That's too damned high!

[Reeltarded]

We're blowing the shit outta high prices! -destroys competition's used car with explosives-

Have MM O100JT it's a 385-0-385 JTM 45/100 PT.

Dood, I don't use anything near 500v on any builds, much less 530-545. Not going to happen. They stopped manufacturing tubes that will withstand 500 within the margin of error on my local service.

Some ideas for dropping B+ or repurpose PT:

1. Cage fans in series driving the wind farm that powers the amp. Ignore second law.
2. Logo on amp claims 'Tesla Charging Station'. Play amp only on off-ramps to I-95.
3. Use vintage RCA 6L6s and lobby my state to enstate a deaf penalty.
4. Haphazardly wire heaters and get a GEICO policy on PT.
5. Door stop.
6. Homebrew super collider.
7. Youtube video titled "Voltage Dropping from 3000 Feet AGL!!". Thumbnail is a expression that looks like a drunk drag queen did my makeup. Colab with Smarter Every Day and Slow-Mo guys. Buy a Lamborghini with the income from sponsorship.
8. Drive it up to a local used transformer lot and trade for three 50w replacements.. ok, two, but that's my bottom line..
9. Tweet about it.
10. Bury it in the driveway for mole mitigation. Warn neighbor's cat.. once.. ok.. full disclosure: this is a cat mitigation idea.
11. Aim it at Andromeda to either make alien contact or destroy it.
12. Slam it on a cement slab until it's only about 60% efficient.
13. Finish this coffee and do anything else.
14. Buy Bitcoin next time it spikes.
15. One word: Transformerpult!

meh


M

[Reeltarded]

1C0F508A-3CBB-4D80-8653-0F9FB56DB1E4.jpeg

[bepone]

you can use 7027 tube, it can withstand this voltage, also old 6L6GC can, using this in old ampegs V4

[Reeltarded]

No way. I can't let a PT dictate an amp build. I normally build on 400v lol

I have tubes that can take the voltage. I am not throwing them away on voltage.

[bepone]

understand completely, coz i was many times in the same situation!

you can try to reduce with cheap russian horse rectifire 5C3S / 5Ц3C

[Colossal]

You could do a few things with that PT:

1) Sell it, and we never speak of it again

2) Build something big bottle, tube rectified, and fixed or cathode biased:

385VAC x 1.24 GZ34 = 477VDC
Pair of KT88s each individually cathode biased, Trainwreck power supply...

3) Build something solid state rectified and choke input filtered:

385VAC x 0.90 SS Choke input = 347VDC

[Reeltarded]

Umm hmmmm.. uuhhhhh.. eeeeeeew.. mmmmmmmm..

Mostly grunting.

I was just loking into the pile for somthing to do. I don't know if any of that works out in my Marshall-centric worldview.

[Phil_S]

Full wave, choke input power supply. It will drop B+ about 50%. You'll need to model the circuit to get a better idea, and you'll need a choke that will handle the full amount of current in the audio circuit, not one of those wimpy chokes that goes between the plates and the screens.

[Reeltarded]

I'll choke you!

That all sounds fun, but I'm sort of sold on the smplicity of hings I know best.

.. and choking people? Oh man.. all the practice since the internet!?

[Phil_S]

Unhand me! Choke that PT instead. Look, this is what I did with one that delivers 825VAC on the HT secondary. Its simple.

Red numbers are actual measured voltages. The 45% rule is just about spot on. Your 770 will give you B+ around 345. The PT used on this project is a model that doesn't have enough mA for a pair of big bottle tubes, but you get the idea. I don't know much about chokes. I'll guess you need 5H @ 150-200mA or so, depending on tube choice.

$20-30-ish plus shipping Hammond 159S or 159R should be OK. It won't break the piggy bank. What else will you do with that beasty PT? I see your list. I vote doorstop or toe stubber.

C'mon Miles, order one, and get on with it.

[Reeltarded]

Saved. Will take a look.. after I get done choking these state officials!!

[tony hunt]

a question from one of the back seat rows:
does this choke need to be a swining choke?

Or is a Marshall so weedy that it doesn't matter?

[Reeltarded]

.. well, well look what we got, fellas.. where'd ya get that weird innernet name..

0E5F9CE7-E2BF-4B57-BEBD-CD2B3C0D44EA.jpeg

Hmmm?

Look here, you cain't just waltz in on your sixty-fifth post and start asking questions. We got rules.

Rules for people with weird electretcal frequencies:

1. You cain't just waltz in.
2. Sittin' n the back row makes you look like you done it.
3. Umm.. we got rules.
4. Take your hat off when you on the innernet; have some manners.
5. Mmmhmm...

These rules may seem arbitrary to you, but I assure you they are a protection scheme to keep questionable practices safe and relevant.

Let me ask you a question

0E5F9CE7-E2BF-4B57-BEBD-CD2B3C0D44EA.jpeg

if that is your real name..

How much tea do you take with your milk?

I'll bet your damned biscuits are cookies.

Cookies and sausage gravy sucks. Now, why don't you go clot some cream and make sure you put it on your weird cookie before the jam so the jam slides out and runs down your arm to your elbow, you got me, fella?

Areight.

[didit]

Hullo Miles --

He's +1 GMT, so EU not UK -- so perhaps Netherlands, Switzerland or Spain. Swing and a ...

But seriously, get out y'all's own way. Yet another Marshall maybe? Baaa !

Build something in spirit of a high plate D-style, MusicMan variant derived as your template model. And had HAD been to better schools, might've put in a small H choke before the first bulk filter. Don't be intimidated by voltage greater than you've been accustomed.

Best .. Ian

[Reeltarded]

Gol'dangit! He got to Ian!