Just seen this thread, and I'll likely be interested in a couple of boards when you're done.
I can solder SMT's too.
I can solder SMT's too.
I have had some more thoughts. Why not move the big power caps (c34, c23) to the top of the PCB. This should allow you to shorten the signal paths quite a bit, and by moving them up there the high currents that pass inside them will not be tempted to induce noise in points there the signal is still very weak. I may be wrong about this, but it’s the safe thing to do. Then again I see the new Bryston amps have there power caps spread to the corners of the board; I’ve never understood the benefits of doing that. The input stage will still need a separate long run right from the cap. What do others think about this?
You may also want to give people the option of using the old transistors for (t13,t14,t8,t9), if the new ones are not available in there part of the world. To allow people to use the old metal can devices, all you would need to do is to add an extra hole on the board, so instead of the medal pin being straight with all the others in would be pulled out a little bit.
As for the SMD devices if there are only 4 of then in the whole amp I think people can manage, or else they will have to go point to point. If the PCD makers bill out the area as a rectangular board you have space to do it both ways.
By the way is the addition of the input caps (c8,c9) really necessary? The original leach amp did not use them?
None of these are criticisms. I’m just trying to make things better, I think it already is a grate pcd design, however I’m a crazy obsessive perfectionist that just can leave things alone.
You may also want to give people the option of using the old transistors for (t13,t14,t8,t9), if the new ones are not available in there part of the world. To allow people to use the old metal can devices, all you would need to do is to add an extra hole on the board, so instead of the medal pin being straight with all the others in would be pulled out a little bit.
As for the SMD devices if there are only 4 of then in the whole amp I think people can manage, or else they will have to go point to point. If the PCD makers bill out the area as a rectangular board you have space to do it both ways.
By the way is the addition of the input caps (c8,c9) really necessary? The original leach amp did not use them?
None of these are criticisms. I’m just trying to make things better, I think it already is a grate pcd design, however I’m a crazy obsessive perfectionist that just can leave things alone.
I almost forgot a balanced input is something people have asked for in the past. I don’t own any balanced equipment myself, however personally just in a case I ever did it would be a very cool thing to have, balanced inputs usually imply “a quality amp”.
nowadays many amp designers are not in favour of rfc choke in the output , what do you think - have you tried seeing the results by omiting it
Well I think that it’s a case of ”what can happen” if you omit either a Zobel network or an output inductor.
When we DIY we have a great luxury that manufactures don’t have.
We don’t need to worry about all the different setups that the end-user might come up with. I have chosen to include (Like the original Leach) both a Zobel network and the output inductor and I’m not going to recommend anyone what to do or use/omit.
I’m sure not going to say that it’s a component that can be omitted – simply by means of me testing it in a one off setup.
I believe there has been a great discussion on this very topic somewhere else on the forum.
The conclusion is that the options stay on the PCB, and the recommendation is to enable the options, but of cause the decision will be up the individual builder.
I hope this helps
\Jens
When we DIY we have a great luxury that manufactures don’t have.
We don’t need to worry about all the different setups that the end-user might come up with. I have chosen to include (Like the original Leach) both a Zobel network and the output inductor and I’m not going to recommend anyone what to do or use/omit.
I’m sure not going to say that it’s a component that can be omitted – simply by means of me testing it in a one off setup.
I believe there has been a great discussion on this very topic somewhere else on the forum.
The conclusion is that the options stay on the PCB, and the recommendation is to enable the options, but of cause the decision will be up the individual builder.
I hope this helps
\Jens
BrianGT said:
Wow those are realyl nice!!! can you post the Victoria Magnetics info thats on the label. i cant quite read the address, or see if there is web info and a phone number.
jarek said:
Be carefull with those! there are quite a few counterfits on the market. the problem got so bad with the 5200's that most Mfg quit using them!
Zero
Is the better base response the result of doubling the cap you labeled c12 ? Would I be right that this cap can be raised even higher (The Brystons use 2200uf). Did this cause any dc drift problems that forced the unfortunate necessity of putting C7 and C1 in the signal path?
Hello,
Well at some point it makes no sense to keep making C12 bigger. The size of the cap has nothing to do with the added input caps. I just placed them on the PCB in order to have the option. Since ill use the amps in an active system, I will have no need for these as the DC blocking capacitors are already present in the active crossover.
\Jens
Well at some point it makes no sense to keep making C12 bigger. The size of the cap has nothing to do with the added input caps. I just placed them on the PCB in order to have the option. Since ill use the amps in an active system, I will have no need for these as the DC blocking capacitors are already present in the active crossover.
\Jens
Hi,
Dc blocking in the preamp is excellent. only 1 expensive cap to buy and chosen for best sound.
Take care if all you power amps are DC coupled particularly if you have 2 in parallel from 1 filter. The input bias voltage of the two(or more) input bases may interact and completely upset the carefully chosen bias conditions.
This warning applies more to Bi-amping rather than active speakers.
regards Andrew T.
Dc blocking in the preamp is excellent. only 1 expensive cap to buy and chosen for best sound.
Take care if all you power amps are DC coupled particularly if you have 2 in parallel from 1 filter. The input bias voltage of the two(or more) input bases may interact and completely upset the carefully chosen bias conditions.
This warning applies more to Bi-amping rather than active speakers.
regards Andrew T.
Hi Jens ,
I downloaded your Gerber 10 , after extracting the files they do not open
as windows want to know which programme created them , could you
help please ?
Are these for the plans or the pcb ???
Regards
Rajeev
I downloaded your Gerber 10 , after extracting the files they do not open
as windows want to know which programme created them , could you
help please ?
Are these for the plans or the pcb ???
Regards
Rajeev
Gerber files are text files and you must have a Gerber viewer or a pcb cad program, almost any modern program.
Your project has truly come a long way.
What is needed now would be some formulas:
One where someone could plug in the rail voltage and get the values for the protection circuit.
And another where someone could plug in the rail voltage, number of devices, and load they are driving and get the wattage.
What is needed now would be some formulas:
One where someone could plug in the rail voltage and get the values for the protection circuit.
And another where someone could plug in the rail voltage, number of devices, and load they are driving and get the wattage.
Would it be possible to use Zetex ZTX1056A's and ZTX795A's for the small signal transistors? People have been raving about these transistors. If there a good substitute, it could be worth a try.
They will fit on the board, so I can not see anything wrong with trying them.
I think they will work, but this have to be tested of cause. They look lige great transistors, maybe I'll give them a try when I get the new boards.
Good luck
\Jens
I think they will work, but this have to be tested of cause. They look lige great transistors, maybe I'll give them a try when I get the new boards.
Good luck
\Jens
Dear Jens ,
I downloaded the free version of the viewmate , but this also does not open all the 10 Gerber files , I only want to know if all these are of pcb only .
Next for protection what is the voltage across the emitter and base of T-10 & T-12 YOU taken into account to switch them on to shut down the drive to the driver trs .
Regarding C-33 , Prof leach has mentioned that this is NOT of any advantage in the performance of the amp , what do you say ?
Thanks
Rajeev
I downloaded the free version of the viewmate , but this also does not open all the 10 Gerber files , I only want to know if all these are of pcb only .
Next for protection what is the voltage across the emitter and base of T-10 & T-12 YOU taken into account to switch them on to shut down the drive to the driver trs .
Regarding C-33 , Prof leach has mentioned that this is NOT of any advantage in the performance of the amp , what do you say ?
Thanks
Rajeev
Regarding the gerber files, they are gerberX and must be loaded with the .apt file.
C33 can be omitted if you don’t like the result.
\Jens
C33 can be omitted if you don’t like the result.
\Jens
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