jacco vermeulen said:
... So much so for HK not recycling their model numbers!
Should learn to keep my mouth shut on second-guessing such policies...
Carlos
jacco vermeulen said:
Ohh My God! This transistors like so good!
I talking with a friend about the HA-II and my friend speak to me, who HA-II need to change the capacitors! ALL UNITS!
Because, the Gradiente use a 70v capacitor, and the voltage the HA-II uses is 69vcd!
Brazilian Friends, change the capacitors!
Yeah... and other friend, speak to me if possible the STR-1250 is seemed a JVC designs, because the Gradiente make a agreement with JVC company.
Thanks to all replys,
I will post in here the Gradiente A-1, other famous amplifier.
The unit show in the E Bay picture, was "made" here also
Was received in a "free of taxes" capital, Manaus, the main Amazon State town.
The place was free of taxes to help the place development.
Unfortunattelly, factories installed there, started to make agreements with foreign factories to send here equipment without brand....no brand name on them...also panel Silk screen works were done here.
This model first was sell with the brand CCE on it and followed for Polivox that used the same model as PR1500 and PR1800.
The second, Polivox, latter bougth by Gradiente, made the entire equipment here, since the power cable to the last screw.
Those days, we had importation not allowed, and this was done to country development...but they made the old trick.... "The cat is hidden but the tail appear!"..... one door was oppened to enter some imported "make up" equipments.... the one you show, the Harman Kardon, was one of them.....i had this one, worked hot and produced a very nice sound.
regards,
Carlos
Was received in a "free of taxes" capital, Manaus, the main Amazon State town.
The place was free of taxes to help the place development.
Unfortunattelly, factories installed there, started to make agreements with foreign factories to send here equipment without brand....no brand name on them...also panel Silk screen works were done here.
This model first was sell with the brand CCE on it and followed for Polivox that used the same model as PR1500 and PR1800.
The second, Polivox, latter bougth by Gradiente, made the entire equipment here, since the power cable to the last screw.
Those days, we had importation not allowed, and this was done to country development...but they made the old trick.... "The cat is hidden but the tail appear!"..... one door was oppened to enter some imported "make up" equipments.... the one you show, the Harman Kardon, was one of them.....i had this one, worked hot and produced a very nice sound.
regards,
Carlos
Gradiente A1
This is a Amplificator from System One, the most delicius and sofisticated from your year, 1978. This is much used in PA systems, because this is make much power. But your protection system isn't good.
The trasistors of power stage is a 2SD665 and 2SB645. You can substitute the transistors to MJ21195/96 to substitute the original transistors if the transistors blow.
The Ci of protection (LM3900), you can't found... The datasheet of the LM3900 . I can't see a direct substitute of this.
The Rui Monteiro speak from your origins:
"This Gradiente A1 not based on other specif international amplifier. This is maked with combat the PM5000 ( PM5000 is a amplifier based on a Dynaco ). The A1 is the frist amplifier with Par Diferential!"
Especifications:
Potência por canal:
0,05% THD / 20Hz-20kHz : 200W RMS/8ohms, 350W RMS/4ohms
0,05% THD / 1kHz : 210W RMS/8ohms, 360W RMS/4ohms
Potência em ponte : 700W RMS/8ohms (0,05% THD)
Resposta em freqüência:
1 Watt: DC a 130kHz (-3dB)
Pot. Máx. 0,05% THD: DC a 80kHz (-1dB), DC a 130kHz (-3dB)
Distorção Harmônica Total (THD): 0,03% (20Hz-20kHz)
Distorção por Intermodulação: 0,02% (8 Ohms)
Relação Sinal/Ruído: 100dB
Separação entre canais: 90dB (1kHz), 70dB (20kHz)
Fator de Amortecimento (Damping): >200 a 1kHz, 8 Ohms
Slew-rate: 80V/us
Filtro subsônico: -1dB a 18Hz, -15dB a 10Hz
Sensibilidade: 1,5V para 200W/8 Ohms
Impedância de entrada: 10K Ohms
Consumo: 60VA (sem sinal), 600VA (máx 8 Ohms), 1100VA (máx 4 Ohms)
Peso: 28,5 Kg
Schamatic:
Link
This is a Amplificator from System One, the most delicius and sofisticated from your year, 1978. This is much used in PA systems, because this is make much power. But your protection system isn't good.
The trasistors of power stage is a 2SD665 and 2SB645. You can substitute the transistors to MJ21195/96 to substitute the original transistors if the transistors blow.
The Ci of protection (LM3900), you can't found... The datasheet of the LM3900 . I can't see a direct substitute of this.
The Rui Monteiro speak from your origins:
"This Gradiente A1 not based on other specif international amplifier. This is maked with combat the PM5000 ( PM5000 is a amplifier based on a Dynaco ). The A1 is the frist amplifier with Par Diferential!"
Especifications:
Potência por canal:
0,05% THD / 20Hz-20kHz : 200W RMS/8ohms, 350W RMS/4ohms
0,05% THD / 1kHz : 210W RMS/8ohms, 360W RMS/4ohms
Potência em ponte : 700W RMS/8ohms (0,05% THD)
Resposta em freqüência:
1 Watt: DC a 130kHz (-3dB)
Pot. Máx. 0,05% THD: DC a 80kHz (-1dB), DC a 130kHz (-3dB)
Distorção Harmônica Total (THD): 0,03% (20Hz-20kHz)
Distorção por Intermodulação: 0,02% (8 Ohms)
Relação Sinal/Ruído: 100dB
Separação entre canais: 90dB (1kHz), 70dB (20kHz)
Fator de Amortecimento (Damping): >200 a 1kHz, 8 Ohms
Slew-rate: 80V/us
Filtro subsônico: -1dB a 18Hz, -15dB a 10Hz
Sensibilidade: 1,5V para 200W/8 Ohms
Impedância de entrada: 10K Ohms
Consumo: 60VA (sem sinal), 600VA (máx 8 Ohms), 1100VA (máx 4 Ohms)
Peso: 28,5 Kg
Schamatic:
Link
SD665/2SB645, Ambiente seemed to have a thing for Toshiba devices, good supply line i suppose.
BTW:
there is no point in using a fast Burr Brown opamp like an OPA627 or OPA637 for a DC servo.
DC servo circuits usually have a filter at the entrance to prevent the opamp from interfering with the music signal, the idea of course is that the opamp deals with DC only.
Downside of an LM741 is the high input voltage offset, can be as high as 5mV, and voltage drift is 15 uV/C.
And it is not the most quiet, voltage noise is 30 nV/sqrt(Hz).
An OPA627 has excellent input voltage offset: 100 uV typical.
Also very good voltage drift: 0.8 uV/C, and low noise:10nV/sqrt(Hz).
But it is a very expensive opamp.
For less you can do even better:
OP77: voltage offset= 20-45 uV, voltage drift= 0.1 - 0.2 uV/C
OP177: voltage offset=10-25 uV, voltage drift=0.03-0.1 uV/C
Noise same as the OPA627.
In case you have plans for swapping DC servo opamps on a Gradiente and it is difficult to find those:
i still have a tube of military OP07AZ and can send you some.
Numbers of the OP07AZ : 25uV offset - 0.3 uV/C drift-10nV/sqrt(Hz)
BTW:
there is no point in using a fast Burr Brown opamp like an OPA627 or OPA637 for a DC servo.
DC servo circuits usually have a filter at the entrance to prevent the opamp from interfering with the music signal, the idea of course is that the opamp deals with DC only.
Downside of an LM741 is the high input voltage offset, can be as high as 5mV, and voltage drift is 15 uV/C.
And it is not the most quiet, voltage noise is 30 nV/sqrt(Hz).
An OPA627 has excellent input voltage offset: 100 uV typical.
Also very good voltage drift: 0.8 uV/C, and low noise:10nV/sqrt(Hz).
But it is a very expensive opamp.
For less you can do even better:
OP77: voltage offset= 20-45 uV, voltage drift= 0.1 - 0.2 uV/C
OP177: voltage offset=10-25 uV, voltage drift=0.03-0.1 uV/C
Noise same as the OPA627.
In case you have plans for swapping DC servo opamps on a Gradiente and it is difficult to find those:
i still have a tube of military OP07AZ and can send you some.
Numbers of the OP07AZ : 25uV offset - 0.3 uV/C drift-10nV/sqrt(Hz)
Can you send to me any OP07AZ? I will make a HA-II prototype. With modern transistors and with good capacitors.
In your opinion, what is the best? PM5000 or HA-II.
Please, when you need to contact me my email is: felnavarro@gmail.com
Thanks a lot.
Felipe Navarro
In your opinion, what is the best? PM5000 or HA-II.
Please, when you need to contact me my email is: felnavarro@gmail.com
Thanks a lot.
Felipe Navarro
Gradiente x JVC receivers
Mod_Evil,
There are two Gradiente receivers that are the same models from JVC units:
STR-800 = JVC VR-5505
STR-1000 = JVC VR-5515
http://www.audiorama.com.br/gradiente/receiver.htm#STR-800
http://www.audiorama.com.br/gradiente/receiver.htm#STR-1000
http://www.audiorama.com.br/jvc/receiver.htm
The STR-1050 and STR-1250...
http://www.audiorama.com.br/gradiente/receiver.htm#STR-1050
http://www.audiorama.com.br/gradiente/receiver.htm#STR-1250
... are actually based on the STR-900...
http://www.audiorama.com.br/gradiente/receiver.htm#STR-900
... with the front panels using the same JVC style of the STR-1000.
The back panel and dimensions of STR-1050 and STR-1250 are the same style of the STR-900 and they don´t have a direct twin in the JVC line, as the STR-800 and STR-1000.
I know this, because I have one STR-1250 and one STR-1000 here. 😀
Best Regards,
Farjon.
Mod_Evil,
There are two Gradiente receivers that are the same models from JVC units:
STR-800 = JVC VR-5505
STR-1000 = JVC VR-5515
http://www.audiorama.com.br/gradiente/receiver.htm#STR-800
http://www.audiorama.com.br/gradiente/receiver.htm#STR-1000
http://www.audiorama.com.br/jvc/receiver.htm
The STR-1050 and STR-1250...
http://www.audiorama.com.br/gradiente/receiver.htm#STR-1050
http://www.audiorama.com.br/gradiente/receiver.htm#STR-1250
... are actually based on the STR-900...
http://www.audiorama.com.br/gradiente/receiver.htm#STR-900
... with the front panels using the same JVC style of the STR-1000.
The back panel and dimensions of STR-1050 and STR-1250 are the same style of the STR-900 and they don´t have a direct twin in the JVC line, as the STR-800 and STR-1000.
I know this, because I have one STR-1250 and one STR-1000 here. 😀
Best Regards,
Farjon.
mod_evil said:
Felipe,
mailed you the OP07s today(monday), including a stapled-on green gift sticker for your customs guys.
As my emails in Portuguese do not seem to be that good, em Ingles:
If my female neighbor is attractive and tempting, why try to invite a fashion model in a hotelroom bed ?
The general purpose BC transistors are made by Philips, Siemens and a whole bunch of others. These can be bought in any store around the globe for very little, and offer excellent value for money.
Toshiba SA968/SA970/SC2238/SC2240 were produced for audio purposes.
The 1301/3280 output devices are the 120 watt die versions of the 150 watt 2SA1302/2SC3281 that are still regarded as among the best ones to use for output stages. Devices with high bandwidth, very linear.
Hfe values are significantly higher for the Toshibas, especially BL versions.
Linearity is much, much better too, place the Hfe/Ic graphs of the Toshibas next to the ones of the BC's.
Unlikely , that the output devices of the PM5000 were exotics.
So, the HA-II has both in the LTP, Vas, driver and output stage, devices that are at least a class higher.
An opamp servo, i see as a more elegant way of handling DC than adding a bipolar electrolytic capacitor to the feedback loop. Some do not.
By the components and the specs alone, the HA-II has the potential of performing better than the PM5000.
560pF caps at the Vas of the PM5000 are a bad sign, a power amplifier that is 1 dB off at 20KHz is more of an historical relic to me.
Oh yeah.
Send a photo of your neighbor to me!
Oh yeah, i will make a prototype of HA-II with OP07AZ.
A Audiophile friend, speak to me who HA-II isn't good for BASS. This is good for Mid-Bass and Treble.
He speak PM5000 is VeryGood, to Bass. Very Good to driver a Subwoofer. A friend make a test and compare this, and comprove this.
Oh yeah...
Thanks a lot of mr.Jacco Vermeulen. You're a good people!
Farjon,
I speak in the other mensage. Gradiente, have contracts with JVC. Is possible, one or two receivers is a "xerox" of a JVC 🙂 Do you have registred on www.AudioDicas.com.br ( portuguese )?
Thanks a lot for all replys.
Send a photo of your neighbor to me!
Oh yeah, i will make a prototype of HA-II with OP07AZ.
A Audiophile friend, speak to me who HA-II isn't good for BASS. This is good for Mid-Bass and Treble.
He speak PM5000 is VeryGood, to Bass. Very Good to driver a Subwoofer. A friend make a test and compare this, and comprove this.
Oh yeah...
Thanks a lot of mr.Jacco Vermeulen. You're a good people!
Farjon,
I speak in the other mensage. Gradiente, have contracts with JVC. Is possible, one or two receivers is a "xerox" of a JVC 🙂 Do you have registred on www.AudioDicas.com.br ( portuguese )?
Thanks a lot for all replys.
mod_evil said:
It's very simple: the HA-II total capacitance is not enough for good bass. As a general rule, in a Class-AB or B amp you need at least 10.000uF for every 50w of power to have good bass response.
I know there's nothing written around confirming this, but it has been my experience when building amps.
Carlos
Hello Carlmart, Mod Evil and other friends.
The STR1250 schematic, the power amplifier unit (18 or 36W) was asked for a local friend.
So...i made it a little bit more clean...do not know if Felipe already publish some simulation with a better image... well, i will post this one, as i made it more clear to observe.
regards,
Carlos
The STR1250 schematic, the power amplifier unit (18 or 36W) was asked for a local friend.
So...i made it a little bit more clean...do not know if Felipe already publish some simulation with a better image... well, i will post this one, as i made it more clear to observe.
regards,
Carlos
Attachments
Carlos ( DestroyerX )! Thanks for that!
Can you put in here the schematic of the Gradiente M-246 or M-366?
Can you put in here the schematic of the Gradiente M-246 or M-366?
carlmart said:
The whole PS looks like the intention was to save money.
Not just the 5.000uF caps that should have a higher voltage rating.
Look at the parallel doubled rectifier diodes.
Also the 10 volts capacitors for the higher voltage front end rails, placing them on top of the output stage rails means saving, also means less voltage stability compared to fully separated powersupplies.
I can imagine that the transformer used was barely up to the task.
The entire schematic smells pretty Japanese to me, top notch transistors with low budget periferics.
Yes Jacco...correct!...need more capacitance to avoid block low frequencies
Also the input capacitor can be changed...increased...thank you Jacco...cooperation is important....i really forgot that.
That's the best spirit...cooperation!!!
Mod Evil...i think i have many Brazilian schematics, but they have been published separated..... at least, the best ones, i can do it...but i will turn a bad guy to forum management, as i iwill use bandwidth, already knowing, that those things were already shown...... i can do it....but i think i should not.
Well, as i have some close relationship with you Felipe, i will use that sittuation to tell something that is not so kind to say...as you will forgive me, knowing the intentions not beeing bad.
In my point of view, of course i cannot be sure if i am rigth or wrong, as people thinks different, there are many cultures with many rules, some of them opposite related each other...but i think, and i want to say, that everyone, may have the obligation, to read entire forum at least once!...to avoid questions already answered, or to avoid publish things already published.... this seems a shame to the ones that already read the forum, as show clearly that people did not read in advance to open threads.... seems very much strange in my mind....this is common, are there many cases...i already made many times those things...the difference is that, when i remenber those things i made, and i believe you too Felipe, i feel enormous shame on me.....no problems to go to.....but returning, i will still be making this suggestion.
regards,
Carlos
Also the input capacitor can be changed...increased...thank you Jacco...cooperation is important....i really forgot that.
That's the best spirit...cooperation!!!
Mod Evil...i think i have many Brazilian schematics, but they have been published separated..... at least, the best ones, i can do it...but i will turn a bad guy to forum management, as i iwill use bandwidth, already knowing, that those things were already shown...... i can do it....but i think i should not.
Well, as i have some close relationship with you Felipe, i will use that sittuation to tell something that is not so kind to say...as you will forgive me, knowing the intentions not beeing bad.
In my point of view, of course i cannot be sure if i am rigth or wrong, as people thinks different, there are many cultures with many rules, some of them opposite related each other...but i think, and i want to say, that everyone, may have the obligation, to read entire forum at least once!...to avoid questions already answered, or to avoid publish things already published.... this seems a shame to the ones that already read the forum, as show clearly that people did not read in advance to open threads.... seems very much strange in my mind....this is common, are there many cases...i already made many times those things...the difference is that, when i remenber those things i made, and i believe you too Felipe, i feel enormous shame on me.....no problems to go to.....but returning, i will still be making this suggestion.
regards,
Carlos
We had a Quasar factory, a Quasar brand in my country
here, down in South America, the Quasar was very famous, in special in Brazil, and also known in other countries of this continent.
They have operated from the mid seventies to mid eigthies when they close their doors because of hard competition.
They have made interesting amplifiers, with technologie advanced to the seventies.
Here a sample of one of the last models... the schematic.
regards,
Carlos
here, down in South America, the Quasar was very famous, in special in Brazil, and also known in other countries of this continent.
They have operated from the mid seventies to mid eigthies when they close their doors because of hard competition.
They have made interesting amplifiers, with technologie advanced to the seventies.
Here a sample of one of the last models... the schematic.
regards,
Carlos
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