DUAL SE amp...

[DummyLoad]

as a side project i've been thinking about constructing a 2ch SE amp. recently, i acquired some schumacher wound one-electron UBT-2 iron for a price i couldn't pass up. anyway, was thinking about switching to strap mono & split for stereo - leaning towards the 6L6GC and 6550 output tube types, or even 2x paralleled 6V6GTA/ch. any thoughts/suggestions about which/what pre-amp(s)? 

--pete

[kagliostro]

Hi DummyLoad

Nice idea, I would use two different preamps and may be also two different PA output tubes

may be also one PSE and the other simple Se

as to use it in parallel or with a "balance" as to chose the % of the signal from each one

Which preamps ? ........ At your taste

it will be an head with a separated speaker cabinet composed by two joined separated units, as to have it in use joined, when used paralleled or separated as to increase the stereo effect

K

[rzenc]

6550 output tube

Sounds interesting! How much voltage will you use on plates/G2?

any thoughts/suggestions about which/what pre-amp(s)?

How about a revibe front end coupled to 6550 power?

Hope this helps!

Best Regards

R.

[DummyLoad]

6550 output tube

Sounds interesting! How much voltage will you use on plates/G2?

any thoughts/suggestions about which/what pre-amp(s)?

How about a revibe front end coupled to 6550 power?

Hope this helps!

Best Regards

R.

around 400-450V and around 380V for G2

revibe idea is cool and a candidate. perhaps a triode > TS > pentode > CF for the 2nd ch...

--pete

[kagliostro]

perhaps a triode > TS > pentode > CF for the 2nd ch...

Something like one of this ?

K

[rzenc]

around 400-450V and around 380V for G2

revibe idea is cool and a candidate. perhaps a triode > TS > pentode > CF for the 2nd ch...

--pete

Nice!! How much power do you spect from such monster?

Another possibility for 2nd channel:

Triode - gain control - triode - pentode - triode - cf - tonestack

Makes up for riotstarters

Best Regards

R.

[DummyLoad]

35-40W total.

Triode - gain control - triode - pentode - triode - cf - tonestack

Makes up for riotstarters

too much gain perhaps???

respectfully,

--pete

[rzenc]

too much gain perhaps???

Is it? 

So...how about changing positions?
triode - gain control - triode dc coupled to pentode - triode - cf - tonestack?

I don't know if you are into high gain. I built a preamp using similar topology:
triode - gain - triode - triode dc coupled to triode - drive control - triode - dc cf - tonestack.... I think I found my way to high gain territory...

It might sound bizarre but connected to a ss poweramp (I wanted to know how much disto preamp was generating) it sounds massive. When connected to Marshall 9200 pumping 4x12" (friend set ) sounds incredible....Fits perfectly for highspeed riffs and  brutal soloing..

If you get interested in such stuff, pm me and I will send you schema...

Best Regards Pete!!!!

R.

[DummyLoad]

Something like one of this ?

thanks K! interesting layout - more to the point, interesting to see someone actually used that octal pentode in a production amp.

yes, similar layout, but without the LTPI and add a CF.

thanks for sharing. 

--pete

[kagliostro]

Hi Pete

If you want to see the complete circuit of the Selmer Zodiac twin 30 (a very unusual amp on the channel 2 Tone Control) I've sent it to Doug and now it is on the library of schematics

http://www.el34world.com/charts/Schematics/files/selmer/selmer_zodiac_twin30_.pdf

Franco

[DummyLoad]

that schematic was drawn by one of our forum members.

 

--pete

[echuta13]

That is such a great asset for the schematic library!     

Back on topic...  Looks like Swart is releasing a stereo SE amp: http://swartamps.com/swart_st-stereo.htm

[HotBluePlates]

Something like one of this ?

thanks K! interesting layout - more to the point, interesting to see someone actually used that octal pentode in a production amp.

Matchless didn't use the 6SH7 long. I think there were claims about availability or microphonics, but 6SH7's are generally pretty cheap from places that stock radio stuff (I have some signal generators that use that tube).

The Clubman 35 switched to use an EF86 in that position fairly early on. I used to have an EF86-equipped Clubman 35.

[DummyLoad]

Something like one of this ?

thanks K! interesting layout - more to the point, interesting to see someone actually used that octal pentode in a production amp.

Matchless didn't use the 6SH7 long. I think there were claims about availability or microphonics, but 6SH7's are generally pretty cheap from places that stock radio stuff (I have some signal generators that use that tube).

The Clubman 35 switched to use an EF86 in that position fairly early on. I used to have an EF86-equipped Clubman 35.

good to know. it seems that most octal tubes are prone to being microphonic - my opinion based on my limited experience working with them anyway. how did you like the clubman? decent? would you own another? i built a matchless DC30 clone - the EF86 channel for a friend, as i recall, it was a decent sounding amp. we used salvaged baldwin organ iron.

PS: standel coming along... :-) mechanical drawings coming together and the second breadboard is almost done. i'm leaning towards a head rather than a combo for greater flexibility of speaker options.   

--pete

[kagliostro]

Here is an old Marconi Equivalent Tube Manual

http://www.introni.it/pdf/Marconi_tavole_sostituzione.pdf

at page # 16 you can see that 6SH7 8 pin tube can be replaced with a 6AU6 7 pin tube (who gives more gain)

K

[kagliostro]

I've just recognized that also the Gibson Ga-46 uses a pentode in V2 position (labeled as V3 & V4 on the schematic)

http://www.el34world.com/charts/Schematics/files/gibson/GA-46.pdf

as pot with intake for the tone control a rotary switch with in series resistors must be used because as we know no pot with intakes are available nowaday


K

[HotBluePlates]

how did you like the clubman? decent? would you own another? i built a matchless DC30 clone - the EF86 channel for a friend, as i recall, it was a decent sounding amp. we used salvaged baldwin organ iron.

Yeah, it was a Marshally-enough sounding amp. At the time I think I was most excited by the build style of the electronics.

I'd probably make something like it again, but being that I don't gig I just don't need anything in the 30w+ range unless I want absolute clean.

I guess that means I really didn't need the Standel, but I just wanted to build it, so here it is...