I've started a new amp build.. tweed Princeton 5F2-A

Make it loud here.
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wproffitt
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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by wproffitt » Fri Apr 15, 2022 9:46 am

That looks great! I’ve been waiting to see the fully populated board for a couple of days now. It’s oh-so-satisfying to get all of the components soldered in, isn’t, it?😀.

-Where are you getting your cab? I got mine from Mather and his work is REALLY nice, but there are loads of good options out there.

-I was just going to wire up a fuzz pedal this summer but think I may need to build a B15 clone for my bass now instead because of the rash of cool build threads on here of late. :fp:

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by i love sharin foo » Fri Apr 15, 2022 4:23 pm

hulakatt wrote:
Thu Apr 14, 2022 5:34 pm
Oh, that's a lovely wiring job! Very nice.
Thank you!

øøøøøøø wrote:
Thu Apr 14, 2022 7:24 pm
Beautiful work, nicely done!
Thanks Brad! I tried to think a few steps ahead the whole way through. I am really pleased!

luau wrote:
Fri Apr 15, 2022 5:55 am
Looks great! I've got one coming up and I hope it looks half that nice. :D
Thanks Tom! I'll be anxious to see what you are into. I love watching builds unfold, too.
tribi9 wrote:
Fri Apr 15, 2022 7:27 am

Ditto on the comments. This build looks great.
Thanks!!
rbrcbr wrote:
Fri Apr 15, 2022 9:16 am
Wow, this looks great. Also, amplifier design is so foreign to me that I seeing the board all wired up is basically an abstract image to me. I've been interested in building my own amp for a bit, but have mostly been terrified of frying myself. Maybe one of these days when I've got some spare change I'll convince myself to DIY something, and learn a useful skill or two while i'm at it.
Amps really aren't too bad. Read up on safety is my best advice. Whenever I am in side one that is running, I close myself in a room with no one else and no distractions. I only do it when I know I have plenty of time. And triple check everything! Never assume that something has been discharged. Put a meter on it first!
wproffitt wrote:
Fri Apr 15, 2022 9:46 am
That looks great! I’ve been waiting to see the fully populated board for a couple of days now. It’s oh-so-satisfying to get all of the components soldered in, isn’t, it?😀.

-Where are you getting your cab? I got mine from Mather and his work is REALLY nice, but there are loads of good options out there.

-I was just going to wire up a fuzz pedal this summer but think I may need to build a B15 clone for my bass now instead because of the rash of cool build threads on here of late. :fp:
Thanks! It is definitely a great feeling to watch a box of parts transform into a real amp. Especially when you spent weeks tracking all the parts down! My cab is coming from Guitar Cabinets Direct. It's a standard narrow panel 5F2 cabinet with a 10" baffle. https://guitarcabinetsdirect.com/cabine ... princeton/
The whispers cut like hard rain, Like sugar in a hurricane

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by wproffitt » Fri Apr 15, 2022 5:52 pm

i love sharin foo wrote:
Fri Apr 15, 2022 4:23 pm

Thanks! It is definitely a great feeling to watch a box of parts transform into a real amp. Especially when you spent weeks tracking all the parts down! My cab is coming from Guitar Cabinets Direct. It's a standard narrow panel 5F2 cabinet with a 10" baffle. https://guitarcabinetsdirect.com/cabine ... princeton/
I’m think you’ll be glad you went with the 10” baffle. The originals were 8s, right? Correct me if I’m wrong, but the whole thing, when assembled shouldn’t weigh more than 20 lbs, right?

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by i love sharin foo » Sat Apr 16, 2022 9:11 am

wproffitt wrote:
Fri Apr 15, 2022 5:52 pm
i love sharin foo wrote:
Fri Apr 15, 2022 4:23 pm

Thanks! It is definitely a great feeling to watch a box of parts transform into a real amp. Especially when you spent weeks tracking all the parts down! My cab is coming from Guitar Cabinets Direct. It's a standard narrow panel 5F2 cabinet with a 10" baffle. https://guitarcabinetsdirect.com/cabine ... princeton/
I’m think you’ll be glad you went with the 10” baffle. The originals were 8s, right? Correct me if I’m wrong, but the whole thing, when assembled shouldn’t weigh more than 20 lbs, right?
Yeah, the originals had an 8" speaker. I too think the 10" will be perfect. There was also an option for a 12", but I think I like a 10" in a smaller cabinet like this. I am not sure what it will weigh in at. It can't be too much!
The whispers cut like hard rain, Like sugar in a hurricane

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by i love sharin foo » Sat Apr 16, 2022 9:27 am

I finally had some time to fire it up and see what doom awaited me. There's always that moment of trepidation as you are flipping the switch. But nothing... no smoke, no exploding capacitors, no arcing. I checked all the voltages from the power transformer first with no tubes making sure everything was where I expected. And it was... a B+ of 509v (but with no load of course). With tubes fitted it measured 414v which again, is right about where I anticipated, if not a bit lower actually. And simultaneously I get the screech of a backwards output transformer primary :fp: So, I swapped the primary and added three 15v Zener diodes to the center tap on the 315. Now I am reading 376v which is right where I wanted to be. And it sounds way better now. Before it was a lot cleaner and stiffer. Now it has the crunchy, grindy, fuzziness that are so great about these little tweed guys. I didn't expect that drop in voltage to make that big of a difference, but it did. My plate voltage on the 6V6GT is now sitting at about 340v, with about 38.5 milliamps. I think that will work out.

The swapped OT primaries (the red and blue wires):
Image

And here you can see the 3 15v Zener diodes in series. I dropped about 38v with those.
Image
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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by johnnysomersett » Sat Jun 18, 2022 12:26 am

Coming back to see if this has been wrapped and up finished yet? Or are you still waiting on the cab?
Silly Rabbit, don't you know scooped mids are for kids?

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by hexes » Sat Jun 18, 2022 10:56 am

looking good so far! I have been lucky that i’ve never had to swap OT primaries.

I have a 5f2 shoehorned into a 5f1 chassis and love the 8” speaker, however I built a 5f10 Harvard and thought 10” was absolutely killer on it.

Can’t wait to see the end result. This hobby is the most addicting thing I’ve ever done… All I want to do is build amps.

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by jthomas » Sat Jun 18, 2022 11:39 am

It is an addicting activity. Kind of like building wonderful-loud 3-D jigsaw puzzles. Congrats on the new amp!

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by Paul-T » Sun Jul 31, 2022 7:25 am

Looking good. Really nice lead dress.

I built a tweed F52a with 10" Jensen (all Hammond xformers, 290CAX for PT) during lockdown and it sounds awesome with my JM, probably the best it's ever sounded.
"classic marked down to 20 pence bargain bin fodder'

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by i love sharin foo » Sun Aug 07, 2022 5:50 am

Thanks everybody! It's been all buttoned up for a while now, cab and all. I've been pretty busy lately with other things tugging at my spare time and haven't had a chance to post some finished photos. I aim to resolve that shortly. I reused the old Jensen P10R that I had lying around. During a shipping mishap a couple years ago, the leads were broken off at the cone. I repaired it myself and it does work fine. But it has a ragged buzz at certain frequencies that cam out after all that. I'd like to stick a lower wattage Weber in there one day. It has been a really fun little amp to build and play. The volume is great for home use and it takes pedals really well. Surprisingly, the character of the amp and dirt pedals seems to be present at all times. A lot of times, one tends to take over the other.
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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by MrShake » Tue Aug 09, 2022 3:35 am

I have little of substance to add other than this thread has been a fantastic read, and has me thinking about whether I need a small tube amp like this in my life...

Great work and enjoy that box of rock!

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by hulakatt » Tue Aug 09, 2022 2:13 pm

MrShake wrote:
Tue Aug 09, 2022 3:35 am
I need a small tube amp like this in my life...
I'm just gonna say yeah, you do ;)
She/Her

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by MrShake » Tue Aug 09, 2022 4:10 pm

I have the coolest wife. She listened and agreed with my recent "my 50W amp just isn't cutting it live" rant. She doesn't mind the half-dozen amps in our one bedroom apartment. She plays drums and hunts for deals and supported my recent purchase of not one but TWO heads of indeterminate functionality.

And if I buy* another amp in the next year, she will straight up murder me.

And be totally justified.

(*Free amps and space-savng heads under $75 excepted)

So I will happily live vicariously through other people's project threads like this one.

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Re: I've started a new amp build.. tweed Princeton 5F2-A

Post by hulakatt » Tue Aug 09, 2022 4:34 pm

I hear ya. I'm going through a spell of selling a lot of my gear for various reasons but with some of the leftover funds, I am planning to buy one of Mojotone's new Hiwatt Custom 50 kits and finish the work on my Orange ppc412 restoration.
She/Her

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