Which A470 and why?

[selloutrr]

http://www.merrenaudio.com/about_us

[RJ Guitars]

Great Discussion. The common "Wreck" Heyboer transformers I sell were all built to specifications provided by Rob Hinson. Rob left these part numbers open (unprotected) so we could all have access to them. He is the most knowledgeable guy I know on transformer technology and has been very generous in sharing that knowledge with us. The Express and Liverpool transformers appear to be clones of the old Stancor transformers, much the same as the Trainwreck specification output tranny that Pacific sells.

The HTS-8093-1 is clone of the Dynaco-470 tranny minus the ultra-linear taps. From the notes I have from Heyboer, the use of the M19/29 steel rather than the M6 was intended to "give it a little hair". This is apparently a specification that the early Wreck clone guys and Heyboer developed. I can only speculate they had good info to work with and the results have been consistently producing great sounding amps for many years. The Heyboer transformer compliment that became the "Wreck Clone Standard" was given in this thread: http://ampgarage.com/forum/viewtopic.ph ... ht=heyboer This transformer set has been used in dozens if not hundreds of Rocket clones and the reports are consistently favorable.

The Edcor transformer that Mark Fowler mentioned is not a clone of the Dynaco and uses a 5 layer wind rather than a Dynaco style 7 layer winding. It's way beyond me to understand the complexities of transformer behavior well enough to make good technical comparisons. I have found that your ears are the critical metric in judging if you have the right one - YMMV.

rj

[RevD]

I have found that your ears are the critical metric in judging if you have the right one - YMMV.

rj

I suspect Ken could tune around whatever he was using (I often wonder how much folklore of what Ken used was because of what he had laying around haha.) The man was a Master.

Regards,

Don

[hitchcaster]

The A470 is an Ultra linear design . I would bet that KF's mod was to stuff the unused tap inside the end covers. That's what I do with them. Insulated of course.

From what I've researched. The Dynaco A470 transformers were worked on/rewound by Merren before being used in TW Rocket.

can you say or show where you got this info from? i just asked chris about express and rocket trannies and he said the only trannies he did for ken were from scratch. unless he was just replying to the express part of my question which was about both amps. im still chasing this "transformers for rocket" thing

[Colossal]

The A470 is an Ultra linear design . I would bet that KF's mod was to stuff the unused tap inside the end covers. That's what I do with them. Insulated of course.

From what I've researched. The Dynaco A470 transformers were worked on/rewound by Merren before being used in TW Rocket.

can you say or show where you got this info from? i just asked chris about express and rocket trannies and he said the only trannies he did for ken were from scratch. unless he was just replying to the express part of my question which was about both amps. im still chasing this "transformers for rocket" thing

Hitchcaster,

Both Selloutrr and Billyz have moved on from AmpGarage some years ago, so I'm not sure if you'll ever get a reply. When guys were first building Rockets, member Robert Hinson (rhinson) had Heyboer modify A470s to use non grain oriented steel and ditch the U/L taps. There may have been something done with the interleaving pattern, but not sure IIRC. This OT was offered by Rhinson and then the line card later passed to RJ.

EDIT: Duh, I reread up a little further into this thread and RJ spells out the modifciation

[hitchcaster]

From what I've researched. The Dynaco A470 transformers were worked on/rewound by Merren before being used in TW Rocket.

can you say or show where you got this info from? i just asked chris about express and rocket trannies and he said the only trannies he did for ken were from scratch. unless he was just replying to the express part of my question which was about both amps. im still chasing this "transformers for rocket" thing

Hitchcaster,

Both Selloutrr and Billyz have moved on from AmpGarage some years ago, so I'm not sure if you'll ever get a reply. When guys were first building Rockets, member Robert Hinson (rhinson) had Heyboer modify A470s to use non grain oriented steel and ditch the U/L taps. There may have been something done with the interleaving pattern, but not sure IIRC. This OT was offered by Rhinson and then the line card later passed to RJ.

EDIT: Duh, I reread up a little further into this thread and RJ spells out the modifciation

ok thanks.. yeah i forgot Selloutrr is gone, thats too bad.. i was hoping he would respond since he has info on this (and many other things).. ive tried the heyboer, pacifics, and original a470... i still don't think the rocket has been fully uncovered. just guess work thats gotten things closer. notice selloutrr said the rocket had A470's that were modded or rewound.. getting rid of UL taps is not a "mod" as far as im concerned thank you for the response

[Roe]

any experience with this a470 from LM audio: https://www.laboratoriomusicale.net/en/ ... eplica-new

[ViperDoc]

I just got asked this from Phil at Heyboer:

“Do you want the Dynaco A470 4.3K HTS-8093-1 or 5.2K HTS-9633 OT? Both have been sold for the Rocket.”

Which would you recommend? I believe the A470 is an ultra linear design (where you’d cap and stuff the UL taps). Is the 5K2 the Express OT?

EDIT: I'm getting a price breakdown from Phil about the A470. If anyone is interested in a full Rocket PT/choke/OT package from Heyboer, let me know.

[Colossal]

You want the 4k3 Dynaco A-470-S. The Heyboer wound OT eliminates the ultralinear taps the original had.

[ViperDoc]

You want the 4k3 Dynaco A-470-S. The Heyboer wound OT eliminates the ultralinear taps the original had.

Even if you plan on not using them? Just trying to figure out what to tell Phil. He has RJ's A470 diagrams. I'll ask him about the "-S". Thanks, dude.

[Mark]

I just got asked this from Phil at Heyboer:

“Do you want the Dynaco A470 4.3K HTS-8093-1 or 5.2K HTS-9633 OT? Both have been sold for the Rocket.”

Which would you recommend? I believe the A470 is an ultra linear design (where you’d cap and stuff the UL taps). Is the 5K2 the Express OT?

EDIT: I'm getting a price breakdown from Phil about the A470. If anyone is interested in a full Rocket PT/choke/OT package from Heyboer, let me know.

I thought the 5.2K HTS-9633 OT was used in the Liverpool amp as an alternative to the 6.6K primary. Don’t quote me though.

[ViperDoc]

HTS-8093-1 is the Heyboer OT code for the Dynaco 7-layer build up without the UL taps, 4K3 primary.

[Roe]

pacific offers one with a 5k5 primary

[Mark]

pacific offers one with a 5k5 primary

What is the part number on it?

I thought RJ did initially build a Rocket with the 5.2K transformer before finding out it was the wrong part.

[Roe]

pacific offers one with a 5k5 primary

What is the part number on it?

I thought RJ did initially build a Rocket with the 5.2K transformer before finding out it was the wrong part.

[PAM-OT-35-72R]
https://cdn.shopify.com/s/files/1/0519/ ... 1646167340