Intact Audio

dave slagle wrote: Femm is freeware

I am drawing all sorts of giggles as I consider what I am going to turn up Googling ISO the download site... thanks.
Douglas

hey-Hey!!!, The bottom picture looks good to me; it is about what I hoped for. Can you extract expected L values v. DC current in order to compare it to a straight gap choke? It is indeed the non-linear behaviour I'd be looking for with such a design. It looks like it might serve well without requir...

hey-Hey!!!,
Has anybody tried a making a slanted gap choke? Spacer under one thin leg of the E, and none at the other? what does the L v. standing current look like? Enough variation in L to make a gentle saturation swinger for input service?
cheers,
Douglas

40-50ma seems like a lot of current for a 45. dave As usual, my memory seems to have failed me. The curves show it more comfortable at 35 mA. that'll teach me to read the sheets before looking for parts. Good thing it's less current, that should make things a bit easier. Still looks like a supply t...

Hey-Hey!!!,
So what happens when you reduce the number of stages around which the errors need summed carefully?
cheers,
Douglas

Don't worry about the SE blasphemy...:) I'm working with a friend. Don't tell my father I am working with the 45. He still remembers fondly being able to source better tubes for his projects back in the 30's when his High School mates ran the competition phone company...:) Glad to hear you are worki...

Hey-Hey!!!, I am preparing to build a 45 SE amp. Right now, it is laid out something like this: Input TX of ~4:1 step up. SE:SE to drive the first 45's grid. IT, a 1:1, probably Bifilar, capable of 40-50 mA of DC. 80% Ni core if possible. OPT, a 5k:speaker. The question I have is about the IT. Is th...

One of my Tek 502A's has a camera mount...:) So for an average of air and ____, what do you suggest? 49 Ni? I think I'm running higher wattage than 80 Ni would stand. I should measure power output in the amp's current state, I think it would be close. How many watts per square inch can 80% Ni do at ...

Hey-Hey!!!, So...perm goes down, so I'd want to start with more, and gap it( eventually) to a value equalling 3.5%Si Iron ( as it would be replacing M6 in an existing design. No sense trying to eval gap v. not gapped with two different coil geometry. Since the design in question is not running to th...

Hey-Hey!!!, I would like to try a PP output TX with an airgap. I'd like to use an existing coil geometry. In order to facilitate a fairly easy set of experiments, I would be comfortable trading power capacity in order to use higher perm/lower max flux density core material. I should do some measurem...

Hey-Hey!!!, from Dave...Can we please operate under the assumption that we will always be responsible and able to understand the situation where lack of inductance is the Achilles heel. Just to be sure I get this, we're not going to consider what happens if we take an ungapped inductance, with just ...

Hey-hey!!!, Let's see if we can determine why the airgapped inductors( of any sort ) seem to sound better. With the parameters listed perhaps some information can be teased out of the discussion. Less change in L with signal magnitude Tolerance of DC is increased Quote the replies so the list can be...

Hey-Hey!!!, I don't think that this sort of thing would be easy to wind. That was not the point though. Matter of fact, I can't think of very many ways to make the winding job any more difficult. The end of layer is also going to ind up in the very middle too. I thought that the cross over would tak...

on measuring for capacitance, assuming we can stay out of the regions where core performance is changing the inductance, the capacitance is fairly easy. It needs two precision caps( Tek time base are nice in .01, .1 and 1 mike values ). You make two resonance frequency measurements. C is the sum of ...

Hey-Hey!!!, from Sir Slagle: do you mean inductance? what frequencies are we talking about? Well, since I was only measuring voltage across the inductor and a series resistor, I was measuring impedance. I did it at 40, 120 and 360 cps( as nearly as I could measure in 3x increments of frequency ). Th...

Hey-Hey!!!, This is for a PP grid choke. The 4 mil Si steel is M1 maybe? M4 at 11 mil, M3 at 9 mill and M2 at 7 mil. On the gap, I suspect that the more constant inductive value presents a more even load. If L isn't varying all over the place, neither is the self resonance point. I did a bunch of st...

Hey-Hey!!!, It would be the loop antenna ref. I took a look at an RF inductor I have and it is done in three sections( axially pie wound ), with each of the sections mobius wound. Looks sort of like a spool of string. I would like to try this method crossed with layer winding. Since the layer finish...

Hey-Hey!!!, I have seen it used where minimum noise, at minimum mass, with minimum mass are all quite important. I have seen standard Si steel fall flat on its face in the same service, so I have some faith that although the numbers are going to show its better side, that it is worth investigating. ...

This is quite interesting.

http://www.jfe-steel.co.jp/en/products/ ... index.html

cheers,
Douglas

did I mention I want some?

Hey-Hey!!!,
I came upon a ref to winding methods to reduce winding capacitance. It was called 'Mobius', and looks like a reasonable means to achieving a 50% reduction, all else being equal.

Are you familiar with it Sir Slagle?
cheers,
Douglas

Hey-Hey!!!, Been considering a means to use more Iron( or perhaps Nickel ). The OPTx coupled linestage works quite well still. So, for the input stage of an amp, to do the phase splitting a 1:1 bi-filar TX. Keep the primary and secondary isolated( in circuit ), and CT the the secondary. Ground the s...

Hey-hey!!!, there is a distinct change of character after ~15 mins of play. It is an improvement, and seems to fill out what could be called thin but accurate mids. What i'd like to do is use one of those laser temp measuring pistols on the windings. Take a few shots as the time went by and see what...

Hey-Hey!!!, I have had this linestage up and running for a while. I tracked down and fixed a few mistakes I made whilst building its predecessor. They are much closer now in terms of overall performance. The TX coupled buffer would likely benefit from an increase in input Z( via changing the first g...

I got impatient( and it paid off!), I assembled the circuit with AC on the filaments. It was quiet. Holy smoak! 5687 is not supposed to do that. The operating conditions: 15 mA idle, as measured by 2.25 volts across the 150R primary used to self-bias the cathode follower. 80% Ni core set to .004&quo...

I agree, but would like the concept of 'keeping them for a long time' defined. Perhaps a time starting when a modification was done? as long as I am usefully tweaking, and recording data to your satisfaction( and reporting it as well ), the loan can be extended. On the serious side, I'd want to buy ...

Hey-Hey!!!, Alright..how is the low level linestage project comming along? I have a nice valve circuit which will be OK with anything from 100 to 400 DCR of the primary. Nearly no DC voltage across it at all. Biasing the buffer stage with the DCR. It is a cathode follower, and quitesimple actually. ...

well, I can do a -6 or so negative side with a +20V. The PT is 55-17-0-17-55, and with the neg rail taken from the LV taps... This leaves me something between 15 and 25 mA as idle current. Is this going to be an issue? will you have to re-gap? Considering the ~100R source impedance, I don't see trou...

Hey-Hey!!! I would be quite happy to take the cast off's. I would not say that the 40V is written is stone. Variac on the PT's primary and I can do what ever I want. +10 mA is no sin at lower voltage either... Well, on the DC biasing, I think an unbalanced bipolar supply might be best. A -4 volt neg...

Hey-Hey!!!, I have a buffer linestage in the works, with( of course ) a cap output. It is a low voltage SS deal. +/- 40V, a cascoded MOSFET like a CCS, but the lower gate is the input, and the lower source is the output, and it is riding a full CCS. The thing would run ~10 mA, and have output Z of 1...

I did come in through the front door, so I have heard of Intact Audio. The question might have been a bit poorly worded. I wonder about the general type and layout. I am up agianst voltage swing issues, and am trying to sort out the topology. The rest will follow more or less by common sense. With t...