Glo Champ

[PRR]

> -37.75V Vgk so we need ~~53VRMS

26.7 V RMS.

[DummyLoad]

> -37.75V Vgk so we need ~~53VRMS

26.7 V RMS.

oh yeah, duh! it's SE...  

that stage ought to be doing at least that... at least sim says it is...  :-\  

[PRR]

1958 Radio Shack industrial catalog:

[DummyLoad]

VERY UNSAFE homemade plate cap - don't try this at home... i'm a professional idiot.  

[kagliostro]

Hi ISOTone DummyLoad

Can I suggest, as a temporary solution, to use a motorcycle spark pipe ? 


Kagliostro


  Merry Xmas 

[DummyLoad]

thanks kagliostro, i'll see if i can find something that fits after the holidays.

happy holidays to too! 

[PRR]

.

[DummyLoad]

sorry, it's been on the back burner. i need to get some sound clips posted and you don't want to hear my playing - not even if yer three sheets to the wind. i'll see if i can arrange for a friend to come by and record some sound bits.
PRR, you requested some additional telemetry - g2 currents, etc.. it's late - i'll grab it tomorrow after i get back from work.

respectfully,

--ISOTone

   

[DummyLoad]

PRR, here it is... i replaced the G2 resistor w/ a 500Ω - down from 1KΩ.

at idle, vR500Ω is 4.2V - under heavy loading (hard picking/strumming and dimed) i see 11-11.5V with an occasional pk. to 12V. this is measured with a fluke 87.

so, at idle - we have 8.4mA @ ~~500V g2 - roughly 4.2W - full power 11.5V, @ 23mA or 11.5W - i think we are still safe here; thoughts?

the dynamics have improved remarkably and seemingly so has the output power, amp seems to have a lot more bite now. i'm using a godin LG w/ hot humbuckers.

i'll slap a 1KHz tone and dummy load on it to get some power output telemetry later on this afternoon and update unless you direct otherwise.

i really love this amp - i'm going to experiment with another peanut tube for a smattering more nastiness; you may or may not approve - it's the 5840W. i'll post up some bias conditions of what i think will work

are we insane? 


--ISO 

[PRR]

So you have 500V(?) supply, G2 was 492V-476V, is now 496V-488V.

> dynamics have improved remarkably and seemingly so has the output power, amp seems to have a lot more bite

Hard to understand any "wow!" change from 2.5% increase.

Is it possible to have Buttery switch resistors behind your back and see if you consistently know the difference? (If that's just too much trouble and danger, I understand.)

> are we insane?

Hmmmph. Not like some snowplow truck owners. I just saw a sig boasting a 5 inch exhaust system. I re-piped my truck with 2.25" and now I feel teeny. Which is stupid, because this truck has as many pistons and as much horsepower as BOTH the cars in the drive put together, and AFAICT I can't use more than 1/5th of that at 5MPH on slick surface.

[DummyLoad]

Hard to understand any "wow!" change from 2.5% increase.

true. maybe it's because it has been a while since i/we fiddled with it?   

Is it possible to have Buttery switch resistors behind your back and see if you consistently know the difference? (If that's just too much trouble and danger, I understand.)

should not be too much trouble... however, buttery has been pretty busy lately and scarce around these parts. hopefully he'll chime in and get a break long enough to spend a small bit of time on it with me.

honestly, i've been spending more time with the burger king amp i posted just after x-mas. it's a lot more sane of a project to work on by myself. then it's on to a 4 x 6V6 princeton reverb for a friend - i'm trying to sell him on a single channel vibroverb instead. the glo champ has to be a slow and methodical and well thought out project - it's just too damn dangerous to cut corners on and slip-shod together.

5 inch exhaust system...

sounds about as useful as those 26" wheels and rubber bands for tires guys are putting on their cars these days..   BTW, did you ever get the idle kinks worked out? 

[DummyLoad]

i have worked on some of the mechanics some. all comments and/or suggestions welcomed. the tube is housed in a perforated aluminum cage. i'll try to get an elevation view done in the next day or two.




--ISO
   

[PRR]

I have found the mother-lode of H-K tube data.
http://www.tubecollectors.org/h&k/h&k.html

The HK1554 has a suggested condition for Audio, Class A, Single Tube at 350 Watts output. 4,000+W push-pull B with a mere 150W grid drive. 250W filament will keep you warm tonight. (2 deg F last night.) The 3054 will do more, but at 30" tall is not going to fit in a Combo.

[DummyLoad]

I have found the mother-lode of H-K tube data.
http://www.tubecollectors.org/h&k/h&k.html

The HK1554 has a suggested condition for Audio, Class A, Single Tube at 350 Watts output. 4,000+W push-pull B with a mere 150W grid drive. 250W filament will keep you warm tonight. (2 deg F last night.) The 3054 will do more, but at 30" tall is not going to fit in a Combo.

thanks for sharing that link. impressive tubes. 

i actually kicked around the idea of P-P AB1 with a pair of HK257B (4E27A/5-125B) for a 150W+/- amp, but i think trying to buck hum with directly heated cathodes is more a hassle than it's worth, also, designing a clean +/-20A DC heater supply that can take power-on surge of those heaters with a respectable life span isn't trivial, so, meh! i do have all that iron laying around, + i should at least use it, no? that's what i was doing fooling around with those KT120 SE with 750V B+. thinking a winter studio amp might be something to tackle in the future.

getting down to 20's or teens here basically shuts down the city - stay warm! hope all is well otherwise. oh yeah, shouldn't you be finishing up your tube amp book? ;-)

30" bottles? depends on your definition of combo! CMI as shown in the attached pic. might work. pass the soldering iron and send in the roadies. 

[PRR]

1947's TV transmitters used flocks of 4E27(HK257).

[DummyLoad]

i see another tube in that lineup i've been wanting to experiment with: the 6AG7 used as a transformer loaded reverb tank driver or headphone amp.



--pete

[PRR]

Like Crosby, Stills, and Nash, and Young.... Heinz, Lewis, and Kaufman did several sorts of business under several names at several places.

Here is an L&K Los Gatos ad touting the 254.

[PRR]

Before that: Lewis' name on the brand and a 125W Pdiss claim.

[uki]

WOW !! Another really nice thread !!

[PRR]

Ya shudda bought them in 1948.

[shooter]

guessing '48 was a good year for bargain hunters across the globe 


the OEMS sold us, well priced us $8,000 for the pair, we got them from an Eimac rep for $4000
lasted about 18khs before they started diftin or sparkin


3CX800A7
YC156A

[PRR]

Replaced by:

[DummyLoad]

Replaced by:

I have a couple of those.

Planning to re-visit this project around the end of summer, only with octal tubes for the preamp - Lineup something like this: 6J7 > 6SF5 > TS > 6SF5 or 6J5 > 4E27A.


--Pete

[jojokeo]

Replaced by:

I have a couple of those.

Planning to re-visit this project around the end of summer, only with octal tubes for the preamp - Lineup something like this: 6J7 > 6SF5 > TS > 6SF5 or 6J5 > 4E27A.


--Pete

Probably not the "longest" thread but holy cow Pete I would nominate for the longest amp time project? Just kidding kinda but I've had several amps that I "thought" was finished only to opened up years later to modify or perform various other mods or improvements. Hope you get it glowing as you wish loudly and proudly once again - which I know you will.

[PRR]

...using a HK257B/JAN-4E27....

Or for different flavor: https://www.ebay.com/itm/175325794001
GK-71 ( 4E27 ) Vintage generator pentode tube Original Package NEW NOS
Russian improved work-alike for HK257.

There's apparently many places to buy these.

Check entire datasheet for differences.
https://frank.pocnet.net/sheets/018/g/GK71.pdf
(heater way different?)

[DummyLoad]

...using a HK257B/JAN-4E27....

Or for different flavor: https://www.ebay.com/itm/175325794001
GK-71 ( 4E27 ) Vintage generator pentode tube Original Package NEW NOS
Russian improved work-alike for HK257.

There's apparently many places to buy these.

Check entire datasheet for differences.
https://frank.pocnet.net/sheets/018/g/GK71.pdf
(heater way different?)

Nyet comrade! 

Interesting looking tube; is much larger than the 4E27 - At least it seems as such. Looks like the plate material is graphite?

--Pete

[kagliostro]

An hungarian friend that sometime arrive here in Italy  to the radio amateur Flea Market in Pordenone and Marzaglia, some time ago had a large stock of those tubes, unfortunately this Is of any help for you ☹️
(Also he often has GU81 tubes)

No chances for the 813 or 811 ?

Franco


EDIT

Don't know about expedition cost

https://www.ebay.com/itm/175325794001?_trkparms=amclksrc%3DITM%26aid%3D1110011%26algo%3DHOMESPLICE.DISCLISTINGS%26ao%3D1%26asc%3D20191002092920%26meid%3D4c46ce5a01464540a54feeee5503f570%26pid%3D101096%26rk%3D6%26rkt%3D12%26sd%3D304614261394%26itm%3D175325794001%26pmt%3D1%26noa%3D0%26pg%3D2332490%26algv%3Ddefault%26brand%3DSoviet&_trksid=p2332490.c101096.m3021&amdata=cksum%3A1753257940014c46ce5a01464540a54feeee5503f570%7Cenc%3AAQAHAAAA4OF5%252BpTTB9eWzF1iVTnQDCtZCCH3fRXts9K%252BhqfJSnqTbPXeAWObzUMuLaXlvjluaHjMzX4v0J%252BqyoFbajHJTzndBS0GrKNqz6gS438ukFOrQBCmnH6JmdcwYVYZavYhUajYGiw4wbSsIR%252BSUnYKI%252Fnh9vDO8YYBCtDW4MoZ6jB3A9CHoZK%252Bq6EpH8yeHvWeyKOxNk%252BqUmloLnrU%252BmOerXcZUp5NAJf4WT7HOt%252F%252BlSHuHpbWsFSC9FBflS9hY427u0nqpUYp5qg0eTTaLDJLsft53q%252B2TMIAEMssq6Lz7MzU%7Campid%3APL_CLK%7Cclp%3A2332490


https://www.ebay.com/itm/284906185255?hash=item4255bb6227:g:Sq4AAOSw3tpi2qYk&amdata=enc%3AAQAHAAAA4A0dkBoRCSnk2ojgVADC57IGhFzYuK2F71FFkUujcCiDHEdR13nbNmX92vGfRGxuJ%2BYdj7KFx7AmzGjEFVMc5bUWuJq4STwBE8bnegVbqmIGT0f2yljYHemw0ZBr54qtN%2B3uOyhQYW2f0T2a%2BuKFoQPZeSe3MD5bYXJOUDs4cH5J0yRRosHmiENXJcjIXPWzOG2yO3KrCf0yKDC2OSmxj8lcKc8n6NGxSczygR8Fu2fKUDzOmtFTZG998rHQa1NJhHuML9CCEZ32MkM1yIfGnhTJIhahWY7Cg%2Fijeyv%2BIc7W%7Ctkp%3ABk9SR9jfkZDhYA


Pete Millet build an SE with 813 as Power tube, but il was used in triode mode


http://www.pmillett.com/813_se_triode_amps.htm