What's in the pipeline for Amp projects?

[mountainhick]

I've got bassman ot laying around that I've been wanting to do a Blackvibe - based bass amp with. I seem to recall someone running a thread about one of those in the not so distant past.

yep

Bass Amp idea??

One obvious thing to try would be a negative feedback loop back to the PI. You could basically copy the NFB from any BF type Fender as a starting point, and why not use a temporary pot in the loop to determine a resistor value that works best. Just as an experiment, I'd be tempted to try and...

www.tdpri.com

 

[Peegoo]

I've got a vintage Eico integrated amplifier, running three 12AX7s and two EL84s with an EZ81 rectifier. I'm going to convert it for guitar.

There's some surgery necessary (cut out the selector switches, all but one input jack, etc.), so I'm modifying the schematic and I'll use that as my road map. I'll tweak the tone stack for guitar; the original Tape Out jack (J5) will become a line out. I'm also adding a fuse and a three-wire mains.

Here's the schematic in progress, with some more butchering necessary.

 

[mountainhick]

I've got a vintage Eico integrated amplifier, running three 12AX7s and two EL84s with an EZ81 rectifier. I'm going to convert it for guitar.

There's some surgery necessary (cut out the selector switches, all but one input jack, etc.), so I'm modifying the schematic and I'll use that as my road map. I'll tweak the tone stack for guitar; the original Tape Out jack (J5) will become a line out. I'm also adding a fuse and a three-wire mains.

Here's the schematic in progress, with some more butchering necessary.

I've got to get cracking on an HF-87 refurb, with possible conversion to HF-89 (fixed bias). For Hifi, not guitar!

 

[mk_716]

Vibro champ, reverberocket, low voltage Harvard and a rh-84 stereo on deck.

The list changes while I work other things, some Vox thing might sneak in. I'm interested building something in the brown/blond family too, kinda waiting to see how the Harvard turns out...

Some talented peeps on this board, beautiful work!

m.

 

[Lancer X]

Thanks for the support. Best to you too! Anemia sucks.

What's you mod list now for the 5F6a?

This girl is mostly @robrob's Micro Bassman design, with a few of his other 5F6A mods shoehorned in, plus some additions per other TDPRI users.

The platform:
* EF-80 pentode push-pull power section making about 3.8W output
* 10" Weber AlNiCo in a custom Princeton Reverb combo cab
* LTP phase inverter
* EZ81 rectifier

The mod list:
* Channel 1 is normal 5F6A Bassman
* Channel 2 is @robrob's Plexi-esque "Lead" voicing
* Signal can be sent to either/both channel - mix and match via volume pots
* push-pull normal/bright switches on both channels
* Gain boost switch (approximates a 12AX7 in V1 a la JTM45)
* 3-way negative feedback switch (5F6A / JTM45 / none)
* @King Fan artificial elevated center tap
* Type-2 master volume
* post-preamp output volume (pre-phase inverter)

 

[Dan Miller]

Just got the parts (almost all of them) for an Uncle Doug Supro Tremo-verb and am just about done prepping the chassis.

Also need to get back to my Princeton Reverb and Ampeg B15n builds....

 

[FXBDM 1832]

And now I have just realized that a 5e4-a is really not that far from a 5e3 if you have the real estate (which I do) and that I have 90% of the part to convert mine… maybe I will just make a parts kit in a ziploc and finish the 5e3 build and see if I like it or if I want something else.

 

[Jerry garrcia]

glad you are in remission and hope it lasts! That disease can really break you down mentally and physically, and monetary if you live in that kind of a country.
For amps:
1) BR-3 with all metal octal tubes
2) B15-NC
3) a 5F2A with 6SL7 and probably parallels 6K6’s
4) Rob’s Stereo amp with 6SL7’s
5) now it’s getting hard. I want to build a sort of GA-20/30 but with only plate cap tubes and probably 807 output tubes. Just for the eyes
6) a vibro champ with octals (never built me a tremolo circuit)
7) a 5F2A with 6SL7 and an EL34.

During my projects I will be building a couple of the SE 6SJ7, 6SN7 and 6L6 for some musicians that liked the tone of it. A thread somewhere.

Will also need to learn how to recone a speaker and learn the basics of the field coil speaker. And finish some guitars including a couple of 6 string cigar box guitars. And combine that with work, family, sleep, social life, drinking and training.

 

[Lingwendil]

5F2A with 6SL7 and an EL34 sounds fun!

Eventually I'll do a 6SL7 6V6G 5F2A for that all-octal charm.

Another idea on the opposite side of the coin is an all russian 6n2p and 6p43p-e 5F2A.

 

[leewongfei]

I have a ton of parts for another 5e3. First, I need a new eyelet board, and after a great deal of frustration, here is the before and after.

I have acquired about 4 different 5e3s from people who messed up their builds.

 

[tele_savales]

I made a probably misguided decision to go over this amp for my buddy, for my cost in parts. I've never seen much less worked on anything anywhere near as complex. I've been tracing the circuit from the schematic for days, as it hasn't arrive yet. It's a Unique 26R. Basically close to a Magnatone 460. Unknown if it even works, but it looks completely untouched and there's no signs of catastrophic failure.
True vibrato w varistors, transformer-less reverb, all kinds of interesting stuff.

 

[Jerry garrcia]

5F2A with 6SL7 and an EL34 sounds fun!

Eventually I'll do a 6SL7 6V6G 5F2A for that all-octal charm.

Another idea on the opposite side of the coin is an all russian 6n2p and 6p43p-e 5F2A.

“Unfortunately” I have to many tubes of the non-Russian kind. Have also considered an 2x6sq7 + 6K6 for a higher gain home practice amp

 

[FXBDM 1832]

I am vacillating between a high gain practice amp and a reverb unit for my 6k6 radio pull. I will be interested in your build.

 

[mountainhick]

And now I have just realized that a 5e4-a is really not that far from a 5e3 if you have the real estate (which I do) and that I have 90% of the part to convert mine… maybe I will just make a parts kit in a ziploc and finish the 5e3 build and see if I like it or if I want something else.

No first hand experience with the Super, but they look significantly different to me!

 

[mountainhick]

glad you are in remission and hope it lasts! That disease can really break you down mentally and physically, and monetary if you live in that kind of a country.
For amps:
1) BR-3 with all metal octal tubes
2) B15-NC
3) a 5F2A with 6SL7 and probably parallels 6K6’s
4) Rob’s Stereo amp with 6SL7’s
5) now it’s getting hard. I want to build a sort of GA-20/30 but with only plate cap tubes and probably 807 output tubes. Just for the eyes
6) a vibro champ with octals (never built me a tremolo circuit)
7) a 5F2A with 6SL7 and an EL34.

During my projects I will be building a couple of the SE 6SJ7, 6SN7 and 6L6 for some musicians that liked the tone of it. A thread somewhere.

Will also need to learn how to recone a speaker and learn the basics of the field coil speaker. And finish some guitars including a couple of 6 string cigar box guitars. And combine that with work, family, sleep, social life, drinking and training.

Thanks Mr garrrcia,

All of the above, but things have been on the upswing health wise. Might last a while, might not...

That's a LIST! for sure.Looking forward to seeing your progress.

 

[mountainhick]

I made a probably misguided decision to go over this amp for my buddy, for my cost in parts. I've never seen much less worked on anything anywhere near as complex. I've been tracing the circuit from the schematic for days, as it hasn't arrive yet. It's a Unique 26R. Basically close to a Magnatone 460. Unknown if it even works, but it looks completely untouched and there's no signs of catastrophic failure.
True vibrato w varistors, transformer-less reverb, all kinds of interesting stuff.

Project an a half!

I am going to do a point to point soon, but the layout looks simpler than that. Looks hard to work on with components layers deep.

 

[mountainhick]

I am vacillating between a high gain practice amp and a reverb unit for my 6k6 radio pull. I will be interested in your build.

In the same package or either/or?

Thanks for reminding me about on board reverb. I was going to build a couple console radio deconstructions into octal GA-40 style amps, but already have decided to retask a different project because of the scrounged PT voltage/amperage to a GA-40 channel, a 12AY7 channel with PP-6AQ5s, a bit less than 6V6s.

Maybe make one or both of those old consoles into single channel with reverb!

 

[FXBDM 1832]

No first hand experience with the Super, but they look significantly different to me!

Looking at the schematics side by side, everything up to the V1 coupling Caps is the same, the coupling caps and everything up to the gain stage right before the PI (v2a on the Deluxe, V3a on the super) is different. the gain stage after the tone stack and the PI are the same (except feedback which I already installed on the 5e3 and the bypass cap on the gain stage) and the power stage is the same except with fixed bias. The main difference is the tube and tone stack in between those blocks. Power supply has a choke instead of the first voltage dropping resistor, and slightly higher voltages (my current B+1 is at 335 and the schematics I have for the super gives 385, but I can switch my rectifier tube to get some of that back) Since I am doing ptp and using a radio chassis, that’s not a very complex thing, looks like. I would just add a tube socket next to the pots. I think you might have just talked me into it.

 

[FXBDM 1832]

In the same package or either/or?

Thanks for reminding me about on board reverb. I was going to build a couple console radio deconstructions into octal GA-40 style amps, but already have decided to retask a different project because of the scrounged PT voltage/amperage to a GA-40 channel, a 12AY7 channel with PP-6AQ5s, a bit less than 6V6s.

Maybe make one or both of those old consoles into single channel with reverb!

Either or. I have a small radio pull with octal tubes and a 6k6 power section. Either I make it an AX84 something or a 6g15 clone.

 

[mountainhick]

Looking at the schematics side by side, everything up to the V1 coupling Caps is the same, the coupling caps and everything up to the gain stage right before the PI (v2a on the Deluxe, V3a on the super) is different. the gain stage after the tone stack and the PI are the same (except feedback which I already installed on the 5e3 and the bypass cap on the gain stage) and the power stage is the same except with fixed bias. The main difference is the tube and tone stack in between those blocks. Power supply has a choke instead of the first voltage dropping resistor, and slightly higher voltages (my current B+1 is at 335 and the schematics I have for the super gives 385, but I can switch my rectifier tube to get some of that back) Since I am doing ptp and using a radio chassis, that’s not a very complex thing, looks like. I would just add a tube socket next to the pots. I think you might have just talked me into it.

I thought you initially were comparing it to the 5E3 as similar. Not really important, I just misunderstood. So indeed, something different than a 5E3.