Hi all,
I'm new at the gainclone. That's why for the shortcut, I order Brian GT's board+kit.
Will there be any advantage to make dual mono power supply for the gainclone kind of amp? (popular approach on the common solid state amp)
Also, currently I have an average 4-ohm load speaker (min is 3.9 ohm), what transformer voltage/power rating is the best for this load? (value before the rectifier)
What if next time I change my speaker to 8-ohm one, do I need to change the transformer, to get optimum result with this load?
Of course my questions above are for 'soundwise' decission. And I understand that 'best' and 'optimum' is subjective person-to-person.
So I would really appreciate for any opinions.
Regards,
---
David A.W.
I'm new at the gainclone. That's why for the shortcut, I order Brian GT's board+kit.
Will there be any advantage to make dual mono power supply for the gainclone kind of amp? (popular approach on the common solid state amp)
Also, currently I have an average 4-ohm load speaker (min is 3.9 ohm), what transformer voltage/power rating is the best for this load? (value before the rectifier)
What if next time I change my speaker to 8-ohm one, do I need to change the transformer, to get optimum result with this load?
Of course my questions above are for 'soundwise' decission. And I understand that 'best' and 'optimum' is subjective person-to-person.
So I would really appreciate for any opinions.
Regards,
---
David A.W.
Selamat Pagi David,
If you spent the rest of your life reading through this part of the forum, you would still not have a definitive answer 😉
Some like separate PSU's for each channel, some a single one.
I have tried both and can't honestly decide which I like best.
If you use transformers of at least 160VA rating, you could build two PSU's either of which would be capable of powering a Gainclone. You would then have the choice of trying one or two.
As regards the speaker impedance, if you use transformers with 18 volt secondaries they will do for both 8 and 4 ohm speakers.
If you spent the rest of your life reading through this part of the forum, you would still not have a definitive answer 😉
Some like separate PSU's for each channel, some a single one.
I have tried both and can't honestly decide which I like best.
If you use transformers of at least 160VA rating, you could build two PSU's either of which would be capable of powering a Gainclone. You would then have the choice of trying one or two.
As regards the speaker impedance, if you use transformers with 18 volt secondaries they will do for both 8 and 4 ohm speakers.
My ten pence worth: Dual mono psu will give a more forceful sound that will fill a big room but could get a bit harsh. One transformer will probably give you a softer sound (easier listening 😉 ) and personally I prefer that. I don't notice any difference in sound quality between having an integrated psu (in the amp case) or a separate psu connected to the amp with a cable.
My advice, similar to Nuuk's, is to start with one transformer and try that. At a later stage you can add another, in a seperate case, or the same case if it is big enough. This way you will save money initially, then if you prefer the dual mono psu sound you can keep it that way, or use the new transformer on another GC (once you build one GC, you will probably want to try another at some point anyway 😉 )
My advice, similar to Nuuk's, is to start with one transformer and try that. At a later stage you can add another, in a seperate case, or the same case if it is big enough. This way you will save money initially, then if you prefer the dual mono psu sound you can keep it that way, or use the new transformer on another GC (once you build one GC, you will probably want to try another at some point anyway 😉 )
Nuuk said:
Are you saying that it should be exactly 18 volts or at least 18 volts? I read this same place else but can't remember.
Not exactly 18 volts but the general rule is lower voltage/higher current for speakers with lower (4 ohm) impedance and visa versa.
As a guide, the cut off point if you want to use 4 ohm speakers, should be somewhere around 20-22 volts (before rectification). 18 volts is quite a common voltage for transformer secondaries and that's why I quoted that figure. 😉
Well also depends on the price of the transformers you acquire. If you can get a 18V 3A transfomer for $3 and a 18V 6A transformer for $25, then sure I would be much more willing to get the two seperate ones. My logic being your spreading the load....like doubling the surface area 😀
Peter Daniel said:
I don't see how it would add more power, unless the initial transformer was underpowered for 2 channels. Would using seperate secondaries (4 windings) on a larger transformer have the same effect as dual mono?
I have a 1kVA 4x25vac transformer that I was going to use for my bridgeclone.
--
Brian
I guess 47Labs transformers were underpowered😉
But I think that overall impression of more dynamics applies here as well as improved soundstage.
But I think that overall impression of more dynamics applies here as well as improved soundstage.
In general, when in doubt about Peter's statements please refer yourself to:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=31157
I happen to think that dual mono with separate GNDs and balanced operation is the only way to go but don't have Peter's stature in the forum to say it out loud, or to make a big deal about it. 😉
http://www.diyaudio.com/forums/showthread.php?s=&threadid=31157
I happen to think that dual mono with separate GNDs and balanced operation is the only way to go but don't have Peter's stature in the forum to say it out loud, or to make a big deal about it. 😉
BrianGT said:
The same transformer core won't allow that perfect separation that two different cores, separate power cords, and separate power generators and electrical lines to your house would afford, by, IMO, it'll do.
grataku said:
Over my head technically. How does balanced operation relate to dual mono?
I am planning to go 95% dual mono, with the only common item being the 120VAC feed, and I will be using a 20A outlet for that to decouple as much as possible.
I just read the Steven's review in the enjoythemusic.com that he prefered only one Humpty (instead of two as the complete dual mono).
Peter D. - Any comments from you as one of the ChipAmp experts ? 😉
PS: I already bought two of (18-0-18V, 180VA, US$14 each) toroidal transf for my first NIGC (4 Ohm speakers).
Peter D. - Any comments from you as one of the ChipAmp experts ? 😉
PS: I already bought two of (18-0-18V, 180VA, US$14 each) toroidal transf for my first NIGC (4 Ohm speakers).
Peter Daniel said:
What does the "Grataku" mean?
BTW, Peter, I wonder why your AMP1 don't be 25W? Do you have plan to put a DC speaker protector into your futuer amp?
Grataku is a forum member who made previous comments.
Why would it be 25W if it can be 50W?😉
I don't think DC speaker protector is necessary in a well designed (op) amp. The initial units had the coupling caps at the input, but later we were not installing those (for pure listening satisfation).
Why would it be 25W if it can be 50W?😉
I don't think DC speaker protector is necessary in a well designed (op) amp. The initial units had the coupling caps at the input, but later we were not installing those (for pure listening satisfation).
Peter,
Thanks for the definition of "Grataku" ( new word for me today!)
IMHO, running the chip at 50W may be too high, the SPIKE protection might be activated, partcularly, if the speaker impedence drop under 8Ohm at some frequncy (re: the datasheet).
uhm.... , the price of speakers is expensive, that's why I prefer to be on the safe-side. Do you mean if there is a coupling cap (1.0-4.7UF) it's safe/very low possibility to have dangerous DC voltage at output (even we also obmit the cap in the feedback loop which ensure DC untiy gain) ??!
Note: I am a real newbie, pls be patient with my questions/comments. 😉
Thanks for the definition of "Grataku" ( new word for me today!)
IMHO, running the chip at 50W may be too high, the SPIKE protection might be activated, partcularly, if the speaker impedence drop under 8Ohm at some frequncy (re: the datasheet).
uhm.... , the price of speakers is expensive, that's why I prefer to be on the safe-side. Do you mean if there is a coupling cap (1.0-4.7UF) it's safe/very low possibility to have dangerous DC voltage at output (even we also obmit the cap in the feedback loop which ensure DC untiy gain) ??!
Note: I am a real newbie, pls be patient with my questions/comments. 😉
leadbelly said:
It doesn't, just making a point.
Remember? There is no right or wrong _it's all subjective. 😉
Anyway Peter, I like the Petek GC, is that tiger maple you use for the sides?
I just thought it was an opportunity for a joke, but I really didn't mean it😉
It is Zebrawood and it gets much nicer when sealer (or oil) is applied. This Patek indeed deserves it's name, it is so cute and features almost watchmaking precision😉
But it's possible only with those chip amps. Rodd was listening and didn't dismiss it😉
It is Zebrawood and it gets much nicer when sealer (or oil) is applied. This Patek indeed deserves it's name, it is so cute and features almost watchmaking precision😉
But it's possible only with those chip amps. Rodd was listening and didn't dismiss it😉
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