yes.... I Know....I'm starting a #183 build!

[norburybrook]

Well the bug has bitten again.


I've ordered a chassis from Taylor @Amplified nation and I'm going to make my final ODS. I'll have done all the main ones then and I can rest in my bed.



I've ordered a special power transformer so I can get near the 465vDC on the layout with the EL 34's. I'm going for 345-0-345 instead of the 320-0-320 do you think that will be enough?


I've also ordered a special 1750ohm Marshall OT too and a 3 henry 100ma choke.


If anyone who has built one of these has anything relevant to interject at this early stage please do so.



I've a feeling it's not going to be a whole lot different to my #102 but I have to find that out for myself I think....it will be 100w though so that will be a difference.





Marcus

[martin manning]

I'm going to make my final ODS.

Uh huh...

I've ordered a special power transformer so I can get near the 465vDC on the layout with the EL 34's. I'm going for 345-0-345 instead of the 320-0-320 do you think that will be enough?

Do a simple ratio based on what you got previously for plate voltage, say it was 430, then 465/430*320=346.

Are you getting 7.5A heater current for the EL34’s?

[xtian]

You go, Markus! The #183 is the only 100w ODS I've built. Love it. I used ClassicTone iron, and noted about 440v plates when finished.

Here's my build thread:

https://ampgarage.com/forum/viewtopic.php?t=30282

...I see that you commented on my thread, Marcus, so you're already aware.

Happy building!

[norburybrook]

I'm going to make my final ODS.

Uh huh...

I've ordered a special power transformer so I can get near the 465vDC on the layout with the EL 34's. I'm going for 345-0-345 instead of the 320-0-320 do you think that will be enough?

Do a simple ratio based on what you got previously for plate voltage, say it was 430, then 465/430*320=346.

Are you getting 7.5A heater current for the EL34’s?

Martin I am, this is what I've spec'd

Primary, 115V-230V-240V@50Hz
- Secondary anodic, 345V-0-345V@400mA
- Secondary bias, 60V@100mA
- Secindary heaters, 3,15V-0-3,15V@7,5A
- Secondary aux, 6V@1A
Horizontal Mounting with 1 top cover


anyone care to share their preference when it comes to EL34 tubes? I've not done El34's yet.


M

[xtian]

I find JJ capable and adequate. Can’t drive them to distortion without neighboring communities complaining.

[rogb]

RFT East German Siemens EL34. Long lasting and great sounding when broken in, need a few hours on 'em. I wouldn't waste money on any other ELs, unless you can find some Mullards

[norburybrook]

RFT East German Siemens EL34. Long lasting and great sounding when broken in, need a few hours on 'em. I wouldn't waste money on any other ELs, unless you can find some Mullards

I've got a set of Mullards but they're old ones pulled from an old amp. They work fine, do output valves wear out sonically or if they're working do they just keep their sound until they die?


M

[martin manning]

Marcus are you getting the PT from the same source as one you have used before, and did you specify the same secondary current? I ask because people talk in terms of idle voltages, where the current is maybe half of that required at full power.

[Synchu]

I seem to like EH 6CA7 as most suitable for all my EL34 needs (besides now virtually unavailable Siemens EL34). Tung Sols are also a viable alternative.

Niki

[norburybrook]

Marcus are you getting the PT from the same source as one you have used before, and did you specify the same secondary current? I ask because people talk in terms of idle voltages, where the current is maybe half of that required at full power.

yes, Savino is making the transformers for me @inMAdout. They're rated for 4 push pull EL34'S

Marcus

[norburybrook]

I seem to like EH 6CA7 as most suitable for all my EL34 needs (besides now virtually unavailable Siemens EL34). Tung Sols are also a viable alternative.

Niki

thanks Nikki,

they look interesting, might give those a try.

I've got about 10 old mullards sat in a box here that I can try as well, it's nice to know there's new alternatives. I 've a feeling that when talking about output tubes most people would be referring to amps like Marshalls where they're driven hard. I've a feeling in the Dumble that isn't the case which means there'll be less sonic differences to worry about.

A friend of mine who made a load of ODS amps said he could hear absolutely no difference when swapping 6L6's for EL34's in the same amp at normal gig volumes.


M

[Synchu]

While the power amp in ODS types is less part of the equation, I still seem to hear a difference. Stage volume, band situation - all bets are off - I was glad when I could hear myself

As for the PTs - to put another vote up for InMadOut - Savino is always spot on with mine ( +/- 1 to 2 volts - loaded - ).

By the way, I just got a vintage Traynor YGL3 Mark 3 that I intend to rebuild into Wonderland/ODRS #60/BM HRM mashup.

It is 4 x EL34 (still with its original Phillips branded Mullards 6CA7) as well, besides being an exemplary piece of excellent design, nuclear blast proof build and an overall over-engineered piece of greatness.

It seems winter is EL34 time

Niki

[norburybrook]

el34 time here we come.

I'm on tour at the moment with Georgie Fame so don't have any spare time. Interestingly when I was learning his songs I thought the band sounded great on one particular album. I asked him who the guitar player was and he said Robben Ford. Robben played in his band live too after that , along side Will Lee, Steve Gadd and Richard tee

https://www.bing.com/videos/search?q=ge ... ORM=VRDGAR


I Finish in December then have some duo dates with my partner and also starting a new album for 'jones' https://www.propermusic.com/artist/Jones-19692

I've produced all his albums.

Then in January I hopefully will start an album with Mike D'Abo who wrote the 5 million airplay hit 'build me up buttercup' and Handbags and glad rags. We're in pre production/negotiations at the moment.

Somehow in between all this I'll get some soldering time in, although looking at it all laid out like this I don't know when!


M

[Synchu]

Fantastic. Sounds like a great (and busy) winter, sneaking in a 183 build, though, sounds possible.

I typically start building amps when it's busiest at work

Niki

[talbany]

A friend of mine who made a load of ODS amps said he could hear absolutely no difference when swapping 6L6's for EL34's in the same amp at normal gig volumes.

I kind of agree with this statement But I wouldn't say "no difference" It also depends on which PI your using either the Bluesmaster or the 183/124/102 (fender type). The ladder being a bit hotter driving the grids harder. Still by the time you get the thing to the point where the output section starts to go things in the room start rattling A thing of beauty!
For me, there are a few things I notice about the Pentodes that are pretty cool. 1st would be the touch sensitivity is elevated I generally find myself backing off a bit with the 34's and not needing to play as hard to get the thing to really respond. The 2nd would be something about how the mids are a bit more forward sounding. Almost like you can climb in the note (if that makes some sense) they also compress faster than the 6L's and will break-up quicker if you can get em there. when they go they are smoooth.
The negatives:
They dont seem to have that big full low-end bloom like the 6L's but still with a quad of 34's is not that big of a deal!. The 34's have a wimpy screen supply and are a real finicky tube, and have a tendency to drift around and don't like the back of a truck. (especially the new ones). Wing C's /Siemens/RFT/Amperex 6C7 soft vacuum (killer) and Mullards are all good sounding tubes!.

I've got a set of Mullards but they're old ones pulled from an old amp. They work fine, do output valves wear out sonically or if they're working do they just keep their sound until they die?

Depends on how many hours they have on them. Generally what happens is they start to drift further apart becoming mismatched. Remember they all have to be fairly closely matched if you want the output section to be balanced.You may also want to go with a 10k PI balance trimmer and do some swapping around if you find a quad that are not closely matched!.If you get them in and they sound good use em till they don't or die!

Tony