John Curl's Blowtorch preamplifier part II

[john curl]

Congratulations SY, you can more easily build with SMD parts than me. With my 1000's of leaded jfets available to me, I think I will stick to the old stuff.

 

[SY]

Congratulations SY, you can more easily build with SMD parts than me. With my 1000's of leaded jfets available to me, I think I will stick to the old stuff.

I bothered to learn and keep my skills a bit more current. It's tougher when one gets old, as I'm rapidly doing.

I've got "1000s" of vacuum tubes available to me. Nonetheless, it's important for me to have as many tools in my engineering arsenal as possible.

 

[john curl]

My tech, just yesterday, borrowed my 'stereo microscope' to do some SMD work. Perhaps I should get some new hand tools, but I can do just fine without SMD, for the most part.

 

[gk7]

Here is a short history that I recently dug up. I hope that it answers some questions that come up, time after time.

Thanks John for posting this, I really enjoy reading it.

 

[a.wayne]

What !

We having a who's the oldest guy race now , toobs vs Jfets ......


Enjoyed that read JC, i do think you need to change that 30 to 40 on page 1 mostly enjoyed the part with the phycologist , necessary input i may add ....

 

[a.wayne]

After some coaching from Jan Didden, I managed to learn how to do SMD, despite my poor vision and hand skills (the right tools are vital!). It's all part of progress, learning, and not getting stuck in 1968. I still wouldn't want to try a fine pitch 128 lead package, but opamps, FETs, resistors, et al, are not at all difficult.

We are staring at the floor drooling ......

 

[scott wurcer]

What !

We having a who's the oldest guy race now , toobs vs Jfets ......


Enjoyed that read JC, i do think you need to change that 30 to 40 on page 1 mostly enjoyed the part with the phycologist , necessary input i may add ....

I'm surprised you have not tried battery PS's with those speakers of yours. There is stuff available for phone cabinets or small electric locomotives that put just about any linear supply to shame. Stuff that can explode those puny 1/2" copper bars (easily BTW).

 

[john curl]

It was written more than 15 years ago. YOU have to update it. It now starts from 50 years ago.

 

[a.wayne]

Funny you mentioned copper bars , I'm experimenting with flat 1/2 inch wide copper wire to connect to the amplifier , im pretty impressed with the sound i have the conductors spaced 1 inch apart i will do another pr at 1/2 and compare...

I used to use battery power on the pre-amp stuff, never for the amp ...

 

[PMA]

Copper bars - skin effect, inductance. Nobody cares?

 

[a.wayne]

Absolutely , but if it works better than round .....

 

[fireworks]

Here is a short history that I recently dug up. I hope that it answers some questions that come up, time after time.

Great post.

 

[gpapag]

For a DIY site to INSIST that we use SMD devices, is beyond rational.

This is the first post in which You acknowledge the nature of this forum.
I think that this year we will do better.

George

 

[scott wurcer]

Absolutely , but if it works better than round .....

It would not effect your kick butt bass in any case. Is your argument technical or other re the skin effect?

 

[scott wurcer]

im pretty impressed with the sound i have the conductors spaced 1 inch apart i will do another pr at 1/2 and compare...

Fair enough but my impression is you are in the "above the law" camp when it comes to what you do and don't hear.

 

[a.wayne]

Explain ....

i can give you measured data or i can also report my subjective findings. Before i went for heavy gauge round and it did not work , this works much better , its not used on the bass , its used on the mid/ high ribbon drivers ..

I may drag it in one day and measure RLC , my rig only measures up to 40k ...

 

[fas42]

Funny you mentioned copper bars , I'm experimenting with flat 1/2 inch wide copper wire to connect to the amplifier , im pretty impressed with the sound i have the conductors spaced 1 inch apart i will do another pr at 1/2 and compare...

Spaced, side by side - or, one above the other?

 

[vacuphile]

a.wayne, I don't think it can be that. Either something else is wrong in your setup and you are looking for a cause, or it is in between the ears, not in what excites them.

 

[a.wayne]

No its not that , so you would be wrong .....

 

[a.wayne]

Spaced, side by side - or, one above the other?

Side by side ....