BEST VOX TRANSFORMERS?

[Colossal]

If you are going to build a real Rocket, which is a very slightly modified Top Boost channel, your B+ needs to be even lower.

[ViperDoc]

If you are going to build a real Rocket, which is a very slightly modified Top Boost channel, your B+ needs to be even lower.

I went on a transformer buying spree when Classictone announced they were going bust. I picked up a couple of Trainwreck spec transformer sets in that venture. Some chime in my future, hopefully!

EDIT: Now I see what you mean. I'd need an HT with a 234-0-234 winding if I'm headed into Liverpool territory? What I have won't do that. I see Pacific makes what might be the best option at 250V-0-250V?

https://cdn.shopify.com/s/files/1/0519/ ... 1633189815

Regarding Pacific's TW OT, it offers a 7.5K primary. Wouldn't you want 4K for a 4xEL84 amp, or is that part of the TW sauce?

[ViperDoc]

If you are going to build a real Rocket, which is a very slightly modified Top Boost channel, your B+ needs to be even lower.

I got Pacific Transformers on the phone today. I asked what they had on hand for TW-style PTs and they guy said they "only have 'standards' on hand that were built by 'other builders'". No idea what that means. I know this is likely in the wrong thread, but I can't for the life of me find a Rocket-specific PT schematic anywhere. RJ posted a drawing of a Liverpool in the TW docs that shows a 234-0-234 PT secondary. Is that the kind of low HT you're talking about? Other than custom-winding the correct spec, what's out there that would work for a Rocket without using a bunch of zeners? Any idea?

[pdf64]

How about the Heyboer HTS-9144 listed in the Rocket Documents thread BOM?

[martin manning]

I have a set of Pacific transformers from Allyn, said to be for the Rocket, with the following specs:

PT 2111:
Primary
Black-Black – Line in
Secondary
Red-Red - 5V Filament
Yellow-Yellow - 280v
Yellow/Green-Yellow/Green - 250v
Yellow/Red – HV CT
Brown-Brown - 6.3V Filament
White/Brown – 6.3V CT

OT 2117 (like Dynaco A470):
Primary
Blue/White-Blue - Plates (4k3 a-a)
Green/White-Green - Screens (20% DL only - not used in Rocket)
Red - CT
Secondary
Black - Ground
Brown - 4 Ohm
Orange - 8 Ohm
Yellow - 16 Ohm

[ViperDoc]

Very good work, guys. Yes, I was wrong about the PT. There is a 250-0-250 secondary option on the PT I saw, this one: https://cdn.shopify.com/s/files/1/0519/ ... 1633189815

This is the OT on www.pacificaaudiomagnetics.com: https://cdn.shopify.com/s/files/1/0519/ ... 1633190816

I will look for the part numbers you listed, Martin & pdf64, I appreciate you sharing those.

[joeboo88]

I have an iron set from RJ - for my Rocket
the PT is a Pacific made for RJ, which has 2 taps 250 - 0 -250 and a 280 - 0 - 280
I found the 280v tap sounds better to me.
I also have the same OT that Martin listed.

I built an AC30 with an EF86 instead of the normal channel.
The PT is a Hammond 275 0 275 and a Hammond 4K OT and a 20H choke. (these are not the Hammond AC30 iron)

I also have a Liverpool with the Hammond 275 0 275 PT and an Edcor 5.2K OT
I used a big giant Zener diode that drops 30V - so its running at the plates around 320, I also tried the amp without the zener and it still sounds good, a little hot because of the ss rectifier.

These 3 amps sound way different from each other. which is a good thing, but they all sound great to me, I guess what I'm getting at is, I don't think any of them have the iron
they are supposed to (designed for?) , but they sound great anyways.

[Colossal]

I have an iron set from RJ - for my Rocket
the PT is a Pacific made for RJ, which has 2 taps 250 - 0 -250 and a 280 - 0 - 280
I found the 280v tap sounds better to me.
I also have the same OT that Martin listed.

Joe,

Where did you end up with your plate voltage and/or your rectified B+ under the 250VAC taps? Should be quite low (275-280?). Did you find the higher voltage to be clearer, less bass? Plate voltage on V1 would be quite low also (<100VDC).

I built an AC30 with an EF86 instead of the normal channel.
The PT is a Hammond 275 0 275 and a Hammond 4K OT and a 20H choke. (these are not the Hammond AC30 iron)

Sweet.

Again, where did you end up with your B+ on this one. There are so many EL84 variants that guys have done here over the years. Did you do the classic Vox voiced EF86? Sorry for the 20 questions!

[joeboo88]

hey Dave. I had to search around , when I used the 250 tap on the Rocket I had 294 on the plates and you are correct I had under 100V on V1. I remember, I couldn't figure out
why I was getting crackling when plugging into the input jack. Xtian and Jana helped me by getting me to install a .1uf cap at the input jack to ground ....something about the molecules not knowing where to go because of the low voltage on V1 sorry can't remember... lol
The Rocket is very bassy as you know, but I'm sorry I can't remember if there was a difference. The amp seems cleaner with the the 280 tap....maybe I should revisit the 250V tap
I don't have the voltages written down for the 280V tap..sorry

Anyways I just measured my AC30, because its a head. I have a 30H choke and actually have 290 on the plates... I never gotten around to posting that build.
I got the schematic from RandalP3000, https://ampgarage.com/forum/viewtopic.php?f=10&t=20627...

The EF86 has a 6 position tone knob. I also put in a MV on this and works really good on this amp.
Joe

[Colossal]

hey Dave. I had to search around , when I used the 250 tap on the Rocket I had 294 on the plates and you are correct I had under 100V on V1. I remember, I couldn't figure out
why I was getting crackling when plugging into the input jack. Xtian and Jana helped me by getting me to install a .1uf cap at the input jack to ground ....something about the molecules not knowing where to go because of the low voltage on V1 sorry can't remember... lol
The Rocket is very bassy as you know, but I'm sorry I can't remember if there was a difference. The amp seems cleaner with the the 280 tap....maybe I should revisit the 250V tap
I don't have the voltages written down for the 280V tap..sorry

Thanks, this is great. Yes, you would need a blocking cap to keep DC off the guitar when you get the plate voltage down that low.

Anyways I just measured my AC30, because its a head. I have a 30H choke and actually have 290 on the plates... I never gotten around to posting that build.
I got the schematic from RandalP3000, https://ampgarage.com/forum/viewtopic.php?f=10&t=20627...

The EF86 has a 6 position tone knob. I also put in a MV on this and works really good on this amp.
Joe

Again, very helpful. I remember Randall's dual 86 build; pretty cool.

Thanks for your comments, most appreciated.
Dave