[lawrence2357]

An additional comment (that may or may not be relevant).. In H7M the choice of driver tubes means only the power tubes can be rolled.

I've got a H7 with a Jan Philips 6922 valve, will this not also work in the M model?

 

[kvik]

Well, if it works in H7, I guess it should work in H7M.

I was under the impression that 6N1P is not directly interchangeable with ECC88/6DJ8/6922/E88CC/ECC85/6AQ8.

https://en.wikipedia.org/wiki/6N1P

 

[Grumpy Old Git]

I Read the ads. Frankly, I would only buy, if I could test them in person (bringing needed tubes). Chassis damage and non-functiioning tubes to me adds up to careless handling and possible overall malfunction. With this in mind the asking price is OK, provided they actually work.

From what I have read, H3 will be the more neutral sounding (coherence), and H14PE the more intimate sounding (cosiness). Based on H7 reviews I would expect H7M to be more akin to H14PE than to H3.

I view the three as being on the same level, but with different sound signatures.

Thanks for your views, they would be covered by ebay protection if they are dud. And because the seller is also UK based a return would not be an issue.

 

[lawrence2357]

Well, if it works in H7, I guess it should work in H7M.

I was under the impression that 6N1P is not directly interchangeable with ECC88/6DJ8/6922/E88CC/ECC85/6AQ8.

https://en.wikipedia.org/wiki/6N1P

A few years ago I asked Wieslaw about it and he said "Yes in this amp you can use 6N1P, E88CC, 6922." (That was for the H7.)

Strangely, in mine I tried a Voshkod 6N1P-EV and it shut down after about an hour, but works perfectly with the Jan Philips 6922. I don't know why this is

PS I noticed it's you that posted all the useful info on Hoved-Fi, thanks for that

 

[kvik]

A point about customization.. My rack is only 34 cm deep, so the standard depth of 35 simply doesn’t work for me. Therefore I had the first amp fitted into 30x30, and the current into 30x40. At least on paper there is a H6M version (6N13S+6N8S) with a ‘horizontal’ layout of 21x40 (see below). I assume some of the other designs can be size-customized as well.

 

[kvik]

I also asked for my amp to have a removable bottom plate, as I wanted to replace the stock hard plastic feet with some sorbothane feet. With a wooden chassis on a wooden rack on a wooden suspended floor I felt I should try to limit structural vibrations reaching the tubes. These are the ones I use, 2 of the smaller (4-12kg) in front and 2 larger ones (10-25) at the back where the transformers add more weight. Don’t ask me about sound differences, I haven’t compared the two, it wasn’t intended as an audiophile tweak, just as a practical precaution.

 

[kvik]

Just an update on my testing of the H1 with my M1060s. It sounded a little "cuppy" at first in comparison with the HD650s, but I got used to it. Certainly no issues with volume level which didn't get above 20%. I then tried them with the H6M2 and found the sound more full and enjoyable. I suspect that, despite the power of the H1 the H6 was more able to deal with the low impedance of the planars, but this isn't scientific.

Just as a teaser I'm showing you a pair of his custom balanced monobloc amps . Unfortunately I haven't got a cable for any of my headphones so I had to resort to using them as a single ended pre into my H20 with fixed volume. But once I get the cable (any ideas where, I need dual 3 pin XLR into HD650 or M1060, or M1570 (takes non standard mini XLR) which is on order, they will rock I'm sure

Am curious about the monoblocks, did you get the cable to try them as headphone amp? did you get any info from Wieslaw about them?

 

[lawrence2357]

Am curious about the monoblocks, did you get the cable to try them as headphone amp? did you get any info from Wieslaw about them?

The cable arrived on Friday but I've had a busy weekend, I'm going to try them next week. I've also bought a silver balanced cable for my HD650s (4 pin XLR) to plug into the 2x3 pin to 4 pin XLR adaptor.

 

[lawrence2357]

A few pictures of my newly arrived H12G below. Originally inspired by Parallax PL519, but has manifested as very much a screen drive amp in its own right..

OTL, dual mono, class A, triode strapped 6E5P as driver, screen driven 6P45S as power, auto-bias, TKD 2CP-2511 potentiometer, pre-out, min. recommended HP-impedance 100Ω, chassis 30x30 cm, weight 8.5 kg

The simple no-nonsense look works for me personally, but I suspect some will find it a bit boring. Also, this amp is not really intended for tube rolling, people with that inclination will be better served elsewhere.

As the amp only arrived a few days ago, and having limited previous OTL-experience, I need a bit of time with the amp, before I will comment on the sound. The headphones I plan to use are AKG K240DF|K340|K400|K500 and Beyerdynamic T70, and I will probably seek out others to try as well.

This being the very first Eufonika second grid amp, the model was named H12G. Wieslaw has already build a second unit for one of his regular customers, and intend to built a third unit for himself to further experiment with and improve upon the design.

This is very interesting as I have an amp that uses the same power valves (H9M).

Would you mind explaining what screen drive means please? Is that why you need a third transformer?

 

[kvik]

Bear in mind that I just commission others to build amps for me. This is because I don't have the necessary skills and knowledge to build them myself, and not the time and interest to acquire this. Though I do research before and during a commision, my understanding will hence be rather limited.

So, my understanding of screen drive is, that it is a way to make pentode and tetrode tubes behave in a similar linear way as triode tubes, and it is one of more ways to triode-strap a pentode/tetrode tube.

The point would be to achieve a triode-like sound, using inexpensive and readily available pentode/tetrode tubes - You could call it a poor man's triode amp. The trade-off would be reduced output power (compared to pentode/tetrode mode).

I recall Wieslaw mentioning H9M when H12G was being build. He thought very highly of 6E5P as triode-strapped output tube in that amp. In H12G it funtions as driver tube, though, and I am not sure it does as good a job there, at least not in this particular design.

There is a dedicated thread on the site you mentioned earlier, google translate isn't perfect, but you will get a sense of the whole journey from conception to termination.

If you google 'triode vs pentode', and sift through the various results, you will get a sense of the triode 'thing' (or what people say and think).

 

[Grumpy Old Git]

Have any of you guys got a copy of the H7M manual you could email me?
Or is the manual pretty much generic across the Eufonika range? If so, could someone email a copy of their manual please?
I've been in touch with Eufonika and not had a reply so far.

 

[lawrence2357]

Not sure there is a manual has anyone ever seen one?

What do you want to know?

 

[muckyfingers]

I never received a manual, nor was offered one for my H5.

 

[wave0nl]

Received my h22m yesterday

 

[kvik]

Very, very nice!