Mark A. Gulbrandsen said:
I can't really imagine how your thread won't be square, if the hole is drilled properly.
But since you use all those fancy taps it may be an issue. You see, older taps were shaped in such a way, that tapping action was self guiding and the tap couldn't be not square in a hole. That's why I prefer to use those older type and using drill gun helps further to start tapping properly. I remember when I used to do it by hand, the smaller holes where always hard to start.
I never used jigs or mills for tapping and all my work was always very accurate. But I'm also pretty skilled with hand drills (not exaggerating I have at least 20 different types of them)
PS: I remember when in 80's I was playing with those things, taps where available in sets of 3 (for manual work). First one had barely any threads ( and was intended to start a hole), then was an intermediate one (to do the real tapping work) and finally the finishing tap, to make the final thread.
First i want to preface this comment - your work is absolutely top
notch! ...and i knew the minute the "tapping" subject came up
we were in for some heart felt serious posts! Tapping brings out
the beast in DIY'ers (for some strange reason)
But, at this point in time, why build an A75 instead of an Aleph 2?
Parts on hand? asthetics? ability to drive low-impedance loads?
Works better in your bi-amp/tri-amp setup?
I'm not trying to slagg you off, was just wondering. The Aleph 2
seems to follow the PassLabs ideal of simpler circuits - better sound.
Please don't take this wrong... it was worth it for you to build this
amp, just for the lovely pictures!
m. (who uses the Peter Daniel method for tapping... and it works!)
notch! ...and i knew the minute the "tapping" subject came up
we were in for some heart felt serious posts! Tapping brings out
the beast in DIY'ers (for some strange reason)
But, at this point in time, why build an A75 instead of an Aleph 2?
Parts on hand? asthetics? ability to drive low-impedance loads?
Works better in your bi-amp/tri-amp setup?
I'm not trying to slagg you off, was just wondering. The Aleph 2
seems to follow the PassLabs ideal of simpler circuits - better sound.
Please don't take this wrong... it was worth it for you to build this
amp, just for the lovely pictures!
m. (who uses the Peter Daniel method for tapping... and it works!)
Yes, the work is indeed top notch, on equal level with best that we've seen here. So you qualify for DIYer.
Building A75 brings slightly different pleasure than Aleph. Whoever never did it, don't know what I'm talking about: all those TO-3 devices mounted in rows and there are 24 of them per channel. I'm still using my A75 amp for subwoofers.
Building A75 brings slightly different pleasure than Aleph. Whoever never did it, don't know what I'm talking about: all those TO-3 devices mounted in rows and there are 24 of them per channel
. I'm still using my A75 amp for subwoofers.
Tapping
Just wanted to let you know that in 10 minutes I broke off a 4-40 and a 6-32 tap in the hole when I was tapping by hand into heat sinks for my GC. After one broke I just switched to the other wich then broke. They were getting tough to spin, so I should have known. But it was after many beers so not really my fault. Your stuff looks very good. Nice work. Keep us updated.
Just wanted to let you know that in 10 minutes I broke off a 4-40 and a 6-32 tap in the hole when I was tapping by hand into heat sinks for my GC. After one broke I just switched to the other wich then broke. They were getting tough to spin, so I should have known. But it was after many beers so not really my fault. Your stuff looks very good. Nice work. Keep us updated.
moe29,
> work is absolutely top notch!
Thanks I realy apreciate.
>why build an A75
Because the Aleph X was not created at the time of choice, second I wanted Power!
Also I needed to drive my electrostatics speakers, Martin Logan Aerius i go low at 1.7 Ohm >15kHz
This A-75 is built for 80/100 watts pure class A.
Peter,
>Equal level with best that we've seen here
Thanks so much, I have made plans for 1 month before starting the project,
so many nights, not hard work, but pleasure and delight...
lgreen,
I will keep posting...
Special thanks: to Peter Daniel who sold me the cap's and 750 Plitron transfo's
to Norman Chow who sold me the 48 TO-3 Mosfets lost in his closet !
Great thanks: to Norman Thagard and Nelson Pass to make such things happen !
Special reward: My girlfriend Danielle, because hi-fi is not a girls thing, she is giving me great support.
To be done: install the PCb for regulation and temperature security (2 big 24DC relays 30 Amps for standby ) and fan supply
Install the mosfet's on the pre PCb, work the cabling...
Then the fun will start
, put the scope on and finish the tests....
Future projects: One X-BOSOZ with CCS and Phono Pre. integrated
with separated power supplies ; 6/7 input's with 2 balanced and Tape in/Tape Out
+ 2 output 1 balanced + 1 for subwoofer...
I want to get reed of my NAD C350...
> work is absolutely top notch!
Thanks I realy apreciate.
>why build an A75
Because the Aleph X was not created at the time of choice, second I wanted Power!
Also I needed to drive my electrostatics speakers, Martin Logan Aerius i go low at 1.7 Ohm >15kHz
This A-75 is built for 80/100 watts pure class A.
Peter,
>Equal level with best that we've seen here
Thanks so much, I have made plans for 1 month before starting the project,
so many nights, not hard work, but pleasure and delight...
lgreen,
I will keep posting...
Special thanks: to Peter Daniel who sold me the cap's and 750 Plitron transfo's
to Norman Chow who sold me the 48 TO-3 Mosfets lost in his closet !
Great thanks: to Norman Thagard and Nelson Pass to make such things happen !
Special reward: My girlfriend Danielle, because hi-fi is not a girls thing, she is giving me great support.
To be done: install the PCb for regulation and temperature security (2 big 24DC relays 30 Amps for standby ) and fan supply
Install the mosfet's on the pre PCb, work the cabling...
Then the fun will start
, put the scope on and finish the tests....Future projects: One X-BOSOZ with CCS and Phono Pre. integrated
with separated power supplies ; 6/7 input's with 2 balanced and Tape in/Tape Out
+ 2 output 1 balanced + 1 for subwoofer...
I want to get reed of my NAD C350...
Alain,
Great job!
Alain and all:
the carbon steel of the broken tap dissolves over the course of 24hrs using a mixture of readily available acids that leaves the Al absolutely untouched. It's a trick an old machine shop guy taught me and which I have readily forgotten. I will ask the guy for the correct proportion af acids again if anyone is interested. As I said it takes a little patience. You can use the 24hrs to cool off and go buy more taps.
Great job!
Alain and all:
the carbon steel of the broken tap dissolves over the course of 24hrs using a mixture of readily available acids that leaves the Al absolutely untouched. It's a trick an old machine shop guy taught me and which I have readily forgotten. I will ask the guy for the correct proportion af acids again if anyone is interested. As I said it takes a little patience. You can use the 24hrs to cool off and go buy more taps.
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