Hi, I'm looking for a Headphone amp, I have a budget of £50. Have seen
this at Richer Sounds but haven't auditioned it yet. Any recommendations for any others.
I will be using it on a Shanling MC30 through the pre outs.
If you don't mind a portable amp there are a few options around that price - the JDS labs CMoy is quite nice also the popular PA2V2 from Electric Avenues are both under £50 to name a couple.
If you're handy with a solding iron maybe try knocking up a CMoy variant without a volume control as you're using the Shanling as a pre-amp.
Not really keen on a portable. Been doing some research on the B-Tech BT928. With a few mods it seems to be a good bit of kit. So I think I will go with that and do the mods, should cost less than my £50 budget.
Hi marineman. Please post a review of the amp, it has been mentioned before and it would be interesting to hear what you think of it.
OK, picked up Btech BT928 today. Will give it a test later . I will be using Grado SR80i's and Sennheiser HD40's (at least 25 years old) if I can find them.
First impression of the Btech BT928 with Grado SR80i
♫ Shanling MC30 ♫ Denon TU-1800DAB ♫ iPod Touch 8GB (4th generation) ♫ Quad 11L ♫ Chord Company Crimson interconnects ♫ Chord Company Carnival Silverscreen ♫ iBasso CB07 Line Out Dock Cable ♫ Atacama Equinox ♫ Atacama Nexus 6 + Atabites ♫ Btech BT928 ♫ Grado SR80i ♫ Sennheiser HD40 ♫
FM&DAB - Radio 3&4, Classic FM and Jazz FM international.
CD - Various Jazz & Classical plus 60's and 70's oldies.
iPod - Fleetwood Mac, Etta James and Audio Book.
It has a cheap pressed steel case and cheap black plastic knobs, but for the price I wasn't expecting much more.
It sounds a lot better than I had hoped. Midrange is quite delightful the bass is deep, turn the tone control full up and the sound becomes linear, and fully down the treble is almost non existent, so I will leave it in 'neutral' for now and let it run in for a while. On the whole I am very pleased, a real bargain at £29.95. (expert review needed - over to you What Hi*Fi SV)
My problem now is I have to unplug the speakers while using headphones, but I will make a speaker 'kill' switch to get over that problem.
After a bit of research I find it can be improved, and so I will be modding it in the future, this will include disconnecting the tone control and changing the capacitors & resistors. I will also replace the case (I have a blank full size aluminium amp case I got off ebay a while back) I can incorporate the speaker kill switch into that as well.
I just had a look online at these as I had never seen one before.
Some German guy has pulled his apart and posted pictures of the PCB's online, I redrew the circuit from the pictures (I would post it but I don't use Picasa or Flickr and you cant attach files on this forum unless someone can tell me how to) if you remove the tone control you will need to change some resistors as there will be to much gain, especially for low impedance headphones. You could supplement a switch and resistor in place of the tone control, then attach the switch to the front panel where the tone control was, something like a DP rotary switch would be nice you could then use the old knob. This would then give you switchable gain for different impedance cans, calculate the resistor values for a gain of 3.5 and about 9 this will cover most cans up to 600 ohms.
All I would say is don't follow all of the mods online as some of them will cause stability issues, this will become more imperative if you do some op-amp rolling. Also changing the resistors to metal film won't make a blind bit of difference.
Do you have a link to the web page please.
marineman wrote:Do you have a link to the web page please.
Whoops it's not German lol. Not sure why you wanted this and I Have not got a clue what it says. I just used the pictures of the PCB to reverse engineer the circuit. Looking at the pictures of the mods he's done I would take much notice, doesn't look like he knows what he is doing.
Just wanted a look at the components they use, Black Gate caps are what I use for repairing Sky HD PSU's.
Cheers for the link eggontoast.
Build and modding threads are very popular, could you post photos of what you are doing, thanks?
I think I will go with that and do the mods, should cost less than my £50 budget.
david05murray wrote:I think I will go with that and do the mods, should cost less than my £50 budget.
I know this is going to seem hypocritical as I am someone on the net. But just be advised that not all those mods are 'good' and some can cause instability so I would advise caution, but this is just my opinion and obviously you can do what you want. Looking at the circuit there are various mods that can be done, the tone circuit could be replaced with a bass boost, as previously mentioned you could add a gain switch. Replacing some of the electrolytics could slightly improve sound quality etc.
I have left it to 'burn' in for 24 hours +. My friend just brought his Creek OBH-11 round for a comparison and we both agree that there isn't much between them (considering the Creek is 3x more expensive). I will leave it alone for now and see how it goes.
If I remember correctly the Creek is based around the NE5532 op-amp also.