Ceriatone HRM 50 Build - HELP NEEDED!!!

[steve_p]

I checked the voltages again - they're still off, so I've decided to redo the wiring aroung the valves.

I'm taking the heater wires out, and want to redo them last "in the air". Anything speak against this? Also, I have some copper non-tinned wire which I'd like to use - is that a problem? Getting the same silicon stuff ceriatone uses could be difficult.

Found another anomaly: the two 22M resistors at V1 aren't very close to 22m - the one off pin 7 is about 18-19M (the reading moves around a lot), the one off pin 6 is about 26M Could this be causing my problems? The 220k is close to spec.

Can I check the voltages without the heater wire connected, or doesn't that make any sense?


Cheers

Es

Good call on taking a step back and re-doing your preamp wiring.
I'm not sure what type of wire Nic ships with his amps, but any wire with properly rated insluation should work.
Most folks use wire with 600V insulation, either PVC or Teflon. Tinned/untinned doesn't really matter.
If at all possible, try to use solid conductor wire for your signal wires. It helps keep the wiring neat. I attached a photo or two of one of mine that shows decent lead dress around the preamp tubes.

Also, don't worry too much about the slightly off readings on those 22m resistors. Most DMMs have trouble making super-accurate readings at such high resistance levels. Your meter may have a +/- 5 or 10% accuracy spec up in that reigion. Couple that with the probably 5% tolerance on the component itself, then those readings don't seem too wacky.

Definitely do your heater wiring last and get them up off the floor, away from any signal conductors.

Good luck!

Steve

[passfan]

The voltage seem all over the place - as others have also told me!
When I measured those voltages an hour or so ago, I also measured 35mV on Pin 6 of V2. I was re-routing some of the wires slightly as they were touching the heater wires, and suddenly I was getting 208V at the same position...




Cheers

Es

This is of concern to me. Pin 6 should be 208 volts as it is a plate pin. The fact it was something else that changed after you moved some wires is indicative of a cold (or bad) solder connection. These will cause the problems you were alluding to with this statement.

When playing quietly, like single notes and picking very lightly, all appears OK. However, if I really pluck the strings hard or play a chord, there is a sudden very loud pop and an increase in volume! I think this is most dominant on the clean channel.
Help! I can't really think of anything to check - I've probably checked the V1 wiring 20 times.

Your solder joints are suspect. Check for and find the loose connection on pin 6 at V2 and then check it out. If still getting loud when you strike a chord hard start at the input and re sweat some joints until it just stays loud. When it gets loud that is the correct level.

[The_Nuge]

Hi!
I spent the last two hours re-soldering everything, starting at V1. And I'm not done yet, so I'll call myself meticulous

Should hopefully get the rest done tomorrow so that I can do some testing!

Cheers

Es

[The_Nuge]

Hi!

So I spent the last 2 days re-wiring the valves with the heaters up in the air, re-using and re-twisting the wire supplies by Ceriatone (yes, I'll post pics tomorrow). Prior to that I'd re-wired the inputs and volume controls, so I was really looking forward to the amp working. Having finished the wiring job, I hoovered the amp out, having first modified the hoover (yes, the wife will probably kill me tomorrow) and then fired it up.
Still got 3.5-4V on pin 7 on V1, so I wasn't expecting much... Got lots of modulated squealing when I plugged in a guitar
About half an hour ago I then found out that I have two defective 12ax7s... A brand new Sovtek 12AX7 WC and an old EH that I had
Put a Tung-Sol in V1 and voila! Everything works, the amp is very quiet (hum-wise) and sounds good!
I have a TAD "high-end" in V2 and a Tube-Town Standard in V3, V4 & 5 are Tube Town 6L6 GC. Would you guys keep it that way? I also have some JJ 6L6 and 12ax7s...

Thanks for all the help you guys provided - I probably wouldn't have finished before Xmas - if at all - without you!

Cheers

Es

[martin manning]

Good show, Es! It's always good to be sure that you have a good working set of tubes installed for start-up and troubleshooting, but not too good, in case there is a melt-down. They are probably the most likely component to be out of spec or failed. It may have worked for you before all the housekeeping, but I'm sure it looks and sounds better now than it would have before.

Preamp tubes will probably give the most variation in tone and noise levels, so I'd recommend rolling through what you have and find a combination that you like. You'll want a quiet tube in V1 (try that high-end there), but sometimes the quietest one does not have the best tone.

[vibratoking]

Congrats on getting it working! Feels good doesn't it?

I would recommend 'living' with the amp for a week or so before rolling tubes, tweaking or anything else really. Play the amp alone and with a band if you can. Get to know it. In my opinion, it takes some time to get a good feel for what the amp does and does not do. Then consider what you might change.

[dcribbs1412]

Congrats
Troubleshooting is a big part of learning...for me anyway
I might be late...but this looks kinda like a 2nd or 3rd Gen build not a HRM
as in title of thread. Anyways thanks for sharing

Darin

[The_Nuge]

Congrats on getting it working! Feels good doesn't it?

I would recommend 'living' with the amp for a week or so before rolling tubes, tweaking or anything else really. Play the amp alone and with a band if you can. Get to know it. In my opinion, it takes some time to get a good feel for what the amp does and does not do. Then consider what you might change.

It does feel good

I'll have another check inside it tonight and have a re-twiddle of the trim pots - then I'll put it in it's cab and play it for a while!

BTW, any idea why Ceriatone recommends biasing these rather cold?

Cheers

Es

[The_Nuge]

Congrats
Troubleshooting is a big part of learning...for me anyway
I might be late...but this looks kinda like a 2nd or 3rd Gen build not a HRM
as in title of thread. Anyways thanks for sharing

Darin

You probably saw the pictures of the "let-yourself-be-inspired-by-the-wiring-in-this-one-amp"! I'll post pictures of mine tonight!

Es

[CHIP]

Congrats on getting it working! Feels good doesn't it?

I would recommend 'living' with the amp for a week or so before rolling tubes, tweaking or anything else really. Play the amp alone and with a band if you can. Get to know it. In my opinion, it takes some time to get a good feel for what the amp does and does not do. Then consider what you might change.

It does feel good

I'll have another check inside it tonight and have a re-twiddle of the trim pots - then I'll put it in it's cab and play it for a while!

BTW, any idea why Ceriatone recommends biasing these rather cold?

Cheers

Es

HAD, AFAIK biased his amps on the cold side. #183 was biased @ 30ma at 465 DVC plate voltage, for EL34 tubes.

[The_Nuge]

Here are some more pictures as promised:

Guts

[img2000]http://niffko.com/g2data/gallery2/d/169 ... C_0037.JPG[/img]

More guts
[img2000]http://niffko.com/g2data/gallery2/d/169 ... C_0038.JPG[/img]

I think the heater wiring came out OK:
[img2000]http://niffko.com/g2data/gallery2/d/169 ... C_0039.JPG[/img]

Sitting along with the Klein-U-Lator on top of my YJM "Quarter Stack" (soory about the pic quality):
[img3008]http://niffko.com/g2data/gallery2/d/169 ... C_0040.JPG[/img]

Et voila!
[img2000]http://niffko.com/g2data/gallery2/d/169 ... C_0041.JPG[/img]

At the moment I've got her running in to one half of the 2x12" with Celestions, as it will be another couple of weeks before I get the 112 D-Style cab done.

I had another quick check before putting the chassis away, and still have a couple of issues:
V3A / V3B: I can't get V3A to be higher than V3B for some reason, even though this was happening a few days ago (Tube Town 12AX7). Mind you, a few days ago the amp didn't actually work very well! Tips would be appreciated!

HRM trimmers: I set those roughly as recommended by Ceriatone: Bass 100K, Mid 12K, Treble 260K - has anyone measured their settings? I found some for the BM, but those appear to be different.

Sound: The clean channel is really nice, but I find that the OD channel lacks "cream" - what should I be looking for here? I've got a TAD 7025 Highgrade in V1 and a Tung-Sol 12AX7 / ECC83 Reissue in V2 - plus the aforementioned Tube Town in V3.

Cheers!

[martin manning]

It has shaped up considerably since the earlier pics! The V3 plate voltage anomaly may be due to a tube in which the two triode sections are not vary well matched. Try another tube in that position and see if the situation changes. What are your plate voltages now on V1, V2, and V3?

[passfan]

Congrats , you just built one of the harder amps to build. I always turned my OD trimmers down to under 50 %. You need to spend time playing it to get a feel for tweaking it. You're actually not done with it yet. Tune your ear to it. Listen to some you tube clips of dumbles and then start tweaking.

[ToneMerc]

Congrats , you just built one of the harder amps to build. I always turned my OD trimmers down to under 50 %. You need to spend time playing it to get a feel for tweaking it. You're actually not done with it yet. Tune your ear to it. Listen to some you tube clips of dumbles and then start tweaking.

10x........I find HRM's to be challenging to say the least. That OD entrance network, LNFB on V1 and the post OD tonestack doesn't help with gain when in OD mode. I also find that voltages on V1 are also critical and it helps to have another hand to tweak the trimmers.

I suggest you roll(leave behind any preconceived notions which brand you think will sound good) through some preamp tubes, documenting V1 and V2 voltages and listening. Once you get a baseline, start tweaking trimmers, for starters.

Your work has just begun.

TM

[Cygnus X1]

Looks great, HNAD!