Rockett Transformers

[joe6v6]

Ive looked around on the site and the BOM and I dont see what transformers to use in a rockett. I know I could fake it but id like to hear what people are using and the recomended specs. .. Thanks : JOE

[dartanion]

There are a bunch of options, however I think the dynaclone ot is preferred. Heyboer or pacific pt. Hammond choke.

Where you been Joe?

[joe6v6]

There are a bunch of options, however I think the dynaclone ot is preferred. Heyboer or pacific pt. Hammond choke.

Is 330-0-330 180ma too hot? ive seen posts where people want lower voltage for more dirt. The voltage chart shows some pretty low voltages, 290v B+ ?

Where you been Joe?

Just havent been around this forum much, ive still been lurking on several others. Plus Ive had to go back to working for a living which has cut into my amp building time

[drhulsey]

... what transformers to use in a rocket...

Joe, look in the Trainwreck files for Rocket Files.
https://tubeamparchive.com/viewtopic.php?t=5684
Ron Worley has a BOM. The Heyboers are listed on the hardware page (3), about 1/4 of the way down the page.[/url]

[rawnster]

I used....

PT: Edcor 245-0-245 (get it from RJ)
OT: Heyboer HTS-8093-1

Very pleased with the tone.

[joe6v6]

Thanks Tim , I looked that BOM over 5 times & never saw them. .. Tx : JOE

[M Fowler]

I used Edcor 245-0-245 PT and Dyanco A470-S OT

Mark

[Blind Lemon]

I've built a couple of Rockets with the Heyboers and a couple with the Edcors......in fact I have one of each right now and I can't pick my favorite. Both sets sound very close, I think that components you pick for the board and speaker choice will make a bigger difference in tone. I'm almost finished with a KT66/EL34 Rocket with the Edcor set, this one is going to be fun to experiment with after I get it running.

For a combo I "REALLY" like the Warehouse 10's. 2 of these speakers in a combo cabinet have great response and is very easy on the back. Very versatile amp, chicken pic'n to classis rock.

BL

[drhulsey]

...I looked that BOM over 5 times & never saw them...

It took me a few times, too

[RJ Guitars]

There have been numerous long threads on transformers in the Rocket amp...

I've been a student of the Rocket for a few years now and I still have to admit that it's still not entirely clear to me exactly which tranny combination KF used in his Rockets.

I was just about convinced that the Rocket used a 250-0-250 tranny for power, a modified Dynaco 470 for the output tranny, and a 15H choke. Then every now and then something pops up to make me question whether that's the absolute final answer... but I believe it is darn close even if it's it's not dead on.

In my studies I've found that it looks like only about a half dozen Rockets were built and first two were around for quite a while before the Rocket amp was added to the product line... some hearsay and some fact in that info.

I've got a note from Phil at Heyboer where he mentions that the HTS-8093-1 mod to the Dynaco 470 is basically the loss of the UL leads and use of M-19 steel. The steel change takes some of the glassy edge off and warms them up a bit. What I haven't really nail down is whether the Heyboer mod trannies were made after those first couple amps were made or not.

From the amps built using the EDCOR trannies that I've been selling it seems like these amps do well using a very good HiFi type tranny... makes sense if we are talking about a Dynaco 470 design in the originals.

There are several great sounding Rockets using various iterations and originals of the Dynaco 470 transformers. The EDCOR's are not based on Dynacos but were custom wound for me using one of their HiFi tranny designs... a scenario similar to the Stancor HiFi trannies that KF used in his builds.

rj

[M Fowler]

rj

For some unknown reason I was thinking the Dyanco 470-s was a copy of or replacement for a Stancor? But what do I know.

Mark

[rhinson]

There have been numerous long threads on transformers in the Rocket amp...



I've got a note from Phil at Heyboer where he mentions that the HTS-8093-1 mod to the Dynaco 470 is basically the loss of the UL leads and use of M-19 steel. The steel change takes some of the glassy edge off and warms them up a bit. What I haven't really nail down is whether the Heyboer mod trannies were made after those first couple amps were made or not.




rj

as i've posted before, the heyboer mod trannies were originally done by me a couple yrs back----my specs to heyboer and my part number (same with the power trannie some are using). they are/were just an educated guess based on some remarks by dave funk a long time ago on another forum regarding the dynaco and the mods involved. since no one has had a real rocket to look at in the francesca sense, all one can do about the trannies is make an educated guess. ken liked m19 for the other amps, but he may have used m6 here since that's what the original dynacos used-------or not. since this is supposed to be a "cleaner" amp some might like the extra chime and definition that m6 seems to add-----or not. it's all a matter of taste. rh

[RJ Guitars]

There have been numerous long threads on transformers in the Rocket amp...

rj

as i've posted before, the heyboer mod trannies were originally done by me a couple yrs back----my specs to heyboer and my part number (same with the power trannie some are using). they are/were just an educated guess based on some remarks by dave funk a long time ago on another forum regarding the dynaco and the mods involved. since no one has had a real rocket to look at in the francesca sense, all one can do about the trannies is make an educated guess. ken liked m19 for the other amps, but he may have used m6 here since that's what the original dynacos used-------or not. since this is supposed to be a "cleaner" amp some might like the extra chime and definition that m6 seems to add-----or not. it's all a matter of taste. rh

Rob, I should have acknowledged you earlier... I think you are among the most informed authorities on the transformer history in the various wrecks. Also, a thank you for your unselfish donation of your part numbers and specifications for us all to use.

It sounds like the Heyboer HTS-8093-1 was conceived and built long after those early Rocket amps were finished? I need to go back and read Derek Ferwerdas notes on his Rocket but I think he got it from Ken in the early 90's. If we compare that date to the one on the line card that Phil quoted from then we'd know if it was the chicken or the egg that came first.

I think most knowledgeable folks agree that the Rocket output tranny was either a Dynaco or a modified form of it... can you add any further credibility to that thought?

When I get back from my current travels I'll look up that note that Phil sent me about the HTS-8093-1 iron and post it for us to look at.

thanks,

rj

[rhinson]

There have been numerous long threads on transformers in the Rocket amp...

rj

as i've posted before, the heyboer mod trannies were originally done by me a couple yrs back----my specs to heyboer and my part number (same with the power trannie some are using). they are/were just an educated guess based on some remarks by dave funk a long time ago on another forum regarding the dynaco and the mods involved. since no one has had a real rocket to look at in the francesca sense, all one can do about the trannies is make an educated guess. ken liked m19 for the other amps, but he may have used m6 here since that's what the original dynacos used-------or not. since this is supposed to be a "cleaner" amp some might like the extra chime and definition that m6 seems to add-----or not. it's all a matter of taste. rh

Rob, I should have acknowledged you earlier... I think you are among the most informed authorities on the transformer history in the various wrecks. Also, a thank you for your unselfish donation of your part numbers and specifications for us all to use.

It sounds like the Heyboer HTS-8093-1 was conceived and built long after those early Rocket amps were finished? I need to go back and read Derek Ferwerdas notes on his Rocket but I think he got it from Ken in the early 90's. If we compare that date to the one on the line card that Phil quoted from then we'd know if it was the chicken or the egg that came first.

I think most knowledgeable folks agree that the Rocket output tranny was either a Dynaco or a modified form of it... can you add any further credibility to that thought?

When I get back from my current travels I'll look up that note that Phil sent me about the HTS-8093-1 iron and post it for us to look at.

thanks,

rj

yes phil will tell you those are my numbers and my changes to the original dynaco unit (steel, winding pattern,splits, etc) done just a couple of yrs ago. the dyanco winding pattern is a specific entity, and probably ubiquitous to the various winding companies around as they would all have the original dynaco spec sheets or at least have done a tear down yrs ago in order to replicate one for the various vintage hifi guys that build and need repro units. heyboer never made any "real" a470 modded units for k.f. back in the day as far as i know.
also the heyboer trannies we use for the komet style builds we do were done first by me at heyboer (way back in 2005 i think) and those are for public use as well. rh

[M Fowler]

rhinson,

Would you recommend to use the same Heyboer OT tranny I used for my komet 60 build in a Rocket pre into two EL34 power section for around 60 watts into 4, 8, 16 impedance. Also the PT could be the same right?

Mark