Indeed G2 tweaks and bias adjustment

[mrarroyo]

Mike (PinkFloyd) can build one at 24 VDC and 2.5 amps. I know cause I have one!

[PinkFloyd]

Jun 8, 2011 22:51:18 GMT mrarroyo said:

Mike (PinkFloyd) can build one at 24 VDC and 2.5 amps. I know cause I have one!

Sssshhhhooooooosh!

[PinkFloyd]

[mrarroyo]

Oops, I should have kept my big trap closed. www.rock-grotto.co.uk/smilies2/shy.gif

[davepaul]

Hi, new boy Davepaul here - been following this thread for weeks, just got my G2 so thought I'd join and try a few of the more simple tweaks.
My thoughts on the heat issue - the rear heatsink is causing more problems than it's solving! It receives heat by radiation and convection from the front one (the heat source) that has already left the system and then has to be "re-lost" The only heat it gets rid of for the first time is what it receives by conduction through the small hexagonal connecting rod - which I can't imagine is that much. My plan is to replace this connecting rod with a 12mmX12mm block to substantially increase conduction and drill holes in the perspex cover to assist convection, so making the rear heatsink more effective.

[Deleted]

While modding a G2 the last time I took the liberty of measuring the temperature of the front and rear heatsink.
The difference was only a few degrees which surprised me a bit given the thickness of the thermal conductor.
The rod between the 2 heatsinks does seem to conduct more heat than what gut feeling was telling me, so am glad I measured it, It probably works pretty well because the connection rods are brass.

The more surface, the better it cools, the lower the thermal resistance to the rear heatsink the better also.
Since the difference is only a few degrees the extra cooling action with a thicker connection may be marginal.
The added surface of the connection rod will also add in cooling so you might get a few degrees extra off this way.

What would be interesting is measuring the temperature of the front and rear heatsinks before and after the mods.
allow the same time to heat up under the same circumstances,

The idea is good, Mick did a similar thing but also connected cool looking cooling cylinders on top which also dissipate heat.

[davepaul]

I'm confused I thought it was heliharris who created that awesome heatsink assembly - still since the 2 heatsinks are so similar in temp perhaps it means that heat transfer between the back of the front one and the front of the back one (if you see what I mean) is so efficient -due to how close they are and being pretty much enclosed - then one heatsink would be almost as efficient.

[Deleted]

Mick = heliharris

If you take out the small rod between the 2 heatsinks the back one doesn't get hot anymore.
The thermal conduction from the small rod is better than 'expected' IMO.
The rear one is not heated because it is close by radiation or standing air, at least I don't think so.
If you want to find out, simply take out the connecting rod.
I reckon the front heatsink will get much hotter and the rear one will stay at room temp or slightly above.

Increasing the width/surface of the small rod, as you suggest will result in lower temperatures but I figure it will only be a few degrees less, yet every degree temperature drop is welcome.
Heliharris his surface is much bigger and thus the cooling action also.

I hate heat on PCB's and parts.. it shortens the lifetime of the PCB, solderjoints (especially those) and the electrolytic caps close to the heat source.

[Deleted]

The most efficient cooling system for my G2 is the base i have mine on.

I think it looks perfectly respectable but not perfect, but it does the job very cheaply.

It is in fact a laptop cooling stand, powered by a usb connection, runs almost silent, does not degrade the SQ in any way, and only cost me £7.50 delivered.

OK i already had extra cooling heat sinks on mine, plus an aluminium bottom plate, this brought the temperature down a great deal from standard, but this base makes a huge difference, can easily pick the amp up when running, buy gripping the original heat sinks between my fingers, which are only warm to the touch after 1hr or more running time.

There is a photo somewhere (page 14 reply 327) in this thread, showing the base described with my G2 and a few other bits and bobs positioned on it.

Mick.

[Deleted]

Inspired by the Sunrise amp I was gathering up an order to include the parts for the G2 heater power supply mod.

The 100uH inductor has me stumped. Apart from 100uH and axial is there another parameter to choose e.g. current? I seem to have too many possibilities left to choose from.

As Frans is enjoying himself on holiday somewhere I'm hoping another modder can remember!

Cheers...

[Deleted]

Hi,
FWIW I (carefully) drilled some extra holes through the perspex top of my G2, 5 x 5mm above each pair of heat sinks, and I think it helped (certainly did not hinder ). Since then it's been modded (fully Fransified) with Al lower base plate so maybe not doing much now.
Dave.

[Deleted]

Jul 5, 2011 14:15:16 GMT @cjarchez said:

Inspired by the Sunrise amp I was gathering up an order to include the parts for the G2 heater power supply mod.

The 100uH inductor has me stumped. Apart from 100uH and axial is there another parameter to choose e.g. current? I seem to have too many possibilities left to choose from.

As Frans is enjoying himself on holiday somewhere I'm hoping another modder can remember!

Cheers...

Anybody? : (

[Deleted]

Jul 6, 2011 11:09:08 GMT @cjarchez said:

Jul 5, 2011 14:15:16 GMT @cjarchez said:

Inspired by the Sunrise amp I was gathering up an order to include the parts for the G2 heater power supply mod.

The 100uH inductor has me stumped. Apart from 100uH and axial is there another parameter to choose e.g. current? I seem to have too many possibilities left to choose from.

As Frans is enjoying himself on holiday somewhere I'm hoping another modder can remember!

Cheers...

Anybody? : (

I think you will have to wait till Frans returns for the answer to that Chris, as i havn`t a clue.

Mick.

[PinkFloyd]

I have revisited this amp and have been experimenting with alternatives to the 25V / 6800uF. Without raising the standoffs, and fitting some obscene erection, I have had great results with 3300uF / 35V Panasonic NHG caps.

They fit perfectly, are 105C rated and sound great! (typical fluid, easy going Panasonic house sound).....

Try them out

[Deleted]

I have had great results with 3300uF / 35V Panasonic NHG caps

I knew I missed something off my last order!

Grrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrowl

[davepaul]

Hi, got all the bits now, coupling, bypass and power supply caps and about to take the plunge and tweak! ( I'm a virgin - it's my first time !!) but I'm a little nervous. My new, stock G2 has the IRF 510's fitted as standard and I've got the Samwha 2200uF 16v coupling caps but if I set the bias at 15.5v as suggested by Solderdude ( page 12 of this thread ) for the IRF 510 will the 16v cap be sufficient or is a 13v setting better despite being close to making things unstable?
Also I've got the 3300uF 35v Panasonic NHG power supply cap as per above but would adding a couple of 1000uF 35v Panasonic NHG in parallel below the circuit board be a good idea ??I do so want my first time to be a success - hoping someone with experience will help.
Dave

[danielrigler]

Hi!

I have an Indeed G2, and I like it so far. I use it with a Beyer 880PRO (250Ohm). My only problem is that the crosstalk is very big, and there seem to be a distortion at higher volumes. Can you recommend any mods that can help reduce these problems? Thanks.

[Deleted]

Yertiz;

rockgrotto.proboards.com/index.cgi?action=gotopost&board=b&thread=5213&post=71360

[Deleted]

Jul 5, 2011 14:15:16 GMT @cjarchez said:

Inspired by the Sunrise amp I was gathering up an order to include the parts for the G2 heater power supply mod.

The 100uH inductor has me stumped. Apart from 100uH and axial is there another parameter to choose e.g. current? I seem to have too many possibilities left to choose from.

As Frans is enjoying himself on holiday somewhere I'm hoping another modder can remember!

Cheers...

anything between 50uH and 1mH will do.
It may be axial, toroidial, radial, SMD and Q is not of importance, nor is the resonance frequency.
as long as it can take > 250mA (0.25A) DC it will do it's job.
The core material does have some influence but not very much in this case.

for instance farnell: 1864497

[Deleted]

Jul 14, 2011 11:04:07 GMT danielrigler said:

Hi!

I have an Indeed G2, and I like it so far. I use it with a Beyer 880PRO (250Ohm). My only problem is that the crosstalk is very big, and there seem to be a distortion at higher volumes. Can you recommend any mods that can help reduce these problems? Thanks.

Download this pdf:
www.mediafire.com/?ccw7g2f8u97elpd

[Deleted]

Hi Frans,

Good holiday? That went quick

Cheers for the info on the inductor, as I needed to place the order I played safe and ordered one capable of 1A! It's a bit of a monster but at least it'll do the job (Farnell 9752102)

[Deleted]

Hi, Frans

Hope you had a good vacation. The noise I had written to you about turned out to be a defective input connector cable that was cutting out intermittently. Now all is well with my fully 'Fransified' G2, and I just love the way it sounds! See photos below:







I have a Project Sunrise kit on order (should be here Monday), and am looking forward to putting it together soon!

Thank you so much for all your help and expertise!

All the Best!
Israel

[Garage1217]

Wow looks really good!

[Deleted]

Jul 17, 2011 6:33:20 GMT Garage1217 said:

Wow looks really good!

Thank you, Jeremy!

Today I have been experimenting with different in-line output resistors with the G2, trying to make my AKG K701's sound somewhat less toppy. After reading Frans's article on amp output impedance, I decided that a somewhat high in-line output resistor will tame the K701 high frequencies, and balance the sound better, so I wired a small box with a couple of 110 Ohm resistors (one for each channel) connecting two 6.3mm jacks on each side, and plugged it in-line with the output of the G2, which has a 10 Ohm output resistor for a total of 120 Ohms, and the results were encouraging. I then decided to go one better, and made another box with 168 Ohm resistors for a total of 178 Ohms, and now, lo and behold , the K701's sound is dramatically improved! The highs are tamed down, the bass is somewhat increased, and the wonderful K701 wide sound stage is still there in all its glory! Because of the higher resistance, I have to turn the amp volume to about 2:30 o'clock, and I think this is good for better tracking. The bass is still not as full as the bass in my HD650's, but it is very good. I am willing to trade a little of it for the great sound stage of the K701's. I love the sound of the HD650's when played with the 10 Ohm amp output resistance, but to my ears they do not have the wonderful broad sound stage of the K701's. So, now I have more options to drive myself crazy with in opting for different combinations of various sources playback, etc.

Cheers!
Israel

[ozelui]

Hello everyone!

Glad to see this post keeps on going! Just a few questions to those who could help a little...

I would love to have one of those "custom made" Aluminium base plates for my G2, for those
LM317 which at 15.5V bias, are having heatsinks reaching 82ºC...Is anyone selling them? I noticed that at least two members have them installed. :-)

My unit is in process of being "Fransified", until now I have added:

-Rubycon 3300uF 35V for Power supply
-Sealed trimpots (quite hard to find them)
-470uf 10V Oscons for cathode bypass
-Panasonic FM 2200uF 25V for output caps
-Wima MKS2 3,3uF 50V
- Also have a matched NOS Sylvania 7308 waiting to join the party once upgraded unit is fully burned in.

Result? Astounding!!Even with the stock tube it rocks! And unit is still missing the heater mod! Anyway, I intend to order a PS amp for Spain but first I would love to push G2 to the limit! ;-)

Love this forum!