Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Mats on September 08, 2015, 09:39:22 am

Title: Dual 5Y3
Post by: Mats on September 08, 2015, 09:39:22 am

Hi
Im trying to get my schematics in order. I got to this one, Angela Super Singel-Ended.
My question here: Dual 5Y3 in a PSE amp ??
Perhaps its just a cool thing, with two rectifiers.
The schematic says, the PT is Fender Deluxe or equivalent.
Can that PT really handel two 5Y3 ?
/Mats

Title: Re: Dual 5Y3
Post by: Willabe on September 08, 2015, 09:50:59 am

5Y3 draws 2A, Deluxe/Reverbs use GZ34/5AR4 they draw 1.9A. Latter Deluxe? Reverb's used 5U4, 3A current draw.

So 2x5Y3=4A heater current draw. Even if the Fender PT had a 3A/5v heater that's still 1 amp short.

Why not just use a single GZ34? Just have to watch the B+ plate dcv. A single 5V4 (2A heater) will give less B+dcv than a GZ34. (Our host Doug sells a new 5V4 that's spot on for dcv compared to a NOS 5V4 for a very good price.)

Or Classic Tone might make a small PT that has enough 5v heater current and B+ current to run 2x5Y3's and 2x6V6's? SE 6V6 Champ's only draw ~40mA B+. So 2xParallel SE 6V6= ~80mA. 

Title: Re: Dual 5Y3
Post by: sluckey on September 08, 2015, 10:04:22 am

If I paid $50 for a transformer that was rated for 5V@2A I definitely would not put a 4A load on it. I think the dual rectifiers are just show. I'd put a 5AR4 in it and move on.

Title: Re: Dual 5Y3
Post by: Mats on September 08, 2015, 12:21:12 pm

Hi
Thanks for answers.
Yes, 4A for dual 5Y3.
Thats, as you say, its just for show.
I wonder why they put it in there in the schematic ?
/Mats

Title: Re: Dual 5Y3
Post by: shooter on September 08, 2015, 01:53:20 pm

Quote

I wonder why they put it in there in the schematic

Marketing?

I did a build that where I wanted "symmetry"  and the tube regulator made it "un-balanced"  so I took a bad octal, drilled out the base, stuck in and led and used it as a power indicator, walla, 2 tubes for balance

Title: Re: Dual 5Y3
Post by: kagliostro on September 08, 2015, 03:15:27 pm

Quote

I wonder why they put it in there in the schematic

Having two rectifier tubes in parallel halves the resistance and modify the drop of voltage, so there is an increase in B+ level

may be the reason is this ?

K

Title: Re: Dual 5Y3
Post by: DummyLoad on September 08, 2015, 04:42:38 pm

Quote from: kagliostro on September 08, 2015, 03:15:27 pm

Quote

I wonder why they put it in there in the schematic

Having two rectifier tubes in parallel halves the resistance and modify the drop of voltage, so there is an increase in B+ level

K

again, quoting sluckey, just use a 5AR4 if that's the case.


--pete

Title: Re: Dual 5Y3
Post by: billcreller on September 11, 2015, 08:28:22 pm

What if I have a lot of 5Y3s & no 5AR4s ?

Title: Re: Dual 5Y3
Post by: shooter on September 11, 2015, 09:12:37 pm

Quote

So 2x5Y3=4A heater current draw

I didn't do the math tween tube cost and tranny but I'm thinking the tube looses, well, unless you have lots of dual 5Y3 trannies :icon_biggrin:

Title: Re: Dual 5Y3
Post by: foghornleghorn on September 18, 2015, 12:58:06 pm

I used two 5Y3GTs in a 4x6V6 amp with an AES tweed Bassman PT. So 3A 5V winding. It has not given any problems. I sold it a while ago to a pro player and have had no frantic phone calls about it since.


So I'd say a 3A winding is OK, but I wouldn't put two 5Y3s on a 2A winding, I think that's asking for trouble.

Title: Re: Dual 5Y3
Post by: Mats on September 21, 2015, 11:20:16 am

Hi
Thanks
If 3A is OK for a up and running amp.
Perhaps the winding 5V 3A, of that PT is underrated a little
and can deal with the dual 5Y3 at 4A.
/Mats