Tube Amp Network | Robin | Activity

Robin replied to the topic Does 290AX need an artificial center tap? in the forum 2 Stroke Amplifier Design and Building

Sat, 07 Jan 2023 18:15:54 +0000

You can use the 6.3v center tap (green & yellow) to ground OR the 2-100 ohm resistors as an artificial center tap, but not both. Good luck, enjoy.

Robin replied to the topic High(er) Voltage in the forum 2 Stroke Amplifier Design and Building

Fri, 06 Aug 2021 17:13:09 +0000

I have NOS 5Y3s that output 50 volts lower right out of the box compared to a new manufacture 5Y3 or a SS rectifier. I put a 1/2 power attenuator in all my 2Stroke inspired builds these days and it works well, allowing you to dime the amp (for tone) and have an output of around 2 watts. It’s still loud though 🙂

Robin replied to the topic Impedance Switch Question in the forum 2 Stroke Amplifier Design and Building

Mon, 21 Sep 2020 16:23:45 +0000

Hi Jordan, I use the carling switch for that, Antique Electronics # P-H494, You might also consider a Carling 3 position switch P-H520 to add a Mute/Standby function to the On/Off switch. It’s a great way to add that switching option without having to drill another hole in the chassis and adding another switch.

Robin uploaded a new picture: 86 special 2.jpg

Sat, 06 Jun 2020 00:11:48 +0000

Robin replied to the topic 2 Stroke component question.. in the forum 2 Stroke Amplifier Design and Building

Sat, 06 Jun 2020 00:08:01 +0000

I can’t tell from the component board because the leads are on the back but it looks like it goes to the power tube socket as the cathode bias resistor, bypassed by that cap next to it. All my 2Strokes have a 500r/ 10w resistor bypassed with a 25uf/ 50v cap. The attached photo shows my very first 2Stroke layout, it works great.

Robin replied to the topic squeal when at high volumes in the forum 2 Stroke Amplifier Design and Building

Fri, 05 Jun 2020 23:32:58 +0000

I agree with Andy, it’sounds like it might be parasitic oscillation. Can you post a photo of the whole chassis? Pushing the leads around with a chopstick might reveal a problem.

Robin replied to the topic Squeal in my 5B6 in the forum 2 Stroke Amplifier Design and Building

Thu, 21 Feb 2019 02:39:46 +0000

That will do it, with a squeal in a new build or OT replacement, that’s the first thing to check.

Robin replied to the topic Help with voltages and possible signal grounding in the forum 2 Stroke Amplifier Design and Building

Thu, 21 Feb 2019 02:37:57 +0000

Did you find a six for your amp?

Robin replied to the topic "Best" or good 12" speaker for a stock Two Stroke in the forum Speaker Talk

Thu, 21 Feb 2019 02:27:44 +0000

Jensen Falcon Jet 12. Eminence Cannibals Rex is good too but from what you said, I’d try the Jensen Falcon Jet.

Robin replied to the topic Modding the boost/voice switch in the forum 2 Stroke Amplifier Design and Building

Mon, 22 Oct 2018 01:05:38 +0000

Here’s the schematic for the switchable rectifier, build it on the back of the rectifier socket, using the 4 unused lugs. 1N4007 diodes work great.

Robin replied to the topic Modding the boost/voice switch in the forum 2 Stroke Amplifier Design and Building

Mon, 13 Aug 2018 16:19:06 +0000

Greetings,
You could try changing the cathode bypass caps (C8 & C9). Remember you’ll have halve or double the value of the cap to hear an appreciable difference. You could also try lowering the plate voltage on the preamp tube to get a bit less headroom and add more grind. Also, you could easily add a solid-state full-bridge rectifier. It’s…[Read more]

Robin replied to the topic Novice tube amp webinar offered in the forum General Amplifier Discussion

Thu, 02 Mar 2017 20:16:07 +0000

I hope some of you were able to enjoy the free 4 week “introduction to tube amps”, webinar hosted by Gerald Weber, it was really good with a lot great info shared.

Robin replied to the topic Novice tube amp webinar offered in the forum General Amplifier Discussion

Thu, 02 Mar 2017 20:16:07 +0000

I hope some of you were able to enjoy the free 4 week “intoducition to tube amps”, webinar hosted by Gerald Weber, it was really good with a lot great info shared.

Robin replied to the topic Novice tube amp webinar offered in the forum General Amplifier Discussion

Thu, 02 Mar 2017 20:16:01 +0000

I hope some of you were able to enjoy the free 4 week “intoducition to tube amps”, webinar hosted by Gerald Weber, it was really good with a lot great info shared.

Robin replied to the topic Novice tube amp webinar offered in the forum General Amplifier Discussion

Thu, 02 Mar 2017 20:15:53 +0000

I hope some of you were able to enjoy the free 4 week “intoducition to tube amps”, webinar hosted by Gerald Weber, it was really good with a lot great info shared.

Robin replied to the topic Novice tube amp webinar offered in the forum General Amplifier Discussion

Thu, 16 Feb 2017 17:01:32 +0000

February 16, 2017, Tonight is the third “Tube Amp Webinar for the Novice” meeting presented by Gerald Weber. Last week there were over 90 attendees. Tonight night Gerald will discuss the different sections of a Fender Princeton circuit and explain how each one works and how they go together. The Power Supply, Preamp Section and Output section…[Read more]

Robin started the topic Novice tube amp webinar offered in the forum General Amplifier Discussion

Fri, 10 Feb 2017 00:09:39 +0000

Gerald Weber is offering a free tube amp webinar for the novice for the next few weeks. Here’s the message from Gerald:

Here is the registration email for the free webinar I am hosting. You are invited to attend for FREE.
Free Webinar Hosted by Gerald Weber on Every Thursday in February for those that are wanting to learn how the electrons are…[Read more]

Robin replied to the topic My Two Stroke build, blogged! in the forum 2 Stroke Amplifier Design and Building

Tue, 07 Feb 2017 17:54:48 +0000

Looking good! I can’t see your grounding scheme from the photos but isolating the power supply grounds from the input/preamp side will help keep the amp quiet. Run the grounds from the filter caps to the power supply side of the chassis, maybe to a lug on one of the power transformer mounting screws. And the preamp grounds together on the…[Read more]

Robin replied to the topic Power Tranny Problems? in the forum 2 Stroke Amplifier Design and Building

Tue, 07 Feb 2017 17:42:31 +0000

Follow the instructions in this link: http://www.geofex.com/ampdbug/pwrtrans.htm
It is possible that the PT is blown but it’s also possible that it’s something else in the power supply, a bad tube can cause damage to other components. When a fuse blows, it’s not because the fuse went bad, use the light bulb current limiter you built when you…[Read more]

Robin replied to the topic Testing Different Tubes in 2 Stroke in the forum Tube Talk

Wed, 20 Apr 2016 12:50:23 +0000

From time to time, the question of how to get more headroom with a Two Stroke comes up.
As the Two Stroke design is very much in the vane of a “black face” style amp, it’s never going to be as clean as some other designs. But the new Tung-Sol 7581A may offer a significant delay in the onset of breakup and provide a cleaner tone at higher…[Read more]

Robin posted a new activity comment

Sat, 23 Jan 2016 17:50:56 +0000

Hi Steven, welcome the the TAN site.
The schematic and layout posted in the Wiki section are better for building the kit. Note that the three circles marked 1M on the layout are actually 2 1 meg pots (Volume and Tone) and the other circle represents the input jack with a 1 meg resistor across the two outside terminals (assuming the input jack…[Read more]

In reply to - Steven became a registered member

Robin changed their profile picture

Mon, 17 Aug 2015 23:56:38 +0000

Robin changed their profile picture

Mon, 17 Aug 2015 23:55:24 +0000

Robin uploaded a new picture: 86 amp x 2 front sm…

Mon, 17 Aug 2015 23:54:30 +0000

1-12", EL-84 cathode biased, 12AX7 preamp with EF-86 overdrive stage.

Robin replied to the topic Amplifer design books in the forum Amplifier Design and Construction

Mon, 17 Aug 2015 23:46:25 +0000

Hi tubessence, Welcome to TAN! One of Marlin’s books is now out of print, I think it’s the Designing Power Supplies… title, but much of the content of the books is posted on his website: http://www.valvewizard.co.uk/
His books are great. As you already know, Dave Hunter’s book The Guitar Amp Handbook is super too, my personal favorite for…[Read more]

Robin replied to the topic Amplifer design books in the forum Amplifier Design and Construction

Mon, 17 Aug 2015 23:46:25 +0000

Robin started the topic New TAN site forum test in the forum General Amplifier Discussion

Wed, 05 Aug 2015 21:24:09 +0000

This is my first post to the new site. Thanks for getting it up and going Andy. The photo is my first TwoStroke, built to DH’s book specs, except I used a turret board instead of a eyelet board for the components. It’s still going strong.

Robin started the topic New TAN site forum test in the forum General Amplifier Discussion

Wed, 05 Aug 2015 21:24:09 +0000

Robin started the topic New TAN site forum test in the forum General Amplifier Discussion

Wed, 05 Aug 2015 21:24:09 +0000

Robin started the topic New TAN site forum test in the forum General Amplifier Discussion

Wed, 05 Aug 2015 21:24:09 +0000

This is my first post to the new site. Thanks for getting it up and going Andy

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Tue, 02 Jun 2015 04:19:30 +0000

Remember that both of these designs are based closely on a Fender Tweed Champ (5E1/5F1)circuit. Fender never put a Grid Stopper resistor on the power tube of the Tweed Champ but Dave Hunter added one (which is a good idea). You can find more info here: http://www.valvewizard.co.uk/gridstopper.html

The cathode bias values are the same on both…[Read more]

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Tue, 02 Jun 2015 04:19:30 +0000

The cathode bias values are the same on both…[Read more]

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Tue, 02 Jun 2015 04:19:30 +0000

The cathode bias values are the same on both…[Read more]

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Tue, 02 Jun 2015 04:19:30 +0000

The cathode bias values are the same on both…[Read more]

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Tue, 02 Jun 2015 04:19:30 +0000

The cathode bias values are the same on both…[Read more]

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Sat, 02 May 2015 20:34:27 +0000

I have not used a 6V6 that much, after trying a number of different tubes, I pretty much stick with a good 6L6. The Two Stroke has surprising volume, I added a 1/2 power switch to mine so I could dime it and still have reasonable stage volume (using it as a monitor and mic-ing it into a house system).

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Sat, 02 May 2015 20:34:27 +0000

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Sat, 02 May 2015 20:34:27 +0000

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Sat, 02 May 2015 20:34:27 +0000

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Sat, 02 May 2015 20:34:27 +0000

Robin replied to the topic Two Stroke vs. Maggie power tube circuit in the forum Effects Design and Construction

Thu, 30 Apr 2015 08:57:17 +0000