The shielded cable off wiper of the volume pot took care of the noise. The line out wire was replaced with shielded cable too.

I tried putting in a switch to compare the stock plate resistor values with B15-nc values. The B15-nc values sound deeper to my ears. I think it?s worth listening to the different plate resistor valves.

Regards

Mark

Thanks for your reply. However a noise gate won’t help the Aunt Peg. Most of the noise is getting into the amp is from the wiper of the volume pot. Coax cable on the wiper of volume control is removing a lot noise. The small chassis makes the layout of the amp harder.

Regards

Mark

Previous advice from Nik.

I'd perhaps try a shielded wire for the line out, and lift it away from the heaters, AND the NFB wire going to the impedance selector.

Or, pin 1 of the PI comes from volume pot, through a 470K resistor.

Perhaps run shielded wire from pot, place 470K direct on tube socket, as well.

I usually don’t find noise there, but the position of the OT primary wires, in relation to the power tube grid wires, are critical. Perhaps play with these positions as well? Try to lift the grid wires (J and K) a bit, and see how it reacts?

The advice from Nik was effective and I appreciate the lengths he went to in assisting me.

Great advice from Nik.

Mark

As for the noise, I happened to have aunt peg today.

I was testing with JJ 6SL7s, and they were quiet.

BUT, I then tested with some NOS Russian 6sl7 equivalent, and it was pretty noisy. In fact, some of them even made the amp buzz a lot to the point of vibrating!

So the tubes really matter, especially at the V1 slot. The V2 (PI) slot doesn’t seem to matter that much.

The JJs were carefully selected. They are not perfect, some did come noisy but I weeded them early. NOS also seems to work very well, almost all NOS 6SL7s of good pedigree were problem free tested with the Aunt Peg.

Here's some things that really help:

1) You can DC reference the heater center tap. You can take the DC reference at the PI node, and use like 330K to drop it into 10uF/160V resistor paralleled with 68K resistor.
This helps!

2) The 470K resistor going into PI from volume pot.
  Change this to smaller, even like 1K, and tie direct at tube socket. From volume pot, use shielded wire to this resistor.

3) Tried separating grounds, didn’t help as much as above.

Hope this helps, let me know...

Thanks!

Nik

Re: Ceriatone Aunt Peg issues
I tried isolating the preamp/P.I. stage earth connections from the output stage earths and I didn’t hear any significant difference. I put a 270pF silver mica cap across the plates of the P.I. stage and that made a bit of difference, but nothing significant. I shorted out the 470K grid stopper to the P.I. stage as it would enable me to earth the input to the grid of the P.I. stage, I had dead silence when the input is earthed, when I turned the volume up the hum/noise reared its head, thus the issue has to be with the input to the P.I. stage (pin 1 of the 6SL7 valve.)
The other changes might have had an effect as I thought I tried earthing the input to the P.I. grid before, I could be wrong though.

Regards

Mark

I bought my brother an Aunt Peg in 2020 as he plays bass and is a fan of the old Ampeg tones.

I should start with saying that I like Nik putting rare and exclusive amps into the hands of players for a reasonable price. I’m a fan of Nik’s amps, friends and techs have seen them and liked the tones and quality of the amps. However, that’s doesn’t mean I shouldn’t address any shortcomings.

The Aunt Peg amp is a lot of fun and sounds great. What doesn’t sound great is the noise levels. From day one it had greater noise when in cathode bias mode than fixed bias mode. There are a few differences between modes, firstly the 6L6’s are passing 42mA in fixed bias mode as opposed to 60mA in cathode bias mode. To eliminate this as a possibility I temporarily biased the fixed bias to 60mA’s. It made no difference in noise levels. The earth connection for cathode bias is on the preamp earth connection, which I found a little questionable. I moved the cathode bias earth to the same location as the fixed bias and that made no difference to the noise whatsoever.

There are a few other high current earths on the preamp node such as the centre tap of the power transformer HT secondary, centre tap of the heater, earth connection of the bias supply, earth connection of the first filter caps in the supply. I moved many of these to the output earth node and heard little difference in noise levels.

While in a high gain amp this would be fatal, it will work in a low gain amp such as the Aunt Peg. I was wondering if any Aunt Peg owners have experienced this sort of thing.

Nik offers great customer service and promptly gave me advise almost immediately. I have been working through this advice. Though as previously stated the earthing is of concern to me.

Please let me know if your thoughts.

https://www.valvewizard.co.uk/Grounding.html

Regards

Mark

To attempt to answer your question the transformers set will determine how the amps will sound. In the early days of the 18 watt forum this was a topic of discussion.
I have an early Mercury 65 Amps transformer set in my 18 watter and it’s quite jangly and has strong mids when pushed. I don’t know if this was the transformer set use in 65 Amps production amps.

If I have criticism of the transformer set, it is that it could have more bass response. It’s adequate with a Les Paul, but a bit lacking with a Strat.

I hope that’s of some assistance.

Regards

Mark

Agreed, which clips.

 Tim Caswell's latest amps with the MIDI stuff is interesting. DIY will have to lift their game. 😃

Mark

I suppose the question remains how accurate is this amp?

I have seen a few other circuit diagrams floating around and Nik's version does look a little different.

I imagine trying to find any info on these amps is near impossible.

Mark

Pictures?

Dear Guys

I'm wondering if you can tell me of the location and size of the holes to mount the stock 18 watt chassis to cab?

I'm having a 2 X 12" cab built and I want to make sure that I tell the builder the correct location of the holes so it is just so easy to bolt the chassis to the cab.

Thanks in advance for all your assistance.

Yours Sincerely

Mark Abbott

Dear Wolfgang

That should sound pretty good as you are also able to get PI distortion. The only down side of that style of master volume is, speaker dampening and presence control operation are effected.

The one meg master volume pots prior to PI effect clean tones and the bass rolls off on low master volume settings.

How are you finding it's operation?

Yours Sincerely

Mark Abbott

What does the master volume circuit look like?

Yours Sincerely

Mark Abbott

Thanks for the reply Jack. In regards to the tone sensitive thing I am referring to distorted tones, I have found I always have had greater control over an amp with my guitars volume control with a valve amp than a transistor amp.

Fender transistor amps and a Sansamp come to mind here. Of course this is a generalisation and there are bound to be amps that break this generatisation, but this is what I have experienced.

I wish you hadn't mentioned the Peavey Bandit, I use to play with a guy who used a Peavey Bandit, I hated the sound he got out of that amp!

When I think of lush transistor amps I think of the Roland JC-120, though the distortion and reverb (from memory) left something to be desired.

That is a shame about Pritchard, if you are going to make a solid state Fender, well you are wasting your time, why not simply buy the valve Fender?
He really needs to go beyond what he has already done. I was very curious about his PRS amp, but.....

Yours Sincerely

Mark Abbott

So what were the quirks?

From my experience you can get good tone from a SS amp or even a good pedal for that matter, but for me, I think the touch sensitive thing just isn't there with SS amps.

It is a funny thing to describe. I should point out that I am not a die-hard valve guy and I do own a Guitarport as it is very convenient, but it doesn't sound like an amp no matter how loud I turn up the monitors,

I have found with a good valve amp, it sounds good at nearly any setting.

Anyway tell me more about the Pritchard amp?

How does the Overtone compare to it?

Yours Sincerely

Mark Abbott