36W Turretboard Layout

Double-Bubble! Place for discussing the 36W version...

Moderators: CurtissRobin, colossal, zaphod_phil, Daviedawg, Graydon

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

0 x

User avatar
JMPGuitars
Super Duper Admin
Super Duper Admin
Posts: 3954
Joined: Tue 09/18/12 8:00 pm
Location: South Central, MA
Contact:

Re: 36W Turretboard Layout

Post by JMPGuitars »

crgfrench wrote:
Mon 08/10/20 7:04 pm
Some build Pix
https://photos.app.goo.gl/WCrKAMyZXRyYhsV26
Put up a gallery here: galleries/
1 x
'I installed a skylight in my apartment yesterday... The people who live above me are furious.' - Steven Wright

Modern Ground Schemes
Soldering Technique
B+ Voltage Reduction
Amplifier Tools & Parts Info


Web Design: DolceVittoria.com
Guitars / Amps / Effects: JMPGuitars.com
(anti)Social: Facebook · Instagram
Items for Sale

geoff 1965
Verbose poster
Verbose poster
Posts: 1118
Joined: Mon 01/04/16 3:52 pm

Re: 36W Turretboard Layout

Post by geoff 1965 »

awesome build Craig! attention to detail is superb and good to hear it sounds great as well, your'e friend is a lucky man!
1 x

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

JMPGuitars wrote:
Mon 08/10/20 7:41 pm
Put up a gallery here: galleries/
Done; thanks Josh I didn't know the site even had galleries!
1 x

User avatar
JMPGuitars
Super Duper Admin
Super Duper Admin
Posts: 3954
Joined: Tue 09/18/12 8:00 pm
Location: South Central, MA
Contact:

Re: 36W Turretboard Layout

Post by JMPGuitars »

crgfrench wrote:
Mon 08/10/20 9:45 pm
JMPGuitars wrote:
Mon 08/10/20 7:41 pm
Put up a gallery here: galleries/
Done; thanks Josh I didn't know the site even had galleries!
Ha, check out the Archive gallery too. There's a TON of stuff in there.
1 x
'I installed a skylight in my apartment yesterday... The people who live above me are furious.' - Steven Wright

Modern Ground Schemes
Soldering Technique
B+ Voltage Reduction
Amplifier Tools & Parts Info


Web Design: DolceVittoria.com
Guitars / Amps / Effects: JMPGuitars.com
(anti)Social: Facebook · Instagram
Items for Sale

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

Honey dripping off a hot buttered biscuit.
1kHz into the TMB channel, controls at 1/2 ("noon") and MV cranked. Measured at the FX loop send.
20200814_002633.jpg
You do not have the required permissions to view the files attached to this post.
0 x

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

Here is a summary of my build process
https://m.youtube.com/watch?feature=you ... y7GnsaEYJY
3 x

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

Here are the final voltages annotated on the schematic
36WschematicVoltages.png
You do not have the required permissions to view the files attached to this post.
0 x

Daviedawg
Superior Amp Tech
Superior Amp Tech
Posts: 748
Joined: Fri 01/08/10 2:00 am
Location: Scotland

Re: 36W Turretboard Layout

Post by Daviedawg »

Just for information in case it is useful. The Orange TH30 I have been repairing also switches the output impedance from 16 ohm to 8 ohm when it switches the cathode bypass to two valves from four.

Dd
1 x

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

Updated process video with some final build pix:
https://m.youtube.com/watch?feature=you ... 62g#dialog
0 x

User avatar
Bieworm
Verbose Moderator
Verbose Moderator
Posts: 2287
Joined: Mon 02/10/20 8:24 am
Location: Belgium

Re: 36W Turretboard Layout

Post by Bieworm »

Craig.. how is the sound on 18 watt mode? Does it differ from an 18W or is it very good?
I would like to adapt this on a tremolo TMB ...but 36w and 18w switchable
0 x
"THIS should be played at high volume..preferably in a residential area"

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

To my ear, in half power mode it's identical tone-wise but a few dB quieter. I gave it to its owner before doing any speaker A/B testing or demo recordings but I'm hoping to have him record some demos for me.

I did use a matched quad and the bias resistors are 75+75 Ohm so I would expect it to sound similar in 18 and 36 watt mode, as it does. Ceriatone uses 68+62 Ohm bias resistors so there might be a touch different sound if you built one that way.
0 x

User avatar
colossal
Moderator
Moderator
Posts: 450
Joined: Thu 05/10/07 2:00 am
Location: Moving through Kashmir

Re: 36W Turretboard Layout

Post by colossal »

Did you notice any more headroom and apparent punch/grunt, girth, and/or depth (e.g. more 3D, broader, more reverby) in 36W mode?
0 x

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

Nope. It's pretty identical. I do get more headroom when I turn on the NFB switch though. I voiced my Normal channel like a Tweed Deluxe and my TMB channel like a Plexi, so the cleanest setting is plug into the normal channel and switch NFB ON. Dirtiest setting is plug into TMB channel, dime volume and switch NFB OFF ( & set MV to desired loudness). Punchiest/girthiest is plug into TMB Hi gain jack, jumper TMB Lo gain jack to Normal Hi Gain jack, leave NFB OFF and use all 36 Watts.
1 x

User avatar
Bieworm
Verbose Moderator
Verbose Moderator
Posts: 2287
Joined: Mon 02/10/20 8:24 am
Location: Belgium

Re: 36W Turretboard Layout

Post by Bieworm »

Thx craig for the info!

My plan is to mostly play on 18w mode. I'm thinking about making both EL84 pair separately on-off switchable. That way I can alternately use one pair so they wear off the same. It's going to be a single channel amp anyway. For clean mode I'm thinking about a switch to lift the cathode caps from the 2nd preamp stage..
1 x
"THIS should be played at high volume..preferably in a residential area"

User avatar
colossal
Moderator
Moderator
Posts: 450
Joined: Thu 05/10/07 2:00 am
Location: Moving through Kashmir

Re: 36W Turretboard Layout

Post by colossal »

crgfrench wrote:
Sat 09/12/20 11:04 pm
Nope. It's pretty identical. I do get more headroom when I turn on the NFB switch though. I voiced my Normal channel like a Tweed Deluxe and my TMB channel like a Plexi, so the cleanest setting is plug into the normal channel and switch NFB ON. Dirtiest setting is plug into TMB channel, dime volume and switch NFB OFF ( & set MV to desired loudness). Punchiest/girthiest is plug into TMB Hi gain jack, jumper TMB Lo gain jack to Normal Hi Gain jack, leave NFB OFF and use all 36 Watts.
Thanks for the tone report, Craig. That's interesting. Reason I ask, is that a lot of guys report a sense of more apparent weight, if you will, with the same preamp, but into a 4xEL84 power amp versus 2xEL84. An AC15, for example, does not sound or feel the same as an AC30. Of course there is the volume difference, larger output transformer, and pushing a second speaker will spread the sound out a bit more so that's not quite an apples to apples comparison.
1 x

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

colossal wrote:
Sun 09/13/20 8:08 am
...An AC15, for example, does not sound or feel the same as an AC30. Of course there is the volume difference, larger output transformer, and pushing a second speaker will spread the sound out a bit more so that's not quite an apples to apples comparison.
True. Plus, the Vox circuits are different. e.g., the AC30 Top Boost uses a shared 1k5 + 22/25 on the first tube's cathodes whereas the AC15 has a 1k5 + 22/50 on one triode and a 6k8 with no cap on the other triode. plus quite a few other differences. So I would expect an AC15 to sound different from an AC30. On the other hand, switching to half power in my 36W is the exact same circuit and components, so I would expect it to sound very similar yet quieter when going to 18W.
2 x

User avatar
Bieworm
Verbose Moderator
Verbose Moderator
Posts: 2287
Joined: Mon 02/10/20 8:24 am
Location: Belgium

Re: 36W Turretboard Layout

Post by Bieworm »

Is the bigger Iron (PTx and OTx) not giving a different sound on 18 watt mode than the regular 18w Iron gear?
0 x
"THIS should be played at high volume..preferably in a residential area"

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

Bieworm wrote:
Sun 09/13/20 11:36 am
Is the bigger Iron (PTx and OTx) not giving a different sound on 18 watt mode than the regular 18w Iron gear?
That is a good question! Unfortunately I could only speculate as I have no way to make a direct comparison. The 36W OT is Heyboer HTS7717 from GDS, while the 18W OTs I have used have all been Heyboer HT6135 from Mojotone. PT also from GDS here, vs the 6179 from Mojo.

The way to test this would be to swap in the 18W iron and run the amp at 1/2 power. That would be an interesting test. Can't happen here with this particular build, since it's already delivered to its owner. However I have (almost) enough parts kicking around to actually do that with another amp. That won't be happening this year, for sure, as I'm back on an 18W Fullerwell build now (using a Drake 784-103 OT repro from Chris Merren). But perhaps after that? ...
0 x

User avatar
crgfrench
Frequent poster
Frequent poster
Posts: 827
Joined: Fri 04/27/18 3:02 am

Re: 36W Turretboard Layout

Post by crgfrench »

geoff 1965 wrote:
Tue 07/14/20 4:22 pm
give us some feedback on that effects loop when it's finished
Quick note on the FX loop: The original board worked great (switching FX in & out), but was causing strange randomly intermittent volume spikes and drops as well as nasty noise that sounded like "radio station hiss between stations". I removed it from the amp and examined it closely, and found that the cathode leg of C5 was not soldered into the board, just sitting there dry in the via. I contacted Saul, who was awesome and sent me a replacement board immediately. While waiting for the new board, I soldered the cap leg myself and reinstalled the first board, but unfortunately there must have been some other issue too as the noise issues persisted. I pulled the board again, and because the owner had been waiting 3 months at that point offered to deliver him the amp sans FX loop (the 3 months was caused partially by a 1 month delay of the pink tolex thanks to the USPS but that's another story); he wanted the amp so I delivered it with the promise to install the new FX loop when it arrived. Well it arrived quickly, but the guy can't stop playing the amp long enough to give it up for a day! So someday hopefully soon I'll get it back and install the new loop board for him. In the meantime he's plugging into the High gain British channel jack, sending to his pedalboard from the Lo gain British channel jack, and taking the return into the High Gain American channel jack. This gives him a wet/dry control via the volume controls on each channel. But it is an "all front-end" solution, vs the buffered loop between the preamp & PI.
0 x

Post Reply