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Post by Deleted on Aug 5, 2011 7:29:48 GMT
The bottom plates are not for sale somewhere and were made by Mick on a one-off basis.
easiest solutions:
look for a heatsink with about the same dimensions as the acrylic bottom plate ( or slightly larger) and use that (probably cool looking too).
Or find/buy a square piece of aluminum of about the same thickness (or slichtly thicker) and size of the acrylic base plate and file the edges nice and round (not easy to get this right I reckon)
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Post by ozelui on Aug 30, 2011 7:08:08 GMT
While looking for a heatsink, as a n00b, I have another question related to power supply...
I have found a UK web site which makes custom linear PSUs: (www.custom-hifi-cables.co.uk)
Which type/size is the Indeed G2 connector? 2.1mm center pin, right?
Does the new PS amp have the sime type as the indeed?
Now question for admin if possible ;-) : Are there any future plans for a 24VDC PSU for G2/PS amps such as the lovely Pinkie V3i? My DacMagic loves it! ;-)
Now I´m missing the heater mod on my G2 but I´m not sure about small ceramic caps...which voltage should they be?
Regarding the other electrolytic caps, for those who have already the heater mod implemented...have you used nichicon, panasonic FC, FM, Elna´s...?
Thanks in advance for any input which clarify any of above questions!Love this thread!!
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Post by pad on Sept 12, 2011 17:57:44 GMT
Hi guys, after reading a lot here I decided to buy a Indeed G2. Long story short, recently arrived.
Sound fine out the box, but I will try the mods as time goes on. Crosstalk seems to be an issue. Thanks for the great mod pdf guide!
It has a weird noise on the pot, like tunning an old radio, around 9 to 12 o'clock. Any ideas? Bad pot?
Also, any advice on a cheap but good tube? I've paid 70USD on amp+shipping, so I'm having a hard time paying the same (or more) for a Mullard or Telefunken.
Regards,
Raphael
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Post by Deleted on Sept 13, 2011 21:52:12 GMT
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Post by lebachelourd on Feb 10, 2012 18:50:56 GMT
hello everybody, my name is Cyril i am from France and with a friend we have some problem with an Indeed Amp G2. The cause of the problem: during a bias adjustment, i have touched the heat sink of the amp and i have made a short-circuit (big flash). The amp is over. i have changed one LM317 and one IRF630, the amp still not responding. in details , the heating filament doesn't run. I don't now where i can test the amp for seeing where is the problem.
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Post by Deleted on Feb 10, 2012 21:14:07 GMT
Welcome to the forum.
I would start by inspecting the red LED and replacing both small transistors.
Which points exactly did you short ?
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Post by ozelui on Feb 21, 2012 9:53:52 GMT
Hello!
I am looking for some suggestions regarding output resistors for my HP + amp combo:
HPs: Sennheiser HD555 (soon will upgrade to HD650) and AKG K701
Indeed G2: Fully "fransified" unit: 15.5V bias and 6,875ohms for class A current adjustment (22 + 10 ohms in parallel).
Mike sent me (he is a great source for parts and at a nice price!! ;-) ) as output resistors a 68ohm set and also an interesting Allen Bradley carbon composite 100 ohms resistors...
Should I go for the 100ohms resistors? As far as I know, they will improve sound on K701´s but not sure how Senns will responds to this increase...
Obviously I´m waiting for that Project Horizon amp...:-)
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Post by Deleted on Feb 21, 2012 11:34:43 GMT
HD555 needs as low as possible (10 Ohms) and will become fat and boomy on 100 Ohm.
HD650 also low Ohmic (say below 30 Ohm).
K701 100 Ohms or 120 Ohms
The horizon is in test phase in the USA.
When it has arrived at my doorstep and have tweaked it, it will be marketed.
I expect in a month or so.
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Post by vmedchagr on Mar 12, 2012 8:08:03 GMT
Hi There is nothing wrong with the pot. Mine came with an 6n11 tube. I had the same problem. I changed the tube with an 6922 jan philips made in the 70's. No noise from the pot. The 6922 needs less current than the standard one Indeed is using (Chinese made). If you want to keep the tube that came with the amp, in order to save money, try to adjust the bias a little bit higher. My amp was not adjusted at all, it had 10.47V left channel & 14.96V right channel. Indeed says that 11.5V is fine, i succeeded great results with 12.8V per channel. When you do the adjustment you will have to be patient, the two channels interact , which means adjusting left will affect right channel also.  Hi guys, after reading a lot here I decided to buy a Indeed G2. Long story short, recently arrived. Sound fine out the box, but I will try the mods as time goes on. Crosstalk seems to be an issue. Thanks for the great mod pdf guide! It has a weird noise on the pot, like tunning an old radio, around 9 to 12 o'clock. Any ideas? Bad pot? Also, any advice on a cheap but good tube? I've paid 70USD on amp+shipping, so I'm having a hard time paying the same (or more) for a Mullard or Telefunken. Regards, Raphael |
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Post by Deleted on Mar 12, 2012 8:23:52 GMT
The 2 channels interact because at 13V the LM317's are not in their linear range, they simply do not work as they are supposed to at that voltage.
They do not work symmetrical in this case and are introducing the crosstalk and distortion.
Even that distortion (measurably very high and a-symmetric) is missed by many owners and trained ears alike, I must admit.
The optimal range for a stock indeed is 15.5V to 16V which was also confirmed to be correct by Pink Floyd (Mike) when adjusting 'by ear'.
A 'hidden' problem this causes, doesn't seem very appearant when doing the (static) adjustments.
Once 'stabilised' the amp appears to work correctly/stable with 12V bias voltage.
However, as soon as the amp does what it is supposed to do (amplify AC signals and not being run static) the bias adjustment changes continuously dependent on musical content (voltage swing) and is literally all over the place degrading performance MEASURABLY during play.
This is quite considerable, yet not very audible for most people.
after the heater mod there is no interaction anymore and is dynamically as stable as statically as the LM's are always in their minimum range.
Distortion is measurably (even considerable) lower in this case.
The audibility of this improvement depends on the listener I suppose.
How much the pot 'scratches' depends on the grid leakage current of the tube (an aspect of the triode).
This is dependent on the emission, gain and physical construction of the tube.
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Post by vmedchagr on Mar 14, 2012 11:14:12 GMT
Hi, just 2 questions. Do you have any reasonable explanation why in some tubes (like 6922) bias does not go more than 14.7V . Whatever adjustment I do it cannot go more than that value  . Tubes are NOS & test very strong on my tube tester. For the money paid, I'm pretty satisfied with this little amp, it drives my BeyerDynamic DT250 with ease, these headphones are 80ohm , do i need to modify the output resistor to make them sound better ? |
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Post by Deleted on Mar 14, 2012 14:19:57 GMT
The tubes are TOO good in this case.
In order to accommodate better tubes (those with higher than average emission) you can change 2 things.
a: the cathode pots (increase in value)
b: increase the current of the anode current source.
a: will give you a wider range but with a small adjustment the bias voltage may vary a lot.
This can be 'improved' by mounting small multi-turn pots.
b: this will allow the better tubes to be adjusted properly but the lesser tubes (and 12AU7 e.t.c.) may not adjust properly anymore as the 'range' one can adjust in is not increased but only 'shifted'.
I have never heard the DT250 but the graphs predict the sound won't change much with a lower or higher output resistance.
a matter of trying I guess.
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Post by vmedchagr on Mar 27, 2012 6:20:12 GMT
Hi I was tempted to test the 8audio board so i did. I used 5Watt wirewound resistors & top quality capacitors. I put IRL510 instead of IRF510 & bias is 13.5V as mentioned somewhere in this forum. The good thing is that the amp works great, it needs about 20 minutes to get stabilized bias measurements & they are much more precise if you use a 5k pot instead of 1k. The only weird thing is this : Only the IRL510 from the right channel gets hot (but you can touch it without getting burned). Left channel IRL510 & 317 regulators are running cool. Is this considered to be normal  |
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Post by Deleted on Mar 27, 2012 6:29:07 GMT
No.... they should be equally hot.
Check the resistor values of the LM317 (next to the adjust pots) and the voltage across it (should be 1.25V)
I have a suspicion one of the values might be incorrect.
It also explains why you have to wait so long to get stable readings.
Possibly the heater current is too small (unless you did the heater mod) and takes longer to heat up.
What's the heater voltage ?
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Post by vmedchagr on Mar 27, 2012 6:37:52 GMT
Thank you very much I will check it out tonight. I think you got a point there, maybe I've done some mistake with the resistor values on the left channel. I'll keep you posted.  |
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Post by jalvan on Mar 27, 2012 16:11:28 GMT
FINALLY !! i fount it ! - its the solder joint of the pot wiper, it didnt wet well so the connection to pin3 was open
it probably put too much load on the pot and shorted it too and also on the circuit. i replaced the pot and resolder and its working ok
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Post by jalvan on Mar 27, 2012 17:28:16 GMT
so in conclusion a few things i learned and might help other noobs trying this mods: get a good solder iron and desoldering pump this thick pcb is not easy to solder and desolder with cheap equipment on the other hand its really hard to break it and it can stand many mistakes also desoldering braid and some extra flux (i use goot) ALWAYS check for continuity ! i replaced the cheap pots with precision, one turn pots the same size and it make a difference: first its much easier to bias the voltage, second the distortion on low vol now gone and third the leds (mainly the blue) does not flicker a bit and actually they lit very bright now also getting 5-10 good quality pots from ebay is a good idea since they cost just 1$ and if one of them accidentally opens you can always replace them lastly MANY thanks to solderdude who manage this forum and help me a lot (and was very patient for my troubles) you rock! thanks |
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Post by vmedchagr on Mar 28, 2012 7:33:19 GMT
You where right  . One of resistors although it states 35ohm it wasn't. I changed it with another one & now everything is normal. Is 13.6V bias ok (i'm using IRL510 - LM317 - cc88 tube), or should i go a little bit higher ? Thanks for your helpful advice. Vassilis No.... they should be equally hot. Check the resistor values of the LM317 (next to the adjust pots) and the voltage across it (should be 1.25V) I have a suspicion one of the values might be incorrect. It also explains why you have to wait so long to get stable readings. Possibly the heater current is too small (unless you did the heater mod) and takes longer to heat up. What's the heater voltage ? |
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Post by Deleted on Mar 28, 2012 9:38:43 GMT
IRL needs 13.5V bias
IRF needs 15.5V bias
regardless of the used tube.
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Post by statix on Apr 6, 2012 3:40:24 GMT
Quick question about replacing the MOSFET's in the Indeed amp. When installing the new IRF510 MOSFET, do I need to add some more thermal grease (a.k.a. thermal compound)? Or will the heatsinks transfer enough heat even without adding more thermal grease?
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Post by Deleted on Apr 6, 2012 6:16:32 GMT
I recommend using IRL510 instead of IRF510.
IRL will give 50% more output power (than IRF) and lower distortion and an even wider bandwidth.
Also I can highly recommend you use insulation kits (plastic ring and silicone spacer) to mount the MOSFET's
This prevents the 24V being present on the heatsinks.
With silicone insulators you don't need heatsink compound (thremal grease).
Some have destroyed valuable sources by accident while touching the center RCA pin to the heatsink.
Without silicone (or when using Mica spacers/insulators heatsink compound is recommended.
The thinner the layer the better.
put a tiny amount on the MOSFET and wipe it flat/off with something like a creditcard.
VERY little is required.
Using a lot of this stuff so iy ouzes out will give worse thermal coupling.
With IRF set bias to 15.5V with IRL to 13.5V
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Post by vmedchagr on Apr 11, 2012 19:00:50 GMT
I also fitted the IRL510 to my indeed & done all the mods, cathode caps, better heat resistant capacitors etc.... Congratulations to the members here. It is a completely different amp now & much more dynamic . By the way 13.5volt must be measured at pin 1 & 6 of the tube anode  , am I correct ? Not the (+) of the output capacitor. |
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Post by vmedchagr on Apr 13, 2012 9:43:41 GMT
Bad English here, i wrote it again.
Can someone tell me why when adjusting bias close to 13.5Volt anode voltage, voltage at pin4 goes to 7.8Volt .
I have to keep bias to 11volt for the anodes in order to have 6.3volt. at pin 4.
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Post by Deleted on Apr 13, 2012 9:50:17 GMT
The bias voltage = the anode voltage.
So if it is 11V it cannot be 6.3V at the same time.
What points are you using to measure the reported voltages ?
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Post by vmedchagr on Apr 13, 2012 9:59:14 GMT
Well i measure 11v bias at pin no1 & no6 of the tube & 6.3v at no4.
If i adjust the pots to go 13.5v at 1,6 then voltage at no 4 rises to 7.8v.
Is there a possibility of a weird tube behaviour here?
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: -
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. One of resistors although it states 35ohm it wasn't. I changed it with another one & now everything is normal.
, am I correct ? Not the (+) of the output capacitor.