The Monoblock Amplifier

After lot of discussion on the forum and interest shown by members, we are thinking of a monoblock amplifier which would satisfy the needs and goals of Roots circle.

It shall have the following features[some of them were mentioned by lev]:

4 X NL4 Speakons [1+/2+ joined, 1-/2- joined]

Illuminated power switch, probably a blue one

Balanced XLR male-female IN-OUT

One Potentiometer[But i am against it]

Input sensitivity selector via DIP switch 1.44V, 2.88V, 5.76V

Current Draw and Voltage Meter, yet to decide which ones though.

Plugin Fuses Automotive types, they are heavy duty and less prone to loose contact, removable from back panel.

10SQMM 3 Core mains cable without any plug OR 32A Neutrik POWERCON connector.

Front CLIP/SIGNAL indication

Vents for Push-pull Tunnel Cooling + Dual 5 inch switchable Fans

These above mentioned features are mostly for front and back panel.




Kanwar

Awaiting comments and suggestions smiley1

smiley20

To keep cost down, you could

a) Supply with 32A Powercon instead of Powercable
b) Supply with only Digital Ammeter (No Voltmeter)
c) Include 25hz/24db non defeatable high pass/subsonic filter as standard
d) Include current limiting to protect against out of spec current draw
e) External Breaker "switch" on rear panel

Sorry, have to keep the rest, it sounds too good. :lol:

Which direction is fan air flow? In thru the front, out the back is nice and standard.

Also due to typical "honest" performance of monoblocks, you could probably consider a 4K and 5K Version.

Also, Strong sub amps like CA18/Crown MA5000Z have detection of over voltage supply (E.g dodgy generator), and shutdown requiring power cycle.

Poorer quality amps, just go bang. smiley2

levyte357 wrote: smiley20

To keep cost down, you could

a) Supply with 32A Powercon instead of Powercable
b) Supply with only Digital Ammeter (No Voltmeter)
c) Include 25hz/24db non defeatable high pass/subsonic filter as standard
d) Include current limiting to protect against out of spec current draw
e) External Breaker "switch" on rear panel

Sorry, have to keep the rest, it sounds too good. :lol:

Which direction is fan air flow? In thru the front, out the back is nice and standard.

Also due to typical "honest" performance of monoblocks, you could probably consider a 4K and 5K Version.

Also, Strong sub amps like CA18/Crown MA5000Z have detection of over voltage supply (E.g dodgy generator), and shutdown requiring power cycle.

Poorer quality amps, just go bang. smiley2

Thanks Lev,

I will go for 32A Powercon, Digital Ammeter,25hz/24dB HP[permanent]

Regarding current limiting, i will employ a soft limiter.

If you want circuit breaker at back panel, what is the use of mains fuse then..? shouldn't we keep either one of them?

Air flow would be Intake Front to Exhaust back-flow.

It will incorporate a mains over-voltage protection feature also, tripping the amp around 260VAC upwards.


Kanwar

Kanwar wrote: Thanks Lev,

I will go for 32A powercon, Digital Ammeter,25hz/24dB HP[permanent]

Regarding current limiting, i will employ a soft limiter.

If you want circuit breaker at back panel, what is the use of mains fuse then..? shouldn't we keep either one of them?

Air flow would be Intake Front to Exhaust back-flow.

It will incorporate a mains over-voltage protection feature also, tripping the amp around 260VAC upwards.


Kanwar

Excellent.

I see what your saying about mains fuse/breaker.

Some amps have breaker at back, some have breaker'd switch, some have internal breaker.

These are my 2nd favourite mono blocks

www.jahtubbys.co.uk/equipment.html


2000 WATT - 10000 WATT - ULTRA HIGH DRIVE

ALL AMPS FAN COOLED / 4 FANS ON BIGGER MODELS

SHORT CIRCUIT / OVERHEAT PROTECTED

Owners mod fronts to their desire.
JTS has years of experience of using/selling roots monoblocks, so you can be sure every fuse is there for a reason. smiley2

You get the picture though, front or rear mounted fuses.

I like the QSC 4050/5050 Method of of rear mounted switch breakers.

Looks like the JTS also has fuse per speakon !?

Advantage of everything on the front is, if amp mounted in rack with rear rack lid attached (with fans), any amp breaker/fuse problems can be sorted quickly from front.

EDIT:Regarding limiting input signal... It really does have to be perfect.. The Peavey GPS3400 has best limiter (DDT Compression) I've heard..
Overdrive it into clipping, and you hear no difference in output sound quality.

Again direct comparison to "another" amp I had, meant sound of crunching biscuits and slurping coffee when clipping occured... :shock:

levyte357 wrote: Excellent.

I see what your saying about mains fuse/breaker.

Some amps have breaker at back, some have breaker'd switch, some have internal breaker.

Owners mod fronts to their desire.

You get the picture though, front or rear mounted fuses.

I like the QSC 4050/5050 Method of of rear mounted switch breakers.

Looks like the JTS also has fuse per speakon !?

Lev,

I will go with automotive Fuse at back panel then.

Yes, JTS has fuse per speakon, IMHO its not a good idea as far as solid path for audio current is concerned.

Next i have to consider then Fan running options :

1. Constant ON running

2. Temperature dependant variable speed control

3. Temperature dependant ON-Off lets say switch the fan to full on if temp of heat sink crosses 50C.[IMHO this is better than variable speed]



Kanwar

levyte357 wrote: EDIT:Regarding limiting input signal... It really does have to be perfect.. The Peavey GPS3400 has best limiter (DDT Compression) I've heard..
Overdrive it into clipping, and you hear no difference in output sound quality.

Again direct comparison to "another" amp I had, meant sound of crunching biscuits and slurping coffee when clipping occured... :shock:

I don't prefer hard limiting on clipping, a soft one gives best results. smiley1 , i always let the amp to clip upto 5-10% max.

what are the prices like on the JTS's??

if you're going to be putting 5KW down one cable...........lol


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Kanwar wrote: After lot of discussion on the forum and interest shown by members, we are thinking of a monoblock amplifier which would satisfy the needs and goals of Roots circle.

It shall have the following features[some of them were mentioned by lev]:http://www.freespeakerplans.com/index.php#

4 X NL4 Speakons [1+/2+ joined, 1-/2- joined]

Illuminated power switch, probably a blue one

Balanced XLR male-female IN-OUT

One Potentiometer[But i am against it]

Input sensitivity selector via DIP switch 1.44V, 2.88V, 5.76V

Current Draw and Voltage Meter, yet to decide which ones though.

Plugin Fuses Automotive types, they are heavy duty and less prone to loose contact, removable from back panel.

10SQMM 3 Core mains cable without any plug OR 32A Neutrik POWERCON connector.

Front CLIP/SIGNAL indication

Vents for Push-pull Tunnel Cooling + Dual 5 inch switchable Fans

These above mentioned features are mostly for front and back panel.




Kanwar

Kanwar why are you against one potentiometer? Also will you use the same case as the stereo version? This would be a good idea so you can space out components and ensure adequate cooling of components. Also how will the layout be if you want the airflow from front to back?
I think the best way would be having a fan or preferably two fans blowing directly onto the heatsink/op stage. Also agree with Saul about the heavy duty speakons x 4 wired in parallel .