Point to Point Wreck?

[bcmatt]

I'm wondering if there is anyone on here who has (gasp!) made a Liverpool or Express pure Point to Point.

I'm not deluded enough to say that it is at all better, but I'm wondering how it went, if attempted.

I'm building a T-Rex (for brother-in-law), and Express(for Joe) and a Liverpool (for me), but I am still waiting for the eyelet board material that I ordered from Watts Tube Audio(turretboards.com). It looks like cool stuff, but it's been over a month and still hasn't arrived. I have everything else waiting for me to start, and I wonder if it got lost in the mail.
Would I break every law in the universe to try Point to point on a Wreck?
I think I might try it with the T-Rex since that is supposed to be a Christmas gift and I am running out of time left to work on it. I suppose that wouldn't be as sacrilegious as the other two anyways.

Anyone know any other good places to find board material and a staking tool? If I have to re-order, I don't want to be victim of the same internet scam twice (if that is possibly what happened).

[fzfwyv]

lastwinj....where are you?

[bcmatt]

lastwinj....where are you?

I'm in the South Eastern Corner of British Columbia, Canada. I got everything shipped to Eureka Montana, and I drive over the border to pick them up (makes all shipping way cheaper and faster).

[jjman]

Mine's PTP but not a pure Express schematic. It's still evolving. (Pic is a few generations ago.)

https://tubeamparchive.com/viewtopic.ph ... highlight=

If you want a pure Express it's probably "better" to go with the standard approach. This way you have the world (and this group) as a reference for every possible issue.

If you're adventurous and like to do things your way, and don’t want to clone, I’d definitely like to see another PTP build.

There’s a lot of extra stuff on mine that’s not needed for an Express circuit (Trem, PPIMV, separate cathode bias adjustors)

[bcmatt]

Mine's PTP but not a pure Express schematic. It's still evolving. (Pic is a few generations ago.)

https://tubeamparchive.com/viewtopic.ph ... highlight=

If you want a pure Express it's probably "better" to go with the standard approach. This way you have the world (and this group) as a reference for every possible issue.

If you're adventurous and like to do things your way, and don’t want to clone, I’d definitely like to see another PTP build.

There’s a lot of extra stuff on mine that’s not needed for an Express circuit (Trem, PPIMV, separate cathode bias adjustors)

Hey! Very Cool! I do remember seeing that thread now, I guess I just didn't search the right words today when trying to find it. I think you are giving me the guts to try at least the T-Rex like that. I'd be interested to see some more gut shots from other angles to get a better idea of your style on how you spaced your wires and such. This will be my first full amp of P2P. Did you have to do any mods due to hum, or did things seem to work pretty well in that regard?

[rooster]

Call Ken, if you used Paypal something is fubar.

As to the point to point thing, very cool thought. Frankly, to do it with a typical chassis would require a total reboot on the layout - and I see where jjman kinda went for this. On the other hand, RJ is doing a tweed Fender type chassis and is maybe getting to something chassis-wise that is more do-able. Have either of you considered this type chassis?

Well, more power to you cats. I think the layout is king with this build, however that is not to say that it can't be improved upon. I am spending more time with this notion than a PTP build, FWIW. .............But you might surprise us all, carry on.

[jjman]

Mine's PTP but not a pure Express schematic. It's still evolving. (Pic is a few generations ago.)

https://tubeamparchive.com/viewtopic.ph ... highlight=

If you want a pure Express it's probably "better" to go with the standard approach. This way you have the world (and this group) as a reference for every possible issue.

If you're adventurous and like to do things your way, and don’t want to clone, I’d definitely like to see another PTP build.

There’s a lot of extra stuff on mine that’s not needed for an Express circuit (Trem, PPIMV, separate cathode bias adjustors)

Hey! Very Cool! I do remember seeing that thread now, I guess I just didn't search the right words today when trying to find it. I think you are giving me the guts to try at least the T-Rex like that. I'd be interested to see some more gut shots from other angles to get a better idea of your style on how you spaced your wires and such. This will be my first full amp of P2P. Did you have to do any mods due to hum, or did things seem to work pretty well in that regard?

I'll be opening her up again soon to play with the power resistors. I need a little higher voltage on my PI to make the 6v6s clip before the PI. I’ll take some more pics. I’m also gonna try to add a parallel effects loop for reverb/delay units. Currently placing these types of effects in front does really work properly.

I spent much time contemplating and drawing the initial layout before starting. No hum and no layout related issues. One “mistake” I made was to point the bell of the power tranny towards the tubes. (It’s not a lay down type.) My trannies are 90degrees towards each other but I didn’t know the hum inducing bad stuff comes directionally out from the PT’s bells. Got lucky though since it doesn’t hum.

I used a chassis that’s larger than needed. 3” tall 17” long. It’s Hammond and a standard thickness which is pretty thin at that size. Since my trannies are on the corners there’s not much sagging.

I may do the VVR thing after I get the PI running better and succeed or fail with the parallel loop. I would VVR only the 6v6s since I have trem. But I need to learn about VVR before I can take that step. At least I have plenty of room for it.

[jjman]

Working on the PI voltages today so here are the pics:

[img960]http://home.comcast.net/~jjsant3250/DSCF40005.JPG[/img]

[img960]http://home.comcast.net/~jjsant3250/DSCF40003.JPG[/img]

[img960]http://home.comcast.net/~jjsant3250/DSCF40001.JPG[/img]

[img960]http://home.comcast.net/~jjsant3250/DSCF40002.JPG[/img]

[bcmatt]

So, I am now visiting my parents in their town along with my sister and brother-in-law (who gets this T-Rex). My Father and I are finishing off the cabinet today.
Anyways, I don't think this really counts as pure point-to-point, because I can imagine much shorter distances between some components, but didn't want to change too drastically from the grounding style that I know.
I will just continue to wait endlessly for my turretboard to arrive from Ken Watts and USPS before I start my Liverpool or my friend's Express. I don't want problems due to my impatience. I don't see any advantage to this terminal strip mess that I create.

Anyways, maybe I could be helped on this issue of a high-pitched squeal when the amp is turned up. I am fine when I use the VVR to any significant degree, but running the amp without it almost guarantees this thing to lose control. Flipping the NFB switch can be helpful. It's slightly safer in one position than the other.

Possibly significant details:
The ground from OT goes to output jack, which is grounded right where the VVR is grounded/ first Filter caps are grounded.
The NFB switch is on the front panel to fill the hole where an MV knob would be. A red wire goes from the 8 ohm connection on the Lorlin to the front NFB switch. Does length matter on that? Should it be shielded or something?

So, any ideas how I can solve this? I'm including a few pictures. Here's a link to the schematic:
http://mhuss.com/18watt/schematics/18wTRex.pdf
[/img]

[stubbyfex]

This is my first post, and my first TW Express. Being an amp tech/owner
of a repair shop for over 25 years, I thought I would try my hand at a point to point Express. I used terminal strips, with Sozo caps and regular carbon comp resistors. I mounted the terminal strips all in a row, close to the tube sockets. The biggest problem I had was the output transformer's lead dress. By moving the primary wires close at all to the phase splitter wires would cause extreme hiss, and very loud hum. It was a real eye opener to me. I guess the TW gain is such that lead dress is very very important. If I move the chassis around, sometimes the leads shift positions, so I'm considering using glue like Ampeg did in their early amps to keep the leads in one place.
I'd also like to thank all you folks for the wonderful advise you give people here on this forum. I believe that knowledge should be shared, and that by doing so, we all get closer to that perfect tone we all are searching for![/i]

[swarty]

One thing to consider with these PTP builds is the flexibility to put the V1 an inch or so from the input jack. This makes the whole lead dress issue almost disappear.