Low Cost Linear PSU for Temple Audio Monoblocks?

[Alp]

I had been running my four Temple Audio monoblocks very nicely on 16V Li Ion batteries for a couple of years until one of the batteries died recently. Since they are around £60 each to replace, and I would probably replace both, I started wondering if there are affordable linear PSU alternatives which will hopefully last longer than two years. Sean at Custom Hi-Fi Cables was very helpful but his DC1, DC2 and DC3 PSUs are much more than I want to spend at present. A couple of Mark Grant's S-Booster PSU would also end-up in the same territory.

There are some Chinese Linear PSUs like this one 2017-HiFi-PSU-25VA-DC16V-1-5A-Linear-Power-Supply-for-Upgrade (http://www.ebay.co.uk/itm/2017-HiFi-PSU-25VA-DC16V-1-5A-Linear-Power-Supply-for-Upgrade-AURALiC-Aries-Mini-/272497900179?hash=item3f7223fa93:g:uTcAAOSwEzxYX7v S). Stanley Beresford has also suggested Lab PSUs. Has anyone tried any of these different options or something similar? If so, are they any good, or would you recommend something else? (The monoblocks can take up to 18V but 18V linear PSU's seem to be as rare as hens teeth.)

[Firebottle]

You will need something with a lot more clout than the 1.5A supply you linked to.

If you want linear then look at the 10A and 30A (up to 15V) versions here: http://www.kcb.co.uk/shop2/contents/en-uk/d115.html

:cool:

[Light Dependant Resistor]

The current from the supply you link to is insufficient. Minimum spec would appear to be 2.5 amps @ 16v but more amperage in reserve is always an attribute

If it was me I would source a 160va toroidal for each + rectifiers and capacitors. There are many ways of going about power supplies for
power amps but there is general agreement an unregulated supply meets most requirements. Then again a Quad 303 benefited greatly
from regulation. Generally too where you can section the psu using a full wave rectifier for each phase is better than one rectifier doing each
phase and centre tap. Using 2 full wave rectifiers is possible in a dual rail design, but as always a schematic is essential as a starting point
to see what the manufacturer intended.

Let me know if you need more help

Cheers / Chris

[Alp]

You will need something with a lot more clout than the 1.5A supply you linked to.

If you want linear then look at the 10A and 30A (up to 15V) versions here: http://www.kcb.co.uk/shop2/contents/en-uk/d115.html

:cool:

Many thanks. These look like real beasts. The 30A versions have fans, so not sure about the noise from those. The original wallwart for each monoblock only delivered 3A, so as Chris posted 10A for four them them should just be enough (I have a small listening room so they are never used anywhere near full volume). Have you tried any of them for audio applications?

[Alp]

The current from the supply you link to is insufficient. Minimum spec would appear to be 2.5 amps @ 16v but more amperage in reserve is always an attribute

If it was me I would source a 160va toroidal for each + rectifiers and capacitors. There are many ways of going about power supplies for
power amps but there is general agreement an unregulated supply meets most requirements. Then again a Quad 303 benefited greatly
from regulation. Generally too where you can section the psu using a full wave rectifier for each phase is better than one rectifier doing each
phase and centre tap. Using 2 full wave rectifiers is possible in a dual rail design, but as always a schematic is essential as a starting point
to see what the manufacturer intended.

Let me know if you need more help

Cheers / Chris
Thanks Chris. I am hoping to buy something off-the-shelf. If there is a schematic available I might ask you to take a look (my electrical engineering knowledge is superficial at best!).

[The Black Adder]

The SBooster ones Mark Grant sells are good.

[Light Dependant Resistor]

Thanks Chris. I am hoping to buy something off-the-shelf. If there is a schematic available I might ask you to take a look (my electrical engineering knowledge is superficial at best!).

Hi Alastair
A capacitance multiplier supply would be great for your purpose. http://sound.whsites.net/project15.htm
I would go straight to the bottom of the page and use the Mosfet design noting it has a few issues regarding load current,
here I would use a larger voltage initial supply and current regulate / shunt regulate following the mosfet stage, however it is single ended positive.

With your amplifiers - they could be single ended ie one voltage rail ( usually positive ) or dual rail
If dual rail there is a positive supply and a negative supply. You need to design for one or the other
so observe what the manufacturer provides as a power supply, and how the amplifier is constructed.

Ideally you need the transformer to be about 2x more capable with amperage than the amplifier hence my earlier suggestion of a 160va toroidal transformer
With these they have 2 separate windings which should ideally be designated one to each channel. Designing as Monoblock if you can do it, always reaps rewards that you
wish you had allowed for in the first place Noting if dual rail or monoblock your project may require 2 transformers.


With AC voltage to get DC we divide by .707 So 12V AC when rectified provides 16.9V DC
If 15v AC when rectified we end up with 22v DC which could be easily regulated to 16 or 17v using a LM338 device, capable when on a heatsink of 5 amps current

Semiconductors usually have a forward biased voltage drop on their output, ( the exception being voltage gain if they are arranged as common base or common gate )
hence allowing for that you will end up with 1.2v less voltage in the above designs, so a bit above 15v - which I think should be OK for your project.

Maybe make some sketches of what is proposed- once you know if single ended or dual rail supplies are needed.

Does that look like a good starting point? I am unsure you will get the level of design seen above, in off the shelf products. ...as DIY is always a few feet in front.

Cheers / Chris

[wee tee cee]

Have you thought about a big car battery? I ran 4 temple monos on one feeding a Stan DAC/hpa as active pre. About £50 for the battery from a motor supplier/£10 for wiring and inline fuse/switch.

There is a battery powered t amp thread on here somewhere with pictures.

I preferred the big lead acid battery to any linear PSU i tried.

Just a thought.....

[Alp]

Tony, Thanks for the suggestion. One of your posts inspired me to try the monoblocks, which are great. I had seen your suggestion of a lead acid battery before I settled on the Li-Ion ones. I'm just not to keen to have such a thing inside house (plus charger) and have no where to put it out of sight in my listening room. If I can't find a suitable linear supply, I might just end-up with a couple of large capacity (e.g. 40000Mah or 50000Mah) Li-Ion batteries putting-out 12 or 16V.

[wee tee cee]

Alistair,
Glad you are getting on with the monos, when you impedance match them with your speakers they really are rather good.

I have used battery packs on DACs but found even with a Capella headphone amp the immediate current delivery a big battery gives makes a noticeable difference.

Ikea is your friend....they do various cheap as chips wicker type boxes that would hide a battery.

Whip the battery out of your car and give it a go if you can-well worth a try IMHO.

Totally understand regards the aesthetics, Im lucky I have a cellar bellow my listening room so can hide my malarkey from my good lady!!!

[Alan D]

Have sent you a PM.

Regards,
Alan.

[RothwellAudio]

70W from a 16V power supply???? It doesn't matter how many amps it will deliver, you won't get 70W from a single 16V power supply.

So what am I missing?

[Firebottle]

It's probably a BTL (bridge tied load) scenario Andrew, plus max rated output into 4 ohms, for both channels ?

[Alp]

In the end, I decided that Linear PSUs were not going to do it - at least affordably - so I have gone back to a battery. A LiFePO4 - or Lithium Iron Phosphate to its friends - not to be confused with LiPo, as Lithium Polymer is sometimes confusingly written. They are used for high starting current applications like golf carts and motorbikes. Compared to Lithium Polymers, they are much less susceptible to causing fires. Compared to Lead Acid batteries they hold the charge much longer, can deliver higher instantaneous peaks, have a flat discharge profile, have a higher depth of discharge, last much longer (1400 cycles) and are much lighter. The downside is they are much more expensive (~4x) than equivalent Lead Acid batteries and ~2x more than the equivalent Lithium Polymers (a 23500 mAH Li Polymer is only roughly equivalent to 7AH @ 12V).

I am using a 16 AH 12V (actually 12.8V) Tracer battery pack. It is in a nice black and grey package so does not look out of place in a domestic setting. It has a charge-level meter and built-in protection for short circuit, over current , over charging, deep discharge and over temperature. It came with a dedicated LiFePO4 charger (essential).

The sound is excellent and I have never heard my system give such a broad and deep expanse of sound. Due to the lower voltage (12.8V vs. 16V), I had to use the red gain setting on the Temple Monoblocs rather than the blue. It also sounds great powering my Caiman SEG DAC.