Ultraphonix from hell

[rootz]

Those wild guesses come pretty close. It is not a complex amp but it does has loads of room to play with. Switching is especially simple. And dead silent. Really, the bright switches have a very slight pop, but channel switching and boost function not. I hope this scribbled block diagram gives some new insights.

Still not liking the one tube reverb though. There is just not much reverb. Some more tinkering to do.

[Reeltarded]

I love the sound. That thing is a monster!

[bepone]

Yeah, that OT was a very lucky score! So are the NOS Tesla power tubes. I'd love a nice old Schumacher OT, but these are very hard to come by in The Netherlands.

I just build a new reactive load. It is based on the Suhr reactive load, but modelled after my own speakers and cabinets. I added a deep switch that switches the low end resonance from 110Hz to 75Hz.

yes ! one day i will ask, if you have reactive load which sounds good on lover volume why not ?
i have opened my Schumacher, it is a simple build, on paper bobbin (presspan) so probably i will try to copy one in the future

[bepone]

Still not liking the one tube reverb though. There is just not much reverb. Some more tinkering to do.

i dont understand one tube reverb.. what does it mean? if one tube is used for send return, you can use any of european 6V pentode / triodes , good one is ECL86, but also lower numbers will do.
good reverb sound is coming from current passing through the coil, so some output pentode section can be used for drive, triode (on ECL86 mu is 100) for recovery, working nice. reverb feed after first or second half of V1 tube, return enywhere before PI

[rootz]

I love the sound. That thing is a monster!

Thank you very much! Yes, it is! Raunchy when you want, but it does clean up very well with the volume knob on your guitar. I think the centre biasing and interstage signal dumping is in large part responsible for that.

[10thTx]

THANK you for the block diagram showing the topology of the triodes! It is appreciated.

You might try a 12DW7 as your "one tube reverb" and try increasing the cathode caps to 22uf.

Two of my amps have a one tube reverb and I hardly ever have the reverb pot beyond 3 and have all the reverb I need.

With respect, 10thtx

[rootz]

Still not liking the one tube reverb though. There is just not much reverb. Some more tinkering to do.

i dont understand one tube reverb.. what does it mean? if one tube is used for send return, you can use any of european 6V pentode / triodes , good one is ECL86, but also lower numbers will do.
good reverb sound is coming from current passing through the coil, so some output pentode section can be used for drive, triode (on ECL86 mu is 100) for recovery, working nice. reverb feed after first or second half of V1 tube, return enywhere before PI

I think I found the mistake with the reverb. I placed a global master after the reverb mixing stage, just before the PI. This way I could run the clean channel through a resistive divider and loose a clean master on front of the amp. This arrangement works, but loads down the reverb rather much. Would work if there were a triode to recover after the resistive mixers for dry and wet like in virtually any Fender. But there isn't a spare triode left. This reverb arrangement needs the low load of the PI entrance to work correctly.

The plan now: replace the resistive divider of the clean channel with the master pot. The master pot will then become a clean master on the back of the amp. A bit like ODRS #60. Another solution would be to move the presence to the back and put the clean master on front. Still bit of a bummer, I'll miss the global master volume. That is the knob I probably use most on live gigs. But then again, I'd use a Dumbleator too, which could be used as a master volume.

[rootz]

THANK you for the block diagram showing the topology of the triodes! It is appreciated.

You might try a 12DW7 as your "one tube reverb" and try increasing the cathode caps to 22uf.

Two of my amps have a one tube reverb and I hardly ever have the reverb pot beyond 3 and have all the reverb I need.

With respect, 10thtx

I think I've found the reverb problem. The ecc81 is already pushing some good current, so the driver should be up to the task. Gain of the recovery stage is pretty much maxed out. I made one alteration over the standard design Normster gave us: the master after the reverb. That just loads the signal to much. Just need some simple rewiring to do. Biggest culprit: finding some spare time. Another up side of the rewiring will be the bigger signal hitting the PI from the clean channel. That will be much more fun when the amp is running flat out! Now I lose just a tad too much signal before the PI.

[10thTx]

Rootz,

IF you have time and IF you have any availability or interest in sharing ...................... would you please consider editing the attached GIF file to indicate any critical errors and important changes that are needed? Whatever you are comfortable sharing, I would be interested in and grateful for. You could print off the GIF file and make notations/edits and scan it back into the thread (OR use Windows Paint or something similar to make edits).

Again, from your video .......... it seems you have figured out getting superb OD tone at very low volumes. I think that is something many of us have aimed for and perhaps fallen short on. So, I see your build as quite unique, innovative and filling a niche that other designs often miss.

I am very interested in what you have going on for the tone shaping and gain between V1a and V2a? I'm intrigued by that? I can't tell from the photos what might be going on with that?

I've revised the previous posted schematic that I put up on the first page of this thread. Note some changes on this one. I put the voltage divider with a master volume on the clean channel prior to the DPDT. My sense is either the voltage divider OR the master volume would be useful but probably not both?

I did not put a master volume after the DPDT switch because the OD channel essentially has a pot acting as a master volume on that channel already and two in series would seem redundant to me. So there is a seperate MV on both clean and OD channels.

I added a passive FX loop prior to the reverb insertion point. (delay before reverb) I changed the cathode caps on the reverb from 4.7uf to 10uf and 22uf (recovery) and indicated a 12DW7 instead of a 12AT7 or 12AX7. I've successfully added one tube reverbs to quite a few different amp designs and I think the 12DW7 idea is worth trying in my experience using the "12AU7" triode as the send triode and the "12AX7" triode on the recovery side.

There is a 2nd page on the ExpressSCH schematic that has guesses on the PT, B+ power rail and a possible fixed biased approach. All unverified and just wild guesses?

THANK you again for what you have generously shared and given back to the amp building community! Congratulations on a fantastic sounding build!

With respect, 10thtx

[Reeltarded]

Tone control setup.. it's the tone stack.

100k/250p-.02u-.02u. These are common UP values in Fenders. Dale plates in close values. 180/130k are instead 160/120k plates. The Marshallized ODS section is HUGE bypass boost plate and 390p OD1. Both channels into Marshall CF to OD TS.

Do you remember me talking about a single tone control being placed on OD1 and I can't remember who talked about adding tone to OD2 and it being problematic to the overall sound? This amp is a perfect example of why it belongs on the earlier stage. The secret to getting a driven sound at low volumes is treble dump in the circuit and much less gain cut on the OD entrance string. 330p for the channel and the switching driver stage has WAY huge unknown.

This amp is literally reverb and 6 parts different values than my amp's schematic for UP with Marshallized ODS. What Bas did with plate bypass, I handle with slope and Marshall TS pot values. V2a is the second footswitch boost.

Instead of making some new schematic, look at 183 but with UP values clean channel. Add 820R stage driving 100k CF before PI.. You are 95% to this circuit.

[rootz]

I don't know Reeltarded, I ran this amp flat out trough my new reactive load and it sound friggin' huge! It is not specifically designed for the best sounds at low volume and also not to be dark (not that you were saying exactly that, but that could be an implication). But I kept close to Dumble values and I think that is key. Also key: trimmers! I can trim the boost stage, the CF entrance and the mids on the clean. Those trimmers allow you to set, not only the amount of OD, but also how the 3rd triode in the OD channel is hit. That one is unbypassed, so does compress more than it clips hard on the grid. So how much compression do you want? The CF already clips hard with a heavy load (which a tone stack is).

Clean is standard UP values. I had a 470k/470k divider, but replaced it with a 1meg pot. The overall master is gone. Might try a 250k clean volume pot next. I mostly like what heavier loads do. Seems to compress a bit more, or do I hear that wrong?

I have the passive loop behind the reverb. This way the reverb entrance does not get loaded by the Dumbleator output pot.

As to tone shaping. I don't like the standard treble speaker combo's of 470k//470pF. Coupling: I don't like putting a lot of lows and having to add a resonance. Bypassing cathodes: I don't like high value bypass caps. This is where I like to cut low end if needed. 4 gain stages offer a lot of gain and tone shaping possibilities. Use them.

IMHO a 4 gain stage amp should clean up nicely, especially with single coils. Don't cut too much high end, or it will sound muffled. But also don't boost it too much, otherwise your cleanish sounds will be rather brash and raspy.

I'm going to demo this amp to a potential dealer (or maybe not, I don't know) next Saturday. So for the time being I keep the specifics under the bonnet.

And as Bepone said, the vintage Drake 784-139 OT does help a lot. Always loved their sound. But the bit mushy low end and creamy highs is all preamp.

[10thTx]

I'm going to demo this amp to a potential dealer (or maybe not, I don't know) next Saturday. So for the time being I keep the specifics under the bonnet.

Ah OK, understood. I certainly respect that. I am just a hobbyist and was coming from that perspective. THANK you for what you have generously shared. It is appreciated.
If you want or need me to delete what I've posted, just PM me and I'll attend to that.


Reeltarded, I appreciate your offering more direction and definition. Grateful for your help there.

Some of what has made this more difficult to understand regarding the Ultraphoenix aspect is this statement from Talbany :

The UP mod does not exist as any 1 design or 1 amp ..It's a custom mod for a particular customer using a multiple of different circuits

Respectfully, 10thtx

[Reeltarded]

I don't know Reeltarded, I ran this amp flat out trough my new reactive load and it sound friggin' huge! It is not specifically designed for the best sounds at low volume and also not to be dark (not that you were saying exactly that, but that could be an implication). But I kept close to Dumble values and I think that is key. Also key: trimmers! I can trim the boost stage, the CF entrance and the mids on the clean. Those trimmers allow you to set, not only the amount of OD, but also how the 3rd triode in the OD channel is hit. That one is unbypassed, so does compress more than it clips hard on the grid. So how much compression do you want? The CF already clips hard with a heavy load (which a tone stack is)..

Directly, what I observe is the boost stage has a.. coupler value bypass. The common OD1 has a 330p bypass. The cathode driving stage is unbypassed. This is all good stuff! I have a many stage rebuild on a JTM45/T that is a slightly different approach by using multiple bright selections on a first stage that is UP but with a tiny coupler, and a 47k+100k variable slope range. I operate it dirty like you turning on your boost. All stages in.

Every stage has a front panel gain control. I can dime my master and use the last driven stage as a master, or crank that one to 5-6 and use the previous stage as the master.. or similar next earlier stage and when it gets to the input stage with every gain around 5-7 and the treble moderated it's basically a legato volcano. If all stages are moderated (2-4 range) with the first two making all the gain, slope and brights can make the amp do tweed to JTM, convincingly.

I love your amp. When I get my switcher version done I'll put some examples up.. UP!!

[Reeltarded]

Some of what has made this more difficult to understand regarding the Ultraphonix aspect is this statement from Talbany :

The UP mod does not exist as any 1 design or 1 amp ..It's a custom mod for a particular customer using a multiple of different circuits

Respectfully, 10thtx

I have been chasing UP since the first one I heard. The Marshall on Youtube, The Blonde Showman, 3 Deluxes, maybe 7 or 8 Bandmasters.. 3 Bassman heads.

The basic is this for Fenders:

V1a
180k plate
2k7 cathode
25u bypass
.022u coupler

TS is
47k to 100k slope
250p to 500p treble
.022u mid
.002u bass

V1b
130k plate
unbypassed 910k cathode shared with other channel. 1k8 if no second channel.
Coupling value can be .1u, .047u, or .022u. The smaller one sounds better, in my opinion.

470k mixers instead of 270k, usually.

The Youtube Marshall is a /T model. That is the wildest clean sound I have ever heard. Very much like a 4x10 Bassman with volume on 3. The OD section in that amp makes it growl similar to the Showman, Bandmaster, or Bassman heads.. just a lot more.

For ref the Youtube Marshall

[10thTx]

Great information! And the amp in the YouTube sounded beautiful! Amazing tone. Very nice playing also.

Thanks for sharing. It is appreciated.

With respect, 10thtx