36 Watt OT Primary Impedance

[keith]

4K seems to be the primary impedance normally used. Is a 3300 pri to low(the seconday is 8 ohm only).

Thankyou,
Keith

[krash]

no it's not too low.

it will just sound a little different.

[keith]

it will just sound a little different.

Sound- wise, I guess that means, more like the 60's Clapton/Cream sound vs the 80s/90s AC/DC sound?

Keith

[krash]

i couldn't say.

neither clapton nor ac/dc were using a 36W tho... so i'd say it'll not sound like either of them.

with 3.3K primary, you'll get a little less total power, more distortion, and IMHO, a creamier kind of sound, looser.

[Plexi]

i couldn't say.

neither clapton nor ac/dc were using a 36W tho... so i'd say it'll not sound like either of them.

with 3.3K primary, you'll get a little less total power, more distortion, and IMHO, a creamier kind of sound, looser.

Where do you get you info to back the statement you posted?
Many people use a 3.4k 50 watt plexi type tranny for some of these amps. As for the sound you might get,alot depends on the circuit used,speaker cab and guitar,for the sound your looking for.

Richie

[keith]

Richie, are the amps you were referring to in an el84 (or similar)36 watt setup? If so, thats a good thing.
As for the sound comparison, I was trying to generalize, all equipment being the same except for the OT pri imp. The Clapton being a Crossroads type sound vs the AC/DC Back in Black sound, or smoother vs harsh. Not really sure how, or the correct way, to describe the tone/sound differences in words.

Thanks to all, for the replys.
Keith

[Plexi]

Richie, are the amps you were referring to in an el84 (or similar)36 watt setup

Yes, Nik uses a 50 watt transformer for his 4x EL84 36,or the same OT for his plexi type2 x EL34 amp.

All being the same... Or what your meaning is..if 2 of the same amps were exact..tube types and circuits..just the OT's different in imp, rated.
Between a 3.3k and 4k.. not a big difference.. But there would be some.
I would say the 3.3k would be the more powerful or rawer sounding..and the 4k more smoother sounding,with a little less power,if you were using the EL34s . Also some slight frequency changes between them,and distortion %. you would find more of a difference in something like a 3.4k compared to a 6.6k
You can go here. http://www.sowter.co.uk/ and click the PP output,and look at how things change. You should get a good idea.

Now when you get into tube types,voltages,and different circuits between the more ACDC amps and the Clapton amps.. you can also see why they sound different.
Richie

[krash]

Richie,

I thought we were talking about EL84 amps. I don't have any idea how things sound different with EL34 amps.

This is my subjective opinion, obviously, based not on changing output transformers but changing the speaker load so the impedance reflected back to the tubes changes, in the range of 10-20% difference such as 3.3K to 4K and in my own amps.

I gladly yield to your more well-informed input.

[Plexi]

I thought we were talking about EL84 amps

I thought the same thing at first too..since when someone mentions the 36 watter..i just assume its a 4x El84 amp. but the same should apply to a 4x El84 amp too.

For example.. the trainwreck amps. If you used the 6.6k and 2xEL34, the amp puts out about 35 [good] watts.. if you used a 3.4k tranny,you'd get more power out of it. Of coarse alot depends on the voltages the tubes are run at,and how the amp is biased,and many factors. The frequencies would also change.
I guess if anyone has used a fender OT in a marshall amp..or a marshall OT in a fender amp,you'd hear the differences of how they reacted.

Richie

[krash]

For example.. the trainwreck amps. If you used the 6.6k and 2xEL34, the amp puts out about 35 [good] watts.. if you used a 3.4k tranny,you'd get more power out of it. Of coarse alot depends on the voltages the tubes are run at,and how the amp is biased,and many factors. The frequencies would also change.
I guess if anyone has used a fender OT in a marshall amp..or a marshall OT in a fender amp,you'd hear the differences of how they reacted.

Richie

Right ... ok. Well I guess going from 6.6K to 3.4K is going to make a much more dramatic difference than 4K to 3.3K.

[keith]

I thought we were talking about EL84 amps

This is a 4 x el84 amp. The amp is a cathode switching type, for 18 watts. The reason I asked about the 3300 pri (has an 8 ohm sec), is that in 18 watt mode, the impedance would be closer to 6600 ohms. The transformer I am using now, is 3700 pri and 4 sec with an 8 ohm speaker. In 18 watt mode, the pri imp jumps to 7400. Looks like thats a bit high for the 18watt sound.
The whole Idea, is to be able to retain the 18 watt sound and the 36 watt sound. The amp sounds great with the current 3700pri transformer, but the 3300pri transformer may provide a better sound (in 18watt mode)at normal volumes.
For grins, I'll attach a photo of the current amp progress. I'm still making additions, some of which aren't seen on the photo. 4xel84 or selectable 4x6v6. Half power switch. Reverb, JA front end, 36W power. Switchable gain boost w/adj boost gain, 5 pos voicing, normal and TMB.
Sounds very good currently (but extremely loud in 4x mode), and extremely quiet(no buzz/hum etc). Everything working, but don't have the reverb hooked up yet.

[Plexi]

Matchless used a 4k for both a 2x EL84 and a 4X EL84 amp. When using a half power type switch..your going to have that. Seems it will have a give or take,depending on which way you choose to go with the tranny. Some trannys have 2 primary taps. You could use that with a switch ,to switch between the 2. The liverpool also is about what you are describing.
That OT has a 5200 and 6600 primary taps. So you can hear what this value sounds like its at 5200. Here is a sample of it,some tele pickin..
http://homepage.mac.com/geekmacdaddy/.M ... le%202.mp3
And a more rock sound with LP and cranked more.
http://users.zoominternet.net/~jdhall/a ... 20lead.mp3

There isn't a big difference in power with it on half power,and the sound tone is about the same.

Here is a 2x EL34 Single ended amp.. for an example
http://homepage.mac.com/geekmacdaddy/.M ... hblade.mp3

Richie