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by Cressy Snr
Fri Jan 18, 2019 6:28 pm
Forum: Everyones Projects
Topic: The "Not OTL" 13E1 Build
Replies: 13
Views: 231

Re: The "Not OTL" 13E1 Build

That's a really low impedance valve It should have a good damping factor too.. good work Steve... I sort of wish I had kept mine now.. I'm glad you didn't but I can understand how you might feel. When I built the Alexandra Palace thing ten years ago I didn't really know how to keep the 13E1 under c...
by Cressy Snr
Fri Jan 18, 2019 1:25 pm
Forum: Everyones Projects
Topic: The "Not OTL" 13E1 Build
Replies: 13
Views: 231

Re: The "Not OTL" 13E1 Build

I've had an interesting couple of days with this amplifier. The Hammond 1627SE 2K5 output transformers sound considerably less 'thick' with the whole of the secondary winding in use and series connected end to end as it has to be with 13E1s, which need a 1.25K reflected primary load. The transformer...
by Cressy Snr
Wed Jan 16, 2019 6:34 pm
Forum: Everyones Projects
Topic: The "Not OTL" 13E1 Build
Replies: 13
Views: 231

Re: The "Not OTL" 13E1 Build

Yep, they are still made; at least the nine pin noval base valve is. Mine are the gold plated pin version by New Sensor, under the Electro-Harmonix brand.

The "Alexandra Palace" amplifier may yet rise again; except this time it'll actually have enough gain! :mrgreen:
Image
by Cressy Snr
Wed Jan 16, 2019 12:10 pm
Forum: Everyones Projects
Topic: The "Not OTL" 13E1 Build
Replies: 13
Views: 231

Re: The "Not OTL" 13E1 Build

The 1627SE are configured for 16 Ohms to give a 1.25K load for the 13E1 when an 8 Ohm speaker is connected. If I'd never heard a single tube OTL with this valve, I could quite easily live with this. The 6H30pi is an excellent match in terms of synergy, for the 13E1, which does bode well for the OTL ...
by Cressy Snr
Wed Jan 16, 2019 11:58 am
Forum: Everyones Projects
Topic: The "Not OTL" 13E1 Build
Replies: 13
Views: 231

The "Not OTL" 13E1 Build

OK so now the breadboard for the 13E1 OTL has been recycled into a circuit with output transformers, namely the relatively inexpensive Hammond 1627SE. The object of this exercise was to forcibly stop the breadboard development of the OTL, otherwise I would have just carried on with the OTL breadboar...
by Cressy Snr
Tue Jan 15, 2019 6:36 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

OK,
That's the end of the breadboad adventure.
Next the proper build. I'll start a new thread for that.....eventually.
Thank you and goodnight. :)
by Cressy Snr
Tue Jan 15, 2019 3:27 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

I am really tempted in the meantime to try something with this 13E1 (NOS from the 1960 or later ?) myself. Just starting with one tube for experimenting. The biggest limitation with the 6C33 was the 60W max which was easily reached with 470mA/130V and the necessary min peak output power even for 15...
by Cressy Snr
Tue Jan 15, 2019 3:24 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

jack wrote:
Tue Jan 15, 2019 3:07 pm
Really hoping to make Owston to hear this! Been (passively) following since the start - great project.
There'll be a veritable gaggle of OTLs there, so you'll have plenty to choose from if Ray and Dave (Thermionic Idler) get their projects done in time.
by Cressy Snr
Tue Jan 15, 2019 3:22 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

pre65 wrote:
Tue Jan 15, 2019 3:07 pm
Cressy Snr wrote:
Tue Jan 15, 2019 2:37 pm

This one can be the comparison with the boxed up OTL at Owston.
Have you got enough transformers to do both ?
I think I've another 2x115V somewhere, so hopefully yes.
by Cressy Snr
Tue Jan 15, 2019 2:37 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

Can't let a good breadboard go to waste, so have lashed an amp up using the 50s 13E1s, with output transformers: http://i.imgur.com/YFw26XE.jpg Not as good as the OTL, but the same overall 13E1 kind of presentation. The valves are only running 100V and 113mA as the 1627SE OPTs will only take 150mA m...
by Cressy Snr
Mon Jan 14, 2019 6:56 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

One more time! https://i.imgur.com/Fbv3zTV.jpg Steve, apart from changing to the 6H30pi and using the same power supply for driver and output stages (with the commensurate component value updates) is this your final schematic? Cheers Yes for dual power supply. If you are using the 6SN7 Aikido front...
by Cressy Snr
Mon Jan 14, 2019 5:39 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

Steve's amp really does sound amazing! It did very nice things for some of our favourite records. Those valves *seriously* need the full steampunk treatment though! Oh yes they are definite candidates for the full steampunk look. I have plans afoot for two steampunk amps actually. My 1950s 13E1s do...
by Cressy Snr
Mon Jan 14, 2019 12:48 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

Well the OTL has now left the room and is awaiting it's turn to go in a box, so it's Ray's project that's now the focus of attention.

I'll stick a schematic up as soon as I can be arsed to work it out for 6H30pi :)
by Cressy Snr
Sun Jan 13, 2019 8:08 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

The best part of using the 6H30 is that it ca be easily replaced by a 6H6p or 6H1p and more. My guess is, from listening to all 3 tubes in my sound systems (AR, SE OTL ), that a 6H30 might sound too sterile in a single output tube OTL. The 6H6p might sound warmer with more bass, the 6H1p a little m...
by Cressy Snr
Sun Jan 13, 2019 7:48 pm
Forum: Everyones Projects
Topic: Remember These?
Replies: 390
Views: 9184

Re: Remember These?

Oh and it was great to see Dave and Meredith, this afternoon. Some great music and great company. :)