[chrisdrop]

Anyone know how to date these? They are Marconi Osram 6J5Gs. They look physically identical (inasmuch as I can see inside them), but the text is more worn off on one)

The text looks like 7A 4138, but I am not sure if that is even date related.

The only other markings on the other side are only very faintly visible on the left tube. I believe that is the "Made & Patented in England".

 

[L0rdGwyn]

Sharing a little DIY side project I have been working on the last few days.

I have @whirlwind 's GOTL on hand for some surgical modifications. Similar to what I did with my GOTL when I had it, I have replaced his loctal sockets for the C3g with octal sockets set up for 6/12J5. The heaters for the SN7 socket have been daisy-chained to the new sockets, such that all three are affected by the rear switch, allowing the use of 12J5 as well.

The loctal sockets for the C3g are pretty large, larger than most octals on the market. We went with Beltons, as they are one of the few that are a drop-in fit without doing any significant metalwork on the chassis.



I offered to make one other change that IME has always had a positive effect on the sound - adding a CCS load to the driver tubes.

Joe decided to give it a try! So CCS boards were added to the interior. I adjusted the bias of the SN7 socket such that all of the tubes being used there would remain at happy bias points with the CCS load (ECC31/32/33, 6/12/25SN7).



Waiting for a few resistors to arrive to fix the bias, then it will be shipped back home! Sounds great, taking some time to enjoy the spoils while waiting, really enjoyed the all GEC setup this morning. I love the look of those damper diodes

 

[GDuss]

Sharing a little DIY side project I have been working on the last few days.

I have @whirlwind 's GOTL on hand for some surgical modifications. Similar to what I did with my GOTL when I had it, I have replaced his loctal sockets for the C3g with octal sockets set up for 6/12J5. The heaters for the SN7 socket have been daisy-chained to the new sockets, such that all three are affected by the rear switch, allowing the use of 12J5 as well.

The loctal sockets for the C3g are pretty large, larger than most octals on the market. We went with Beltons, as they are one of the few that are a drop-in fit without doing any significant metalwork on the chassis.



I offered to make one other change that IME has always had a positive effect on the sound - adding a CCS load to the driver tubes.

Joe decided to give it a try! So CCS boards were added to the interior. I adjusted the bias of the SN7 socket such that all of the tubes being used there would remain at happy bias points with the CCS load (ECC31/32/33, 6/12/25SN7).



Waiting for a few resistors to arrive to fix the bias, then it will be shipped back home! Sounds great, taking some time to enjoy the spoils while waiting, really enjoyed the all GEC setup this morning. I love the look of those damper diodes

I've asked you this before, but is it still to early to get in the queue for a "LG-OTL"?

 

[chrisdrop]

Sharing a little DIY side project I have been working on the last few days.

I have @whirlwind 's GOTL on hand for some surgical modifications. Similar to what I did with my GOTL when I had it, I have replaced his loctal sockets for the C3g with octal sockets set up for 6/12J5. The heaters for the SN7 socket have been daisy-chained to the new sockets, such that all three are affected by the rear switch, allowing the use of 12J5 as well.

The loctal sockets for the C3g are pretty large, larger than most octals on the market. We went with Beltons, as they are one of the few that are a drop-in fit without doing any significant metalwork on the chassis.



I offered to make one other change that IME has always had a positive effect on the sound - adding a CCS load to the driver tubes.

Joe decided to give it a try! So CCS boards were added to the interior. I adjusted the bias of the SN7 socket such that all of the tubes being used there would remain at happy bias points with the CCS load (ECC31/32/33, 6/12/25SN7).



Waiting for a few resistors to arrive to fix the bias, then it will be shipped back home! Sounds great, taking some time to enjoy the spoils while waiting, really enjoyed the all GEC setup this morning. I love the look of those damper diodes

Cool project. I added the CCS to my office-toy Bottlehead Crack last week. I thought the change was great. I was wondering if anyone ever had a CCS in a GOTL, and *poof* there you have it. I bet it will be great; congrats-in-advance @whirlwind.

Aside from the C3G>6J5 mod, did you change any caps et al?

 

[whirlwind]

Cool project. I added the CCS to my office-toy Bottlehead Crack last week. I thought the change was great. I was wondering if anyone ever had a CCS in a GOTL, and *poof* there you have it. I bet it will be great; congrats-in-advance @whirlwind.

Aside from the C3G>6J5 mod, did you change any caps et al?

No cap changes

 

[jmac1516]

Haven't been on here for ages. Saw some love for the 6bx7s. Great sounding tubes. All six of them and a driver. I hope @paramesh is enjoying his GOTL. He bought all of my GEC 6as7g, GEC U52. I think the GOTL is very photogenic and sounds great. Enjoy.

From an old archive.

6bx7s here as well. Along with the previously mentioned pair of RCA 6c5, everything sounding great!

 

[L0rdGwyn]

I've asked you this before, but is it still to early to get in the queue for a "LG-OTL"?

Lol well I have not designed an OTL yet, have mostly been working on SET designs in some form or another. What was previously my headphone amp is being reworked as a speaker amp, so I will be doing a true headphone amp next. TBD but what I do know is it will be a parafeed amplifier using the Sowter 8665 OPT, potentially a single-stage "spud" design. We will see how it goes!

Cool project. I added the CCS to my office-toy Bottlehead Crack last week. I thought the change was great. I was wondering if anyone ever had a CCS in a GOTL, and *poof* there you have it. I bet it will be great; congrats-in-advance @whirlwind.

Aside from the C3G>6J5 mod, did you change any caps et al?

No cap changes, as Joe said, still using the Russian PIO coupling caps and Sprague Atom bypass caps.

 

[2359glenn]

Cool project. I added the CCS to my office-toy Bottlehead Crack last week. I thought the change was great. I was wondering if anyone ever had a CCS in a GOTL, and *poof* there you have it. I bet it will be great; congrats-in-advance @whirlwind.

Aside from the C3G>6J5 mod, did you change any caps et al?

Technically 1/2 of the 6AS7 is used as a CCS for the other 1/2.
Sounds pretty good and no SS in the audio circuit + would require a large heatsink.

 

[mordy]

@UntilThen thanks for chiming in !!~!

yes now am set for life .. with zillion configurations and now all the holy grails in my chest of tubes
even recently scored the superb and much sought after Tungsol BGRP as a matched pair !

it has been an interesting shoot out between the Slyavania 6SN7 metal base and the Tungsol ..

i been working on a personal matrix for driver and power tube configurations that pair best with various favourite dynamics -
from the VC ( nothing like the ZMF when it comes to tubes ) and the HD6 Series
this exercise over the last 2 months has been a delightful and amazing experience ..

its clear to me ...A great OTL amp is like nice canvas which allows play of tubes and very responsive to tube rolling..
the GOTL is the only amp in experience which i have seen so responsive to tube roll and subtle changes

the journey has just begin ,

Perhaps you will find the time to share your favorite combinations with us when you have tried some of them...it is truly amazing how many possibilities there are.

 

[whirlwind]

6bx7s here as well. Along with the previously mentioned pair of RCA 6c5, everything sounding great!

Your Verite has some wonderful grain.

 

[jmac1516]

Your Verite has some wonderful grain.

Thanks. Monkeypod

 

[Monsterzero]

On tuesday tropical storm Isaias rolled into Long Island. It brought pretty significant gusts of wind and a little light rain,however it wasnt anything drastic. In fact I was outside in the middle of it trying to clear leaves from my pool with little luck. Ive experienced similar winds in Socal with no outages. In Thailand this weather wouldnt even make a blip on the radar. I guess im not in Thailand anymore......
Around 3:30pm the lights started to flicker and then the power went out completely a few minutes later. Judging by the wind and the experiences i have had living in 3rd world countries where severe weather is a nearly weekly event,I figured we'd be without power for an hour or two. certainly not more than six hours.

Well Tuesday turned into wednesday. Wednesday into thursday. Thursday into friday. Friday into saturday. Saturday into today at 10am when finally the electricity came back on.

Hot,humid and dark. No electricity. No A/C. No phone line. No signal for mobile phones. No power to charge anything....and certainly no music.

We lost an entire full sized freezer that was completely stocked with tons of food. Gone. Tossed out.

With the taxes we are charged here,and the prices we pay for electricity(our most recent bill was over a thousand dollars) I expected white glove service and an immediate and effective response. Instead we got nothing. For five days and nights we were on our own with no way to contact the rest of the world.

It is the price one pays when you live in an overpriced Socialist state. I cannot wait to get out of this hellhole called New York.

 

[mordy]

Sorry to hear about your problems. When Sandy hit we were out of electricity for 8 days. The most difficult was coping with Acute Internet Withdrawal Syndrome.
You may be able to file a claim with your local utility and possibly get some money back for the spoiled food.

 

[Monsterzero]

Sorry to hear about your problems. When Sandy hit we were out of electricity for 8 days. The most difficult was coping with Acute Internet Withdrawal Syndrome.
You may be able to file a claim with your local utility and possibly get some money back for the spoiled food.

Apparently we needed to take photos to prove we had food in the freezer. Of course we found this out after the fact. Lesson learned.
I spoke to one of my neighbors the other day who was here for Sandy. The outage for Sandy was shorter than what we just went through. Unbelievable.

Im so livid! Sorry for venting.

 

[mordy]

Will add to my compatibility table if/when we get Glenn's thumb up.
Otherwise, and especially with your disclaimers, I am a little hesitant... Last thing I ever want is for someone to follow my compatibility table and damage his praised GOTL

Hi Zachik,
Got the answer from Glenn - the 6Z7G will work in the GOTL but he was not sure how it would sound.
Well, I have used it now for some 40 hours + and this is what my impressions are:
The bass is very good and extended and powerful; the treble is on the bright side - good detail.
The mid range is pretty good; BUT there is a rough edgy quality to the sound that I could not really filter out with different combinations. It simply lacks sweetness and under the sound microscope sounds gruff and hollow. Mind you, the sound is pretty good, and it is different, but ultimately I prefer a sweeter and more musical presentation.
It was a good try at something unusual and it did not break the bank. A very pretty tube - maybe I will make a headphone hanger out of it....