Congratulations, Macd, i'm glad you have it working and like the sound 
I suggest you build the vbe-multiplier first, then up the bias.
Turning up the bias without thermal compensation may lead to thermal runaway, depending on the size of your heatsink.
Ahh Nordic, finally got the transformers
They look chunky enough,
i hope you got a nice discount for waiting so long.
Best regards,
Klaas
I suggest you build the vbe-multiplier first, then up the bias.
Turning up the bias without thermal compensation may lead to thermal runaway, depending on the size of your heatsink.
Ahh Nordic, finally got the transformers
They look chunky enough,
i hope you got a nice discount for waiting so long.
Best regards,
Klaas
Good Macd...will be an excelent idea... we gonna be very happy to know your findings
Klaas is rigth...will be much more safe.
Having images... please.... post them to us Macd.
I will be waiting your feedback Macd....having images, please, send me and i can post them.
regards,
Carlos
.....................................................................................................
Nordic
Some factories use those stinking material on transformers.
Maybe one entire day under the sun will help your transformer not to smell so bad.
Now you gonna reach 100 watts Nordic.
R10 resistance...change them to 1K8 because of the gain.
regards,
Carlos
Klaas is rigth...will be much more safe.
Having images... please.... post them to us Macd.
I will be waiting your feedback Macd....having images, please, send me and i can post them.
regards,
Carlos
.....................................................................................................
Nordic
Some factories use those stinking material on transformers.
Maybe one entire day under the sun will help your transformer not to smell so bad.
Now you gonna reach 100 watts Nordic.
R10 resistance...change them to 1K8 because of the gain.
regards,
Carlos
Attachments
Re: Yes...this is a need.
Hello Carlos and SandyK.
How are you? This moment the time it is 2.00 after midnihgt here somewhere in north Hellas (Greece!! A strange word!!) and the temperature is 29C. Nice! Sorry for my spelling i'm not so good in english. Many times, when i translate my thoughts from Hellenic language to English i feel that these mutitated. I wrote correct this? Hey Carlos, if gived to you some time the opportunity can you leave some flowers from me in the grave of Ayrton Senna?
SandyK you are a good man. Thanks for the plans. You place me in thoughts. Do you know what happens? From the beggining i tried to build a big power amplifier. If it was successful, then the design of smaller amplifiers will be a easy job. Our difference in thought be located in this exactly. We will talk very soon.
Good night
Fotios
Hello Carlos and SandyK.
How are you? This moment the time it is 2.00 after midnihgt here somewhere in north Hellas (Greece!! A strange word!!) and the temperature is 29C. Nice! Sorry for my spelling i'm not so good in english. Many times, when i translate my thoughts from Hellenic language to English i feel that these mutitated. I wrote correct this? Hey Carlos, if gived to you some time the opportunity can you leave some flowers from me in the grave of Ayrton Senna?
SandyK you are a good man. Thanks for the plans. You place me in thoughts. Do you know what happens? From the beggining i tried to build a big power amplifier. If it was successful, then the design of smaller amplifiers will be a easy job. Our difference in thought be located in this exactly. We will talk very soon.
Good night
Fotios
Destroyer X Amplifier
Destroyer X
I may be about to repeat what others may have already said, but to read through every reply would take a long while.
In addition to the careful matching and thermal coupling,
perhaps you should consider using 2SA970 in the differential pair. Yes, the pinout is different, but easily fixed with an insulating sleeve or 2 on the leads.
The 2SA970 has a much higher hFE than the 2N5401, which will reduce the O/P dc offset by a worthwhile amount, as well as being quieter. They are also available from sources such as Futurlec, for the princely sum of (USD) 10c each !
SandyK
Destroyer X
I may be about to repeat what others may have already said, but to read through every reply would take a long while.
In addition to the careful matching and thermal coupling,
perhaps you should consider using 2SA970 in the differential pair. Yes, the pinout is different, but easily fixed with an insulating sleeve or 2 on the leads.
The 2SA970 has a much higher hFE than the 2N5401, which will reduce the O/P dc offset by a worthwhile amount, as well as being quieter. They are also available from sources such as Futurlec, for the princely sum of (USD) 10c each !
SandyK
Re: Destroyer X Amplifier
Hi sandyK,
Carlos is wanting to reduce the number of options not increase them, hopefully this will reduce some of the confusion. The 2N5401 was chosen because it is a very common choice, especially overseas, where it is easily sourced.
If people match the transistors or not is up to them. VR1 does actually adjust the DC offset. If you look at the PCB you will also see the the input transistors are very close to one another so you can tie them together if desired. They don't mount face to face though as this causes problems making a compact PCB.
Do you work for, have worked for, has a family member of friend that works for, SiliconChip?
EDIT: Ooopps, I didn't see Carlos had answered some of your questions.
regards
sandyK said:
Hi sandyK,
Carlos is wanting to reduce the number of options not increase them, hopefully this will reduce some of the confusion. The 2N5401 was chosen because it is a very common choice, especially overseas, where it is easily sourced.
If people match the transistors or not is up to them. VR1 does actually adjust the DC offset. If you look at the PCB you will also see the the input transistors are very close to one another so you can tie them together if desired. They don't mount face to face though as this causes problems making a compact PCB.
Do you work for, have worked for, has a family member of friend that works for, SiliconChip?
EDIT: Ooopps, I didn't see Carlos had answered some of your questions.
regards
Destroyer X Amplifier
Greg
The only connection that I have with Silicon Chip, is the fact
that I have bought every single issue since it's inception .
I posted the suggestion because it is easily implemented,
very low in cost, and as stated would give the amplifier a lower O/P DC offset, combined with a slightly lower noise floor.
Why not strive for the best possible performance, if the additional cost is so small ? Many people in this forum love to experiment, too,and I am sure that many of them are quite capable of matching transistors.
Despite what most people may think,my personal experience is that very close matching will give the amplifier a better soundstage, as well as other audible benefits.I have heard too many amplifiers with a very clean but unexciting sound (many Silicon Chip designs) and others that sound bloody terrible until thoroughly warmed up. Thermal coupling of the input pair , particularly if they are closely matched will usually reduce the warmup time for best results. Thermal coupling will also help ensure that it stays that way.
SandyK
Greg
The only connection that I have with Silicon Chip, is the fact
that I have bought every single issue since it's inception .
I posted the suggestion because it is easily implemented,
very low in cost, and as stated would give the amplifier a lower O/P DC offset, combined with a slightly lower noise floor.
Why not strive for the best possible performance, if the additional cost is so small ? Many people in this forum love to experiment, too,and I am sure that many of them are quite capable of matching transistors.
Despite what most people may think,my personal experience is that very close matching will give the amplifier a better soundstage, as well as other audible benefits.I have heard too many amplifiers with a very clean but unexciting sound (many Silicon Chip designs) and others that sound bloody terrible until thoroughly warmed up. Thermal coupling of the input pair , particularly if they are closely matched will usually reduce the warmup time for best results. Thermal coupling will also help ensure that it stays that way.
SandyK
Thanks for your input sandyK,
You beat me, I've only been reading SiliconChip since 2003, but I have read just about every post here since 2002.
All changes are easily implemented. This is a cheap, easy and completed design. Carlos could go on forever trying the different options. He made me delete the "alternative transistor" page from the DX Amplifier web site only yesterday, less than 24 hours ago, so your suggestion is very bad timing. I just looked and the 2SA970 was on the list, alternative number 4.
So, I hope you understand, your suggestion is a good one, just Carlos doesn't want any options anymore. You might read back just a couple of pages where Carlos explains the situation.
regards
You beat me, I've only been reading SiliconChip since 2003, but I have read just about every post here since 2002.
All changes are easily implemented. This is a cheap, easy and completed design. Carlos could go on forever trying the different options. He made me delete the "alternative transistor" page from the DX Amplifier web site only yesterday, less than 24 hours ago, so your suggestion is very bad timing. I just looked and the 2SA970 was on the list, alternative number 4.
So, I hope you understand, your suggestion is a good one, just Carlos doesn't want any options anymore. You might read back just a couple of pages where Carlos explains the situation.
regards
Hi,
Two face to face To92s take up less PCB area than separated To92s.
If one puts in four holes - ebce- linking the two "e" and directly opposite ecbe (all at 0.05inch pitch) then the 8holes allow face to face and allow either bce or cbe pinouts and no space wasted. Then just glue the To92 together with instant and that eliminates the insulating air between the cases.
that sounds like an excuse and not a reason.
Two face to face To92s take up less PCB area than separated To92s.
If one puts in four holes - ebce- linking the two "e" and directly opposite ecbe (all at 0.05inch pitch) then the 8holes allow face to face and allow either bce or cbe pinouts and no space wasted. Then just glue the To92 together with instant and that eliminates the insulating air between the cases.
AndrewT said:
Hi Andrew,
No, it was a conscious decision.
Did you have a look at the PCB? You will see that rotating one of the input transistors will complicate the traces. My plan was the grind a small flat face on the curved surface of one of the transistors and mate them that way. Should work and everyone will be happy.
If I was doing a double sided PCB or didn't have a size restriction things may be different.
regards
VBE multiplier is a very helping hand.
Dx corporation loves VBE multipliers.
Short wire is a need.... needing long ones, use shielded cables...grounded shield units.
Insulator will be needed....rubber composite, those Silicone compound, ceramic insulator or Mica old styled insulator (better)
Attach the VBE multiplier into the heatsink.
regards,
Carlos
Dx corporation loves VBE multipliers.
Short wire is a need.... needing long ones, use shielded cables...grounded shield units.
Insulator will be needed....rubber composite, those Silicone compound, ceramic insulator or Mica old styled insulator (better)
Attach the VBE multiplier into the heatsink.
regards,
Carlos
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