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or.... what to do when in quarantine... during lock down 2.0 'Just for fun' I have used my elCheapo Tube curve tracer data to write a small program that will analyse tubes and suggest matched pairs. This GUI shows 16 6CA7 tubes test result files with a corresponding tube no 1-16. By clicking...

After thinking a bit about the comments made here and elsewhere about tube testers I decided to knock together my version of a relatively cheap but versatile tester. My go-to tester has been the uTracer, mainly because it can provide the LTSpice models, but also it was relatively inexpensive...

I have finally boxed my Raspberry Pi controlled P-P amplifier. It ended up rather monstrous! All metal sheet was hand beaten into submission. No a single laser cut to be found in this construction. Summary: P-P output stage using toroidal OPT Bias monitored & controlled by the RPi Takes a...

I am in the process of building a PP 6550 integrated amp - approx 40-50W pc CW. Output stage is fixed bias, but (possible unique?) the grid voltage is controlled by a micro computer board (RPi) that allows the bias current to be varied by the control panel from 20 - 90 mA. It works great, and...

I have been given an Akai 1710 reel to reel player; it is a tube - transistor design that I thought may be worth keeping. Checking the mechanics show the cams in the process of disintegrating, something that is apparently quite common with this model. I suppose it is possible to get the parts...

Since my next build must be a 300B SE... This weekend I used the uTracer to extract Koren model parameters from an EH300B and then used LTSpice to run a quick simulation just to see how close to measurements the simulation is. I characterised the Hammond 1627SE OPT using manufacturer's data...

Hi, Does anyone have any of the above tubes? I would be interested to characterise the tubes on the uTracer. thanks

OK, so I had a pair of Hammond SE OPT's lying around, and needed to do something with them. I was debating doing a traditional 300B SE monobloc, but since I have a few EL34's, 6CA7's and 6SN7's kicking about, I decided to use them instead. The 300B will have to wait! I have used 2mm copper...

Fot those that are interested, I recently purchased 10x6922's all marked "14 05" (is that a date stamp?) I did a quick test (Ia, Gm, Ra,mu) at Va=90V, Vg=-1.2V and got the following spread (Ia only shown, the other parameters follow similar trends) Each pair (1,2 or 5,6) are the triode pairs...

Searching for "thatch" on this forum gave only 2 results, but I guess there are many members that have experienced "hifi" in a thatched roof house? I'm looking at placing a system in a lounge that is pretty large (10x6m approx) and with a high thatched roof, and is probably a challenge. I...

Apart from drowning the iMac in Duncan docks, how do I get it to not play those silly "notifications" through the USB DAC?? I have turned off all "notifications", set "do not disturb" permanently on, set "sound effects" to play though internal speakers muted those, set those to minimum volume...

Not quite in the league of the "power" users on this forum...  :). But I needed an amp for my desktop computer bookshelf speakers, and I needed my first "training wheels" tube project (to amongst others test the SPICE tube models), so the "Baby Bloks" were born. Eejit (on this forum)...

I ordered a u Tracer 3+ plus today... referenced in this forum elsewhere. The site is www.dos4ever.com and it certainly is a wealth of interesting information. I think I will find this a fun project since coincidentally I did my MSc Eng thesis (1981) on the automated extraction of bipolar...

Anyone on the forum taking part in the Argus Cycle Tour this year?  :whistler:

Question: is valve cryo treatment always a post-production process? Or do some manufacturers apply this process themselves during production? I would not think -155C is going to permanently change any metallic or glass materials in the tube. Does it perhaps change the cathode or getter (barium...

Quick question, Does anyone here have a view on the matter of passive intermodulation distortion (PIM) as a contributor to overall audio quality in particular where poor mechanical connections in high current conditions (speaker cables, terminal posts etc.) are influenced by Schottky non-linear...

I think I  understand the original reason why the "minimum of 50 posts or else you may not sell an item on ye forum" rule was established, but is it not counterproductive? :sh1tstirrer: I mean, I'm a man of few words so I would need to go on and on, droning on about this and that as well as the...

Hi, thought it was time to introduce myself, having joined the forum a few weeks ago.... Ufudu, which is Zulu for tortoise, is the name of my Land Rover Series 1 1957, one of my regular forms of transport (along with my 1960 Morris Minor 1000 and eMotion 29er bike) so I have a bit of a...