ampbox chassis eurobox eurocard
amt - a little bit of topic - only very very little
You have a quite nice website and
some interesting service - at least for some of us DIY builders.
Eurobox Amp/ PS Chassis.
The Eurobox will soon morph into an amplifier chassis which will accept Eurocard PCBs
and also aluminum or fiberglass mounting plates for transformers and PCBs.
All can easily be inserted or removed for ease of assembly, modding or updating.
In addition, heatsinks can be fitting internally, with proper ventilation of course,
as well as a version that has external heatsinks
Regards
lineup
http://mywebpages.comcast.net/ampbox/page4.html
amt - a little bit of topic - only very very little
You have a quite nice website and
some interesting service - at least for some of us DIY builders.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Eurobox Amp/ PS Chassis.
The Eurobox will soon morph into an amplifier chassis which will accept Eurocard PCBs
and also aluminum or fiberglass mounting plates for transformers and PCBs.
All can easily be inserted or removed for ease of assembly, modding or updating.
In addition, heatsinks can be fitting internally, with proper ventilation of course,
as well as a version that has external heatsinks
Regards
lineup
amt said:
AMT
You don't mention why you need a preamp. Do you really need gain? Do you have to match impedances? Most often than not an active preamp is not really needed.
Have you tried some passive way of controlling volume? Stunningly transparent sound is availble with nearly no effort if your system is sympathetic.
My ideal for an active pre is one that can provide (nearly) the transparency of a passive with added dynamics, bass power and drive.
Can an opamp pre achieve this? Even some mid-fi cd players (Rotel, Marantz) include a discrete output stage to better cope with real world loads.
Why on earth mention "musical colorations"? If a gain stage does not debilitate the sound does it have to be coloured?
The above comments are only relevant to normal voltage feedback devices. Current feedback opamps may well sound very different.
SY said:
I can believe this. Every few years i spend a few days playing with the latest fashions in opamps - there is just too much net buzz to ignore. And why do i do it? Because opamp circuits are so cute and easy, even with a grossly overdone PS and a separate Jung regulator for each IC and top quality passives they are just dirt cheap and easy. Really tempting. And really good for mid-fi.
Well we all need to play to our strengths, and unfortunately circuit engineering isnt mine. Im just glad that I was able to join the DIY community in some capacity.
Why do I require a preamp? Well simply so that I can drive anything I need to. I started using passive attentuators after reading HHs thread and constructed several.
http://www.diyaudio.com/forums/showthread.php?threadid=2608&highlight=
This really opened up my eyes. I had been using an Adcom GFP750 and prefered the passive mode over the active. So I sold it since it was really just a box to house a remote controlled Alps pot. Not sure if there was any buffering or not.
The problem is that I borrow or use (customers' facelift projects)many different amps and of course, they all dont greet my passives in a friendly manner. I also use Pro amps on occasion, and the 10k unbalanced inputs are really a challenge. And Im getting tired of the cable swapping game. I could just use a buffer but then if I really need some gain, I wouldnt have it. I think everyone needs to have at least one preamp laying around.
The opamp solution is attractive to guys like me that arent adept at complex circuit design or implementation. Look at how many new recruits have gone DIY due to the gainclone. Probably more than Dynaco and Heath had lured in the day. The simplicity is seductive.
amt
Why do I require a preamp? Well simply so that I can drive anything I need to. I started using passive attentuators after reading HHs thread and constructed several.
http://www.diyaudio.com/forums/showthread.php?threadid=2608&highlight=
This really opened up my eyes. I had been using an Adcom GFP750 and prefered the passive mode over the active. So I sold it since it was really just a box to house a remote controlled Alps pot. Not sure if there was any buffering or not.
The problem is that I borrow or use (customers' facelift projects)many different amps and of course, they all dont greet my passives in a friendly manner. I also use Pro amps on occasion, and the 10k unbalanced inputs are really a challenge. And Im getting tired of the cable swapping game. I could just use a buffer but then if I really need some gain, I wouldnt have it. I think everyone needs to have at least one preamp laying around.
The opamp solution is attractive to guys like me that arent adept at complex circuit design or implementation. Look at how many new recruits have gone DIY due to the gainclone. Probably more than Dynaco and Heath had lured in the day. The simplicity is seductive.
amt
Shot Lineup, I'm bussy listening to my Project88 now through headphones...its purdy good.... got mine powered of a 1.5va 2 x 12V pcb mount transformer... wich gets slightly warmish.... will go get a 3va one later.
I nearly had a conniption when I got to RS, they ordered PSU caps which were like $2 each... frikken hell. Anyway they sound good for brand new.
I used Rod's PSU scematics too for p05a, he doesnt give all the values but you can see them in the photo...
Also I am using my PC as source (or rather the earphone out on the logiteck x530 speakers... something I could never do before without coupling all the PSU noise with... But, heck its sounds nice now for sure.
I nearly had a conniption when I got to RS, they ordered PSU caps which were like $2 each... frikken hell. Anyway they sound good for brand new.
I used Rod's PSU scematics too for p05a, he doesnt give all the values but you can see them in the photo...
Also I am using my PC as source (or rather the earphone out on the logiteck x530 speakers... something I could never do before without coupling all the PSU noise with... But, heck its sounds nice now for sure.
amt said:
Today and tomorrow are already in the past, but definitely this weekend
Reference should be a system which works well with a passive and doesn't need gain. I use several passive types: S&B TVC, Alps pot, Seiden attenuator with fixed series and switchable shunts tantalum resistors.
Only active stage i like is a transformer coupled 5687 (4:1).
A base level reality check is a Threshold FET2 described in another thread.
My tube amps seem to work happily with passives. The active stages i test through a Threshold S300.
I don't realy need a reference, I know what live music sounds like, my dad was a drummer for 25 years...
I would say its not as good as Nuuk's class A buffer, but is less full of nonsense- i.e. easier to get right first time around for a noob. I had to redo the PCB like 3 tmies to get that to work without it starting to motorboat at random intervals.
I do not blame the circuit. It just takes a diffirent approach to the opamps I sharpened my teeth on.
Also the power demand is less intensive (smaller/cooler) with the opamp, which is nice as I am makeing an integrated amp, as oposed to haveing a whole case for the preamp.
Still another hour before I can give a fair sound comaprison.
But from the taste I had earlier, I still think the transistor buffer is going to come out tops for purity of sound.
If I had to do the project over and not from mostly scrounged/e-bayed components, I would be able to use the class A buffer without a problem I think...
Next preamp project for me will be an Akido and then I will revisit the transistors.. they seem easier to comprehend with a bit of valve knowledge than alot of chip experience...
I would say its not as good as Nuuk's class A buffer, but is less full of nonsense- i.e. easier to get right first time around for a noob. I had to redo the PCB like 3 tmies to get that to work without it starting to motorboat at random intervals.
I do not blame the circuit. It just takes a diffirent approach to the opamps I sharpened my teeth on.
Also the power demand is less intensive (smaller/cooler) with the opamp, which is nice as I am makeing an integrated amp, as oposed to haveing a whole case for the preamp.
Still another hour before I can give a fair sound comaprison.
But from the taste I had earlier, I still think the transistor buffer is going to come out tops for purity of sound.
If I had to do the project over and not from mostly scrounged/e-bayed components, I would be able to use the class A buffer without a problem I think...
Next preamp project for me will be an Akido and then I will revisit the transistors.. they seem easier to comprehend with a bit of valve knowledge than alot of chip experience...
amt said:
Apparently after my admission of stupidity the AD815 test will have to wait until the new victims arrive.
Meanwhile i tried the equivalent (improved?) Texas offering, the TPA6120. Used mostly cheap industrial parts, 10000uF FA, 317/337, shunt connected Alps pot, BG N output caps.
While the sound is not unlistenable it falls short from the 3 transistor discrete opamp in the FET2. Reduced ambience, shortened hi frequency decay, less emotion. The sound is very clear and precise but too mechanical.
I hate the BG N in coupling position and realise they are partly to blame for the lack of naturalness but until the AD815 arrives i won't mess with DC offset compensation or film caps - the TPA just cannot hold my interest.
Nordic said:
Great, Nordic.
so you say project88 can serve as good headphone amp (with your headphones, at least)
Can't say I am surprised.
most separate so called Line level Preamps
would actually deliver enough current for normal headphones listening.
And especially some discrete ones,
such PreAmps would provide More The Current you need to drive anything,
except for maybe big 4/8 Ohm loudspeakers.
I for now also uses PC earphone output jack ( 3mm stereo plug )
to connect my PC sound to my Stereo Amplifier (an integrated Harman-Kardon HK650 ~2x100 Watt ).
I have ordered a good soundcard with RCA jack out/input.
But delivery of soundcard gas been delayed by this distributor.
Merry Christmas, Nordic (what a name! for a south guy)
And happy watching TV, as well as listening to good music.
lineup
a true NORDIC Guy among all the SNOW outside herehaving a White Christmas - as usual
SY said:
Ah, SY. Hate to admit it when i'm wrong. I guess Christmas helps
Curiosity got the best of me and i put together a 797 line amp. Well, what do you know, plays absolutely fine (Arvo Part Orient Occident at present).
Very different from any other opamp i've heard. Mind you i was prejudiced. Heard many different opinions about the 797 and the suggestion that it sounds flat and uninvolving stuck in my mind.
It's a bit difficult to tame and i have a mild prefence for it in inverting mode but for an opamp it's simply marvelous. The sound is a bit dark but layered and breathing. Within the first few hours the bass was very muddy but later cleared up and now is really deep and powerful. Good dynamics too. Maybe i just prefer bipolar opamps as none of the audiophile types like OPA627/637 AD825/8065/8610 do it for me.
At present it still plays with 317/337 PS and BG N output caps. All resistors are now Caddock. I wonder how will it respond to a better regulator.
Merry Christmas
After a couple of days of listening the initial euforia is slightly reduced. The 797 certainly has a very strong sonic character, which although pleasant with some types of music is certainly not neutral. What it does produce is a very well formed and powerful bass, a bit like a "loudness" effect. The midrange is a bit reticent but pleasant. Unfortunately, exposure to more demanding music showed some issues in the upper ranges.
And just as well as the AD815 is playing again. This chip is very different sounding from the TPA6120. It is so neutral, it's almost uninteresting. Compared to the input pot used as a passive, the 815 adds or subtracts very little, possibly nothing at all. It is still working with cheap metal films, BG N at output and 317/337 PS. The passive components alone seem entirely sufficient to account for a very minor reduction in ambience. And it is a bit bass shy. Maybe the SIL version will correct this.
Amazingly good sounding for a chip. Many thanks to CarlosFM for pointing this great device out.
And just as well as the AD815 is playing again. This chip is very different sounding from the TPA6120. It is so neutral, it's almost uninteresting. Compared to the input pot used as a passive, the 815 adds or subtracts very little, possibly nothing at all. It is still working with cheap metal films, BG N at output and 317/337 PS. The passive components alone seem entirely sufficient to account for a very minor reduction in ambience. And it is a bit bass shy. Maybe the SIL version will correct this.
Amazingly good sounding for a chip. Many thanks to CarlosFM for pointing this great device out.
Give opa2227 or opa2228 a shot, I mean you can get a free sample! the 2228s which I have now are my favourite opamps so far, if demanding of decoupling of at least 10nf per rail.
I just fixed the problem with my upgraded vsps, and it is sounding beautifull - listening to Chris Rea as I type.
They are perfect for those 47k loads.
I just fixed the problem with my upgraded vsps, and it is sounding beautifull - listening to Chris Rea as I type.
They are perfect for those 47k loads.
Nordic said:
OPA228 (single channel chip) OPA2228 (dual version)
is really one op-amp I will consider next time I invest in operational amplifiers
Thanks very much for your report, Nordic
Data, description and datasheets download:
http://focus.ti.com/docs/prod/folders/print/opa228.html
Myself has no practical experience of these.
But I have studied the data and test diagrams and read the application instructions of the datasheet.
Compared to most any other op-amp I know of, suitable for audio
these are my absolute top grade choice.
There are surely op-amps which are faster (video speed)
but this does not necessarily make them better for audio,
when we sum up the whole picture of each op-amp.
Such expensive beasts can give you some troubles,
that AUDIO Op-Amps will NOT give you.
I would call OPA228 / OPA227 Audio Op-Amplifiers,
if ever there is such a thing.
I have heard and read a lot of good about the OP37, the older similar op-amp,
which is to be replaced by this later OPA228.
Already this one, OP37 (OPA37), even if an older circuit,
is obviously still a good choice for hifi audio.
==========================================
As I always like to go for SINGLE CHANNEL op-amps, I would buy OPA228.
Two chips have just about 2x twice the cooling surface, compared to one.
Each channel separate - (dual mono) - is my way of doing things.
This would also give possibility to give each chip its own regulators, power supply.
OPA227 (single) and OPA2227 (dual) are with built in compensaton capacitors.
This makes OPA227 stable for all applications.
But on the other hand the GBW = speed = slewrate, is 4 times lower for OPA227.
Practically this means, that when you need higher voltage gains, say 20-100,
you could do better with OPA228.
While for active filters, crossovers and others circuits with gain 1 - 4
you can preferably use OPA227 / OPA2227.
# LOW NOISE: 3nV/(Hz)
# WIDE BANDWIDTH:
* OPA227: 8MHz, Slewrate 2.3V/µs
* OPA228: 33MHz, Slewrate 10V/µs
Regards & Happy Year 2007
lineup
Lineup Audio Constructions LTD.
Mr. Line up, you are turning very popular..can i ask you to...
register an E-mail adress, at Yahoo Uk for instance, to allow direct communication with you.
Also. offer this adress to our forum...as communication with you are blocked there....no adress provided i imagine.
This will start some "two way" communications between us.
I am sure that there are people that wants to contact you to obtain more informs about projects.
Happy new year to you.
regards,
Carlos
register an E-mail adress, at Yahoo Uk for instance, to allow direct communication with you.
Also. offer this adress to our forum...as communication with you are blocked there....no adress provided i imagine.
This will start some "two way" communications between us.
I am sure that there are people that wants to contact you to obtain more informs about projects.
Happy new year to you.
regards,
Carlos
Using email ot not
thanks for your concern
destroyer X
I wish you were more often here at forum with us
You think of things that other don't think of.
This makes you often can bring New Ideas into topics.
This is one skill Called in this foreign language of english:
Think Out of The Box
There are too many without this capacity at forum.
They not often say anything we haven't heard before.
Instead they can even be suspicious to anything THEY haven't thought of before.
Creativity is almost zero
- they never start any new topics
- never post a new amplifier project
- can not show me one (1) original idea of their own
- not show a new variant of know circuits
In NHL Ice Hockey, where quite a bunch of players come from my European country
they every year rate and name MVP of the year, most valuable players.
In each team we need those ones.
It is for to see them people are willing to pay money and come to see match.
Without such players, out of the ordinary, there wouldn't be no NHL.
========================================
destroyer X,
I know you and me are Two of The Kind
Original human individual
and no copy
made up of other great amplifier designers' papers and patents.
========================================
Have a nice New Year Holiday now, man of the southern western half of earth
I keep my email to myself.
I have too many 'bad copies' that are after me.
Because I tell them they are BAD when they are BAD.
I am not being honest to get popular.
I am telling my straight honest opinion
because this is my true know reality.
The only reality I know.
=========================================
Regards + New Year 2007
to all my many friends here around
those that I have informed and helped
and those who have given something valuable to me
without to resort to low quality bad posts -only making me sad
=========================================
But No Regards to those, they would know themselves who they are
Negative persons, that has taken The Good Spirit out of many topics
and so not been any good for otherwise nice place.
I guess many reading this can see what I mean.
The important thing in life - is not audio or knowing better than other
The important thing in life is to be good
and add some positive to other:
Be helpful and Kind to those that come in your way.
Sad truth.
Some people are not missed too much, when they die.
Other good ones, are remembered by many as a good human being.
New 2007 Year
lineup
http://lineup.awardspace.com/
------------------------------------------------------------------------------------
PS. I keep my email to myself and our board moderators.
So they can do their work and talk to me
if ever again
I will have some bad day like I had some months ago.
MVP super NHL player does not always manage a superior hockey game.
Occasionally they do a mediocre performance among all their other great games.
This is why they show out to be valuable player
.... and yet being Only Humans.
this is why we love them the most
not because they are super tiger woods performers
all the time
but because they have a champion heart and want to be good and do the best they can.
Give father and mother glory
and be good,
as we all can and
as we all should
... instead of being a pain in behind of other members
and
bring disgrace to our fathers and mothers and
our country and family
thanks for your concern
destroyer X
I wish you were more often here at forum with us
You think of things that other don't think of.
This makes you often can bring New Ideas into topics.
This is one skill Called in this foreign language of english:
Think Out of The Box
There are too many without this capacity at forum.
They not often say anything we haven't heard before.
Instead they can even be suspicious to anything THEY haven't thought of before.
Creativity is almost zero
- they never start any new topics
- never post a new amplifier project
- can not show me one (1) original idea of their own
- not show a new variant of know circuits
In NHL Ice Hockey, where quite a bunch of players come from my European country
they every year rate and name MVP of the year, most valuable players.
In each team we need those ones.
It is for to see them people are willing to pay money and come to see match.
Without such players, out of the ordinary, there wouldn't be no NHL.
========================================
destroyer X,
I know you and me are Two of The Kind
Original human individual
and no copy
made up of other great amplifier designers' papers and patents.
========================================
Have a nice New Year Holiday now, man of the southern western half of earth
I keep my email to myself.
I have too many 'bad copies' that are after me.
Because I tell them they are BAD when they are BAD.
I am not being honest to get popular.
I am telling my straight honest opinion
because this is my true know reality.
The only reality I know.
=========================================
Regards + New Year 2007
to all my many friends here around
those that I have informed and helped
and those who have given something valuable to me
without to resort to low quality bad posts -only making me sad
=========================================
But No Regards to those, they would know themselves who they are
Negative persons, that has taken The Good Spirit out of many topics
and so not been any good for otherwise nice place.
I guess many reading this can see what I mean.
The important thing in life - is not audio or knowing better than other
The important thing in life is to be good
and add some positive to other:
Be helpful and Kind to those that come in your way.
Sad truth.
Some people are not missed too much, when they die.
Other good ones, are remembered by many as a good human being.
New 2007 Year
lineup
http://lineup.awardspace.com/
------------------------------------------------------------------------------------
PS. I keep my email to myself and our board moderators.
So they can do their work and talk to me
if ever again
I will have some bad day like I had some months ago.
MVP super NHL player does not always manage a superior hockey game.Occasionally they do a mediocre performance among all their other great games.
This is why they show out to be valuable player
.... and yet being Only Humans.
this is why we love them the most not because they are super tiger woods performers
all the time
but because they have a champion heart and want to be good and do the best they can.
Give father and mother glory
and be good,
as we all can and
as we all should
... instead of being a pain in behind of other members
and
bring disgrace to our fathers and mothers and
our country and family
- Status
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