manufactured b B&G. It's identical to the meanwell in spec and look and was nice and cheap!
Well if it matches the Meanwell spec then it will work really well...

27v is ideal, you'll be able to crank her up to 32v for that extra bit of power from you amp boards...
It's a tapped horn yup! The speakers are now in my possession and in about 1 hour it will all be hooked up and ready to play. To say I'm excited is an understatement!

Unfortunately my source at the moment is either an ipod or a DVD player as I won't have my NOS dac until July. Still should sound fantastic!
Tapped horns are awesome, I remember when I was waiting for the glue to properly dry on that 30Hz monster I made, I ran a few test tones at first, and after that I spent hours sticking on any DVD with some rumble on the LFE channel, so I know that feeling of anticipation... You won't be disappointed.

As for your source, don't worry too much about that, it's easily swapped and while an iPod isn't ideal, something like a Sandisk Sansa Clip is cheap and sounds very good IMO, especially with FLAC files.

Sure it's not considered high end, but I'm still to this day surprised how clean it sounds. :)

It's almost 6am now, so I'm going to get some sleep soon, I'll look forward to hearing your thoughts on it once it's all up and running. :cool:
 
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So they're finished. Like a dumbass I didn't get any pictures in decent lighting, so here's a very unflattering teaser photo:
img2558s.jpg


I haven't really had much of a chance to listen to them as TV is king in the evenings but initial impressions are OK. I think I need to work on their positioning a lot but this was just a test to make sure everything works. There is a hum out of the amp which is irritating and I can't see a reason for it so I hope it's not the power supply.
 
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I've never had any hum on my TK2050 amps when using a Meanwell SMPS... Very strange.

I've be tempted to try using your iPod, with no charger plugged in.

If you're still getting hum then then something is wrong...
 
Soldato
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I wrote hum but I meant hiss. There is a pretty strong hiss from the amp through the speakers. I've tried it with the RCA plugs disconnected so it's not that which leaves me a little bit bemused. The only thing I'm thinking is that I'm using a 2 pin plug not a 3 pin plug so there is no ground going to the power supply. Should still be ok though as most electronics over here are 2 pin..
 
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Didn't see this thread before for some reason. LOVE DIY audio, particularly watching full-range speakers get built, and in future I'd dig a Buffalo II DAC or that kinda thing, as I love a bargain!
 
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Cheeky question for you DIY'ers. Any of you build for others? It's just I'd kinda like an AMB M^3 amp, with a couple of the extras (variable bass boost, not sure about gain but I'm an IEMs guy). The headphone amp on my Yulong D100 DAC is alright, but prefer to get a dedicated amp to connect to the L/R RCA outputs (using the XLRs for studio monitors).

Not sure what it'd even cost but it seems like it'd be cheaper than getting something like a Burson HA 160 or similar to the Matrix M Stage amp but with more flexibility.
 
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I wrote hum but I meant hiss. There is a pretty strong hiss from the amp through the speakers. I've tried it with the RCA plugs disconnected so it's not that which leaves me a little bit bemused. The only thing I'm thinking is that I'm using a 2 pin plug not a 3 pin plug so there is no ground going to the power supply. Should still be ok though as most electronics over here are 2 pin..
Ahh, hiss... I've also experienced a little hiss (white noise) from these TK2050 amp boards, but I've found it to be constant, as in it will not go up or down at all with the input signal. I found this was pretty noticeable with my tweeters in my 2 way setup, and I used an L-pad circuit which reduces the hiss of my tweeters, along with the sensitivity.

It may be worth trying to short the inputs to ground, and also check for DC offset while the inputs are shorted. It should be less than 100mV If you're still getting too much hiss with the inputs shorted to ground try mounting the PCB on a metal Chassis which is grounded, this can reduce hiss a little...

Finally, what sensitivity are your drivers? Remember the horn enclosure will increase your sensitivity at certain frequencies also, so it's worth bearing this in mind and you may find you get similar amounts of hiss with other amps also...
Cheeky question for you DIY'ers. Any of you build for others? It's just I'd kinda like an AMB M^3 amp, with a couple of the extras (variable bass boost, not sure about gain but I'm an IEMs guy).
Hi, I'm actually going to be starting a headphone amp soon as a project, it's mostly SMD parts for low noise and should sound awesome when finished.

If it all goes to plan, and if I have enough free time I may be able to start doing projects for other people. :)
 
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