trinityamps.com

I finally have everything I need to get going on my build!

However I'm struggling with the layout. I'm worried about the preamps being close to the output transformer and equally worried about the output being too close to the power. I've used the headphone trick to determine that the OT needs to be as far away as possible from the PT. (The chassis is quite small for the massive size of these transformers!) I know there's always going to be compromises but I'm struggling to determine which ones are best.

I've come up with 3 possible layouts. Can anyone comment on which is best or recommend an alternative?

Layout 01 - facilitates the neatest wiring, but has noticeable 60hz hum

Layout 02 - gives a quiet output, but puts preamp 1 very close to the OT

Layout 03 - also gives a quiet output and keeps the preamp tubes far away from the OT, but makes for tricky wiring

Any thoughts?

First question is what amp are you building cause the 370fx seems a little over kill for those tubes. (NM I'm assuming you all ready have these transformers) and I assume your gonna be playing with the plate load to make it 4 8 16 r output impedance to get an 8K load

And what are the chassis dimensions

Was thinking like a trainwreck layout like half a rock it. check out Ceri@tone pictures (layout)

need more information. amp, size etc.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

It's a lightning basically, mostly following the Trinity 15 schematic. Yes I have the transformers (and everything else) already, including a 16x8x2 chassis.

I'm only planning on using the 4r output and I will plug an 8r speaker into it to get the 8k load.

I did a bit more thinking and this is what I've come up with now, anyone see any problems?

No ef86 (1 channel) ?

The trainwreck chassis is 17x8x2.5 (not sure on the 2.5) but you have the right depth so 1 inch less length and two el84's less



An idea of what it looks's like.

I'm not telling you what to build (no expert in layouts) just giving you more ideas.

You can move the rectifier and choke to the transformer side and then line up the rest of the tubes in a line.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Thanks everyone, the amp is built and sounds great, but I'm having a little trouble with some of the voltages. It's follows the Trinity 15 / Lightning schematic:

V0 = 354
V1 = 242
V2 = 323
V3 = 270
V4 = 325

Anyone any thoughts why the screen voltage is so low?

Whats the cathode and plate voltages of the power tubes?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

EL84 voltages:
- plate: 363
- screen: 246
- cathode: 9.1

My suspicion lies with the power resistors, because the voltages across 25 & 27 look strange:
- R25: 108.5
- R26: 30
- R27: 82
- R28: 27

Anything else it might be?

Replaced the resistors, no real change :-(

Pics of your build?

_________________
http://pdfelectronics.com

I've come to the conclusion these voltages are actually "right". I have no audible symptoms of anything being wrong.

My suspicion is that someone measured the voltages on a build that didn't have the 22k screen resistor (or had a 4.7k, or fed the screens directly off the B+), and transferred them to a schematic that included the 22k. I *think* I can extrapolate that a 4.7k would drop about 17.5 volts for the same current on my amp (vs the 82V I'm seeing with a 22k).

Anyone any thoughts on this? Anyone have a build they've measured?

Some pics (there's a build thread on diyaudio with more):

Not sure when you say R25, R27, etc. what schematic you are referring to.

BUT I can tell you with Lightning style amps where the PS dropping resistor are all in parallel the screen dropping resistor drops very little voltage. The screens in generally draw very little current in comparison with the other tube's elements. The parallel PS accents this as there is nothing "downstream" from the screen dropping resistor pulling more current.

Not sure if that addresses what you are asking

I have had an amp I thought was wired correctly. Sounded amazing! After doing wiring tracing (I lie, I was admiring my work) I noticed I had the screens connected to the PI node. Screens were getting a lot less voltage than intended, amp was soft, compressed and sounded great. Point is though the amp may be working and sounding good it may not be operating as designed.

_________________
http://pdfelectronics.com

Layout 01 (Neat Wiring, 60Hz Hum): If this layout provides the neatest wiring but introduces noticeable 60Hz hum, it's likely due to the proximity of sensitive components to potential sources of interference, such as the power transformer (PT) or other high-voltage components. Hum can be caused by electromagnetic interference and the coupling of AC magnetic fields. If this layout results in excessive hum, it might not be the best option for achieving optimal signal integrity and noise reduction.
pge outage map

the specifics of your components, chassis, and wiring can all impact the performance, so it's a good idea to consult with cookie clicker experienced tube amplifier builders or experts for more tailored advice and guidance.