New build 2nd gen hybrid reverb with high plates on v1

[martin manning]

Very nicely done Erwin!

[talbany]

It's alive!
Sound, drive, FET, PAB loop and reverb is working.
Little video; phasing is the low quality recording, but you get the idea.

Tony

[erwin_ve]

Excellent! I edited your post to fix the 'youtube' linking. It's a bit odd but you just have to use the part after the end of the url, the unique string of characters and nubmers only.

Youtube links come in like 50 million variants, and rather than trying to support them all, this particular just wants you to use the unique part of the video itself.

Sounds like the phone may have done some AGC on on the levels, it had some kind of 'ducking' and compression if I heard right, but otherwise it sounds great! (my guess is that's the phone audio not the amp)

~Phil

Thanks Phil, you mentioned it before but I forgot the workaround.
Yeah low quality phone movie, I do a proper audio recording once my studio is cleared of all the amp stuff.

[erwin_ve]

Erwin,

That's great that sounds like the perfect amp for me I would love an ODS with built in reverb and a built in loop I have a reverb tank from a Deuce sat here

not sure I could re model one of my current amps though.

Do you have any more boards?



M

Marcus,

Thanks!
I have more boards; do you mean for the reverb or PS(which is different for the built in loop) or both? Let me know.

The reverb driver and recovery circuit are both low impedance. That's why it is incorporated in the built in loop. Im not sure how to do that in a passive loop amp besides using really big mixing resistors which may have an impact on the amp tone. Maybe Martin M. has some ideas?

This built has the dlator components all at the tube socket and terminal strip and that is a real pain to solder.
I would do that part different; on the signal board. My first amp has it that way.

[norburybrook]

Erwin,

I see, yes that makes sense.

Had I got a 4 hole chassis from AN I might have done an onboard loop/reverb but I'm not modding a current amp

I'm going to build a little grab and go Princeton reverb type combo in an old chassis I have been given.


Congrats on the build, sounds great


M

[erwin_ve]

Marcus,

Yeah a princeton is very nice! Are you gonna use the peavey reverb tank.
The reverb tank (accutronics) from the peavey amps are even after 45yrs perfect. I've got another one same model; gonna compare them.

Erwin

[norburybrook]

Marcus,

Yeah a princeton is very nice! Are you gonna use the peavey reverb tank.
The reverb tank (accutronics) from the peavey amps are even after 45yrs perfect. I've got another one same model; gonna compare them.

Erwin

Yes, i put one in my Wonderland/JM amp with the Peavey Transformers and it's the best spring reverb I've had hoping this one will be the same. USA made acusonics


M

[didit]

I'm going to build a little grab and go Princeton reverb type combo in an old chassis I have been given.

Princeton can be cool, so long as you upgrade your speaker, output transformer, etc; and add choke to screen supply etc; perhaps also a "mid" control, LTP PI, and more.

Best .. Ian

[norburybrook]

I'm going to build a little grab and go Princeton reverb type combo in an old chassis I have been given.

Princeton can be cool, so long as you upgrade your speaker, output transformer, etc; and add choke to screen supply etc; perhaps also a "mid" control, LTP PI, and more.

Best .. Ian

Ian,

does it then stop being a Princeton?

M

[didit]

I'm going to build a little grab and go Princeton reverb type combo in an old chassis I have been given.

Princeton can be cool, so long as you upgrade your speaker, output transformer, etc; and add choke to screen supply etc; perhaps also a "mid" control, LTP PI, and more.

Best .. Ian

Ian,

does it then stop being a Princeton?

M

Depends on your faceplate logo. No?

Having aided/abetted tweaks for upgrading a few, the B+ mods (choke too) & speaker are most critical. Personal taste for the LTP—vs cathodyne, but does require another triode. If one does that by foregoing tremolo, gives space for “mid” and perhaps other knobs.

.i

[norburybrook]

Princeton can be cool, so long as you upgrade your speaker, output transformer, etc; and add choke to screen supply etc; perhaps also a "mid" control, LTP PI, and more.

Best .. Ian

Ian,

does it then stop being a Princeton?

M

Depends on your faceplate logo. No?

Having aided/abetted tweaks for upgrading a few, the B+ mods (choke too) & speaker are most critical. Personal taste for the LTP—vs cathodyne, but does require another triode. If one does that by foregoing tremolo, gives space for “mid” and perhaps other knobs.

.i

I want spring reverb and tremolo

I need to fix my tweedle dee first that's gone pop!! never had that before. Anyway we should stop derailing Erwins thread


Erwin...back to you mate


m

[erwin_ve]

No problem Marcus. It's positive forum interaction, nothing wrong with that.
I"ll take it from here

Ive done some measuring. B1 is 442v, the dropping string in the ps, between b3 and b4 is a 24k. This leads to a 170v on v1 tube plate and 180v on the v2 plate. A bit low to me. Dropping 24k resistor is gonna be 22k.
Biased the output tubes at 35mA. Maybe going at bit hotter.
The master clean volume has a 47pF silver mica bypass cap, which make the clean sound a bit steelstringsinger alike, especcially with the high plates on v1.
The built in loop recovery pot has a 150pF ceramic cap. The amp is still bright that way, as being without a loop, but still smooth. 270pF was too much on that spot.

Frontplate is a vinyl sticker. It is the most economic solution. Downside is that edges come loose, not pretty. My plan is to have a alu anodized printed fronplate.
Backplate had the same thing but is out of sight so gonna leave it that way.

[norburybrook]

No problem Marcus. It's positive forum interaction, nothing wrong with that.
I"ll take it from here

Ive done some measuring. B1 is 442v, the dropping string in the ps, between b3 and b4 is a 24k. This leads to a 170v on v1 tube plate and 180v on the v2 plate. A bit low to me. Dropping 24k resistor is gonna be 22k.
Biased the output tubes at 35mA. Maybe going at bit hotter.
The master clean volume has a 47pF silver mica bypass cap, which make the clean sound a bit steelstringsinger alike, especcially with the high plates on v1.
The built in loop recovery pot has a 150pF ceramic cap. The amp is still bright that way, as being without a loop, but still smooth. 270pF was too much on that spot.

Frontplate is a vinyl sticker. It is the most economic solution. Downside is that edges come loose, not pretty. My plan is to have a alu anodized printed fronplate.
Backplate had the same thing but is out of sight so gonna leave it that way.

Erwin,

You can hear the chime in the video, i like it with a strat on the clean that high plate thing really works. I think i messed around with hybrid highlow plates but didn't get it to work. You seem to have hit the sweet spot with this build.

I've used vinyl stickers and if you get the right quality of vinyl it's fine it won't lift. The first 3 amps i made still going strong with the vinyl stickers. You need to specify 'Hi tack' and it wont lift.

M

[erwin_ve]

Marcus,

Good to know on the vinyl Hi Tack thing. When I visited the shop the emlpoyee shouted to the back: "Do we have some vinyl left?
Yeah hybrid High-low seems to work well with this 2nd gen tonestack.

[norburybrook]

Marcus,

Good to know on the vinyl Hi Tack thing. When I visited the shop the emlpoyee shouted to the back: "Do we have some vinyl left?
Yeah hybrid High-low seems to work well with this 2nd gen tonestack.

Indeed it does. I seem to remember i experimented with this on a Bluesmaster 50w combo build but went back to stock except for LNFB on V1 on a switch.


I have a 2nd gen amp......i could experiment......mind you i don't have separate OD/Clean volumes though as it's a full on #40 2nd gen.

M