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Post by andy on Mar 23, 2010 20:17:51 GMT
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Post by Deleted on Mar 23, 2010 20:45:45 GMT
Hi Andy A decent transformer based PSU will always be better, which is why Mike's Little Pinkies are so successful. I would not recommend the use of the JLH at +24V and such a high constant current. It can do up to 500mA if the Current Limiter is used, but it may need a few changes made. It would need a thorough investigation on the bench.I suggest you just go with a decent transformer. Alex |
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Post by Deleted on Mar 23, 2010 20:50:42 GMT
Andy, I have the Rapidonline one, or should i say i don`t, i sent for the one advertised, but received one that was different from advertised, in that it lacks the internal fan,( identical spec otherwise) apparently that one has now been replaced by the one i received. It is a very nice well made PSU, on constantly, runs almost cold, and no noise from unit at all, and sounds great to my ears. I also have the other one Mike recommended, the Maplin one its on the G2 thread somewhere, shop soiled, just a couple of little marks on mine and that works fine too, but runs warmer, and has a very slight, hardly audible hum but was only £16, variable voltage setting, and a set of 8 adaptors. Mick. |
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Post by Deleted on Mar 23, 2010 21:35:02 GMT
I havn`t Chris, understand what your saying ,and kind of thought that one looks right, then i find the tag spacings are way out on spec, compared to the original so it wont go through holes on pcb.  I will stick to the metal work i think.  Mick. |
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Post by Deleted on Mar 23, 2010 21:57:53 GMT
LOL, thanks Chris at least you have made me laugh, and i am MORE than capable of blowing the AMP up myself thank you.  Cheers mate  Mike, can you throw any light on my switch problem reply 520, thanks. Mick. |
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Post by PinkFloyd on Mar 23, 2010 22:13:32 GMT
LOL, thanks Chris at least you have made me laugh, and i am MORE than capable of blowing the AMP up myself thank you. Cheers mate Mike, can you throw any light on my switch problem reply 520, thanks. Mick. Rapid part number 75-0082 That will fit..... you may have to file the lugs down a bit to get them through the PCB holes. You could also try 75-0172 The single switch (the first one) only needs to be soldered between the two tracks (make / break).... there's no real need for DPDT here.... you'd be as well buying both and see which one suits best. Mike. |
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Post by Deleted on Mar 24, 2010 8:17:14 GMT
Ok, thanks Mike, will do.
Mick.
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Post by andy on Mar 24, 2010 12:09:15 GMT
Good to hear that the fan has been removed from the SMPSU, small fans can be quite noisy!
Also wondering about some 12v batteries, i have some 6.5AH somwhere.....
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Post by Deleted on Mar 24, 2010 17:28:24 GMT
Anybody know where i can get a better quality same fitting push on push off switch as this:-   This one lasted all of 50 or less, on - off`s.  Here is my new switch, 3 Amp Double pole from Maplins for £1.99, much better quality, feels nice in operation, hated the original, knew it wouldn`t last long the first time i switched on. Fiddly job to do, as i had to make up some extension tags out of paper clips, so i could position it on the board in a satisfactory way. Bread and butter to you guys i expect, but a milestone for me as i have not done anything like this before, and i`m pleased with the end result, works fine and still sounds great      Yes, i bought 2 because i thought bound to bu""er one up, but i didn`t . Ian(toad) the spares for you mate |
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Post by clausdk on Mar 24, 2010 18:27:26 GMT
Anybody know where i can get a better quality same fitting push on push off switch as this:- This one lasted all of 50 or less, on - off`s. Here is my new switch, 3 Amp Double pole from Maplins for £1.99, much better quality, feels nice in operation, hated the original, knew it wouldn`t last long the first time i switched on. Fiddly job to do, as i had to make up some extension tags out of paper clips, so i could position it on the board in a satisfactory way. Bread and butter to you guys i expect, but a milestone for me as i have not done anything like this before, and i`m pleased with the end result, works fine and still sounds great Yes, i bought 2 because i thought bound to bu""er one up, but i didn`t . Ian(toad) the spares for you mate Fantastic work Mick, cool solution using paperclips  |
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Post by PinkFloyd on Mar 24, 2010 21:06:52 GMT
The grommet size "is" 4.8mm for the feet.... I hade a few kicking about the workshop and the 4.8mm ones are a nice tight fit. the amp sits glued to the deck with these fitted:  Rapid part number 04-0134 I'll buy 100 next time I place a Rapid order and will be happy to send these out for the price of P&P.... 50P UK |
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Post by Deleted on Mar 26, 2010 12:21:36 GMT
Hmmm.. Had a short time to do some more measurements on G1 Miri/indeed/Bravo spec state: input imp. 100k (IRL = 11k (ten times as low, no problem b.t.w.)) output imp: 16-600 (they mean to say you can connect 16-600 Ohms HP's, output imp actuall is 47 Ohm) gain: 20 dB (IRL 25dB) and with a linear vol pot This should at least be log type for this gain/purpose. freq. resp: 10Hz - 60 kHz (+/- 0.25dB) IRL (... 2Hz - 29kHz -3dB ) What does this mean ? Well.. the freq range as specified at +/- 0.25dB IRL is not 10Hz - 60kHz BUT 10Hz to 10kHz. At 20kHz the amplitude is down 1.8 dB ! Is that noticeable ? Hell YES, even 0.5dB down at 20kHz can be perceived. What effect will this have ? You will be listening to a very warm, sweet, lucious rolled off amp. Can this be corrected so it will run flat to 20kHz ? NO not easily ? Is this a bad thing ? No, just enjoy the sound of it ... who cares if the freq curve is not flat. Any HP will have variations well beyond those dB's so... just enjoy it. At the spec'd 60 kHz (+/- 0.25dB) the amplitude is down 9.1 dB IRL. all measurements done with 300 Ohm dummy load. Can somebody please explain WHY the specs they give ar very much besides the truth ?  The explanation is NOT that I do not know HOW to measure b.t.w. nor the test equipment 1GS/s digital scope and 1MHz tone generator. ;D Those that have acces to tone generator and scope please verify the frequency range. Ian's device already has a better vol pot range and much lower gain (17dB) and immunity to stray RF signals is reduced ...  Auto-bias when there is time for it...  Solderdude |
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Post by Deleted on Mar 26, 2010 13:53:29 GMT
Strange that it measures SO bad Frans. The treble is rolled off on all of them but I feel that they have a really 'warm' character with good attack. The distortion thing you flagged up is quite awful. I tried that useful little trick out. However, I do tend to listen at low volume which is maybe why I don't particularly hear it. Lowering the gain will make great improvements to the noise that I was aware of but wasn't bothered too much by because it had to be ridiculously loud to hear it. However, having more travel on the pot makes more sense. Up loud, I had noticed the sound going grainy and blamed the power supply. (Oh well) I have a good supply attached but it stills goes grainy up loud. That may well be the effect of the poor crosstalk. The sound is 'beefy' and 'mellow' in tone in comparison to other amps which is perhaps the first thing I latched on to. I've always felt that the build and heat could be problems but again, the low voltage capacitor on the back is also pretty poor. I have been listening on the K701's so maybe having the top end tilted down makes the headphone sound smoother? The thing is, the K701's would latch on to distortion very easily with their response. I don't know what to say. It measures poor but the sound is attractive. The richness that it has and the character of the amp must have a lot to do with distortions that for some reason, we don't object to hearing!! Thank goodness they're cheapos eh? Ian |
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Post by Deleted on Mar 26, 2010 21:45:00 GMT
I can fix the crosstalk Ian, Would involve using other tubes the likes of ECC81,82,83 and cutting of some copper traces. This cures the distortion/crosstalk but should leave the crappy frequency response (and thus the SQ) intact. I can even make the frequency response a little better (flatter, less rolled off) but the sound of the amp would become more that of all other amps and I believe that is not what you are looking for. The richness and character are because the amp is rolled off the way it now is. Since 20kHz is only down 2dB the attack is not affected and still good enough (a 10kHz square wave still looks a bit like a square wave) Let me know your preferences. |
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Post by PinkFloyd on Mar 26, 2010 22:23:23 GMT
Frans..... try the IRF510.... it adds bags of "top end" sparkle whilst not detracting from the overall warmth of the amp.... Leo has also tried it and seems to like it better than the stock Mosfet. I have been going through quite a few of my amps checking for crosstalk and none of them "audibly" suffer from it like the G1 / G2 does... the only amp I was ever aware of crosstalk on was the Solo but all my Solos have long gone to another home... All of the other amps I own (over 50) have no perceptible "audible" crosstalk so the G1 / G2 are real "party Pieces" and great demonstrators to prove that crap specifications don't, necessarily, equate to crap sound IMO, the IRF630 is the weakest link in this simple "out of spec" design.... fire in an IRF510 and you'll "hear" what I mean.... it really does add some sparkle and energy to the mids / HF. You have been busy "measuring" but you haven't yet commented on the SQ.... I trust you will let us know what you think when you've had a good listen? IRF510 "with" added crosstalk is an even MORE pleasant listen than IRF630 with crosstalk.... please do fit an IRF5** (of your choice) for Ian.... I'm sure he will love the sonics as much as I do. Mike. |
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Post by Deleted on Mar 26, 2010 22:38:07 GMT
He! He! ;D I don't think that Frans wants to get into any more deep Doo Doo than he has already been in ! Frans' instruments ARE his ears !   |
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Post by leo on Mar 26, 2010 23:05:33 GMT
Frans..... try the IRF510.... it adds bags of "top end" sparkle whilst not detracting from the overall warmth of the amp.... Leo has also tried it and seems to like it better than the stock Mosfet. I have been going through quite a few of my amps checking for crosstalk and none of them "audibly" suffer from it like the G1 / G2 does... the only amp I was ever aware of crosstalk on was the Solo but all my Solos have long gone to another home... All of the other amps I own (over 50) have no perceptible "audible" crosstalk so the G1 / G2 are real "party Pieces" and great demonstrators to prove that crap specifications don't, necessarily, equate to crap sound IMO, the IRF630 is the weakest link in this simple "out of spec" design.... fire in an IRF510 and you'll "hear" what I mean.... it really does add some sparkle and energy to the mids / HF. You have been busy "measuring" but you haven't yet commented on the SQ.... I trust you will let us know what you think when you've had a good listen? IRF510 "with" added crosstalk is an even MORE pleasant listen than IRF630 with crosstalk.... please do fit an IRF5** (of your choice) for Ian.... I'm sure he will love the sonics as much as I do. Mike. Certainly gives the impression of more High frequency after the IRF510 is fitted, so far sounds better balanced to me, still a little lighter in bass but thats no problem for me I've resisted the urge so far to stick it on the scope |
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Post by leo on Mar 26, 2010 23:07:25 GMT
BTW tried another valve but it was noisy |
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Post by PinkFloyd on Mar 26, 2010 23:44:31 GMT
Frans..... try the IRF510.... it adds bags of "top end" sparkle whilst not detracting from the overall warmth of the amp.... Leo has also tried it and seems to like it better than the stock Mosfet. I have been going through quite a few of my amps checking for crosstalk and none of them "audibly" suffer from it like the G1 / G2 does... the only amp I was ever aware of crosstalk on was the Solo but all my Solos have long gone to another home... All of the other amps I own (over 50) have no perceptible "audible" crosstalk so the G1 / G2 are real "party Pieces" and great demonstrators to prove that crap specifications don't, necessarily, equate to crap sound IMO, the IRF630 is the weakest link in this simple "out of spec" design.... fire in an IRF510 and you'll "hear" what I mean.... it really does add some sparkle and energy to the mids / HF. You have been busy "measuring" but you haven't yet commented on the SQ.... I trust you will let us know what you think when you've had a good listen? IRF510 "with" added crosstalk is an even MORE pleasant listen than IRF630 with crosstalk.... please do fit an IRF5** (of your choice) for Ian.... I'm sure he will love the sonics as much as I do. Mike. Certainly gives the impression of more High frequency after the IRF510 is fitted, so far sounds better balanced to me, still a little lighter in bass but thats no problem for me I've resisted the urge so far to stick it on the scope Please Leo..... stick it on the scope.... I would rather know the "actual" specs than the "listed" specs..... don't worry about pissing people off, the truth always hurts.... say it AS you SEE it mate..... Me, personally, I feel quite good looking at the "out of spec" G2 and listening to Santana "live" via it....... it's "musical" and has a "soul"..... I can't NOT like what it is doing..... Oye Coma Va!Pinkie. |
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Post by Deleted on Mar 27, 2010 7:16:54 GMT
No listen yet,
I'll let the listening part over to Ian.
Believe it or not I can tell how an amp will sound just by looking at the graphs and figures.
Fixing it is the real diffculty.
Ian's amp will be receiving IRL530 for technical reasons.
Because the amp is modded in so many places at once in the end result it will be impossible to tell which mod has done what.
When modding is done and has Ian's seal of approval I will publish and let you guys figure out where the most can be had.
I simply do not have the time for it.
Why did I not listen at the start when I received it.
Well my musical memory lasts only for max a few seconds.
Ian can compare them side by side which (for me) is the only real way to test.
I 100% trust his judgement and he has similar amps otherwise I wouldn't have even considered this.
I know I handle things like this in a different way than most others.
My results will have to speak for themselves.
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Post by Deleted on Mar 27, 2010 7:42:53 GMT
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leo
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Post by leo on Mar 27, 2010 8:12:52 GMT
Couldn't have put it better myself |
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Post by Deleted on Mar 27, 2010 8:40:56 GMT
I can fix the crosstalk Ian, Would involve using other tubes the likes of ECC81,82,83 and cutting of some copper traces. This cures the distortion/crosstalk but should leave the crappy frequency response (and thus the SQ) intact. I can even make the frequency response a little better (flatter, less rolled off) but the sound of the amp would become more that of all other amps and I believe that is not what you are looking for. The richness and character are because the amp is rolled off the way it now is. Since 20kHz is only down 2dB the attack is not affected and still good enough (a 10kHz square wave still looks a bit like a square wave) Let me know your preferences. Frans, this is mightily impressive!! I thought the crosstalk problem was a bit complex. This is a hard one. Do you keep the character and improve crosstalk or change the sonics as well as the crosstalk? I would say maybe it is possibly better to do both and compare. The trouble is that the signature of the amp may well fade away although it will probably sound cleaner. I know exactly what you're saying Frans. You are very aware that I like the sonic signature, even though the measurements are 'off'. This has become a really interesting thread because it really has brought the issues of measurements/ears and draws two sides together in that some of us have no choice but to simply listen while others look at spec and get stuff to read up to a certain level. The ultimate is a combination. This could take us all back to the original - 'design an amp' idea, because you may well have already done the job Frans, based on a piece of kit that most of the people that have one actually like!! You know when you've done this, it may be useful to send the changes to Peter for an Indeed G3. Or an Indeed G2 mk ii. (For a cost of course!) I hope that Peter is still here reading this stuff becasue he's getting EXCELLENT feedback for future design if his company is actually the company making them. I suspect he's a distributor ..... Frans, do whatever improves the measurements and then I'll directly compare with the other versions and other stuff. Let's face it, it's a cheap piece of kit and if it is fairly easily modifiable to a higher level, then that can't be a bad thing eh? Many thanks for all this. I'm really grateful as I am to all of you guys on RG. Ian |
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Post by PinkFloyd on Mar 27, 2010 12:42:39 GMT
Believe it or not I can tell how an amp will sound just by looking at the graphs and figures.  |
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Post by Deleted on Mar 27, 2010 12:50:12 GMT
Believe it or not I can tell how an amp will sound just by looking at the graphs and figures. I just had to get a copy of that gif!! Ian |
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Cheers mate 
