Rocket Transformers

[sst4270]

I've tried PM'ing a couple of guys here without getting any response.
Can someone tell me where I can purchase a set of transformers to build a Rocket?

Or can someone recommend the correct specs...
I've seen conflicting specs in the threads. My understanding is that I can't use the same fmrs as are used for the Express and Liverpool because the pwr secondaries are different and the output primaries are different.

Thanks in advance,

Steve

[Allynmey]

Heyboer
PT HTS-9144
OT HTS 8093-1
CH Hammond 158L

[sst4270]

Thanks Allyn. Greatly appreciated.

-SST

[67plexi]

Will tonesluts power transformers work on a rocket build?
Heboer is out of stock on the hts-9144 and Hts-8093
the hts-8093 is a Dynaco a470 type output transformer 4300 ohms
have a extra set for sale?
Best Regards 67plexi.

[funkmeblue]

triode electronics sells dynaclone outputs

[selloutrr]

there is a clone on the bay now

http://cgi.ebay.com/A470-Ultralinear-ST ... 18Q2el1247

[Lonely Raven]

That's an UltraLiniar...is that the correct type for this?

Either way, that auction is by Triode Electronics from here in Chicagoland.

http://store.triodestore.com/

They typically carry some Dynaco.

[Fischerman]

Ultra-Linear just has a couple extra taps on the primary...often at 43% IIRC. You don't have to use them and can just tape and stow them and use it like a 'regular' OT. The dual-primary OT from Heyboer that is often used for Trainwreck amps is probably a similar thing but just marketed/used differently.

[jaysg]

Heboer is out of stock on the hts-9144 and Hts-8093

A couple of days ago, Alden told me that Heyboer doesn't stock anything....just saying, that's their business model. I've purchased a couple one-offs from them before. They're not tragically slow to deliver, unless you want it overnighted. That's not going to happen.

The ebay sale is triode electronics. Looks like you could get one for less than their list price.

[Mark]

Okay now I am confused?

PT HTS-9144

The power transformer I have is HTS 5519, and I thought you could build all three amps with this transformer. How does HTS 9144 differ?

Dare I ask, is there a better power transformer for the Express or Liverpool amps?

I'm all too curious.

[Fischerman]

Mark,
I think those are the ones made from KFs line card mentioned in Allynmey's recent Rocket build post. The B+ is only ~275vdc so it's lower than the 'low voltage' taps on those dual-secondary PTs from Heyboer (mine runs at ~305-ish vdc B+ depending on wall voltage using the same 50R Rk; I'm using the 260v taps on one of the dual-secondary Heyboers). And that OT sounds like it's closer to a Vox OT (4300ohm primary vs. the Vox 4200ohm).

[sst4270]

Mark,

The HTS-5199 PT is for Express and Liverpool.
Specs: 120V Pri - Sec: 300/260/0/260/300VAC@300mA, 6.3V@7.5A, 5V@3A

The HTS-9144 PT is a custom spec'd frmr based off of the 5199. It has lower secondary HT voltages: 280/250/0/250/280@300mA. I presume these voltages were chosen to match original Rocket(s) that some very fortunate ones have had the privy to either measure or confirm with owners.

The HTS-8093-1 is also a custom spec'd output transformer based off of the Dynaco A470. Lower Secondaries than the Express/Liverpool OT. Again I presume the same as above.

They are not stocked by Heyboer. So they must be made either one at a time or, Heyboer would prefer, they be made in at least some kind of quantity to help to justify the set up on their production line. (Like 5 or 10). For one offs cost would be around $235/set plus shipping.

Even with a 10 pc each qty order the cost will still be around $190/set. Part of the high cost is that these frmrs used M-6 grain oriented steel. This helps with fidelity as well as heat. As Allyn mentioned the Rocket runs hot with the 50ohm Cathode resistor and is the cleanest of the three types.

Hope this helps.

Steve

[rhinson]

i was the first guy that speced and had made the hts-8093-1 by heyboer. it's the a470 variant and it's not m6 lams--phil is confusing it with the regular a470 units they wind. it has m19/26ga just like the other k.f. stuff and has a slightly more complicated winding pattern so it's more of a pain in the ass for them to wind. the regular dyanco's (which they do for folks as well) is made with m6/29ga -----that's what the triode repros are made with as well. i'm sure either one would sound fine with this amp----i have some vintage units i got off ebay but haven't had a chance to build an amp with them yet.
and actually these units are not that expensive. you just can't get ANY decent sized trannies wound in today's economy for less than $80 + ----raw material cost has practically over past many yrs. plus you get charged labor as well and the difficulty of the build relative to others plays into that. rh

[jaysg]

...the a470 variant and it's not m6 lams--phil is confusing it with the regular a470 units they wind.

Slight aside -- do any of these material issues mean much for power transformers?

[rhinson]

...the a470 variant and it's not m6 lams--phil is confusing it with the regular a470 units they wind.

Slight aside -- do any of these material issues mean much for power transformers?

not really--- if you're gonna play it here in the usa with 60hz juice. in general, you can make the power trannie from anything from m50 to m6. m6 is higher grade grain oriented so there's less core loss and with 2 power trannies of the same size/spec the m6 will run cooler. with trannies the size/purpose of the express, etc. you don't have to do m6 but there's not as much cost diff as there used to be in the old days so i just get the made with m6 anyway.

if shipping export 50hz stuff you need m6----it will definitely run cooler and for the same amount of heat generated/core losses (if acceptable) you could make it a bit smaller compared to the less grades that are 24ga as opposed to the 29ga m6 stuff.

with outputs it's all about the tone. you don't have to really worry about core losses as much from grade to grade, overheating, etc.----it just needs to be sized appropriately of course. rh