*** The DIY Audio Thread ***
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Associate
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Cheers adam. Just wanted to make sure - i found some conflicting advice when using google. Thanks again.
Soldato
Can anyone recommend any high end transistor amplifier kits around the £500 + mark ?? I would love to try an Audio Note kit but cant justify the £1k price tag as well as having to get more efficient speakers. Difficulty of build isnt an issue.
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Yeah, i know. I want to try some black gate caps, and one i need only comes in a 250v rating (ugh...). I wanted to check it would work since they are quite a lot more than regular caps.
Soldato
ordered my transformer and tantalum's for the DAC this morning, should be hear wednesday so progress is slow but sure, ill use the stock caps for a day or two then move to tantalum beads and stick to them for a week or two which ill then replace with oscon. Still very undecided weather to use the onboard opamp upgraded or run it without. What benefits do balanced input/outputs give over standard unbalanced? And what sort of problems would i encounter not having a pre amp yet if i go the route of the opamp free design?
Soldato
I've gone for function over form - amp in a shoe box!
Here it is in action, sounds great!
It's the same as an Amp9 basic, I'm only using 2 channels right now, but I'll be using the other two once I've built some more subs.
Here it is in action, sounds great!
It's the same as an Amp9 basic, I'm only using 2 channels right now, but I'll be using the other two once I've built some more subs.
Take a look at the Truepath over at 41Hz.com, in terms of sound quality it gets rave reviews. Once you spec it up with PSU and a nice chassis and all the other gubbins, you'll be pretty close to £500. It will have plenty of power so you won't have to change your speakers also.
Soldato
quick noob question
I have decided to build my own headphone amplifier...however since I am a beginner and only have very basic electronics knowledge I'm going to start with a CMOY because it's so cheap and because it's very simple.
However, I have no need for portability so would like to use a PSU rather than a 9v battery.
Which sorts are suitable for something like this? Can someone point me to something appropriate at rs-online as that's where I'm ordering all my parts from.
thanks in advance!
I have decided to build my own headphone amplifier...however since I am a beginner and only have very basic electronics knowledge I'm going to start with a CMOY because it's so cheap and because it's very simple.
However, I have no need for portability so would like to use a PSU rather than a 9v battery.
Which sorts are suitable for something like this? Can someone point me to something appropriate at rs-online as that's where I'm ordering all my parts from.
thanks in advance!
Soldato
The best thing to do would be to build a linear PSU and do away with the rail splitter (if there is one). +-15v should work.
All you need is a toroid, some caps and a bridge rectifier.
All you need is a toroid, some caps and a bridge rectifier.
Soldato
sorry I am a complete noob and need some more info than that...
Like I said, this is my first DIY project and I will also be building an Alien DAC in conjunction with the CMOY.....unless the PSU is very simple I'd rather just get an external wall wart of some sort as I don't want to find myself overwhelmed.
Would something like this be appropriate?
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6158925
thanks
Like I said, this is my first DIY project and I will also be building an Alien DAC in conjunction with the CMOY.....unless the PSU is very simple I'd rather just get an external wall wart of some sort as I don't want to find myself overwhelmed.
Would something like this be appropriate?
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6158925
thanks
Last edited:
Soldato
^ That wall wart will be fine. Just make sure you put a power socket on your amp and the circuit has a rail splitter in it.
Soldato
yup it's got a rail splitter in the power supply circuit.
thanks for the help.
thanks for the help.
Soldato
Hi, got my transformer today but seem to be having a weird issue, plugged my tranny up and powered the psu board for the Dac on to check voltages and im getting 5v on the 5v rail, +12v on the +12v rail but -14.7v on the -12v rail.
Any ideas as to what could be causing this, i dont want to plug the DAC board up untill i get it sorted and ive checked the circuit over and it seems fine
Any ideas as to what could be causing this, i dont want to plug the DAC board up untill i get it sorted and ive checked the circuit over and it seems fine
Soldato
41Hz.com Amp9 Basic kit arrived today, I'll have some pics up in a bit. I need to get soldering! 
I'd have a look at the circuit myself, but my DAC still hasn't arrived, yet I ordered it on the 12th... It must be on the slow boat from China. How long did yours take to arrive.
-14.7v on the -12v rail? That's pretty wierd... The + and - 12v rails only power the op-amp. Ideally op-amps prefer to to have matched voltages, but are tolerant of a slight variation, so you'd probably get away with it. Just check the DC offset before plugging it up to your amp. You may be able to use a few diodes to bring the voltage down a little...
I'd have a look at the circuit myself, but my DAC still hasn't arrived, yet I ordered it on the 12th... It must be on the slow boat from China. How long did yours take to arrive.
Soldato
Problem solved, turned out to be the negative voltage reg, so take head and check you voltages any one that get this dac, this is the first time ive attempted to power mine up. Like said above may be fine but better safe than sorry!
Soldato
Resolderd it and it didnt make a difference so i just replaced it, got some pictures ill post shortly, i put the tantalum beads on as soon as i listend to it as the sound stock was to grainy and weak for me to put up with for 2 weeks. ill post results and pics soon.
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Amp6: Round 2
Well, i was rudely awoken by the postman to find Amp6, number 2...
Not pictured are the black gates, which got here very quickly. I didnt go for a complete refit of the capacitors in the end due to the cost: replacing all of the decoupling caps etc would have cost a lot (in fact i worked out it would have been cheaper using OS-con caps, even though you need to buy in multiples of 5 from RS, and would have been nearly half the price of the amp) Instead i went for just a few on the input stage. I posted earlier about voltage ratings etc, and unfortunately the only 3.3uF Black Gates were rated at 250v, so were quite expensive and were pretty big. I was confident they would fit with some bending, but didnt think about the width of the legs, which proved to be a bit of a mistake, and in the end i resorted to filing them down.
I spent quite a while on the soldering, and its a LOT better than my previous effort. And the result is... it works! As of yet, i havent had to make any adjustments, although i will measure DC offset etc and check all the voltages, but no smoke (!) and plenty of sound. There is a faint hiss - the manual suggests it could be the power supply decoupling caps, but i suspect that its probably the source (old creative mp3 player + low bitrate wma's...). Anyway, heres the money shot:
Its a bit ghetto - the ice cream box holds the power supply, but for now it works. I think im gonna buy a passive pre kit from dantimax to control the volume + output to an LCD, and i have yet to decide on the enclosure, but there are some mighty fine examples on head-fi, so i feel that there may be some significant expense still to go...
Well, i was rudely awoken by the postman to find Amp6, number 2...
Not pictured are the black gates, which got here very quickly. I didnt go for a complete refit of the capacitors in the end due to the cost: replacing all of the decoupling caps etc would have cost a lot (in fact i worked out it would have been cheaper using OS-con caps, even though you need to buy in multiples of 5 from RS, and would have been nearly half the price of the amp) Instead i went for just a few on the input stage. I posted earlier about voltage ratings etc, and unfortunately the only 3.3uF Black Gates were rated at 250v, so were quite expensive and were pretty big. I was confident they would fit with some bending, but didnt think about the width of the legs, which proved to be a bit of a mistake, and in the end i resorted to filing them down.
I spent quite a while on the soldering, and its a LOT better than my previous effort. And the result is... it works! As of yet, i havent had to make any adjustments, although i will measure DC offset etc and check all the voltages, but no smoke (!) and plenty of sound. There is a faint hiss - the manual suggests it could be the power supply decoupling caps, but i suspect that its probably the source (old creative mp3 player + low bitrate wma's...). Anyway, heres the money shot:
Its a bit ghetto - the ice cream box holds the power supply, but for now it works. I think im gonna buy a passive pre kit from dantimax to control the volume + output to an LCD, and i have yet to decide on the enclosure, but there are some mighty fine examples on head-fi, so i feel that there may be some significant expense still to go...
grainy???? mine is too smooth stock. I have tried a few opamps. results:
opa2107: super smooth, quite dark and really organic highs. You can really crank the volume and the highs remain silky smooth. This is a cracking opamp, I doubt very much if you could tell this between two 627's. Its funny, you never plug in a burr brown opamp and think WOW, but i garantee you will always end up with it in your system steady state.
AD826: punchy, detailed, aggressive. If you want to brighten you system go with the analogue devices. I use senn HD650s and grados. Its creat with the 650s, but too aggressive with the grados.
OPA2134: somewhere in between. Slightly boosted bass (bloated?) but good snap and steely highs. good cheap opamp.
Which is in my system? opa2107.
By the way, i have read around, the suggested size for output caps on 'art of sound' (or whatever that colourful forum is) of 3 - 10uf seems way high to me. Do the maths, you only need about 0.4 uf to prevent any bass roll off, the next thing this dac will ever see is a preamp or pot, in which case its going to be 10k resistance or more. corener frequency of 3 hz only needs 0.33uf or there abouts. This means you can buy a nice cap for not much cash. The claritycaps sound good to my ears, definate improvement on the wimas.
By the way, I have a spare of each opamp that i am willing to take a small hit on.
opa2107: super smooth, quite dark and really organic highs. You can really crank the volume and the highs remain silky smooth. This is a cracking opamp, I doubt very much if you could tell this between two 627's. Its funny, you never plug in a burr brown opamp and think WOW, but i garantee you will always end up with it in your system steady state.
AD826: punchy, detailed, aggressive. If you want to brighten you system go with the analogue devices. I use senn HD650s and grados. Its creat with the 650s, but too aggressive with the grados.
OPA2134: somewhere in between. Slightly boosted bass (bloated?) but good snap and steely highs. good cheap opamp.
Which is in my system? opa2107.
By the way, i have read around, the suggested size for output caps on 'art of sound' (or whatever that colourful forum is) of 3 - 10uf seems way high to me. Do the maths, you only need about 0.4 uf to prevent any bass roll off, the next thing this dac will ever see is a preamp or pot, in which case its going to be 10k resistance or more. corener frequency of 3 hz only needs 0.33uf or there abouts. This means you can buy a nice cap for not much cash. The claritycaps sound good to my ears, definate improvement on the wimas.
By the way, I have a spare of each opamp that i am willing to take a small hit on.