| sinski |
Hi,
Few days ago i finished my gc. It is just very good 300va/25v transformer and premium kit from Peter Daniel without any changes (no zobel, no input caps). It is just experimental design, so i can play with some components and later put it in one nice case:
http://s7.photobucket.com/albums/y2..._prototype1.jpg
On the photo you can see one zobel netwoerk, but without zobel the sound is more direct, so now the amp is without zobel.
I was taking care when i was building it. First all components and pcbs where cleaned very carefully, than i soldered all compnents one by one using WBT solder with 5% silver. All cables are from Kimber and input cables are teflon isolated Chord. All inputs and outputs are very good quality.
Actuall the amp sounds very good, but ...
The sound is not involving :xeye: and lifeless :sleep: and the bass is not very good.
I compared it to Musical Fidelity A1, Naim Nait 2, Naim Nac72/140. All those amps have less resolution and are not so exact as gc, but they have just punch, prat and strong living involving sound and basslines are much better.
Is there any help possible, or gc ist juts like :sleep: this ? Do i have to wait longer, so the amp will really run in ?
Any ideas ?
:scratch: |
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| filholder |
Hi,
I had the same issue, using a Lm based chipamp with a passive preamp. ie just a pot. Really in my and a lot of otehr people opinion these amps sound better when fed through either a buffer or a preamp. There are many people on this site bteer equiped to tell you why however all i can say is to get the best from mine I first tried a buffer and then later a AD815 based preamp. Both helped a lot though i prefer the later.
Here is Nuuks guide to building a buffer:-
http://myweb.tiscali.co.uk/nuukspot...inclonepre.html
And here is the thread for the preamp i built:-
http://www.diyaudio.com/forums/show...&threadid=40783
With soem kind of active stage these amps really fly, they gain the punch that they are lacking without IMHO.
Phil |
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| peranders |
| quote: | Originally posted by sinski
Is there any help possible, or gc ist juts like :sleep: this ? Do i have to wait longer, so the amp will really run in ?
Any ideas ?
:scratch: |
:idea: Let a friend do the connecting and you must tell which amp you are listening to. Make it 5-10 tries and then see if you can pick the Gainclone. It's a big difference if you can see and know what you are listening to. |
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| lndm |
| I used to use LM3886's and I found they give a very straight performance. They are fairly accurate but lacking flavour IMO. I guess you could make them sound warmer, or anything else you wanted by using a 'colourful' pre stage. I guess I could say that the 3886's are 'open to suggestion' - and suggest you should! |
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| Garnett |
Hi Sinski. I am building the very same kit! I'm interested in the replies you get, because I was worried what I understand may be more defined bass may well also mean quieter bass.
I'm loathe to start work on a second DIY project straight after my first so I guess I'll have to wait and see. In the meantime can you post any more pics? They are really useful for a fellow builder who is very new to Gaincloning.
Would a snubberised power supply help? Perhaps someone else with more knowledge could advise.
In an effort to be helpful, I tried to do a search for relevant threads (Anyone got any good tips on how to search on here? - I certainly haven't found the knack yet).
Anyway I found this post and there are some potentially useful replies.
http://www.diyaudio.com/forums/show...4345#post144345 |
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| jimbo1968 |
| I think you can limit google searches to a particular website, but then why do that? Just google it straight. |
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| sinski |
I was testing gc with different sources. I have two sources -DPA Drive+DAC DX32+passive preamp with 50k blue alps and the variable output of my Benchmark DAC1.
Yesterday o took my gc to my friend and we have tested it with Naim cd3, sony XA30es and DAC1.
The effect was always very similar and the worst was to compare to my old Nait 2 with all tweaks from www.acoustica.org.uk
Nait 2 is just dancing and sparkling with music and gc is very exact, but absolutely lazy and sleepy. Maybe i will try snubber ps. |
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| Nordic |
| As it has been said before, I'll just repeat it, get an active pre or valve buffer. Maybe google Decibel dungeon and play around with some of the implementations on there |
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| sinski |
| Benchmark DAC1 has one active buffer build around ne5532A and a variable output. Connected directly to Naim Nap140, Crimson 620 and Krell 50 (three different power amplifier) sounds very good. Connected to gc is lifeless. |
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| rudi |
| quote: | Originally posted by sinski
Benchmark DAC1 has one active buffer build around ne5532A and a variable output. Connected directly to Naim Nap140, Crimson 620 and Krell 50 (three different power amplifier) sounds very good. Connected to gc is lifeless. |
there is some of your problem
the benchmark DAC1 is a fine DAC but lifeless to start off with. it is very good for recording equipment but does not have the musicallity. then the second problem is the NE5532 .... it isn't very good , you can replace it with a better AD or BB substitute.
have a look at Russ Whites's freebird. it will give it exactly what you are looking for |
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| enzedone |
| I had this same problem with my first one. I then put a better power supply into the next LM3875 with a couple of bridge rectifiers and a couple of filter caps. Much better sound, way more dynamic. I'm no electronics guru, but the power supply seems to be vital in getting a good sound from these chips IMHO. I am building my next one using LM4780, and it will have 40,000uf of filter caps. 40 x 1000uf and 4x bridge rectifiers, so it will interesting to see how this one differs from my previous ones. |
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| Garnett |
| quote: | | I had this same problem with my first one. I then put a better power supply into the next LM3875 with a couple of bridge rectifiers and a couple of filter caps. Much better sound, way more dynamic. I'm no electronics guru, but the power supply seems to be vital in getting a good sound from these chips IMHO. I am building my next one using LM4780, and it will have 40,000uf of filter caps. 40 x 1000uf and 4x bridge rectifiers, so it will interesting to see how this one differs from my previous ones. |
Enzedone: What do you mean by "better power supply". I have one transformer (ripped out of an od marantz) which had various settings and which my mate rigged up for me to have two 24v secondaries.
I'm biulding a premium kit from Audiosector. It came with the bits for two rectifier bridges with 8 diodes each. I was only going to use one rectifier bridge. I thought you only used two if you were powering each channel independently. Is this right? |
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| analog_sa |
| quote: | | The sound is not involving and lifeless and the bass is not very good. |
Hi Sinski
You don't seem to mention your speakers and they may be the main reason for your negative comments. Ime GC type amps are extremely fussy about what they drive, much more than most discrete amps. The GC can't drive well neither my Sonus Fabers nor my ProAcs. No amount of filter capacitance, neither an active pre can change this. If i didn't know how well the chips play into easy, crossoverless speakers i would consider them a complete waste of time. |
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| lndm |
If I remember rightly, the 3886 sounds different with different amounts of gain. I remember forming the opinion that the sound may have had to do with the large amount of feedback in one way or another.
Based on this and on what analog_sa said, maybe you could compensate your speaker load to make them easier to drive. |
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| Bas Horneman |
| quote: | | The GC can't drive well neither my Sonus Fabers nor my ProAcs. |
I concur wiht that statement. I played my LM3875 (BrianGT) kit into a CSS FR125....and they did not drive them very well..(sorta same as my SE 300b AMP)..substituted a P3A for the GC and voila..that amp kicked BUTT and took names. I don't think it (GC) will drive stuff as well as a NAIM. Like Analog_sa says...combine them with the right speakers and you'll have a taste of high end for practically peanuts. |
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| Bas Horneman |
| quote: | | If i didn't know how well the chips play into easy, crossoverless speakers i would consider them a complete waste of time. |
Yup..they sound very nice with my Bastani Prometheus, much better than say a Pioneer A400 except in the speed/transients department. (The Pioneer A400 had quite a reputation as a giant killer a decade or so ago)
But lets face it...even if you get a speaker that combines well with the GC ...it still may not be your cup of tea. |
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| sinski |
My speakers are Spendor 2/3.
http://www.enjoythemusic.com/Magazi...pendorsp23e.htm
They never go under 8 Ohm, are actually easy to drive, have 88dB. I was using them with 2x8W tube amp and my Nait 2 has only 2x20W but sounds like 2x100 ...
If Naim 2 and Musical Fidelity A1 can drive them easily, than gc can also do that. I can play with gc+spendors very loud without any distortion, but the rhytm and prat is completely absent. Maybe i want to much.
Anybody who heard Naim Nait 2 know how this small amp can rock.
Today i have build the snubber ps from chipamp.com .
It seams that the sound is fuller and has more body, rhytm is little better, but some kind of the openess and sound transparence dissappeared. |
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| Bas Horneman |
| quote: | | I can play with gc+spendors very loud without any distortion, but the rhytm and prat is completely absent. Maybe i want to much. |
No..you just want that rythm and prat. Simple. The friend with the Rod Elliot P3A....he wants rythm and prat. I gave him a GC...and he aint using it.:D |
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| Bas Horneman |
| That is not really efficient... in my book. |
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| Peter Daniel |
| quote: | Originally posted by sinski
Today i have build the snubber ps from chipamp.com .
It seams that the sound is fuller and has more body, rhytm is little better, but some kind of the openess and sound transparence dissappeared. |
It shurely disappears and that's why I don't recommend snubbers and large caps.
I would suggest you build a proper chassis and then evaluate the amp again.
I was just listening today to the new GC monoblocks (chassis built in a similar way as AMP-1) based on a Premium kit (no parts substitution) with ProAc speakers, and the they were very much invloving with great bass.
I have a copy of Hi Fi Choice upcoming review of AMP-1, if anyone want's a copy, please e-mail me (6 Meg file). |
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| jleaman |
| quote: | Originally posted by Peter Daniel
It shurely disappears and that's why I don't recommend snubbers and large caps.
I would suggest you build a proper chassis and then evaluate the amp again.
I was just listening today to the new GC monoblocks (chassis built in a similar way as AMP-1) based on a Premium kit (no parts substitution) with ProAc speakers, and the they were very much invloving with great bass.
I have a copy of Hi Fi Choice upcoming review of AMP-1, if anyone want's a copy, please e-mail me (6 Meg file). |
Id Like a copy
jason at zorby-audio.com Please :) |
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| enzedone |
I will be running two transformers with two rectifier bridges for each transformer. I cannot comment on the GC driving different speakers as I only drive BOSE and now my main speakers are IMAGE LOUDSPEAKERS. These are not known to people outside New Zealand. www.imageloudspeakers.co.nz if you want to have a look. Mine are the 416's. But all i can say is when i built a more comprehensive power supply for my second amp using the same chips(Lm3875), ........wow what a difference. especially in the bass, totally amzing...... So it will ineresting to see how this LM4780 sounds compared to the 3875.
Transformers are 300va 25-0-25
Rectifier bridges are 35A 400V |
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| enzedone |
| Here is a pic of the rectrifiers with the filter caps. |
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| enzedone |
| Sorry about that photo loaded it sideways...............doh This is the caps........... in perspex ...(Peter) |
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| enzedone |
| Man......... I just wish i could convince the mrs to allow me to buy a 2000 work bench...Auzzies will know this, then i could at least cut something straight.......ahhhhhhh! |
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| rudi |
| quote: | Originally posted by enzedone
Man......... I just wish i could convince the mrs to allow me to buy a 2000 work bench...Auzzies will know this, then i could at least cut something straight.......ahhhhhhh! |
:D buy one and explain later :devilr:
I know it well, got one myself |
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| tangen |
| quote: | Originally posted by Peter Daniel
I was just listening today to the new GC monoblocks (chassis built in a similar way as AMP-1) based on a Premium kit (no parts substitution) with ProAc speakers, and the they were very much invloving with great bass. |
My speakers are also ProAc and sound really great with the LM3875 premium kit from Peter. I use the kit with a passive pre (Alps blu pot). The kit is feeded with signals from a Pioneer PDS-06 cd player and Peters DAC. I don't miss the bass or something else. Very good, indeed ;)
jan ove |
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| lndm |
| quote: | Originally posted by enzedone
Auzzies will know this |
Speak for yourself :p |
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| DIAR |
I've been listening to my BrianGT LM3875 gainclone (both classic and snubberized 10 mF PS options) for a few days and I must say I am suprised with the quality of sound. I didn't expect much but I still built the amp with good quality materials and put some thought into amp structure also.
My speakers (Zu Druid MK4) are almos perfect match for LM3875. Efficiency is 97 dB and impedance stays above 8 ohms at all frequencys. System synergy is very important.
The sound is not boring clinical hifi. It's much much better. It can really play music. I think it's right up there with the best matched hybrid and all tube amps which I have heard with Druids.
I also have Jordan JX92S MLTL speakers. I'll have to try those too with the GC. They also should perform really well together.
I use the GC with 10 kohm DACT CT2 and intend to build a tube preamp. And I will also order a second pair of LM3875 and start experimenting.
I'm not sure if these links work:
http://koti.kontu.la/jsalonen/cgi/b...803471143484350
http://koti.kontu.la/jsalonen/cgi/b...979971143657073 |
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| Upupa Epops |
| Guys, what did you using before, when you are in trance with this quasicomplementary circuit, primarily designed for commercial electronic ? Do you really mean, that it is " sound end station " ? :cool: |
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| Garnett |
Great looking amp DIAR - very professional (have you got any pics with the lid on?).
What do you recommend when you say "put some thought into amp structure also". What sort of thing should a newbie give consideration to? |
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| karma |
case wiring layout of components;)
no lifeless chipamps here:D |
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| XELB |
Why don't you lower the capacitance near the chip to 1000uF and build a proper PSU ?!? :D
You need a large capacitace PSU, this way you will get a punchy and deep bass :cool:
But remember, large capacitance caps are rubbish in high frequencies :dead:
I use a downgrade of capacitance because of this " bad caracteristic".
You can start with some of 10.000uF(or less F) in parallel and then go down to 6800uF .... till 680uF! ( lots of them in parallel ).
This will give you a punchy and deep bass but also very good treble ;)
PS: large capacitance also reduces da voltage drop in the PSU :cool: |
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| sinski |
| quote: | Originally posted by XELB
Why don't you lower the capacitance near the chip to 1000uF and build a proper PSU ?!? :D
You need a large capacitace PSU, this way you will get a punchy and deep bass :cool:
But remember, large capacitance caps are rubbish in high frequencies :dead:
I use a downgrade of capacitance because of this " bad caracteristic".
You can start with some of 10.000uF(or less F) in parallel and then go down to 6800uF .... till 680uF! ( lots of them in parallel ).
This will give you a punchy and deep bass but also very good treble ;)
PS: large capacitance also reduces da voltage drop in the PSU :cool: |
http://www.diyaudio.com/forums/show...2074#post882074 |
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| Garnett |
| quote: | Originally posted by karma
case |
I was going to use MDF and line it with foil to shield it. Any other considerations?
A PCB keeps my signal path short, anything else? Quality of wires? Length?
| quote: | | layout of components |
I want to keep it small so I was going to put a large heatsink between the transformer and the chips (because I gather the transformer should either be distanced or shielded from the chips to avoid some kind of noise?) Anything else to consider?| quote: | ;)
no lifeless chipamps here:D |
That's what I'm after! |
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| tangen |
| quote: | Originally posted by Upupa Epops
Guys, what did you using before, when you are in trance with this quasicomplementary circuit, primarily designed for commercial electronic ? Do you really mean, that it is " sound end station " ? :cool: |
For your information: Before the LM3875 I used a heavily modified Dynaco ST70 and PAS3 [also commercial electronics ;) ] The main reason for switching amps was not whether or not they are commercial , but how they communicate the artistic intents and musical emotions captured on the LP or CD. So far the LM3875 kit does that better than other amps that I can afford. Of course, this is not "sound end station". If you have made some kits or constructions that outperform Peters kits, I will be happy to try them out.
best wishes
Jan Ove |
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| karma |
mdf is fine you can always use solid wood when its finished. try making a two piece chipamp amplifier and psu
that way you dont need shielding. to much shielding really does change the sound and not in a good way. if you make it one piece
a simple piece of grounded copper or aluminum between the tranformer and the chips is fine.
this amp is next in line for a new case;) |
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| Upupa Epops |
| Jan, Dynaco is old **** and effort for upgrade is useless... Pass 3 - look at distortion and you will see...From this look are chips amps more better...But they are quasicomplements and it give limits in quality. Certainly they are easy to use, but factual quality is little bit far... :cool: |
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| Garnett |
Thanks Karma. I will see what I can do. I might post some pics before I start drilling any holes.
BTW - Loving the retro gauges on that amp!
| quote: | Originally posted by Upupa Epops
Jan, Dynaco is old **** and effort for upgrade is useless... Pass 3 - look at distortion and you will see...From this look are chips amps more better...But they are quasicomplements and it give limits in quality. Certainly they are easy to use, but factual quality is little bit far... :cool: |
Upupa Epops, I'm new to this DIY stuff. What do you use? |
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| peranders |
| quote: | Originally posted by Upupa Epops
Jan, Dynaco is old **** and effort for upgrade is useless.: |
Maybe Dynaco is "skit" but Jan Ove maybe wants some vintage feeling. |
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| tangen |
| quote: | Originally posted by peranders
Maybe Dynaco is "skit" but Jan Ove maybe wants some vintage feeling. |
Dear Upopa and Peranders.
I do not want vintage feeling or "skit", just musical experiences. The electronics that give me that is "good", the rest is "bad". I'm always in search of new possibilities, but I'm so old that I know when someting is "right" or "wrong" (for me of course). My reference is live music, the way I experience it. Some stuff give me something similar to live music, others do not.
But as said before, Upopa: give me a schematic or kit you have developed yourself that is better than Peters kit and I will consider building it.
Peranders: which of your kits are better in making music?
best
Jan Ove |
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| Upupa Epops |
| Dear Jan, my new amp will have fifty two transistors in each channel, fifty diodes, fout opamps etc... Be sure, that will be better than chip one... :cool: Are you need still to build them ? BTW, chip amp I know to make also, look at www.czechaudio.com.... |
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| Upupa Epops |
| Pardon, fifty six... ;) |
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| tangen |
| quote: | Originally posted by Upupa Epops
Dear Jan, my new amp will have fifty two transistors in each channel, fifty diodes, fout opamps etc... Be sure, that will be better than chip one... :cool: Are you need still to build them ? BTW, chip amp I know to make also, look at www.czechaudio.com.... |
I'm not scared about the amount of soldering required :D
But could you please type your url (web site address) once more? I have problems to find it. I suppose the site will have both the schematics and pictures that is necessary?
regards
jan ove |
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| Garnett |
| quote: | Originally posted by Upupa Epops
It is www.czechaudio.com and there PA 03 amplifier... |
Upupa - That looks cool! Do you sell those in kit form? |
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| tangen |
| quote: | Originally posted by Upupa Epops
It is www.czechaudio.com and there PA 03 amplifier... |
Thanks a lot! In what way does this PA 03 differs from other "gainclones" (technically, musically)?
best
jan ove |
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| Upupa Epops |
I did not compare it with other solutions...My idea by designing was to minimalize mistakes by building in case, when amps have more PCB's ( as we are still seeing by other constructions )... If we give to amateurs more " space " for own " creativity ", they often confuse something... ;) My solutions is " confuseless... ;), you must only know well solder up...
At this time I have any PCB's, but isn't problem to let make them... |
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| sinski |
It looks like this thread went south ...
So, what about lifeless and noninvolving gc ?
Any hints ? |
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| tangen |
| quote: | Originally posted by sinski
It looks like this thread went south ...
So, what about lifeless and noninvolving gc ?
Any hints ? |
Sorry, partly my fault :xeye:
Could you please tell me what kind of big caps you are using? They do not look like the Panasonic FC caps that came with my kits. From your photo this seems to be the only part that is not similar to mine.
best wishes
jan ove |
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| tiltedhalo |
IMHO its simply physco-perception, people make up there mind before they have even heard the finished goods.
Case in point double blind tests, it truly is amazing to see what some people think they are listening to when they are not.
A friend off mine came over, another "audio-phile" and remarked on the great detail, depth and sound stage of my Krell, and how much he always liked the sound quality everytime he heard it, but little did he know he was really listening to my just finished BPA300+ chip amp.
Lesson learned, preconception rules most of the time. |
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| XELB |
Sinski, forget if it's from Marantz, because this doesn't mean anything ;)
And BTW, I can't remember a Marantz amp that the competitors didn't add better :dead:
You need a nice trafo, 400VA at least.
(I like to play safe, at least 300VA per channel, now I have 650VA :) )
But with 300VA you should have some "life". ( I have an amp with 350VA trafo and ~50.000uF and it plays very well)
How many capacitance do you have per rail ? I can only see those small caps in the chip boards.....
You should consider at least 40.000uF per rail after the diodes and 1.000uF to 2.200uF near the chip amp.
With these mods, you should have a more dynamic amp.
PS: maybe your speakers like current ;)
Borrow a good trafo from a friend and test it with more VA's and a few more caps. |
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| sinski |
The transformer is very nice 330VA/25V. I measured AC and it is 27.5V.
Maybe it is to much ?
The caps on the pcb are 1500uF Panasonic FC, all parts are original Premium Kit Parts from audiosector.com
Caps are without plastic, some people says it sounds even better.
Yesterday i installed snubber ps from chipamp.com with 2x10000uF Panasonics, and changed 1500 caps on pcb for 100uF+0.1 mkp.
Amp is more dynamic, but lost this great transparence and openess.
Next step will be back to original premium kit with 2200 Pana FC on pcb.
If it will not help, than i will probably buy new transformer with real 22V AC. |
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| sinski |
Some material to build a "real" case is already on the way.
Peter - my transformer is 330VA/25V, but delivering 27V AC. Is it OK, or to much ?
Should i better go for 22Volt AC ?
What is your experience with different voltage for gc ?
Tomek |
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| XELB |
| quote: | Originally posted by sinski
Some material to build a "real" case is already on the way.
Peter - my transformer is 330VA/25V, but delivering 27V AC. Is it OK, or to much ?
Should i better go for 22Volt AC ?
What is your experience with different voltage for gc ?
Tomek |
The question is not for me but......
The LM3886 plays very well near the voltage limit so, you don't have any problem with that!
In fact, when hot and with a voltage near the limit the chip have the best sound, in my opinion.
I once tested the LM3886 with a 1100VA trafo and 32-0-32 V ( this put it near the V limit ) and the dynamics and detail was very refined :cool:
Try good quality caps near the chip, this is important!
Also use 100nF in the chip pins and caps pins.
You can also add 100nF to the 10.000uF capacitors and if you have any additional caps around 3.200uF to 1.000uF, add them after the 10.000uF.
Try this way and then report back.
But remember, you need to leet it burn for at least one day of full play.
Btw, do you have any input or output cap ?
What is your DC offset ? |
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| sinski |
| quote: | Originally posted by XELB
Btw, do you have any input or output cap ?
What is your DC offset ? |
I have no input/output cap. DC offset on one channel is 2mV, another is 40mV
I think i will wait few days before i will change anything again. |
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| lndm |
Sinski, While I do not doubt the things people are saying to you, I feel maybe these differences do not amount to what you are really looking for.
For one, I would not buy a different xfmr at this point. While I agree that capacitors make a difference, if the ones you use are known good, and you have a reasonable amount of capacity, I would avoid spending big just now.
It is my assumption that you basically know how the chip sounds, and while tweaking will help, it is currently preventing you from looking elsewhere :) |
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| XELB |
| quote: | Originally posted by sinski
I have no input/output cap. DC offset on one channel is 2mV, another is 40mV
I think i will wait few days before i will change anything again. |
Good choice.
Let the caps burn for a few days, then make the final test ;)
When you add caps to the PSU it's normal to lose some detail at the first days( especially when you add big caps).... then, after burning in for a few days, sometimes you get what you were looking for ;) |
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| Peter Daniel |
| quote: | Originally posted by sinski
What is your experience with different voltage for gc ?
|
It is also my expierience that with higher voltage the chip sounds better. I wouldn't change the transformer. What is the actual DC voltage, after rectification? |
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| pinkmouse |
| My LM4780 sings with 40V rails, though you do need lots of heatsinking to run it that way. Certainly better than when I ran it on 30V. |
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| lawriebuck |
I reckon it's the Spendors. I have listened to these many times and I think they are lifeless and undynamic. Maybe not so bad at low volume levels or with simple classical music, but forget any loud or complicated music. They also sound a bit "woody".
I don't know what that reviewer was talking about!?!
:) |
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| karma |
| quote: | Originally posted by pinkmouse
My LM4780 sings with 40V rails, though you do need lots of heatsinking to run it that way. Certainly better than when I ran it on 30V. |
im running 49v rails. than again i have big heatzincs
;) |
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| jleaman |
| quote: | Originally posted by karma
im running 49v rails. than again i have big heatzincs
;) |
What is the max rail voltage for these LM3875's? isn't pushing the rail voltage looking for disaster to the chip and the speakers you connect them to ? |
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| karma |
im running a LM4780 at 49v rails
my LM3875s run at 20v to 22v rails |
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| sinski |
| quote: | Originally posted by Peter Daniel
What is the actual DC voltage, after rectification? |
Peter:
After rectification i have 36 Volt DC
Everobody:
What are the best cables i should use to wire gc inside ?
At the moment i used DNM for ls output, some Chord (cable which Chord is making for Naim) on input and solid core beetwen ps and pcb from one Audioquest LS cable.
My transformer has one magnetic screen and extra winding beetwen primary and secondary windings. Maybe a normal transformer will be better ?
Cheers, Tomek |
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| karma |
| wow that was fast. so now how does it sound? |
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| sinski |
I was already writing about it. Bass has a better control, drive and rhytm is better, but some kind of direct sound, openess and transparence dissappeared.
I want to run it one week without any changes and than go back to original premium kit and then decide what i like more, than i will put it in one nice case. |
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| Upupa Epops |
| Is good, twisted all " paired " wires together - SNR will be better.... ;) |
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| karma |
nice:D that setup also works well with the lm4780 in paralell.
really opens up the sound stage. with lots of power on reserve;) |
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| XELB |
| quote: | Originally posted by sinski
I was already writing about it. Bass has a better control, drive and rhytm is better, but some kind of direct sound, openess and transparence dissappeared.
I want to run it one week without any changes and than go back to original premium kit and then decide what i like more, than i will put it in one nice case. |
Sinski, did you add the snubber to the PSU, after those 10.000uF ?
If not, just try 100nF directly in the caps pins ;) ( It's easy add I think you will notice some more detail ) |
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| sinski |
| quote: | Originally posted by XELB
Sinski, did you add the snubber to the PSU, after those 10.000uF ?
If not, just try 100nF directly in the caps pins ;) ( It's easy add I think you will notice some more detail ) |
Yes the snubber sits there. It is the snubber ps kit from chipamp.com
http://www.chipamp.com/supply.shtml
;) |
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| XELB |
OK ;)
Now just let it burn for a few days :cool: |
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| jimbo1968 |
Is that arrows I see on the output wires (edit: supply rails) ?
Perhaps they are the wrong way around. Are they supposed to point towards the output or with the electron flow. |
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| sinski |
| Yes, they are arrows on the cable. I had a piece of one solid core Audioquest speaker cable and i took the pieces of it for the connection beetwen ps and pcb. I just took the arrow showing from ps to pcb, i don't think that at this place it really important ... |
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| jleaman |
| Maybe shorten these wires too :) just to prevent disaster and problems. |
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| Upupa Epops |
| Why ? Amp is goat cheese or wine ? :xeye: |
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| sinski |
| quote: | Originally posted by jleaman
Maybe shorten these wires too :) just to prevent disaster and problems. |
Don't worry, everything is under control. I don' want to shorten wires from the transformer now.
| quote: | Originally posted by Upupa Epops
Why ? Amp is goat cheese or wine ? :xeye: |
All electronic components need some time to settle down. I think that big caps need at least few days to burn in and chip like lm3875 probably weeks. |
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| jleaman |
| quote: | Originally posted by sinski
Don't worry, everything is under control. I don' want to shorten wires from the transformer now.
All electronic components need some time to settle down. I think that big caps need at least few days to burn in and chip like lm3875 probably weeks. |
I didn't say shorten the wires i mean shorten the exposed copper that will cause a short if crossed. Possibly short that nice transformers you have. :) |
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| Upupa Epops |
| Probably week ? Your ears maybe.... it is about psychoacoustic... ;) |
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| XELB |
Are your trafo cables protected with enamel ?
Mine are, this way you never have a short.... but it's always good to isolate the current cables. |
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| Greg Erskine |
| quote: | Originally posted by Upupa Epops
Probably week ? Your ears maybe.... it is about psychoacoustic... ;) |
I tend to agree.
I have just added 2 new LM3875 modules to my amp. The originals are 2 years old. They were all purchased at the same time and are identical using identical components.
I have been swapping between these "old" and "new" amps and didn't noticed any obvious differences. If there were any differences they must have been very minor or the burn in period was very quick and I missed the differences.
I was not testing specifically for "old" and "new" just experimenting with parallelling and bi-amping, so there is a chance that with my random testing procedures I missed something. ;)
regards |
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| Greg Erskine |
| quote: | Originally posted by XELB
Are your trafo cables protected with enamel ? |
Hi XELB,
If you look closely at the picture you can see the enamel has been stripped to 1 or 2 mm before the insulation. With the toriods I buy, this seems to be "standard" practice.
regards |
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| enzedone |
Yes, burning in seems to happen very quickly. I noticed on my first LM3875 that it was a mattter of a couple of minutes, not weeks of playing 12-24 hrs a day. But we could go into a whole new thread on this topic alone.......(burning in speaker wires and their direction of electron flow and god knows what else)......
Brett. |
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| enzedone |
Greg; On your second amp did you use the same power supply set-up? I think i saw some picks of one of your LM3875's a while back. Was it from Brians site? Is your new one similar to that?
Brett |
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| Greg Erskine |
| quote: | Originally posted by enzedone
Greg; On your second amp did you use the same power supply set-up? I think i saw some picks of one of your LM3875's a while back. Was it from Brians site? Is your new one similar to that? |
Hi Brett,
Yes, that's the amp. It changes a lot, lucky I made it easy to reconfigure.
Here's a current picture. The top 2 amps are the originals and the bottom 2 are the new ones. PSU is shared. :D
regards |
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| sinski |
It is interesting that so many threads on diyaudio.com develop their own life and subject completely not depending on the thread title.
:xeye: |
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| Greg Erskine |
hi sinski,
Sorry for my part in distracting your thread. :bawling:
I will take no further part.
PS: Could a moderator delete my posts?
regards |
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| sinski |
Hi,
There was a small break in my gc experiments. In last days i visited few friends with different setups and this is my final opinion:
1. When my gc is connected to a very good living and rocking preamp like naim nac 72/hicap then the music is living and rocking
2. Passive amp is working sometimes better, sometimes worse, but only with a very good preamp there is a real good prat.
3. In a passive mode the snubber ps seems to work better, but snubber IMHO is like kind of "loudness" switch. There is little more bass and punch, but the sound is more tensed and not so natural and i cannot listen so long to he music as with original Premium Kit design.
4. I switched back to original "no snubber" design with 2x1500uF very close to LM3875 and for my taste the sound is more natural, the sound is flowing more naturally and finally i prefer it over the "snubber" version. Sorry Carlos ;)
So now i need a really good rocking preamp. Any suggestions ? |
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| Peter Daniel |
| ModWright SWL 9.0SE is the popular choice with chip amps. |
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| filholder |
I found an AD815 preamp based on the work done in this thread gave me all the PRAT i need. However never having listening to a Naim setup i could compare it. It has given me my best sounding setup by a reasonable margin, very highly recommneded.
http://www.diyaudio.com/forums/show...&threadid=40783
Phil |
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| Nuuk |
| quote: | | ModWright SWL 9.0SE is the popular choice with chip amps. |
It is? :eek: I can find only one other reference to it on the whole of diyAudio (and that was by the same person)! ;) |
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| Peter Daniel |
| Well, it's not particularly diy product, but from what I hear outside diyAudio, the best match for chip amps like Patek, for instance. |
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