PICS: GainClone Monoblock pics

Rarkov · 27th March 2003, 07:37 AM

Hi,
I've built this system for my brother. He wanted to be able to plug his portable mini-disc player into it, so one of the inputs on the preamp is a screened 3.5mm stereo jack. Apart from the cases, everything is made by my fair hands!

I've nearly finished it - I'll post internal pics soon. My brother wanted this as a "classy bedroom amp"...

Goto http://www.rarkovelectronics.co.uk
Click to enter, then on the GainClone link under the Projects heading.

Hope you like them...
Gaz

monguz · 27th March 2003, 11:06 AM

Looks great! Are these custom made cases? Would like to see further details of the construction, inside closeups, etc.

I'm about to finish my "cloning" one of these evenings

This will be a test setup to check the sound of the beast and also if I could have both the chips and the psu in one box. I've installed the transformer pretty close to the IC's so wonder if it will make some noise or hum.

The transformer is a rather small one and not the final, just got it for a few weeks. Also, I use only el cheapo parts for the first time. Anyhow, it will hopefully make me able to decide if this simple circuit is really so fantastic, and if so, then I can put more effort into construting a solid case and all the mechanical details.

Good luck with your Gainclone and keep us informed about your progress!

Regards

monguz

Rarkov · 27th March 2003, 01:48 PM

Hi,
Thanks for your comments. The cases are from Maplins. The manufacturer's part number is AB13. The cases are 6"x4"x2" (wdh). I am only using a 120VA xformer with 25V seconadries. I'm hoping this is going to make the voltage rails droop a couple of volts so that the 35V caps wil be in a safe operating range

I will update the pics with better / internal ones soon. You'll find the PSU extremly cramped and the rest of the boxes are empty! I could have put the Two amps and Preamp together but I wanted a classy 4 box system!

I will give you an idea of sound quality when I finish the PSU cables (The connectors are on back order!)

Gaz

Kram · 27th March 2003, 02:31 PM

hello gaz,

My gainclone is still a rats nest in a cardboard box, I might buy some of those cases on friday afternoon and destroy the rats nest over the week end. Hopefully by this time next week i will have a neat and tidy gain clone.

My set up will be slightly different from yours, I bought two 220VA 2x25V Transformers from RS, i dont think they will fit in the cases you have used, I aslo want to put both channels in one box.

What is the preamp you are using? Is it a passive one?

I just finished Rod Elliotts preamp (project 88) last night, I need to get a box for that too, and some more RCA sockets.

See you later.
Mark

Rarkov · 27th March 2003, 02:43 PM

Hiya Mark,

I swear by those Passive Preamps now!!! I have put my digital one on hold for a while...I run a passive for myself and am building one for this system too.

Your xformers won't fit...Mine are the largest I could get to go in the AB13s...but as a result, the PSU is very underpowered. But I figured that 30-40W (x2) = 60-80W isn't going to hurt the 120VA (W) xformer too much.

I have made extensive use of sticky backed bases and tie wraps so the there are no screws other than the 4 per box holding them together. Very neat - in my opinion. I should also thank Laing Utilities for the cabling, sleeving used and tie wraps! There is a perk to every job!

Gaz

Rarkov · 28th March 2003, 09:32 AM

Hmm...Then it blew up! One of the xformer secondaries has shorted...That serves me right for listening to advice about not needing secondary fuses! I have a new 120VA 18V and 120VA 25V xformer on the way. The 18V is the preference..We'll see how it goes...I also have some fuses coming - funnily enough!

Gaz

Nuuk · 29th March 2003, 07:29 PM

Quote:

I am only using a 120VA xformer with 25V seconadries. I'm hoping this is going to make the voltage rails droop a couple of volts so that the 35V caps wil be in a safe operating range

25 volt secondaries will produce 36 volts (or higher depending on your local mains voltage). The safe way to work out capacitor ratings is to multiply the voltage across them by 1.25 so using caps rated at only 35 bolts is asking for trouble!

Rudy · 29th March 2003, 08:37 PM

Actually with small transformers < 300 W the voltage rating could go up to 10% above the normal voltage ( this without a large load ofcourse )

but the results are ...

25 *1.1 = 27,5VAC

( 27,5VAC * 1.42) - 0.6V ( using 1 rectifier bridge that is ) = 38,5V

...

Greetz Rudy

Rarkov · 29th March 2003, 08:53 PM

Hi,
Well after the bridge rectifier (about a 1.4V drop I would think) the measured outputs were +- 40.1V along the capacitor rails. This dropped to 38V or thereabouts with the load on.

I have reordered the transformers - but with an 18V version this time. I couldn't turn the preamp volume all the way up without the amp over heating, so this should keep things in check!

Gaz

Rarkov · 15th April 2003, 06:40 PM

Well I've finished them and they are amazing!
The lower voltage xformer worked wonders!

Gaz

27th March 2003, 07:37 AM	#1
Rarkov diyAudio Member Join Date: Aug 2002 Location: North East, UK	PICS: GainClone Monoblock pics Hi, I've built this system for my brother. He wanted to be able to plug his portable mini-disc player into it, so one of the inputs on the preamp is a screened 3.5mm stereo jack. Apart from the cases, everything is made by my fair hands! I've nearly finished it - I'll post internal pics soon. My brother wanted this as a "classy bedroom amp"... Goto http://www.rarkovelectronics.co.uk Click to enter, then on the GainClone link under the Projects heading. Hope you like them... Gaz

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27th March 2003, 11:06 AM	#2
monguz diyAudio Member Join Date: Mar 2003 Location: Hungary	Looks great! Are these custom made cases? Would like to see further details of the construction, inside closeups, etc. I'm about to finish my "cloning" one of these evenings This will be a test setup to check the sound of the beast and also if I could have both the chips and the psu in one box. I've installed the transformer pretty close to the IC's so wonder if it will make some noise or hum. The transformer is a rather small one and not the final, just got it for a few weeks. Also, I use only el cheapo parts for the first time. Anyhow, it will hopefully make me able to decide if this simple circuit is really so fantastic, and if so, then I can put more effort into construting a solid case and all the mechanical details. Good luck with your Gainclone and keep us informed about your progress! Regards monguz

27th March 2003, 01:48 PM	#3
Rarkov diyAudio Member Join Date: Aug 2002 Location: North East, UK	Hi, Thanks for your comments. The cases are from Maplins. The manufacturer's part number is AB13. The cases are 6"x4"x2" (wdh). I am only using a 120VA xformer with 25V seconadries. I'm hoping this is going to make the voltage rails droop a couple of volts so that the 35V caps wil be in a safe operating range I will update the pics with better / internal ones soon. You'll find the PSU extremly cramped and the rest of the boxes are empty! I could have put the Two amps and Preamp together but I wanted a classy 4 box system! I will give you an idea of sound quality when I finish the PSU cables (The connectors are on back order!) Gaz

27th March 2003, 02:31 PM	#4
Kram diyAudio Member Join Date: Jun 2002 Location: Durham UK	hello gaz, My gainclone is still a rats nest in a cardboard box, I might buy some of those cases on friday afternoon and destroy the rats nest over the week end. Hopefully by this time next week i will have a neat and tidy gain clone. My set up will be slightly different from yours, I bought two 220VA 2x25V Transformers from RS, i dont think they will fit in the cases you have used, I aslo want to put both channels in one box. What is the preamp you are using? Is it a passive one? I just finished Rod Elliotts preamp (project 88) last night, I need to get a box for that too, and some more RCA sockets. See you later. Mark

27th March 2003, 02:43 PM	#5
Rarkov diyAudio Member Join Date: Aug 2002 Location: North East, UK	Hiya Mark, I swear by those Passive Preamps now!!! I have put my digital one on hold for a while...I run a passive for myself and am building one for this system too. Your xformers won't fit...Mine are the largest I could get to go in the AB13s...but as a result, the PSU is very underpowered. But I figured that 30-40W (x2) = 60-80W isn't going to hurt the 120VA (W) xformer too much. I have made extensive use of sticky backed bases and tie wraps so the there are no screws other than the 4 per box holding them together. Very neat - in my opinion. I should also thank Laing Utilities for the cabling, sleeving used and tie wraps! There is a perk to every job! Gaz

28th March 2003, 09:32 AM	#6
Rarkov diyAudio Member Join Date: Aug 2002 Location: North East, UK	Hmm...Then it blew up! One of the xformer secondaries has shorted...That serves me right for listening to advice about not needing secondary fuses! I have a new 120VA 18V and 120VA 25V xformer on the way. The 18V is the preference..We'll see how it goes...I also have some fuses coming - funnily enough! Gaz

29th March 2003, 08:37 PM	#8
Rudy diyAudio Member Join Date: Feb 2003 Location: Belgium	Actually with small transformers < 300 W the voltage rating could go up to 10% above the normal voltage ( this without a large load ofcourse ) but the results are ... 25 1.1 = 27,5VAC ( 27,5VAC 1.42) - 0.6V ( using 1 rectifier bridge that is ) = 38,5V ... Greetz Rudy

29th March 2003, 08:53 PM	#9
Rarkov diyAudio Member Join Date: Aug 2002 Location: North East, UK	Hi, Well after the bridge rectifier (about a 1.4V drop I would think) the measured outputs were +- 40.1V along the capacitor rails. This dropped to 38V or thereabouts with the load on. I have reordered the transformers - but with an 18V version this time. I couldn't turn the preamp volume all the way up without the amp over heating, so this should keep things in check! Gaz

15th April 2003, 06:40 PM	#10
Rarkov diyAudio Member Join Date: Aug 2002 Location: North East, UK	Well I've finished them and they are amazing! The lower voltage xformer worked wonders! Gaz

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