need help with mono block amp [Archive]

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jasonC

31-03-2015, 22:21

I have two mono blocks amps with psu.
ruby audio power 25 for they are 25 watts
they were by a very small outfit called ruby audio
the insides are very simple with not many parts,no printed boards
they sold on the bay
they are no longer on ebay and their only contact email i had is not working

the problem with the amps are, humming and popping when they are turned on and off.
also one of them does not always work which i think is because
the leads to connect the psu is not that great, so i would like to know if any member with the skills is able
to rehouse the two mono blocks in two new cases and the two psu in two new cases.
also do something about the humming.
i can not solder so can not do myself.
i can provide the cases and i do not of cause expect the work to be done for free.
if any one is able just pm me here :)

Firebottle

01-04-2015, 06:54

jasonC

01-04-2015, 13:38

Hi Jason,

It's a pity you are way down in Portsmouth, if you were round the corner I would help.

Perhaps if you can post some pictures of the kit to give folks an idea of what might be involved?

:cool: Alan

Good idea Alan, will get that done this afternoon. :)
if it helps i can post to anyone willing to help.

The Barbarian

01-04-2015, 13:51

Are they Chinese?

jasonC

01-04-2015, 14:50

jasonC

01-04-2015, 17:13

here is the pictures
mono block amps

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0830_zpsu2ft0woc.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0830_zpsu2ft0woc.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0829_zpsjhhnbei1.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0829_zpsjhhnbei1.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0828_zpswfw76uzj.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0828_zpswfw76uzj.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0826_zps6cisk6sx.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0826_zps6cisk6sx.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0840_zpslxrw8izs.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0840_zpslxrw8izs.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0839_zpsv0azqlhq.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0839_zpsv0azqlhq.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0838_zpsmuqtmbya.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0838_zpsmuqtmbya.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0837_zpsfh8u2ez6.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0837_zpsfh8u2ez6.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0836_zpspqy2xxmd.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0836_zpspqy2xxmd.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0834_zpskyvdodbp.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0834_zpskyvdodbp.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0833_zps6tayyvwv.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0833_zps6tayyvwv.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0831_zpsquibkh5f.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0831_zpsquibkh5f.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0840_zpslxrw8izs.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0840_zpslxrw8izs.jpg.html)

Now the psu pictures

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0847_zpsnuyhymcg.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0847_zpsnuyhymcg.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0846_zpscsqgzgpv.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0846_zpscsqgzgpv.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0845_zps6si0olwx.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0845_zps6si0olwx.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0844_zpsqpdusndn.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0844_zpsqpdusndn.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0843_zpsuxgcczmo.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0843_zpsuxgcczmo.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0842_zpscuwr6old.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0842_zpscuwr6old.jpg.html)

http://i1067.photobucket.com/albums/u440/soncroft7/DSC_0841_zpsnn3onw7s.jpg (http://s1067.photobucket.com/user/soncroft7/media/DSC_0841_zpsnn3onw7s.jpg.html)

pitadavespa

01-04-2015, 17:23

Hi Jason,

I had both the Power 25 and the Power 50.

I never had any problem with humming.
Do they both do it?
Is it a mechanical humm coming from the amps or a noise humm coming from the speakers?
Can it be the psu plug that is not ok?

Regarding popping, they don't have a muting circuit (or something like that) so you better have the volume down when you turn them on/off.

Rubyaudio disappeared. I had good faith on them at the time and liked the amps raw style, but now I have a feeling they (or he) had a lot of good talk and not much more than that, if you know what I mean.
I hope I'm not being unfair, but after seeing the amps inside... :\

Good luck with yours. I'm sure you'll find someone here that can help you.

edit: I also had a passive pre.

jasonC

01-04-2015, 17:36

Did you Luis sell yours on ebay sometime ago as i remember seeing a power 50 on sale on ebay sometime back and it was a auction from someone in Portugal, it was grey unlike my one which is black.
The sound of the amps i really like.
the hum is like the hum you get from a valve amp though it was not that bad when used with a active pre.
It came from the speakers,the amps themselves made no noise.
I think the issue is due to the cables and leads leading to the psu,
also the green light on the amp is pretty useless as in keeps coming lose.
I think the amps themselves work fine.
they just need a better case and cables as i think one of the cables,mains one is the problem.
i think though that they were so cheap that to make money they would need to sell large numbers and they were not the most pretty things to look at.

i had the passive pre too but i did not think much of it so replaced with a better one that really helped make them sound better.
until that point i never knew a passive pre had an effect on the sound.

pitadavespa

02-04-2015, 11:19

Hi Jason,

Yes, I did. It was in the end of 2012, though. Time flies!

They were similar in sound to the power 25 but, because they had more power, they could take a bit more bass from the speakers.

Regarding hum, did you try separating mains , interconnects and speakers cables from each other?
Maybe your interconnects are caching some noise from the mains cables.
Did you try some kind of electric noise filter?

The problem with the green light is the lamp is not well screwed. If you unscrew the green plastic and, with much care and with the power unplugged, using some kind of tong, screw the little lamp in, it should be fine.

--
Luis

337alant

02-04-2015, 18:34

no they are not.
they were handmade here in the uk.
not made using kits from china
i was told by the guy at ruby audio that they were based on crimson mono blocks
i have my phone on charge so will have pictures on here within the hour or two

O dear ! Carjay its not good news I'm afraid
They certainly are not based on any Crimson mono block amplifier they are a very simple chip amp very poorly wired together with what looks like telephone or network cable and a woefully inadequate power supply
You may scorn at the Chinese lM3886 chip amp kits on ebay but they work well and are vastly superior to what you have here Im afraid
sorry to sound negative but I am being honest, they are not even worth rehousing IMO throw the lot in the bin

Alan

Puffin

02-04-2015, 19:19

Radford Revival

02-04-2015, 19:52

I don't like to bring bad news but mirroring what others have said, the construction quality (if unmodified) of these is so glaringly appalling (I generally would never openly criticize but I don't think anyone could possibly disagree in this case?) and the actual value of the components inside so low, money spent paying someone to fix it would be much better spent either commissioning a new ones built properly or buying ready made.

jasonC

02-04-2015, 20:28

thanks for that.
better to be told the truth even if it not good news then be told a lie to make me feel better.
You all clerarly know more then i do, so to not heed your advice would be stupid and disrespectful.
when it comes to diy hifi i know nothing.
i have seen kits on ebay and valve ones but i get worried buying kits frim china.
Thankyou for saving me wasting my money. :)

dowser

04-04-2015, 14:35

If you really like them, they can be cleaned up and made safe, but cost would likely outweigh any resale value. I personally make some very bodgy DIY kit...but I would never actually sell something that looks like that!

Richard

337alant

04-04-2015, 18:13

Have a think about how much money you wish to spend and ask for recommendations
You would be surprised how inexpensive the Tripath T class and Class D amplifiers are and they sound very good on a sound per £ basis

RichyB brought a T class amp to a recent Bake off and it was amazing for a tiny little amp

Alan

Puffin

04-04-2015, 21:01

Jason, the Cambridge P500 power amp on sale on here would have been a good amp to replace your current bun (did you see what I did there......current....Easter)....... Yeah..,,,,,However it looks like it has now been sold.

If that thing masquerading as an amp is supposed to give out 25w per channel, what speakers were you using it with?. Do you need 25w?

As Alan says a Class D/(T) amp might be worth trying. Some will only give as little as 5 real watts, but you would be surprised what they do with those watts. I have a board that you could try if you are interested.

Rob.

walpurgis

04-04-2015, 21:09

Here.

http://theartofsound.net/forum/showthread.php?37544-FS-Cambridge-Audio-P500-Power-Amplifier&p=636070#post636070

It's a bargain at the price.

struth

04-04-2015, 21:31

I have one I might sell. has a few scratches but works great...

Light Dependant Resistor

05-04-2015, 02:24

Hi
The integrated circuit (IC) appears to be a LM1875 which are a 20w device. Every other kit that does these
builds them into a circuit board, which is not only tidier, but important in terms of the IC's performance.
Stray leads that are connecting a amplifier stand every chance of equally amplifying noise and creating
oscillation which is often outside the frequencies of human hearing, If oscillating the audio band that it
is meant to work with will be distorted. Tidiness with input/output and DC supplying amplifiers is essential

A far better IC is the LM3886 which is readily available in kits mounted on a circuit board
in its cheapest implementation is quite good sounding, But can be made exceedingly good
with painstaking attention to detail, the Modulus 86 being one of the best.

If you want to continue on with what you have there you need a schematic and builders guide for the LM1875
reading it cover to cover you should locate all the mistakes being made, and you might be able to get a
reasonable sound with a few hours work. http://www.ti.com/lit/ds/symlink/lm1875.pdf

Observing the application notes see how the circuit works - try and ascertain what components are missing
I would be happy to wire this for you but I am in New Zealand.

To correct the LM1875 present disaster zone you have there, at a minimum you will need to correct the layout,
mount boards properly observing wiring that is DC, wiring that is signal and wiring which is output, making the wiring
as short as possible so DC entry near to where it is needed Signal input observing and using a star earth for ground leads
making that wiring neat, and output observing the recommendations in the users guide.

Cheers / Chris

Desmo

05-04-2015, 11:18

To correct the LM1875 present disaster zone you have there, at a minimum you will need to correct the layout,
mount boards properly observing wiring that is DC, wiring that is signal and wiring which is output, making the wiring
as short as possible so DC entry near to where it is needed Signal input observing and using a star earth for ground leads
making that wiring neat, and output observing the recommendations in the users guide.

Cheers / Chris

Or just bin them and buy something that works....

pitadavespa

07-04-2015, 11:56

O dear ! Carjay its not good news I'm afraid
They certainly are not based on any Crimson mono block amplifier they are a very simple chip amp very poorly wired together with what looks like telephone or network cable and a woefully inadequate power supply
You may scorn at the Chinese lM3886 chip amp kits on ebay but they work well and are vastly superior to what you have here Im afraid
sorry to sound negative but I am being honest, they are not even worth rehousing IMO throw the lot in the bin

Alan

+1 :\

Jason, I was trying not to be rude, since you said you liked the amps sound, but they are really badly made, like other have said. I'm sure that Ruby Audio's talk was just that. Talk and bulls***
Mine had a better (or at least bigger) PSU, though.
Sorry for not telling you the truth back then. :(

They didn't sound like crap if they were not over-driven, but when I bought my Temple Audio monos, they were a BIG improvement over the ruby audio ones. And I really mean big!

I hope you find a good amp that suits you.

Cheers,
Luis

pitadavespa

07-04-2015, 11:57

Jason,

What speakers do you have?