I'm building an amp with big bottles.

ezietsman · 2015-10-09T11:11:33+00:00

? I don't have all the parts yet so this thread will not be moving that quickly yet. I also have to finish my planning and design. I'm taking a classic 1960...

I'm building an amp with big bottles.

psyx

Very pretty EZ! I love how this thread turned out! Inspiring indeed. I think I need to build mine in 2016.

Hasie

I can't remember if you've mentioned it previously. Which class design is this amp?

ezietsman

Hasie wrote: I can't remember if you've mentioned it previously. Which class design is this amp?

I don't understand what you mean. It's a fixed-bias, push-pull, class AB amp with a long-tailed pair phase inverter, like almost every Marshall. Is this what you wanted to know? I've used almost the exact same circuit as the famous 1968 Superlead Mr Van Halen used on THAT album ?

Hasie

ez wrote:
Hasie wrote: I can't remember if you've mentioned it previously. Which class design is this amp?
I don't understand what you mean. It's a fixed-bias, push-pull, class AB amp with a long-tailed pair phase inverter, like almost every Marshall. Is this what you wanted to know? I've used almost the exact same circuit as the famous 1968 Superlead Mr Van Halen used on THAT album ?

Thanks. Yhat's what I wanted to know. I was wondering if it's A or AB. Thank you for clearing that up. Should have known that, as class A amps tend to be lower output and have a single power tube.

ezietsman

psyx wrote: Very pretty EZ! I love how this thread turned out! Inspiring indeed. I think I need to build mine in 2016.

Thanks a lot. I just need to have some logos made to finish up this one (and the other Marshall clones I've built). It is well worth building your own amp. This amp is probably only about a 35 Watt amp with the valve rectifier and maybe 40 Watt or so with the diode rectifier and it is much much too loud without the attenuator, for just about any purpose except using it as a very clean (and loud, it is loud on 1 already) amp. Keep that in mind when you choose what to build.

I have put maybe 10 hours on it by now. It sounds to me like the hissing is decreasing a bit, the hum too, maybe it is just quieter now that it is in the headbox or maybe the valves are a bit more noisy when they're brand new. I'm going to wait until I fit a choke and then I'll re-evaluate the noise. For an amp that literally shakes the floors, having noise as loud as the acoustic sound of an electric guitar is probably not bad (only really that loud when the amp is on 10). The hiss is the loudest part but I'm inclined to leave it be for now. I can always replace the preamp's carbon comp resistors with carbon films, which should make the hiss dissappear almost completely.

Norman86

it looks great dude

ezietsman

I recorded another clip, with my Tokai Breezysound (50s spec Tele) this time.

Amp settings:
Presence: 5
Bass: 2
Middle: 8
Treble: 8
Volume 1: 11 (plugged into high input)
Volume 2: 2 (jumpered into high input)

Amp was set to use the Bass Tonestack, Solid State rectifier and high negative feedback

My JJ GZ34 has given up already. I think the plates are loose inside, I can hear rattling when I shake the tube. I blow the mains fuse when I use it so I guess it is shorting out. They are apparently not very reliable.

Norman86

really nice! hopefully you can get the last gremlins sorted and rock on out!

ezietsman

OK here's some more fun and games.

Firstly, a clip with my Tokai 335. Amp was set to Bass tonestack, high negative feedback and solid state rectifier. I used the speaker impulses again, 4x12 cabinet with G12M and U87 mic.

Secondly, Singemonkey came to try out the amp and while he was playing I was poking around the back of the amp and I noticed this, which I call it the "Mordor effect":

This, it seems, is the screen grids of the KT66 glowing brighter when the amp is pushed hard, as they draw more current. I then did some research and realised that I left out a resistor in my amp. I was working from two different schematics (3 actually) to make this amp. The 50 Watt JMP amps had (back in the day) no resistors on the screen grids of the EL34s. The valves in those days were very robust and cheap, so Marshall didn't bother with limiting the screen current. The JTM45 however, had a 1k resistor then a 470R resistor to each KT66 screen grid. Modern 50 watt reproductions uses a 1k resistor on the screens to limit their current, because modern valves are not that robust. I, however, only installed the 470Rs so my screens are only seeing 470Ω resistance to the screen supply. I think they're pulling too much current and are glowing too much. I'm going to replace the 470Ω resistors with 1kΩ resistors and see if that lessens this effect.

G-Man

A lteast troubleshooting sounds like you're having fun. Hope you figure it all out

ezietsman

OK, so I increased the screen stopper resistors and now the glowing isn't as pronounced. I deem that part fixed now.

The first choke I received had a short, so they sent me a new one. It arrived today. Here it is

I've been playing this amp for a couple of months now. It is pretty great. We've been using it as the bass amp at rehearsals and it works a charm for that also (set to Bass Tonestack and high negative feedback). I don't think it'll have enough volume for gigging with bass though. Maybe, but it will likely be a dirty sound }?

Also ordered two G12M Creambacks. Yay!

lapdawg

Good news! Now you can close the door on that issue.

Also pleasing to see that ClassicTone redeemed themselves - I like their quality & value.
Did they pay for everything? Was there any resistance from them?

ezietsman

lapdawg wrote: Good news! Now you can close the door on that issue.

Also pleasing to see that ClassicTone redeemed themselves - I like their quality & value.
Did they pay for everything? Was there any resistance from them?

They took a week or two to reply after new years but they sent the new part free of charge, I only had to pay VAT.

Now I can wire my amp so that the valve rectifier is always in the circuit, so I can safely use those yummy NOS ones I got from Shaunf and also install the choke so my plexi can be legit.

rikus

Lovely! Enjoy the finished product. Always nice when a thing is done done and not just done enough.

The amp build bug has bitten hard. My main amp looks like it's gone. It started blowing fuses recently (even with all the valves pulled). These Egnaters unfortunately have a bad reputation for blowing transformers... still busy troubleshooting, but not feeling optimistic.

I've been drooling over a Deluxe Reverb since forever and I'm seriously contemplating a kit build now given what the exchange rate has done to new prices (and the fact that those things never seem to pop up second hand)...

Anyway, I'm ranting... lovely build, congrats on getting it done. Enjoy! ?

ezietsman

Rikus wrote: Lovely! Enjoy the finished product. Always nice when a thing is done done and not just done enough.

The amp build bug has bitten hard. My main amp looks like it's gone. It started blowing fuses recently (even with all the valves pulled). These Egnaters unfortunately have a bad reputation for blowing transformers... still busy troubleshooting, but not feeling optimistic.

I've been drooling over a Deluxe Reverb since forever and I'm seriously contemplating a kit build now given what the exchange rate has done to new prices (and the fact that those things never seem to pop up second hand)...

Anyway, I'm ranting... lovely build, congrats on getting it done. Enjoy! ?

?

I played my friend's homebuilt Princeton reverb this weekend. He built it on an Elk chassis and got a new Accutronics reverb tank. That thing is BAWS. Lush cleans and way tighter and rocking overdrive when cranked than my 5E3. I could easily gig one as is, just like I did with my 18 watt Marshall clone.

I'm sure you can fix the Egnater (or have it fixed).

rikus

ez wrote: I played my friend's homebuilt Princeton reverb this weekend. He built it on an Elk chassis and got a new Accutronics reverb tank. That thing is BAWS. Lush cleans and way tighter and rocking overdrive when cranked than my 5E3. I could easily gig one as is, just like I did with my 18 watt Marshall clone.

I'm sure you can fix the Egnater (or have it fixed).

Cool, that's an interesting observation on the comparison with the 5E3 (which is the other obvious diy circuit if you think Fender). Looks like I'm heading down the right path with the BF circuit.

I'll definitively look into what's needed to fix once I've figured out where it's going pear shaped with the Egnater...

funkadelic

Wow! One hell of thread! Awesome stuff! The sound clips sound juicy.

guitarboy2828

Just spent a good few minutes/hours reading through this thread from start to finish, what an inspiration! Well done EZ!!

ezietsman

Paul E wrote: Just spent a good few minutes/hours reading through this thread from start to finish, what an inspiration! Well done EZ!!

Thanks a lot man.

Wizard

ez wrote: I played my friend's homebuilt Princeton reverb this weekend. He built it on an Elk chassis and got a new Accutronics reverb tank. That thing is BAWS. Lush cleans and way tighter and rocking overdrive when cranked than my 5E3. I could easily gig one as is, just like I did with my 18 watt Marshall clone.

I've also got a Princeton Reverb approximation fashioned from a box with Elk on it.
I also needed to replace the reverb tank.
It sounds amazing.