Tube Amp Network | Mark | Activity https://tubeampnetwork.com/members/lesag002/activity/ Activity feed for Mark. Thu, 08 Oct 2026 12:41:02 +0000 https://buddypress.org/?v= en-US 30 hourly 2 e78594b3e4365739b5fba2816944de40 Mark replied to the topic Voltages too high in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/voltages-too-high/#post-8531 Thu, 16 Feb 2023 17:03:18 +0000 Hi Brian.  I don’t recall.  I haven’t touch the amp in years.  I’ld have to get it back on the bench to find out.  All I know is it’s working fine, though the overdrive isn’t as saturated and smooth as I would like.  My bench is in total disarray right now, so I’m not sure when I’ll be able to get it back on the bench to test it.

]]> 0 12daa17a19a087979cd97007d38a2a70 Mark replied to the topic Hammond PT for a Two-Stroke (Rev 2) Amp? in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/hammond-pt-for-a-two-stroke-rev-2-amp/#post-8340 Fri, 03 Apr 2020 01:07:20 +0000 Just chiming in on this old thread to confirm the 290AX works fine. I just swapped the AES 022772 PT that I used initially for the Hammond 290AX to try to compensate for the high line voltage at my house (125VAC), which was presumably resulting in a pretty high B+ of 425VDC with the AES PT. To get the B+ down, I used the 275VAC secondary…[Read more]

]]> 0 7a845220c16d2d2c53db575456721a2f Mark replied to the topic Volume and tone pot not working in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/volume-and-tone-pot-not-working/#post-8339 Thu, 02 Apr 2020 18:50:18 +0000 SOLVED!! The pots were, indeed, bad. They weren’t passing any signal at all! Replaced them with new Bourns pots. Everything works perfectly. I knew the problem wasn’t me wiring, confirmed it by tracing the layout and schematic ala Hoffman’s simple first step for troubleshooting. Highly recommended!

http://el34world.com/Forum/index.php?topic=17701.0

]]> 0 34cbbfda7c67d953f2a1c5b7371eea19 Mark replied to the topic Volume and tone pot not working in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/volume-and-tone-pot-not-working/#post-8337 Sun, 29 Mar 2020 02:55:07 +0000 Image attached.

]]> 0 8d28cffcec457e283da643add2f94fa4 Mark replied to the topic Volume and tone pot not working in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/volume-and-tone-pot-not-working/#post-8336 Sun, 29 Mar 2020 02:52:30 +0000 I don’t know Andy. I’ve looked this thing over and over and over again. I’ve looked at the wiring of other people’s builds too. I don’t see anything wrong this (see pic). The preamp start ground is highlighted by a green circle. The buss wire is an unnecessary paranoid addition because I was afraid that maybe the pots weren’t contacting the…[Read more]

]]> 0 c0630b22d967519bcef4cc83cdd576a8 Mark replied to the topic Voltages too high in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/voltages-too-high/#post-8324 Thu, 19 Mar 2020 21:28:24 +0000 The different rectified DC voltages are from different tubes, 427VDC with a 6L6 plugged in, 435 VDC with a 6V6 plugged in. Sorry, forgot to mention that. Also, yes, two 100ohm resistors are attached to ground for an artificial center tap.

Ok, so I used a different meter and got 5.5 VAC on pin 2 and 3.2 VAC on pin 8. Why on earth my other meter…[Read more]

]]> 0 230e5c4fbfe3fd771e26c7f795646f6f Mark replied to the topic Voltages too high in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/voltages-too-high/#post-8322 Wed, 18 Mar 2020 20:21:55 +0000 Yes, 5Y3, new production Sovtek from Hoffman Amps.

C1= 20uf/500v
C2= 16uf/475v
C3= 8uf/450v

Input voltage = 124vac
Red = 352vac each
Green = 3.4vac each
Yellow = 0vac, ?? it reads 435vdc each, same as at C1

The spec for this PT (from AES) is 120vac primary, 325vac secondary, 6.3vac green, 5v yellow (AC or DC?). Is the 352v secondary reading…[Read more]

]]> 0 51841497e7a289afcc6d9cf7e2b5ed1b Mark replied to the topic Confused about power tube in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/confused-about-power-tube/#post-8321 Tue, 17 Mar 2020 17:10:04 +0000 So, again, here are the specs for the Classic Tone OT:
http://www.classictone.net/40-18031.pdf

Since this OT is limited to either a 5 or 8k primary, and I have it wired up with the 5k primary, I need to figure out which secondary tap/speaker load combination matches the white wire tap on the 125ESE. So, if I use the 4ohm tap on the Classic Tone…[Read more]

]]> 0 fe8c9822418d02bd75fe691c976dbcab Mark started the topic Voltages too high in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/voltages-too-high/ Tue, 17 Mar 2020 16:04:03 +0000 So, I’m getting 427, 381, and 249 volts at each of the filter cap terminals (C1, C2, C3, respectively), which is too high according to the book. I tried a different rectifier tube (brand new 5AR4) and got higher values (e.g. 440 on C1). I’m seeing 165 and 145 volts at pin 1 and 6, respectively on the 12AX7, which is in normal range IIRC. How do…[Read more]

]]> 0 401c7c871fd2d32a225629ae6baca2bb Mark replied to the topic Power Tube Connections in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/power-tube-connections/#post-8317 Tue, 17 Mar 2020 15:54:44 +0000 Got it. Thanks!

]]> 0 c0ba626300ad6807e3d8d2911d0f33bc Mark replied to the topic Confused about power tube in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/confused-about-power-tube/#post-8316 Tue, 17 Mar 2020 15:53:16 +0000 I’m using the Classic Tone OT. I think I’ll go ahead and wire up an impedance switch after all. I would really like to try all of those tubes. I’ll have to figure out which wires to use.

]]> 0 47fd6d03c7736eb68cbfa595d7f2510f Mark replied to the topic Volume and tone pot not working in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/volume-and-tone-pot-not-working/#post-8315 Tue, 17 Mar 2020 15:49:02 +0000 Thanks Andy. I guess I’ll check for the 10th time. I’ll post a pic if I don’t see anything.

]]> 0 5ccaef61ef0d5211a4d2938d4ac307f7 Mark replied to the topic New Build in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/new-build/#post-8308 Mon, 16 Mar 2020 02:47:29 +0000 Looking great!

]]> 0 79b10b0a187995c68371330aac9ab0de Mark started the topic Volume and tone pot not working in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/volume-and-tone-pot-not-working/ Sat, 14 Mar 2020 01:01:20 +0000 So, I’ve got the amp together and it sounds pretty damn good! The only problem is the volume and tone pot aren’t working right. Even with the volume all the way down, it’s still pretty loud, and turning up the volume doesn’t increase the loudness much. The tone pot doesn’t do anything at all. I swear things are wired correctly, I’ve checked it…[Read more]

]]> 0 ece7e21c8093a64490c3992cb1024b02 Mark replied to the topic Power Tube Connections in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/power-tube-connections/#post-8300 Fri, 13 Mar 2020 18:55:31 +0000 One other question. Why does the layout show connections to pin 1 and 6 when those pins don’t even exist and are not referenced in the schematic?

]]> 0 1c9ebe63ba571c5668bb378e9cc661ea Mark replied to the topic Power Tube Connections in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/power-tube-connections/#post-8299 Thu, 12 Mar 2020 23:56:43 +0000 Thanks. Makes sense. Thanks for the link, I hadn’t been to Aiken’s site in years.

]]> 0 7aadeb177eb8ae62ee2d3ee79fc9ce7f Mark replied to the topic Power Tube Connections in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/power-tube-connections/#post-8298 Thu, 12 Mar 2020 21:35:19 +0000 I have the 2015 version of the book that only shows 1 6V6GT tube. It’s wired differently from the TAN layout on this website. I’ll try to scan the layout and post it.

]]> 0 2691b94bfbfb50cb370cbd9ccecbc376 Mark started the topic Power Tube Connections in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/power-tube-connections/ Thu, 12 Mar 2020 21:19:47 +0000 Can someone explain the difference between the output tube wiring in the book layout (from the revised book showing only one output tube) and the revised layout on the TAN website? That is, why are they different? Is the book layout incorrect?

Also, I followed the book’s parts list and got the 1k 2W resister that connects to pin 4 in the book…[Read more]

]]> 0 51d297ac800d6a9b690fcf17c225921f Mark replied to the topic Transformer confirmations in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/transformer-confirmations/#post-8293 Wed, 11 Mar 2020 02:12:46 +0000 Also, how many watts should those 100ohm resisters be?

]]> 0 e0c1a6c64b6edd76d3f213bdbcb69a29 Mark replied to the topic Transformer confirmations in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/transformer-confirmations/#post-8292 Wed, 11 Mar 2020 02:12:00 +0000 Thanks again Tan! Sorry, I guess I don’t understand what a center tap is. I’ll wire the green pair as you say.

There is no green/yellow wire on this PT. There’s a green pair, red pair, yellow pair, black pair, and a red/yellow. I on the book layout, it shows the green/yellow in parentheses “(green/yellow)”. I assume that means that a…[Read more]

]]> 0 d62d56963c32c110070b8967f974c640 Mark replied to the topic Transformer confirmations in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/transformer-confirmations/#post-8289 Sun, 08 Mar 2020 21:21:53 +0000 To be clear, I’m referring to the filament supply to the pilot lamp, 6V6, and 12ax7. It’s only 2A.

]]> 0 6d9ea98af439b2794e6f6789d6c91295 Mark replied to the topic Transformer confirmations in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/transformer-confirmations/#post-8288 Sun, 08 Mar 2020 21:15:48 +0000 So I just realized that the PT is actually the one from Antique Electronic Supply, the one that is listed in the book along with he Mojo and Weber ones. I looked up the specs on it and it says it has a 2A filament supply instead of 4A, like the others. The book specifically refers to the filament having a 4A spec. So, is 2A going to be enough?…[Read more]

]]> 0 a129c4f4c570ded2de9a05f9cce6eebc Mark replied to the topic Transformer confirmations in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/transformer-confirmations/#post-8286 Sat, 07 Mar 2020 23:17:15 +0000 Thanks again Tan! So the input impedance should be 5Kohm then right, if I’m using the blue and brown leads? The secondary looks like it’s just a matter of matching the speaker impedance. In my case, I’m using a 6V6 output tube and 5Kohm primary impedance on the OT, and an 8ohm speaker. So the I should use the black and green secondary wires…[Read more]

]]> 0 707451e58a290a17aeaf83858425f3e8 Mark replied to the topic Transformer confirmations in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/transformer-confirmations/#post-8284 Sat, 07 Mar 2020 17:28:13 +0000 To be clear, the Classic Tone is the OT 😉

]]> 0 5e9d85e6cab632bf2b816b3af775ef05 Mark started the topic Transformer confirmations in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/transformer-confirmations/ Sat, 07 Mar 2020 17:27:34 +0000 I’m using a Hammond TF22772 PT and Classic Tone 40-18031. Can someone confirm that the color scheme in the layout matches these transformers? It appears the red and grey on the OT are not used, correct?

Thanks!

]]> 0 2b1eb4c9248202f361563280e4257a75 Mark replied to the topic Confused about power tube in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/confused-about-power-tube/#post-8282 Sat, 07 Mar 2020 16:50:59 +0000 … with an 8ohm speaker.

]]> 0 ae25ce94bca512db654e644159241f61 Mark replied to the topic Confused about power tube in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/confused-about-power-tube/#post-8281 Sat, 07 Mar 2020 16:49:32 +0000 Thanks Tan! I only have 8ohm speakers on hand, so I was just going to hardwire it with a single output jack for an 8ohm speaker. So, I guess I can only use 6V6 for now. Is there a mod I could do so I can use 6L6 or EL34 with a single tube socket and single output jack?

]]> 0 278d0d0e4d59e850a9a280608fcb1cc5 Mark started the topic Confused about power tube in the forum 2 Stroke Amplifier Design and Building https://tubeampnetwork.com/forums/topic/confused-about-power-tube/ Fri, 06 Mar 2020 20:30:40 +0000 I’m getting ready to build the two-stroke (sourced my parts myself from Hoffman) and going over the “Notes and Updates” document and the layouts. The Notes and Updates refers to the power tube being a single 6L6 but the layouts I have show a single 6V6. Am I missing a more recent layout that’s available somewhere?

Thanks

Mark

]]> 0 712bd6b2a3037447b4d72e6831389bc2 Mark became a registered member https://tubeampnetwork.com/activity/p/4661/ Fri, 06 Mar 2020 19:51:57 +0000 0