Vertical Mount PT for 5e3 head build

[Rocketrob]

Hi all,

My first post here. Great site BTW.

I'm looking for a verticle mount PT for a 5e3 head in a smallish chassis (12x7x2-3/4). I want to use a stand up type for more room inside the chassis. The only ones I've come across are both Hammond.

HX260J (open frame type) 120V, 325-0-325, 150ma, 5V@3A, 6.3V@4ACT
and
HX273CZ (enclosed) 117V, 325-0-325,150ma, 5V@3A, 6.3V@5ACT

Do these seem correct for the job, or are they too much tranny for the job? Also, will using the open frame type cause more interferance being close to the tubes?

Thanks, Rob

[tubeswell]

Hi all,

My first post here. Great site BTW.

I'm looking for a verticle mount PT for a 5e3 head in a smallish chassis (12x7x2-3/4). I want to use a stand up type for more room inside the chassis. The only ones I've come across are both Hammond.

HX260J (open frame type) 120V, 325-0-325, 150ma, 5V@3A, 6.3V@4ACT
and
HX273CZ (enclosed) 117V, 325-0-325,150ma, 5V@3A, 6.3V@5ACT

Do these seem correct for the job, or are they too much tranny for the job? Also, will using the open frame type cause more interferance being close to the tubes?

Thanks, Rob

Either of those will work

[Bruce / Mission Amps]

My experience with Hammond 115v-117v, power trannys suggest that both of those trannys could net you a higher B+ then what a 5E3 needs. 150ma is a little stiff too.
The original PTs were only around 100ma to 110ma or so and built for 115vac line voltages so under a big load they would sag out a little more.
I would not be surprised to to see your B+ at around +400v, or even more.
If you use a NOS 5Y3GT rectifier tube, it will be better.

Regardless, when using either of those transformers, don't use a SOVTEK 5Y3GT with them because your B+ will be around 425vdc-435vdc... or higher depending on your actual main line's wall outlet voltage.
My line voltage was 126vac yesterday.

For classic tone, you are looking for a B+ rail that delivers around 350v-370v max on the plates of the 6V6s while they are idling at around 10-12 watts each.
It would be a simple matter to use a couple 10v-15v, 5w zener diodes in the center tap of the PTs Hi-V secondary to lower the B+ down and you can also use a larger ohm value for the power tube's cathode bias resistor... like 330-360 ohms.
Don't go any higher then 360 ohms though... the amp just will not sound right as compared to a real 5E3 or good clone.


Caveat:
Either of those PTs will let you run 6L6s with a 10 watt, 270 to 300 ohm bias resistor and a 5V4GT rectifier for around 15-18 watts output using any well made 20 watt output tranny and 22-26 watts with a good smallish, 25- to 30 watt 6L6 OT, like those found as a replacement for a silver face Bandmaster or Pro Reverb (as long as it has a 4 and 8 ohm secondary for your speaker).
You would run your 8 ohm speaker on the 4 ohm tap for the 6V6s if you want more variation in tone.

Those would be real RMS type of power ratings... not "pie in the sky" wishful thinking ratings.
It would be similar to a tweed Pro with a 12" speaker instead of a 15"... that is also a great sound.

[Rocketrob]

Thanks for the replies.

The idea of running 6L6s is very tempting; a little more power and clean headroom for gigging I would think. I have an old BFVR that covers that area pretty well, but it's not a tweed sound. Hmmm...

How about this one for lower voltages:
HX-372DX 100,110,120,200,220,240 VAC. 50/60 Hz. 600V CT. 125ma. 5V@3ACT. 6.3V@4A CT.
Using the 120 primary, it should be close to more classic voltages, no?
Rob

[Rocketrob]

This is what I settled on.

PT: Hammond HX-272-DX, 115V, 300-0-300, 125ma, 5V@3A CT, 6.3V@4A CT.
OT: Hammond HX-1608, 10W, 8k primary, 4-8-16 secondary.

I think I can keep the B+ under control with this PT. I know I'm going against popular choice with the OT, but we'll see how it sounds. Hopefully not too hi-fi, but with a little later break up and better bass response. It doesn't have to sound exactly like a vintage 5E3. Just tweedy. If anyone has tried this combination I would really like to hear about it. I will probably start a different thread to discuss the building of this amp; as I'm sure that I will have more questions for you all.

Thanks, Rob.

[Bruce / Mission Amps]

I use the 1608 output in my 18-20 watt EL84 Crusader amps and they always sounded very good. The 10 watt rating is very conservative so it is actually over kill in the 5E3 amps.
I think you'll be just fine with what you have as long as you stick to a NOS 5Y3GT rectifier.

[Rocketrob]

Thanks, Tubeswell and Bruce.
I'll be starting this soon. Gathering parts and making the chassis now.
Rob

[Direwolf]

Check out Edcor. They seem to be getting into the guitar amp xformer business and are great to deal with. I've used their transformers on 2 builds and am very impressed with them both sound-wise and price-wise. The website doesn't come close to listing what they have. If you want a special wound transformer, they will do it for a $20 engineering fee. Once it's done and they have it on file it will cost the same as a regular transformer. I have a PDF file with a lot of their transformers in it. If you're interested, PM me and I'll send it to you. I used the XPWR041 in a 5E3 (340-0-340 120ma, 6.3 4a CT, 5.0 3a) and it worked great. They have some great OTs, too.

[Rocketrob]

The Edcor products look like they're well made; and the prices are very reasonable. Might have to try some on the next build...there has to be a next, right?

Any body know how they sound?
Rob

[tubeswell]

...there has to be a next, right?
Rob

Yep. There's always a next. ;-)

[Direwolf]

On my first 5E3 I used a Weber PT and a Hammond OT. To me, it sounded great. My latest with the Edcor xformers sounds just as good. In my opinion you can't go wrong with Edcor. They have some great people working there and they'll probably do whatever it takes to satisfy the customer. When I first called to order from them I spoke with Phyllis and she really knew her stuff about transformers. I had some questions about the PT after I received them so I called her and found out she wound it and could answer any question I had about it. I really can't speak highly enough about them.

I did a lot of research on them before I ordered and couldn't find any bad words about them. I attached the pdf file I have for them. It's got a pretty good selection for amps.