Does an D-Stile Amp need time to burn in?

[David Root]

Thanx Tony, that answers my question.

Would it be safe to run the amp into a resistive load hours at a time with a 400Hz sine wave? I have a 4 ohm/450W dummy load I built for working on SVTs and another one that will do 100W at 8 ohms.

I'd like to "warm up" as much of the secondary as possible but I don't have any 16 ohm cabinets.

[talbany]

Thanx Tony, that answers my question.

Would it be safe to run the amp into a resistive load hours at a time with a 400Hz sine wave? I have a 4 ohm/450W dummy load I built for working on SVTs and another one that will do 100W at 8 ohms.

I'd like to "warm up" as much of the secondary as possible but I don't have any 16 ohm cabinets.

Dave
Sure.. Obviously a speaker cab with a moving blanket thrown over it would be ideal..Not always pratical though,, A restive load would also work but is a little harder on OPT it's fine.. You really want to send more bandwidth to the OPT than just a 400k wave.. Ken recommends hooking up a CD player to the input (Ken recommend's band of Gypsy's).. No Kidding.. crank it up just enough so you can hear it playing through the OPT.. If you use the resistive load keep an eye on the OPT temp and don't leave it alone of coarse.. fire.. Do it an hour let it rest 20 or so.. Season to taste..Hope this helps..
Tony

[David Root]

Yeah, I don't think my wife would understand the blanket over the cabinet at 03:00 AM. Even if it were a sleeping bag, I would probably end up living in it.

I will try what you recommend. I have that album I think. Doesn't everyone?

How about a white noise generator? (I always thought "White Noise" was a great name for a rock band from Minnesota!).

Or I could just change the frequency every now & then. Can't play 24/7, not retired/divorced.

[llemtt]

I usually don't believe a lot into "magic", I don't believe into "amp break in" a lot too...

I believe replicating a "grail" old amp is more a matter of using exactly those components used 30 years ago rather than "breaking in" their brand new replacements.

Anyway I agree on few "break ins"

- speakers definitely require break in -> attach a filament (6.3V) transformer to them and let then run 10-20h

- caps: some caps change their values by more than 30% while you solder them because of high temperature, then they slowly recover their nominal value -> let them age naturally (don't need tension/current/playing...) at least one month

- new tubes behave as expected only after 10-20h of usage then they remain stable almost till their "end of life" -> leave the amp on at least 24h, playing it's even better because you draw more current from power tubes

I am still not positive on OT "break in" although I can imagine that if some static magnetization is present in the core then playing would help remove it. While the idea that playing and getting them warm starts to melt windings in a good way doesn't make sense to me.

my .02

[roadkingbluzs]

Originally not impressed with my completed D-Lite, but after weeks of playing at rehearsals, it was taken to a gig and it sounded just amazing. I replaced 6V6's with 6L6's rebiased and adjusted pots to taste.
Sad to say I sold it It loved HB's. I think it needs break-in time
My .02

[BobW]

OPT transformers pushed the first 100+ hours will also have a smoothing softening effect as well..You have to push them get em warm..This from Ken Fisher..

Tony

I could imagine that would be due to magnetic hysteresis effects.

I have a more difficult time understanding why there would be a sonic effect in capacitors - especially on the time scale of 100 hours or more.

Zippy, I think the sonic effect in capacitors has more to do with the ESR and ESL parameters changing (settling out) when under initial circuit conditions. I agree sonically caps do change but don't agree with the Sozo article (salesman's explaination) on why and how.

[talbany]

I find it interesting that over the years this forum has discussed in great detail virtually every minor detail (more than once) of the ODS throughout it's various forms and although we all know Dumble used already seasoned iron in most of his amps and yet very little in the way of discussion on this topic..Whenever the topic of seasoned iron is brought up some write it off as mojo or magic.. Personally I don't care believe what you will.. I am just surprised being a Dumble discussion there so many non believers in the theory when it's obvious the man was one.. Just Sayin

Tony

[Zippy]

Whenever the topic of seasoned iron is brought up some write it off as mojo or magic.. Personally I don't care believe what you will.. I am just surprised being a Dumble discussion there so many non believers in the theory when it's obvious the man was one...

I'm NOT saying that it's mojo. I just expressed one possibility of what may change - partial alignment of magnetic domains due to magnetic fields (see the previous page in this thread).

I could imagine that would be due to magnetic hysteresis effects.

[talbany]

Zip
I didn't mean to imply you were the one I was referencing by the Mojo Magic statement..( You Just reminded me of it).The reason I didn't quote your post.. I'll make that clear here now.. I was speaking from what I've read here in past threads concerning the topic where others have..Sorry if I implied that..

Tony

[llemtt]

It isn't mojo, it's specifications!

Today components, even considering good replacements parts, are built differently and possess different specifications... even a 100ohm difference in plate resistance can make an audible "difference" (not even talking about inductance,...)

I think Brandon did an incredible job replicating some famous ODSs mainly by searching and selecting the right components.

Regarding SoZo article I have to notice that they mainly speak about their caps which are "mustard" type, a really different kind from what we are used to use and discuss here.

cheers
teo

[Zippy]

Zip
I didn't mean to imply you were the one I was referencing by the Mojo Magic statement..( You Just reminded me of it).The reason I didn't quote your post.. I'll make that clear here now.. I was speaking from what I've read here in past threads concerning the topic where others have..Sorry if I implied that..

Tony

Thanks, Tony.

I think it would be interesting to play with this notion. I wish I still had a magnetics lab at my disposal. I used to have sufficiently large equipment to either polarize or de-polarize a mass much larger than any trannies that we'd use. If there exists substantial changes in the fractions of relevant magnetic domains, it would change the response and coupling in an OT. Not as much fun as mojo but much more interesting to me.

Be well.

George

[talbany]

Zip
I didn't mean to imply you were the one I was referencing by the Mojo Magic statement..( You Just reminded me of it).The reason I didn't quote your post.. I'll make that clear here now.. I was speaking from what I've read here in past threads concerning the topic where others have..Sorry if I implied that..

Tony

Thanks, Tony.

I think it would be interesting to play with this notion. I wish I still had a magnetics lab at my disposal. I used to have sufficiently large equipment to either polarize or de-polarize a mass much larger than any tranny's that we'd use. If there exists substantial changes in the fractions of relevant magnetic domains, it would change the response and coupling in an OT. Not as much fun as mojo but much more interesting to me.

Be well.

George

Definitely!!.. This brings up a derail here sounds like you have some knowledge in the field.. We all know through hysteresis ( for those who dont know)
The core material, when magnetizing force is applied, retains some of the magnetism. Virtually ALL core materials experience some magnetic memory, and the strength of this is measured in magnetic hysteresis.

Most all of the early Schumachers Blackface as well as most Marshall/ Drakes and off the shelf replacements in my testing point south..However several of the Silverface Schumachers mainly UL's I've used point north.. This to me would imply a change in winding direction I would assume on the secondary correct me if I am wrong.. The ones that point north seem to at least to my ears sound better or more in phase using a reverse phase speaker cable.. This I would assume has something to do with the direction of the winding of the speaker coupled with the direction of the wind of the secondary.. Similar to the phasing of 2 pickups wired together IWA.. Any thoughts on the subject would be appreciated..Thanks

Tony

[Zippy]

Most all of the early Schumachers Blackface as well as most Marshall/ Drakes and off the shelf replacements in my testing point south..However several of the Silverface Schumachers mainly UL's I've used point north.. This to me would imply a change in winding direction I would assume on the secondary correct me if I am wrong.. The ones that point north seem to at least to my ears sound better or more in phase using a reverse phase speaker cable.. This I would assume has something to do with the direction of the winding of the speaker coupled with the direction of the wind of the secondary...

Should be easy enough to test by putting a phase reversing switch in your speaker line. Goes along with the ol' argument that speakers should pop forward on first attack of the string. If the "other" way sounds better, that's the way to go.

This issue always leaves me scratching me head tho'...

What if you use an upstroke on the strings rather than a down stroke? What if you switch between pickups that are reverse polarity/reverse wound (e.g. on a Strat with such a pickup in the middle position, switch from neck or bridge to the middle position)? Seems that after the note starts, you wouldn't hear an effect regardless of transformer polarity.

**********************************************************

Anyhow... Has anyone with a spectrum analyzer ever looked at the output from a fresh amp after it has had its "conditioning" period? Certainly if it is a tube issue, one would have to go through conditioning after each retube. That should give a real quick indicator to eliminating that as a possible player in the "break in" hypothesis.

[Structo]

Yeah it would be pretty interesting if somebody could do a study like that.
The thing about tubes is, as I understand it fresh tubes have a much better treble response than tubes that have a lot of hours on them.
Particularly power tubes.
As they wear the highs start rolling off.
But they wear slow enough that we don't really perceive the loss because we will simply turn the knobs a bit more to get the tone we are familiar with.

[talbany]

Most all of the early Schumachers Blackface as well as most Marshall/ Drakes and off the shelf replacements in my testing point south..However several of the Silverface Schumachers mainly UL's I've used point north.. This to me would imply a change in winding direction I would assume on the secondary correct me if I am wrong.. The ones that point north seem to at least to my ears sound better or more in phase using a reverse phase speaker cable.. This I would assume has something to do with the direction of the winding of the speaker coupled with the direction of the wind of the secondary...

Should be easy enough to test by putting a phase reversing switch in your speaker line. Goes along with the ol' argument that speakers should pop forward on first attack of the string. If the "other" way sounds better, that's the way to go.

This issue always leaves me scratching me head tho'...

What if you use an upstroke on the strings rather than a down stroke? What if you switch between pickups that are reverse polarity/reverse wound (e.g. on a Strat with such a pickup in the middle position, switch from neck or bridge to the middle position)? Seems that after the note starts, you wouldn't hear an effect regardless of transformer polarity.

**********************************************************

Anyhow... Has anyone with a spectrum analyzer ever looked at the output from a fresh amp after it has had its "conditioning" period? Certainly if it is a tube issue, one would have to go through conditioning after each retube. That should give a real quick indicator to eliminating that as a possible player in the "break in" hypothesis.

Zip
Thanks for the shout back..Yeah!! That is generally the concensus..Discussions I've had with Lindy Fralin is the same.. Jon Suhr concurs.. In phase should be as the string moves tword the pickup the speaker should move outward.. After the initial attack cone movement becomes irrelevant..I know what the initial attack phase feels like and this is something totally different.. I guess it's my imagination.. Thanks!!

Tony